JP2009086326A - Planographic printing plate precursor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a planographic printing plate precursor excellent in both an antifouling property in a non-imaging part and sustainability thereof, and printing durability caused by adhesion between an image part and a support body. <P>SOLUTION: This planographic printing plate precursor has an intermediate layer containing a block copolymer containing a structural unit represented by a specific structure (1) and a structural unit represented by a specific structure (2), and an image forming layer, in this order, on the aluminum support body. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a lithographic printing plate precursor, and more particularly to a lithographic printing plate precursor having excellent anti-staining properties for non-image areas and printing durability for image areas.

An aluminum support for a lithographic printing plate (hereinafter simply referred to as a “lithographic printing plate support”) used in a lithographic printing plate is roughened on an aluminum plate for the purpose of improving the printing durability of the lithographic printing plate. Manufactured by surface treatment or other surface treatment. Examples of the roughening treatment include mechanical roughening treatment, electrochemical roughening treatment (hereinafter also referred to as “electrolytic roughening treatment”), and chemical roughening treatment (chemical etching). Furthermore, a method combining these roughening treatments is known.
In a lithographic printing plate precursor, the composition of the image forming layer formed on the surface and the adhesion between the support and the image forming layer have a great influence on the printing durability. From this viewpoint as well, the roughening state is controlled. Thus, a technique for improving the adhesion with the image forming layer is generally employed.
In particular, by forming relatively large unevenness by mechanical surface roughening treatment and smaller unevenness by subsequent electrochemical surface roughening treatment, adhesion of image forming layer, printing durability and aluminum support A technique for improving the hydrophilicity of the body surface is useful.
As a mechanical surface roughening treatment, a method of spraying an abrasive slurry between a rotating nylon brush and an aluminum plate is generally known. Further, as an electrolytic surface roughening treatment, a method of performing alternating current or direct current in a hydrochloric acid or nitric acid electrolytic solution is known.

Regarding the improvement of the adhesion of the support surface to the photosensitive layer, in addition to the treatment of the surface of the aluminum substrate described above, the purpose is to improve the adhesion between the substrate and the photosensitive layer, to improve the developability, to improve the stain resistance, etc. It is known to install an intermediate layer (sometimes called an undercoat layer or an adhesion improving layer).
As a known example, an example in which an intermediate layer containing a polymer compound having a component having an acid group and a component having an onium group is provided on the surface of the substrate is disclosed. (See Patent Document 1). In this patent document, it is described that when JIS 1050 high-purity aluminum is used as a support, excellent performance is exhibited. Such a surface treatment technique is an effective means for achieving both high printing durability and low stain resistance.
In addition, the compound used for the conventional intermediate | middle layer is restricted to what takes a random copolymer structure, and what controlled the molecular structure precisely like the block copolymer is not known.

2. Description of the Related Art In recent years, lithographic printing plate precursors for direct printing plates in which plate making is performed directly from digital data using a laser having an emission wavelength from the near infrared to the infrared region as a light source have been widely used. This is attracting attention because it is superior in handleability and storage stability under white light compared to a conventional image forming layer that is made by ultraviolet exposure.
In a known positive lithographic printing plate precursor for infrared laser for direct plate making, a novolak resin or the like is used as an alkaline aqueous solution-soluble resin. Among them, substances that generate heat by absorbing light and positive photosensitive compounds such as various onium salts and quinonediazide compounds were added to an aqueous alkali-soluble resin having a phenolic hydroxyl group such as a novolak resin. The one having an image forming layer is disclosed as an excellent positive lithographic printing plate precursor for infrared laser from which a high-quality image can be obtained (for example, see Patent Document 3).
In addition, the negative type lithographic printing plate precursor includes a polymerization initiator, a polymerizable compound and a substance that generates heat by absorbing light, a radical polymerization type image forming layer in which an exposed region is polymerized and cured, And a non-processing type image forming layer that does not require a wet development process in which an exposed area is fused to form a hydrophobic area.

In recent years, for these positive and negative lithographic printing plate precursors, further higher printing durability is desired. However, when a known intermediate layer is used, its performance is limited, and even higher durability is achieved. There is a need for a novel interfacial adhesion technique for the intermediate layer that can provide printability and maintain low dirtiness.
Japanese Patent Laid-Open No. 10-282645 JP-A-7-285275

  An object of the present invention in consideration of the above problems is to provide a lithographic printing plate precursor that is excellent in both anti-staining properties of non-image areas and printing durability resulting from adhesion between the image areas and the support. There is.

  As a result of diligent research, the present inventors have found that the above object can be achieved by forming an intermediate layer containing a specific polymer compound and an image forming layer in this order on the surface of an aluminum support. Completed the invention.

That is, the present invention has the following configuration.
The lithographic printing plate precursor according to the invention includes an intermediate containing a block copolymer including a structural unit represented by the following general formula (1) and a structural unit represented by the following general formula (2) on an aluminum support. It has a layer and an image forming layer in this order.

In the general formula (1), R ¹ represents a hydrogen atom, a substituent having 1 to 30 carbon atoms, or a halogen atom. L ¹ represents a single bond or a (n + 1) -valent linking group. Y represents an acidic group or a salt thereof. n represents an integer of 1 to 6.

In the general formula (2), ^{R 2} represents a hydrogen atom, a substituent having 1 to 30 carbon atoms, or a halogen atom. L ² represents a single bond or a divalent linking group. Z represents a substituent having 0 to 30 carbon atoms. However, the general formula (2) does not contain an acidic group.

In the present invention, Y in the general formula (1) is preferably a CO ₂ H group, a phosphonic acid group, a phosphoric acid group, a sulfonic acid group, a phenolic hydroxyl group, or a salt thereof.

  In the present invention, Z in the general formula (2) is preferably an onium group.

  In the present invention, Z in the general formula (2) is preferably an alkyl group.

  In the present invention, the content of the structural unit represented by the general formula (1) is 15 to 95 mol%, and the content of the structural unit represented by the general formula (2) is 5 to 85 mol. % Is preferred.

  In the present invention, the content of the structural unit represented by the general formula (1) is 30 to 80 mol%, and the content of the structural unit represented by the general formula (2) is 20 to 70 mol. % Is preferred.

The image forming layer in the lithographic printing plate precursor according to the invention preferably has the following mode.
The image forming layer can be recorded with an infrared laser, and it is particularly preferable that the image forming layer contains an infrared absorber.
A mode in which the image forming layer has a laminated structure of two or more layers.

Although the mechanism of action of the present invention is not clear, the block copolymer contained in the intermediate layer has an aluminum support adsorptive structural unit (for example, the general formula (1) above) as compared with a conventionally known random copolymer. It is presumed that strong adsorptivity is developed between the aluminum support and the intermediate layer. Furthermore, since the same effect is also exhibited between the intermediate layer and the image forming layer, strong adhesion is exhibited between the aluminum support and the image forming layer, and high printing durability is exhibited. It is estimated that
On the other hand, in the lithographic printing plate precursor according to the present invention, the intermediate layer is dissolved from the support because the block copolymer contained in the intermediate layer easily dissociates from the alkali developer in the non-image area. As a result, it is presumed that the hydrophilic aluminum support is exposed and the anti-staining property of the non-image area is maintained as good.
As the image forming layer of the lithographic printing plate precursor according to the present invention, a positive type in which an exposed portion is solubilized and a negative type in which an exposed portion is insoluble are known. In the present invention, either a positive type or a negative type is known. In the case of having the image forming layer, an excellent effect can be obtained. However, the intermediate layer in the invention can be particularly preferably used for a lithographic printing plate precursor having a positive image forming layer.

  According to the present invention, there is provided a lithographic printing plate precursor excellent in both anti-staining properties of non-image areas and their durability, and printing durability resulting from adhesion between the image areas and the support. Can do. Further, according to the present invention, even when a low-purity aluminum substrate is used, an excellent lithographic printing plate capable of achieving both high printing durability and low stain resistance and giving good printing performance. An original version can be provided.

[Lithographic printing plate precursor]
The lithographic printing plate precursor according to the invention includes an intermediate containing a block copolymer including a structural unit represented by the following general formula (1) and a structural unit represented by the following general formula (2) on an aluminum support. It has a layer and an image forming layer in this order.
Here, having the intermediate layer and the image forming layer in this order on the aluminum support means that the two layers are laminated in this order on the support, and a layer provided as necessary, For example, the existence of known layers such as a backcoat layer, an undercoat layer, and an overcoat layer is not denied.
Hereinafter, each element constituting the planographic printing plate precursor will be sequentially described.

<Aluminum support>
The aluminum support used in the lithographic printing plate precursor according to the present invention is an alloy plate containing aluminum as a main component and a trace amount of foreign elements, and may be a plastic film on which aluminum is laminated or vapor-deposited.
Thus, the composition of the aluminum plate applied to the present invention is not specified, and an aluminum plate made of a publicly known material can be appropriately used.

[Aluminum plate]
The aluminum plate used in the present invention will be described.
The composition of the aluminum material used for the aluminum plate of the present invention may be any known one. In general, in addition to a general-purpose high-purity aluminum plate, for example, a comparison is made such that the aluminum content is 99.4 to 90% by mass. Similarly, a low-purity aluminum plate can be preferably used.
Therefore, as a support in the present invention, it is usually difficult to apply to a high-quality printing plate, and is obtained by rolling a UBC (Used Beverage Can) ingot in which a used aluminum beverage can is dissolved. An aluminum material or a material prepared by mixing UBC ingots with other aluminum ingots at an arbitrary ratio can also be suitably used.

Generally, the foreign elements that may be contained in the aluminum plate include, for example, silicon, iron, copper, titanium, gallium, vanadium, zinc, chromium, zirconium, barium, cobalt, etc., and the content of the foreign elements in the alloy Is preferably 5% by mass or less.
Examples of inevitable impurities contained in the aluminum alloy include lead, nickel, tin, indium, and boron.

  The foreign elements contained in the aluminum plate and the content thereof are preferably Fe: 0.3-1% by mass, Si: 0.15-1% by mass, Cu: 0.1-1% by mass, Mg: 0 0.1-1.5% by mass, Mn: 0.1-1.5% by mass, Zn: 0.1-1.5% by mass, Cr: 0.01-0.1% by mass, Ti: 0.01 To 0.5% by mass, more preferably Fe content of more than 0.30 to 0.70% by mass, Si content of 0.20 to 0.50% by mass, and Cu content of 0.10 to 0.10% by mass. 0.50 mass%, Ti content is 0.02-0.3 mass%, Mg content is 0.50-1.5 mass%, Mn content is 0.1-1.3 mass%, The Cr content is 0.01 to 0.08% by mass, the Zn content is 0.1 to 1.3% by mass, and in addition, inevitable impurities may be included, but the aluminum content Preferably 95 wt% or more, the aluminum content is preferably used in the range of 95 to 99.99 mass%.

  Different elements in the aluminum plate have a significant effect on the uniformity of the pits generated in the electrochemical surface roughening treatment, and can achieve a good balance between printing durability, stain resistance and exposure stability. In order to generate a simple pit, it is necessary to make advanced adjustments such as the type of different elements and the amount added. According to the present invention, due to the presence of an intermediate layer, which will be described later, not only a high-purity aluminum plate but also a support formed by an aluminum plate having a high content of different elements is used, giving good printing performance. It is possible to produce an excellent lithographic printing plate precursor.

In order to use an aluminum alloy as a plate material, for example, the following method can be employed.
First, a molten aluminum alloy adjusted to a predetermined alloy component content is subjected to a cleaning process and cast according to a conventional method. In the cleaning process, in order to remove unnecessary gas such as hydrogen in the molten metal, flux treatment, degassing process using argon gas, chlorine gas, etc., so-called rigid media filter such as ceramic tube filter, ceramic foam filter, A filtering process using a filter using alumina flakes, alumina balls or the like as a filter medium, a glass cloth filter or the like, or a process combining degassing process and filtering process is performed.

  These cleaning treatments are preferably performed in order to prevent defects caused by foreign matters such as non-metallic inclusions and oxides in the molten metal and defects caused by gas dissolved in the molten metal. Regarding filtering of the molten metal, JP-A-6-57432, JP-A-3-162530, JP-A-5-140659, JP-A-4-231425, JP-A-4-276031, JP-A-5-311261, JP-A-5-311261 6-136466 and the like. Further, the degassing of the molten metal is described in JP-A-5-51659, Japanese Utility Model Laid-Open No. 5-49148, and the like. The applicant of the present application has also proposed a technique relating to degassing of molten metal in Japanese Patent Application Laid-Open No. 7-40017.

Next, casting is performed using the molten metal that has been cleaned as described above. As for the casting method, there are a method using a solid mold typified by a DC casting method and a method using a driving mold typified by a continuous casting method.
In DC casting, solidification occurs at a cooling rate of 0.5 to 30 ° C./second. When the temperature is less than 1 ° C., many coarse intermetallic compounds may be formed. When DC casting is performed, an ingot having a thickness of 300 to 800 mm can be manufactured. The ingot is chamfered as necessary according to a conventional method, and usually 1 to 30 mm, preferably 1 to 10 mm, of the surface layer is cut. Before and after that, soaking treatment is performed as necessary. When performing a soaking treatment, heat treatment is performed at 450 to 620 ° C. for 1 to 48 hours so that the intermetallic compound does not become coarse. If the heat treatment is shorter than 1 hour, the effect of soaking may be insufficient. In addition, when soaking is not performed, there is an advantage that the cost can be reduced.

  Then, hot rolling and cold rolling are performed to obtain a rolled aluminum plate. An appropriate starting temperature for hot rolling is 350 to 500 ° C. Intermediate annealing may be performed before or after hot rolling or in the middle thereof. The conditions for the intermediate annealing treatment are heating at 280 to 600 ° C. for 2 to 20 hours, preferably 350 to 500 ° C. for 2 to 10 hours using a batch annealing furnace, or 400 to 600 ° C. using a continuous annealing furnace. Heating is performed for 6 minutes or less, preferably 450 to 550 ° C. for 2 minutes or less. The crystal structure can be made finer by heating at a heating rate of 10 to 200 ° C./second using a continuous annealing furnace.

The flatness of the aluminum plate finished to a predetermined thickness, for example, 0.1 to 0.5 mm by the above steps may be further improved by a correction device such as a roller leveler or a tension leveler. The flatness may be improved after the aluminum plate is cut into a sheet shape, but in order to improve the productivity, it is preferably performed in a continuous coil state. Further, a slitter line may be used for processing into a predetermined plate width. Moreover, in order to prevent generation | occurrence | production of the damage | wound by friction between aluminum plates, you may provide a thin oil film on the surface of an aluminum plate.
As the oil film, a volatile or non-volatile film is appropriately used as necessary.

  The aluminum plate used in the present invention is preferably subjected to H18 tempering as defined in JIS.

Various characteristics described below are desired for the aluminum plate thus manufactured.
As for the strength of the aluminum plate, it is preferable that the 0.2% proof stress is 120 MPa or more in order to obtain the stiffness required for a lithographic printing plate support. Moreover, in order to obtain a certain level of waist strength even when performing a burning treatment, the 0.2% yield strength after heat treatment at 270 ° C. for 3 to 10 minutes is preferably 80 MPa or more, and 100 MPa or more. It is more preferable that The 0.2% proof stress is described in RIKEN Encyclopedia 4th edition (Iwanami Shoten), page 743, and can be measured by using a general-purpose tensile tester.
In particular, when the waist strength is required for an aluminum plate, an aluminum material added with Mg or Mn can be used. However, if the waist is strengthened, it becomes difficult to attach to the plate cylinder of a printing press. Accordingly, the material and the amount of trace components added are appropriately selected.
Moreover, as for an aluminum plate, it is more preferable that the tensile strength is 140-300 N / mm < ² > and the elongation prescribed | regulated to JISZ2241 and Z2201 is 1-10%.

  The crystal structure of the aluminum plate may cause poor surface quality when the surface of the aluminum plate is subjected to chemical or electrochemical surface roughening. It is preferably not too coarse. The crystal structure on the surface of the aluminum plate preferably has a width of 200 μm or less, more preferably 100 μm or less, still more preferably 50 μm or less, and the length of the crystal structure is 5000 μm or less. Is preferably 1000 μm or less, and more preferably 500 μm or less.

  The thickness of the aluminum plate used as a support in the present invention is about 0.1 mm to 0.6 mm, preferably 0.15 mm to 0.4 mm, and particularly preferably 0.2 mm to 0.3 mm.

In producing the aluminum support in the present invention, the aluminum plate may be subjected to a surface treatment such as a roughening treatment, an anodizing treatment, or a silicate treatment, if necessary.
Hereinafter, such a surface treatment will be briefly described.
Prior to roughening the aluminum plate, a degreasing treatment with, for example, a surfactant, an organic solvent, or an alkaline aqueous solution for removing rolling oil on the surface is performed as desired.
The surface roughening treatment of the aluminum plate is performed by various methods. For example, a mechanical surface roughening method, an electrochemical surface dissolution method, and a chemical surface selection It is performed by the method of dissolving. As the mechanical method, a known method such as a ball polishing method, a brush polishing method, a blast polishing method, or a buff polishing method can be used. Further, as an electrochemical surface roughening method, there is a method of performing alternating current or direct current in hydrochloric acid or nitric acid electrolyte. Further, as disclosed in JP-A-54-63902, a method in which both are combined can also be used.

  For aluminum plates with low aluminum purity, from the viewpoint of achieving good and uniform roughening, a method of mechanically roughening, a method of electrochemically dissolving and roughening the surface, and chemically Although it may be difficult to perform part or all of the method for selectively dissolving the surface, even in that case, by forming an intermediate layer composed of a specific polymer described later in the present invention, surface hydrophilicity It is possible to obtain a lithographic printing plate support having good adhesion to the image forming layer.

  The roughened aluminum plate is subjected to an alkali etching treatment and neutralization treatment as necessary, and then subjected to an anodization treatment to enhance the water retention and wear resistance of the surface as desired. As the electrolyte used for the anodizing treatment of the aluminum plate, various electrolytes that form a porous oxide film can be used. In general, sulfuric acid, phosphoric acid, oxalic acid, chromic acid, or a mixed acid thereof is used. The concentration of these electrolytes is appropriately determined depending on the type of electrolyte.

The treatment conditions for anodization vary depending on the electrolyte used, and thus cannot be specified in general. In general, however, the electrolyte concentration is 1 to 80% by mass solution, the liquid temperature is 5 to 70 ° C., and the current density is 5 to 60 A / dm ^2. A voltage of 1 to 100 V and an electrolysis time of 10 seconds to 5 minutes are suitable.

(Silicate processing)
The surface of the aluminum support in the present invention is preferably subjected to a silicate treatment after the surface treatment as described above from the viewpoint of improving the adhesion strength with the intermediate layer.
The method for applying the silicate treatment is not particularly limited, and any conventionally known method can be arbitrarily used. For example, there is a method of immersing the aluminum base in an aqueous solution in which an alkali metal silicate is dissolved. Can be mentioned.
In this case, the concentration of the aqueous alkali silicate solution is preferably about 1 to 30% by mass, and more preferably about 2 to 15% by mass. The pH of the aqueous solution is preferably about 10 to 13 at 25 ° C. In the silicate treatment according to the present invention, such an aqueous solution is kept at 15 to 80 ° C., preferably 15 to 50 ° C., and the aluminum substrate is immersed in the aqueous solution for 0.5 to 120 seconds, preferably 5 to 60 seconds. It is carried out by doing.

As the alkali metal silicate used for the silicate treatment, sodium silicate, potassium silicate, lithium silicate, or the like is used.
In addition, a hydroxide may be added to the alkali metal silicate aqueous solution in order to increase the pH of the aqueous solution. Examples of such hydroxide include sodium hydroxide, potassium hydroxide, lithium hydroxide and the like. The amount of the hydroxide added is preferably about 0.01 to 10% by mass in the aqueous solution, and more preferably about 0.05 to 5.0% by mass.
In addition, alkaline earth metal salts or Group IVB metal salts may be added. Such alkaline earth metal salts include nitrates such as calcium nitrate, strontium nitrate, magnesium nitrate and barium nitrate, sulfates, hydrochlorides, phosphates, acetates, oxalates, borates, etc. A water-soluble salt is mentioned. Group IVB metal salts include titanium tetrachloride, titanium trichloride, potassium fluoride titanium, potassium oxalate, titanium sulfate, titanium tetraiodide, zirconium chloride, zirconium dioxide, zirconium oxychloride, zirconium tetrachloride, etc. Can be mentioned. Such alkaline earth metal salts or Group IVB metal salts can be used alone or in combination of two or more. The addition amount of the metal salt is preferably about 0.01 to 10% by mass in the aqueous solution, and more preferably about 0.05 to 5.0% by mass.

  As another method of silicate treatment, silicate electrodeposition as described in US Pat. No. 3,658,662 is also effective. Combining a support with electrolytic grains as disclosed in JP-B-46-27481, JP-A-52-58602, JP-A-52-30503, and the above-mentioned anodizing treatment and hydrophilization treatment with silicate. Surface treatment etc. can also be applied.

The metal silicate film obtained by such a silicate treatment is formed with a Si element amount of ^{2 to} 40 mg / m ² , more preferably 4 to 30 mg / m ² . The amount of film can be measured by fluorescent X-ray analysis.

<Intermediate layer>
The intermediate layer in the present invention is a block copolymer containing a structural unit represented by the following general formula (1) and a structural unit represented by the following general formula (2) (hereinafter referred to as “specific polymer compound” as appropriate). It is characterized by containing.
Hereinafter, the specific polymer compound constituting the intermediate layer of the present invention will be described in detail.

In the general formula (1), R ¹ represents a hydrogen atom, a substituent having 1 to 30 carbon atoms, or a halogen atom. L ¹ represents a single bond or a (n + 1) -valent linking group. Y represents an acidic group or a salt thereof. n represents an integer of 1 to 6.

In the general formula (2), ^{R 2} represents a hydrogen atom, a substituent having 1 to 30 carbon atoms, or a halogen atom. L ² represents a single bond or a divalent linking group. Z represents a substituent having 0 to 30 carbon atoms. However, the general formula (2) does not contain an acidic group.

  Hereinafter, the general formula (1) will be described in detail.

In the general formula (1), R ¹ is a hydrogen atom, a substituent having 1 to 30 carbon atoms (for example, a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a cyclohexyl group, a methoxy group, An ethoxy group, a butoxy group, an acetoxy group, a propionyloxy group, a methoxycarbonyl group, an ethoxycarbonyl group, a cyano group) or a halogen atom (for example, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom); Among these, more preferred are a hydrogen atom, a methyl group, an ethyl group, a fluorine atom, and a chlorine atom, and particularly preferred are a hydrogen atom and a methyl group.

In the general formula (1), L ¹ represents a single bond or a (n + 1) -valent linking group. Here, the linking group refers to a polyvalent group composed of at least one non-metallic atom, preferably a carbon atom having 0 to 60 atoms, a nitrogen atom having 0 to 10 atoms, and 0 to 50 atoms. These are (n + 1) -valent groups obtained by using oxygen atoms and sulfur atoms having 0 to 20 atoms alone, or by appropriately combining them.
For example, when L ¹ is a divalent linking group, preferably —CR ₂ — (R represents a hydrogen atom or a substituent), —O—, —C═O—, —S—, —S═. O—, —S (═O) ₂ —, —NR—, vinylene group, phenylene group, cycloalkylene group, naphthylene group, and biphenylene group are each independently or appropriately combined. Can be mentioned.
In addition, when L ¹ is a trivalent linking group, a trisubstituted amino group, a trisubstituted alkyl, a trisubstituted aryl, a trisubstituted alkenyl, and the like are preferable. Preferable examples in the case of a tetravalent linking group include tetrasubstituted ammonium, tetrasubstituted alkyl, and tetrasubstituted aryl.
L ¹ is particularly preferably a single bond, —O (CH ₂ ) _a —, —NH (CH ₂ ) _a —, —COO—, —CONH—, a phenylene group, a trisubstituted amino group, a trisubstituted alkyl, A tri-substituted aryl and a linking group formed by combining these (a is an integer of 0 to 20).

In the general formula (1), Y represents an acidic group or a salt thereof. Here, examples of the acidic group include a CO ₂ H group, a phosphonic acid group, a phosphoric acid group, a phenolic hydroxyl group, a sulfonic acid group, a sulfinic acid group, a thiocarboxylic acid group, a dithiocarboxylic acid group, and a boric acid group. Preferably a CO ₂ H group, a phosphonic acid group, a phosphoric acid group, a sulfonic acid group, and a phenolic hydroxyl group, more preferably a CO ₂ H group, a phosphonic acid group, a phosphoric acid group, and a sulfonic acid group. And particularly preferably a CO ₂ H group and a sulfonic acid group.
Y may contain only one acidic group, may contain a plurality of one kind of acidic groups among the above, and may contain a plurality of kinds of acidic groups among the above.

Y in the general formula (1) may form a salt.
As the counter cation in forming the salt, any can be mentioned, but preferred examples include, for example, alkali metal ions (lithium, sodium, potassium, etc.), group 2 metal ions (magnesium, calcium, Strontium, barium, etc.), other metal ions (aluminum, titanium, iron, zinc, etc.), ammonium ions, organic ammonium ions (methylammonium, ethylammonium, diethylammonium, dimethylammonium, trimethylammonium, triethylammonium, tetraethylammonium, tetra Methyl ammonium, tetrabutyl ammonium), phosphonium ions, sulfonium ions, and the like. Alkali metal ions, ammonium ions, or organic ammonium ions are preferable.
Y may be a double salt having a plurality of counter cations.
In the said General formula (1), n is an integer of 1-6, Preferably, it is an integer of 1-3 from the point which balances an acid value and hydrophilicity / hydrophobicity.

  Hereinafter, although the specific example of the structural unit represented by the said General formula (1) is shown, this invention is not limited to these. However, “4.5” in the specific example indicates that the PEO portion is a mixture corresponding to an average number of repetitions of 4.5.

  Hereinafter, the general formula (2) will be described in detail. The general formula (2) does not contain an acidic group and has a structure different from that of the general formula (1).

In the general formula (2), R ² represents a hydrogen atom, a substituent having 1 to 30 carbon atoms (for example, a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a cyclohexyl group, a methoxy group, An ethoxy group, a butoxy group, an acetoxy group, a propionyloxy group, a methoxycarbonyl group, an ethoxycarbonyl group, a cyano group) or a halogen atom (for example, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom); More preferred are a hydrogen atom, a methyl group, an ethyl group, a fluorine atom, and a chlorine atom, and particularly preferred are a hydrogen atom and a methyl group.

In the general formula (2), L ² represents a single bond or a divalent linking group. Here, the linking group refers to a divalent group composed of at least one nonmetallic atom, and preferably a carbon atom having 0 to 60 atoms, a nitrogen atom having 0 to 10 atoms, and a 0 to 50 atoms. Each of the oxygen atom and the sulfur atom having 0 to 20 atoms is a divalent group that can be used alone or in appropriate combination.
When L ² is a divalent linking group, preferably —CR ₂ — (R represents a hydrogen atom or a substituent), —O—, —C═O—, —S—, —S═O—. , —S (═O) ₂ —, —NR—, vinylene group, phenylene group, cycloalkylene group, naphthylene group, and biphenylene group may be used alone or in appropriate combination. be able to.
L ² is particularly preferably a single bond, —O (CH ₂ ) _a —, —NH (CH ₂ ) _a —, —COO— (wherein a is an integer of 0 to 20), phenylene, — * — (CH ₂ ) _b — (* represents a benzene ring, b represents an integer of 1 to 5), and a linking group formed by combining these.

In the above general formula (2), Z represents a substituent having 0 to 30 carbon atoms. However, Z is a substituent which does not contain an acidic group. Examples of Z include, for example, a linear, branched or cyclic alkyl group (eg, methyl, ethyl, propyl, isopropyl, butyl, hexyl, cyclohexyl, octyl, dodecyl, etc.), an aryl group (eg, phenyl, etc.), alkenyl Group, alkynyl group, heterocyclic group, halogen atom (eg, fluorine atom, chlorine atom, bromine atom, iodine atom), hydroxyl group, alkoxy group, aryloxy group, mercapto group, alkylthio group, arylthio group, alkyldithio group, aryl Dithio group, amino group, N-alkylamino group, N, N-diarylamino group, N-alkyl-N-arylamino group, acylthio group, acylamino group, N-alkylacylamino group, N-arylacylamino group, Ureido group, N′-alkylureido group, N ′, N′-di Rukyureido group, N′-arylureido group, N ′, N′-diarylureido group, N′-alkyl-N′-arylureido group, N-alkylureido group, N-arylureido group, N′-alkyl-N -Alkylureido group, N'-alkyl-N-arylureido group, N ', N'-dialkyl-N-alkylureido group, N', N'-dialkyl-N-arylureido group, N'-aryl- ' -Alkylureido group, N'-aryl-N-arylureido group, N ', N'-diaryl-N-alkylureido group, N', N'-diaryl-N-arylureido group, N'-alkyl-N '-Aryl-N-alkylureido group, N'-alkyl-N'-aryl-N-arylureido group, alkoxycarbonylamino group, aryloxycarbonylamino group, N-alkyl-N-alkoxycarbonylamino group, N-alkyl-N-aryloxycarbonylamino group, N-aryl-N-alkoxycarbonylamino group, N-aryl-N-aryloxycarbonylamino group, formyl group, acyl Group, alkoxycarbonyl group, aryloxycarbonyl group, carbamoyl group, N-alkylcarbamoyl group, N, N-dialkylcarbamoyl group, N-arylcarbamoyl group, N, N-diarylcarbamoyl group, N-alkyl-N-arylcarbamoyl Group, alkylsulfinyl group, arylsulfinyl group, alkylsulfonyl group, arylsulfonyl group, alkoxysulfonyl group, aryloxysulfonyl group, sulfinamoyl group, N-alkylsulfinamoyl group, N, N-dialkylsulfuric group Ynamoyl group, N-arylsulfinamoyl group, N, N-diarylsulfinamoyl group, N-alkyl-N-arylsulfinamoyl group, sulfamoyl group, N-alkylsulfamoyl group, N, N-dialkylsulfide group Famoyl group, N-arylsulfamoyl group, N, N-diarylsulfamoyl group, N-alkyl-N-arylsulfamoyl group, dialkylphosphono group (—PO ₃ (alkyl) ₂ ), diarylphosphine Phono group (—PO ₃ (aryl) ₂ ), alkylaryl phosphono group (—PO ₃ (alkyl) (aryl)), dialkyl phosphonooxy group (—OPO ₃ (alkyl) ₂ ), diaryl phosphonooxy group ( -OPO _{3 (aryl) 2),} alkylaryl phosphonooxy group (-O _{O 3 (alkyl) (aryl)} ), an alkoxysilyl group, a cyano group, a nitro group, such as an onium group. These groups may be combined to form a composite substituent.

  Preferred examples of Z in the general formula (2) include linear, branched or cyclic alkyl groups (such as methyl, ethyl, propyl, isopropyl, butyl, hexyl, cyclohexyl, octyl, and dodecyl), aryl groups (such as phenyl) , Alkenyl group, alkynyl group, heterocyclic group, hydroxyl group, alkoxy group, aryloxy group, alkylthio group, arylthio group, amino group, N-alkylamino group, N, N-diarylamino group, N-alkyl-N-aryl Amino group, acyloxy group, acyl group, alkoxycarbonyl group, aryloxycarbonyl group, carbamoyl group, N-alkylcarbamoyl group, N, N-dialkylcarbamoyl group, N-arylcarbamoyl group, N, N-diarylcarbamoyl group, N -Alkyl-N-arylcal Moyl group, alkylsulfinyl group, arylsulfinyl group, alkylsulfonyl group, arylsulfonyl group, alkoxysulfonyl group, aryloxysulfonyl group, sulfinamoyl group, N-alkylsulfinamoyl group, N, N-dialkylsulfinamoyl group, N -Arylsulfinamoyl group, N, N-diarylsulfinamoyl group, N-alkyl-N-arylsulfinamoyl group, sulfamoyl group, N-alkylsulfamoyl group, N, N-dialkylsulfamoyl group, N-arylsulfamoyl group, N, N-diarylsulfamoyl group, N-alkyl-N-arylsulfamoyl group, cyano group, alkoxysilyl group, onium group and the like can be mentioned. These groups may be combined to form a composite substituent.

Further, Z in the general formula (2) is more preferably an onium group and an alkyl group.
The onium group is preferable in that it has a positive charge and can electrostatically interact with the image forming layer, thereby contributing to improvement in printing durability. The alkyl group is preferable because it is hydrophobic and can interact with the image forming layer in a hydrophobic manner, thereby contributing to an improvement in printing durability. Further, since the onium group can interact with the silicate-treated aluminum support, Z is represented by the structural unit represented by the above general formula (2) and the above general formula (1) where the onium group is an onium group. A block copolymer containing a structural unit is preferable in that it effectively functions as an interfacial adhesive.

When Z is an onium group, preferred as Z is an onium group consisting of Group V or Group VI atoms, more preferably ammonium, phosphonium or sulfonium, and particularly preferably ammonium. . Preferable examples of Z are specifically, for example, trimethylammonium group, triethylammonium group, tripropylammonium group, tributylammonium group, methylmorpholino group, pyridinyl group, tri (2-hydroxyethyl) ammonium group, trimethylphosphonium. Group, triethylphosphonium group, tributylphosphonium group, trihexylphosphonium group and the like.
Although any onium counter anion can be selected, preferred examples include halide ions (eg, fluoride ions, chloride ions, bromide ions, iodide ions), sulfate ions, sulfonate ions. (For example, methanesulfonate ion, benzenesulfonate ion, p-toluenesulfonate ion, etc.), tetrafluoroborate ion, hexafluorophosphate ion, borate ion, phosphate ion, hydrogen phosphate ion, diphosphate phosphate A hydrogen ion etc. can be mentioned.

When Z is an alkyl group, Z is a substituted or unsubstituted alkyl group, and the total number of carbon atoms is preferably 1-30. Specific examples of Z include, for example, methyl, ethyl, propyl, isopropyl, butyl, hexyl, cyclohexyl, octyl, dodecyl, 2-hydroxyethyl, 2- (2-hydroxyethoxy) ethyl, 2-methoxyethyl, 2 Preferred examples include -ethoxyethyl, 2- (2-methoxyethoxy) ethyl, 2-poly (2-hydroxyethoxy) ethyl, 2-poly (2-methoxyethoxy) ethyl, benzyl and the like.
In addition, when Z of the said General formula (2) is an alkyl group, it is directly to the carbon atom which comprises a principal chain, the carbon atom of coupling groups other than a methylene group (for example, carbonyl group etc.), or atoms other than carbon. Z up to the methylene group to be bonded is included. In the structural unit represented by the general formula (2), when the terminal alkyl group is a part of the onium group (specifically, for example, a methyl group contained in a trimethylammonium group), Z in the general formula (2) is an onium group, and is not included in the case “when Z in the general formula (2) is an alkyl group”.

  Although the preferable example of the structural unit represented by General formula (2) below is shown, this invention is not limited to these.

The content of the structural unit represented by the general formula (1) in the specific polymer compound in the present invention is preferably in the range of 15 to 95 mol%, more preferably in the range of 30 to 80%. Preferably, it is 40 to 75% of range.
The proportion of the structural unit represented by the general formula (2) in the specific polymer compound in the present invention is preferably in the range of 5 to 85 mol%, and preferably in the range of 20 to 70%. More preferably, it is 25 to 60% of range.

  In addition, the structural unit represented by the general formula (1) and the structural unit represented by the general formula (2) in the specific polymer compound in the present invention may be of only one type each, The structural units represented by the general formula (1) and the structural units other than the structural unit represented by the general formula (2) (other structural units may be combined without departing from the spirit of the present invention. ) May further be included.

Examples of preferable monomers as other structural units include maleic acid, maleic anhydride, dialkyl maleate, N-substituted maleimide, and dialkyl fumarate.
When the specific polymer compound in the present invention contains other structural units, the content of the other structural units is preferably in the range of 0.01 to 60 mol%, and in the range of 1 to 40 mol%. Is more preferable, and the range of 5 to 30 mol% is particularly preferable.

As the structure of the specific polymer compound (block copolymer) in the present invention, a diblock type such as-(A) x- (B) y-,-(A) x- (B) y- (A) z-,-(B) x- (A) y- (B) z-,-(A) x- (B) y- (C) z-,-(A) x- (C) y- (B ) Z, or a triblock type such as-(C) x- (A) y- (B) z-, and a copolymer composed of a large number of block units.
In the above, (A) represents the structural unit represented by the general formula (1), and (B) represents the structural unit represented by the general formula (2). (C) shows structural units other than (A) and (B), the structural unit represented by the general formula (1), the structural unit represented by the general formula (2), and other structures. Indicates one of the units. Furthermore, x, y, and z are integers indicating the number of structural units.

In the present invention, a diblock type of a structural unit represented by the general formula (1) and a structural unit represented by the general formula (2) is preferably used.
In this case, the ratio of structural units in the block copolymer (that is, the number of “structural units represented by the general formula (1)”: the number of “structural units represented by the general formula (1)”) The average value of is preferably 30:70 to 90:10, more preferably 50:50 to 85:15, and most preferably 60:40 to 80:20.

  In addition, the specific polymer compound in the present invention may contain components derived from an initiator, a dormant agent, a chain transfer agent and the like at the terminal or side chain of the polymer.

  The method for synthesizing the specific polymer compound in the present invention can be carried out by a conventional method. Specifically, any synthesis method selected from known methods such as living anion polymerization, living radical polymerization, sequential addition method, polymer reaction method and the like is employed.

  The molecular weight of the specific polymer compound in the present invention may be in a wide range, but the weight average molecular weight (Mw) determined by measurement using a light scattering method is preferably 500 to 2,000,000, More preferably, it is in the range of 2,000 to 600,000. The amount of unreacted monomer contained in the polymer compound may be in a wide range, but is preferably 20% by mass or less, and more preferably 10% by mass or less.

  Although the preferable example of the specific polymer compound of this invention is shown below, this invention is not limited to these.

  Next, synthesis examples of the specific polymer compounds according to the present invention (the above-mentioned specific examples I-2 and I-3) are shown.

[Synthesis Example 1: Synthesis of polymer compound I-2]
In a reaction vessel, 4.4 g of N-methyl-2-pyrrolidone was taken, and 106 mg of 2-cyanopropan-2-yl benzodithioate was added. Separately, a solution A was prepared by dissolving 5 g of 4-vinylbenzoic acid, 38.8 mg of dimethyl 2,2′-azobis (2-methylpropionate) in 23 g of N-methyl-2-pyrrolidone and 2 g of water. Moreover, N, N, N-triethyl-N- (4-vinylbenzyl) ammonium chloride 3.7g, Dimethyl 2,2'-azobis (2-methylpropionate) 16.6mg, N-methyl-2-pyrrolidone 17g, water 1 Solution B dissolved in 0.5 g was prepared.
The internal temperature of the reaction vessel was adjusted to 80 ° C., and Solution A was added dropwise over 5 hours and 15 minutes under a nitrogen stream. Subsequently, Solution B was added dropwise over 3 hours and 30 minutes.
The reaction solution was cooled and added dropwise to 500 mL of acetonitrile to precipitate the produced compound, and further washed in acetonitrile and dried to obtain 6 g of polymer compound I-2.

[Synthesis Example 2: Synthesis of Polymer Compound I-3]
To the reaction vessel, 5 g of N-methyl-2-pyrrolidone was taken, and 110 mg of 2-cyanpropan-2-yl benzodithioate was added. Separately, a solution C was prepared by dissolving 3.7 g of 4-vinylbenzoic acid, 28.8 mg of dimethyl 2,2′-azobis (2-methylpropionate) in 18.5 g of N-methyl-2-pyrrolidone and 1.5 g of water. . In addition, N, N, N-triethyl-N- (4-vinylbenzyl) ammonium chloride 6.3 g, Dimethyl 2,2′-azobis (2-methylpropionate) 28.8 mg, 27.5 g of N-methyl-2-pyrrolidone, Solution D dissolved in 2.5 g of water was prepared.
The internal temperature of the reaction vessel was adjusted to 80 ° C., and Solution C was added dropwise over 5 hours and 15 minutes under a nitrogen stream. Subsequently, Solution D was added dropwise over 3 hours and 30 minutes.
The reaction solution was cooled and added dropwise to 500 mL of acetonitrile to precipitate the produced compound, and further washed in acetonitrile and dried to obtain 6 g of polymer compound I-3. As a result of measuring the molecular weight by the light scattering method, the weight average molecular weight (Mw) was 32,000. Other polymer compounds according to the present invention are synthesized by the same method.

(Formation of intermediate layer)
The intermediate layer in the present invention can be formed by coating on an aluminum substrate by various methods. Specifically, the following two methods are mentioned, for example.
That is, as the first method, an organic solvent such as methanol, ethanol, methyl ethyl ketone, acetonitrile, N-methyl-2-pyrrolidone, dimethyl sulfoxide, a mixed solvent thereof, a mixed solvent of these organic solvent and water, In this method, a solution in which a specific polymer compound is dissolved is applied on an aluminum support and dried.
In addition, as a second method, an aluminum solvent such as methanol, ethanol, methyl ethyl ketone, a mixed solvent thereof, a mixed solvent of these organic solvent and water, an aluminum solvent is used. In this method, the support is immersed to adsorb the polymer compound, and then washed and dried with water or the like.

In the former method, various kinds of solutions containing the specific polymer compound at a concentration of preferably 0.005 to 20% by mass, more preferably 0.01 to 10% by mass, and particularly preferably 0.05 to 5% by mass. It can be applied by the method. For example, any method such as bar coater coating, spin coating, spray coating, or curtain coating may be used.
In the latter method, the concentration of the solution containing the specific polymer compound is 0.01 to 20% by mass, preferably 0.05 to 5% by mass, and the immersion temperature is 20 to 90 ° C., preferably 25 to 25%. It is 50 ° C., and the immersion time is 0.1 second to 20 minutes, preferably 2 seconds to 1 minute.

  Solutions containing the above-mentioned specific polymer compounds include basic substances such as ammonia, triethylamine and potassium hydroxide, inorganic acids such as hydrochloric acid, phosphoric acid, sulfuric acid and nitric acid, and organic sulfonic acids such as nitrobenzene sulfonic acid and naphthalene sulfonic acid. PH is adjusted with various organic acidic substances such as organic phosphonic acids such as phenylsulfonic acid, organic carboxylic acids such as benzoic acid, coumaric acid and malic acid, and organic acid chlorides such as naphthalenesulfonyl chloride and benzenesulfonyl chloride. It can also be used in the range of 0 to 12, more preferably pH = 0 to 5.

The coating amount after drying of the intermediate layer in the present invention is suitably ² to 100 mg / m ² , preferably 3 to 50 mg / m ² , and particularly preferably 4 to 30 mg / m ² . If the coating amount is less than 2 mg / m ² , a sufficient effect may not be obtained. Moreover, even if it exceeds 100 mg / m < ² >, it is the same.

  In addition, the specific polymer compound in the intermediate layer in the present invention may contain one kind alone, or two or more kinds having different kinds of structural units, composition ratios of structural units, molecular weights, and the like are mixed. May be included.

<Image forming layer>
In the present invention, a lithographic printing plate precursor can be obtained by providing an image forming layer on the intermediate layer formed as described above.
In the present invention, the image forming layer provided here may be any known one, but is preferably one that can be recorded in a heat mode or a photon mode, and from the viewpoint of the effect, a heat mode exposure such as an infrared laser. It is preferable that the image forming layer be capable of forming an image.
Further, the image forming layer may have a single layer structure or a laminated structure composed of a plurality of layers.
Hereinafter, various lithographic printing plate precursors having different types of image forming layers will be described.

(Infrared laser recording type lithographic printing plate precursor)
A lithographic printing plate precursor capable of forming an image with an infrared laser suitable for the present invention will be described. These contain a negative or positive image forming layer using a material whose solubility in an alkaline aqueous solution is changed by infrared laser exposure, and a hydrophobizing precursor capable of forming an ink receiving region. A known image recording method such as an image forming layer in which a digitized region is formed is arbitrarily selected.

  First, a positive or negative image forming layer will be described. Such an image forming layer is developed with an alkaline aqueous solution after imagewise exposure with an infrared laser, the alkali developability is reduced by irradiation with actinic rays, and the negative (exposed) portion becomes an image portion region. On the contrary, the developability is improved, and the irradiation (exposure) portion is divided into two types, that is, a non-image portion region.

  Examples of the positive type image forming layer include an interaction release system (thermal positive) image forming layer, a known acid catalyst decomposition system, and an o-quinonediazide compound-containing system. These are soluble in water or alkaline water by the action of the polymer compound that formed the layer being released by the acid or heat energy generated by light irradiation or heating, and are removed by development and non-development. An image portion is formed.

Examples of the negative type image forming layer include known acid-catalyzed cross-linking (including cationic polymerization) image forming layers and polymerization-curing image forming layers. In these compounds, an acid generated by light irradiation or heating serves as a catalyst, and a compound that forms an image forming layer undergoes a crosslinking reaction to be cured to form an image portion, or is polymerizable by radicals generated by light irradiation or heating. The polymerization reaction of the compound proceeds and cures to form an image portion.
The intermediate layer in the present invention exhibits an excellent effect when any of the image forming layers described above is formed, but is suitably used for a positive type image forming layer.
Hereinafter, each image forming layer will be described in detail.

1. Positive type image forming layer As a preferred embodiment of the present invention, a lithographic plate having a positive type image forming layer provided with an image forming layer containing an alkali-soluble resin and 50% by mass or more of the alkali-soluble resin is a novolak resin. The printing original edition is mentioned. As a more preferred embodiment, an image-forming layer containing an alkali-soluble resin and a sulfonium compound or an ammonium compound, and 50% by mass or more of the alkali-soluble resin is a novolac resin, and is recordable by an infrared laser is provided. And a lithographic printing original plate having a positive image forming layer. In addition, it is a more preferable aspect that the positive type image forming layer contains an infrared absorber (A) described later in order to increase sensitivity. The positive image forming layer may be a single layer or may have a laminated structure composed of a plurality of image forming layers.

[Novolac type phenolic resin]
First, the novolac type phenol resin will be described. The novolak resin refers to a resin obtained by polycondensation of at least one phenol with at least one of aldehydes or ketones under an acidic catalyst.
Here, examples of the phenols include phenol, o-cresol, m-cresol, p-cresol, 2,5-xylenol, 3,5-xylenol, o-ethylphenol, m-ethylphenol, and p-ethylphenol. , Propylphenol, n-butylphenol, tert-butylphenol, 1-naphthol, 2-naphthol, pyrocatechol, resorcinol, hydroquinone, pyrogallol, 1,2,4-benzenetriol, phloroglucinol, 4,4′-biphenyldiol, 2,2-bis (4′-hydroxyphenyl) propane and the like. Examples of the aldehydes include formaldehyde, acetaldehyde, propionaldehyde, benzaldehyde, furfural, and the like. Examples of the ketones include acetaldehyde. Ton, methyl ethyl ketone, and methyl isobutyl ketone.

  Preferably, phenols selected from phenol, o-cresol, m-cresol, p-cresol, 2,5-xylenol, 3,5-xylenol, resorcinol, and aldehydes selected from formaldehyde, acetaldehyde, propionaldehyde Or a polycondensate with ketones is preferable, and the mixing ratio of m-cresol: p-cresol: 2,5-xylenol: 3,5-xylenol: resorcinol in a molar ratio of 40 to 100: 0 to 50: 0. -20: 0 to 20: 0 to 20 mixed phenols, or (mixed) phenols whose mixing ratio of phenol: m-cresol: p-cresol is 0-100: 0 to 70: 0-60 in molar ratio And a polycondensate of formaldehyde are preferred.

  As these novolak resins, a polystyrene-reduced weight average molecular weight (hereinafter simply referred to as “weight average molecular weight”) measured by gel permeation chromatography is preferably 500 to 20,000, more preferably 1,000 to 15, 000, particularly preferably 3,000 to 12,000. It is preferable for the weight average molecular weight to fall within this range because it is excellent in sufficient film-forming properties and alkali developability in the exposed area.

  When using the said novolak resin as binder resin of an image forming layer, only 1 type may be used and 2 or more types may be used together. Further, all of the binder resins may be the above-mentioned novolak resins, and other resins may be used in combination. Even when other resins are used in combination, the novolak resin is preferably the main binder, and the proportion of the novolak resin in the binder resin (alkali-soluble resin) constituting the image forming layer is 50% by mass or more. Preferably, the range is 65 to 99.9% by mass.

  As the binder resin that can be used in combination, a commonly used water-insoluble and alkali-soluble alkali-soluble resin having an acidic group in at least one of the main chain and the side chain in the polymer can be used. Phenol resins other than novolak resins, for example, resole resins, polyvinyl phenol resins, acrylic resins having phenolic hydroxyl groups, and the like are also preferably used. Specific examples of the resin that can be used in combination include polymers described in JP-A Nos. 11-44956 and 2003-167343.

[Photothermal conversion agent]
The image forming layer in the invention preferably contains a photothermal conversion agent. As the photothermal conversion agent used here, any material that absorbs light energy radiation and generates heat can be used without any limitation in the absorption wavelength range, but it is compatible with an easily available high-power laser. From the above viewpoint, an infrared-absorbing dye or pigment having an absorption maximum at a wavelength of 760 nm to 1200 nm is preferable.

  As the dye, commercially available dyes and known dyes described in documents such as “Dye Handbook” (edited by the Society for Synthetic Organic Chemistry, published in 1970) can be used. Specifically, azo dyes, metal complex azo dyes, pyrazolone azo dyes, naphthoquinone dyes, anthraquinone dyes, phthalocyanine dyes, carbonium dyes, quinoneimine dyes, methine dyes, cyanine dyes, squarylium dyes, pyrylium salts, metal thiolate complexes, oxonol dyes And dyes such as diimonium dyes, aminium dyes, and croconium dyes.

  Preferred dyes include, for example, cyanine dyes described in JP-A-58-125246, JP-A-59-84356, JP-A-59-202829, JP-A-60-78787, and the like. Methine dyes described in JP-A-58-173696, JP-A-58-181690, JP-A-58-194595, JP-A-58-112793, JP-A-58-224793, JP-A-59- 48187, JP-A 59-73996, JP-A 60-52940, JP-A 60-63744, etc., naphthoquinone dyes, JP-A 58-112792, etc. And cyanine dyes described in British Patent 434,875.

  Also, a near infrared absorption sensitizer described in US Pat. No. 5,156,938 is preferably used, and a substituted arylbenzo (thio) pyrylium salt described in US Pat. No. 3,881,924, Trimethine thiapyrylium salts described in JP-A-57-142645 (US Pat. No. 4,327,169), JP-A-58-181051, 58-220143, 59-41363, 59-84248 Nos. 59-84249, 59-146063, 59-146061, pyranlium compounds, cyanine dyes described in JP-A-59-216146, US Pat. No. 4,283,475 The pentamethine thiopyrylium salts described above and the pyrylium compounds disclosed in Japanese Patent Publication Nos. 5-13514 and 5-19702 are also preferably used. .

  Another example of a preferable dye is a near-infrared absorbing dye described in US Pat. No. 4,756,993 as formulas (I) and (II).

  Particularly preferred among these dyes are cyanine dyes, phthalocyanine dyes, oxonol dyes, squarylium dyes, pyrylium salts, thiopyrylium dyes, and nickel thiolate complexes. Further, the compound described on pages 26-38 of JP-A-2005-99685 is preferred because of its excellent photothermal conversion efficiency. In particular, the cyanine dye represented by formula (a) in JP-A-2005-99685 is preferred. When used in the photosensitive composition of the invention, it is most preferable because it gives high interaction with the alkali-soluble resin and is excellent in stability and economy.

(Degradable dissolution inhibitor)
A decomposable dissolution inhibitor can be further added to the positive image forming layer in the invention. In particular, a substance (degradable dissolution inhibitor) that is thermally decomposable and substantially reduces the solubility of the alkali-soluble resin when not decomposed, such as an onium salt, an o-quinonediazide compound, and a sulfonic acid alkyl ester is used in combination. It is preferable from the viewpoint of improving the dissolution inhibition of the image area in the developer. As the degradable dissolution inhibitor, onium salts such as sulfonium salts, ammonium salts, diazonium salts, iodonium salts, and o-quinonediazide compounds are preferable, and sulfonium salts, ammonium salts, and diazonium salts are more preferable.

Suitable onium salts for use in the present invention include, for example, U.S. Pat. Nos. 4,069,055, 4,069,056, JP-A-3-140140, JP-A-2006-293162, Ammonium salts described in the specification of JP-A-2004-117546, V. Crivello et al, Polymer J. et al. 17, 73 (1985), J. Am. V. Crivello et al. J. et al. Org. Chem. 43, 3055 (1978); R. Watt et al, J.A. Polymer Sci. , Polymer Chem. Ed. , 22, 1789 (1984), J. Am. V. Crivello et al, Polymer Bull. 14, 279 (1985), J. Am. V. Crivello et al, Macromolecules, 14 (5), 1141 (1981), J. MoI. V. Crivello et al, J.A. Polymer Sci. , Polymer Chem. Ed. 17, 2877 (1979), European Patents 370,693, 233,567, 297,443, 297,442, U.S. Pat. Nos. 4,933,377, 3,902,114 No. 5,041,358, No. 4,491,628, No. 4,760,013, No. 4,734,444, No. 2,833,827, German Patent No. 2,904 Examples thereof include sulfonium salts described in JP-A Nos. 626, 3,604,580, 3,604,581, JP-A 2006-293162, and JP-A 2006-258879.
S. I. Schlesinger, Photogr. Sci. Eng. , 18, 387 (1974), T.A. S. Bal et al, Polymer, 21, 423 (1980), JP-A-5-158230, JP-A-5-158230, general formula (I), JP-A-11-143064, general formula ( 1), and diazonium salts represented by the general formula (1) described in JP-A-11-143064.

  Other preferable onium salts include D.I. C. Necker et al, Macromolecules, 17, 2468 (1984), C.I. S. Wen et al, Teh, Proc. Conf. Rad. Curing ASIA, p478 Tokyo, Oct (1988), U.S. Pat. Nos. 4,069,055 and 4,069,056; V. Crivello et al, Macromolecules, 10 (6), 1307 (1977), Chem. & Eng. News, Nov. 28, p31 (1988), European Patent No. 104,143, US Pat. Nos. 5,041,358, 4,491,628, JP-A-2-150848 and JP-A-2-296514. Iodonium salts, J.M. V. Crivello et al, Macromolecules, 10 (6), 1307 (1977), J. MoI. V. Crivello et al, J.A. Polymer Sci. , Polymer Chem. Ed. , 17, 1047 (1979), a selenonium salt described in C.I. S. Wen et al, Teh, Proc. Conf. Rad. Curing ASIA, p478 Tokyo, Oct (1988).

  The counter ion of the onium salt includes tetrafluoroboric acid, hexafluorophosphoric acid, triisopropylnaphthalenesulfonic acid, 5-nitro-o-toluenesulfonic acid, 5-sulfosalicylic acid, 2,5-dimethylbenzenesulfonic acid, 2,4,6-trimethylbenzenesulfonic acid, 2-nitrobenzenesulfonic acid, 3-chlorobenzenesulfonic acid, 3-bromobenzenesulfonic acid, 2-fluorocaprylnaphthalenesulfonic acid, dodecylbenzenesulfonic acid, 1-naphthol-5-sulfone Examples include acid, 2-methoxy-4-hydroxy-5-benzoyl-benzenesulfonic acid, and paratoluenesulfonic acid. Of these, particularly preferred are alkyl aromatic sulfonic acids such as hexafluorophosphoric acid, triisopropylnaphthalenesulfonic acid and 2,5-dimethylbenzenesulfonic acid.

  These onium salts may be used alone or in a plurality of compounds. In addition, when the image forming layer has a laminated structure, it may be added to only a single layer or a plurality of layers, or a compound of a plurality of types may be added separately in layers. Good.

  Suitable quinonediazides include o-quinonediazide compounds. The o-quinonediazide compound used in the present invention is a compound having at least one o-quinonediazide group, which increases alkali solubility by thermal decomposition, and compounds having various structures can be used. That is, o-quinonediazide helps the solubility of the sensitive material system by both the effect of losing the ability to suppress the dissolution of the binder due to thermal decomposition and the change of o-quinonediazide itself into an alkali-soluble substance. Examples of the o-quinonediazide compound used in the present invention include J. The compounds described in pages 339 to 352 of “Light-sensitive systems” by John Coley (John Wiley & Sons. Inc.) can be used, and in particular, o-quinonediazide reacted with various aromatic polyhydroxy compounds or aromatic amino compounds. The sulfonic acid esters or sulfonic acid amides are preferred. Further, benzoquinone (1,2) -diazidosulfonic acid chloride or naphthoquinone- (1,2) -diazide-5-sulfonic acid chloride and pyrogallol-acetone resin as described in JP-B-43-28403 Esters of benzoquinone- (1,2) -diazide sulfonic acid chloride or naphthoquinone- (1,2) -diazide- described in US Pat. Nos. 3,046,120 and 3,188,210 Esters of 5-sulfonic acid chloride and phenol-formaldehyde resin are also preferably used.

  Further, esters of naphthoquinone- (1,2) -diazido-4-sulfonic acid chloride with phenol formaldehyde resin or cresol-formaldehyde resin, naphthoquinone- (1,2) -diazido-4-sulfonic acid chloride and pyrogallol-acetone resin Similarly, the esters are also preferably used. Other useful o-quinonediazide compounds are reported and known in numerous patents. For example, JP-A-47-5303, JP-A-48-63802, JP-A-48-63803, JP-A-48-96575, JP-A-49-38701, JP-A-48-13354, Japanese Patent Publication Nos. 41-11222, 45-9610, 49-17482, U.S. Pat. Nos. 2,797,213, 3,454,400, and 3,544 No. 323, No. 3,573,917, No. 3,674,495, No. 3,785,825, British Patent No. 1,227,602, No. 1,251,345, No. No. 1,267,005, No. 1,329,888, No. 1,330,932, German Patent No. 854,890 and the like. .

  The amount of the onium salt and / or the o-quinonediazide compound that is a degradable dissolution inhibitor is preferably 0.1 to 10% by mass with respect to the total solid content of the image forming layer according to the present invention. More preferably, it is 0.1-5 mass%, Most preferably, it is the range of 0.2-2 mass%. These compounds can be used alone, but may be used as a mixture of several kinds.

  The amount of additives other than the o-quinonediazide compound is preferably 0 to 5% by mass, more preferably 0 to 2% by mass, and particularly preferably 0.1 to 1.5% by mass. The additive and binder used in the present invention are preferably contained in the same layer.

  Further, a dissolution inhibitor having no decomposability may be used in combination, and preferred dissolution inhibitors include sulfonate esters, phosphate esters, and aromatic carboxylic acids described in detail in JP-A-10-268512. Esters, aromatic disulfones, carboxylic anhydrides, aromatic ketones, aromatic aldehydes, aromatic amines, aromatic ethers, etc., as well as lactone skeletons described in detail in JP-A-11-190903, N, N- Examples thereof include an acid color-forming dye having a diarylamide skeleton and a diarylmethylimino skeleton, which also serves as a colorant, and nonionic surfactants described in detail in JP-A No. 2000-105454.

[Other additives]
In the image forming layer according to the present invention, Japanese Patent Application Laid-Open No. 2000-187318 discloses further enhancement of image discrimination (hydrophobic / hydrophilic discrimination) and surface scratch resistance. As described, a polymer having a polymerization component of a (meth) acrylate monomer having 2 or 3 perfluoroalkyl groups having 3 to 20 carbon atoms in the molecule can be used in combination. The addition amount of such a compound is preferably 0.1 to 10% by mass, more preferably 0.5 to 5% by mass, based on the total solid content of the image forming layer according to the present invention.

  In the image forming layer according to the present invention, a compound that lowers the static friction coefficient of the surface can be added for the purpose of imparting resistance to scratches. Specific examples include esters of long-chain alkyl carboxylic acids as used in US Pat. No. 6,117,913. The addition amount of such a compound is preferably 0.1 to 10% by mass, more preferably 0.5 to 5% by mass, based on the total solid content of the image forming layer.

  Further, the image forming layer according to the present invention may contain a compound having a low molecular weight acidic group, if necessary. Examples of acidic groups include sulfonic acid groups, carboxylic acid groups, and phosphoric acid groups. Of these, compounds having a sulfonic acid group are preferred. Specific examples include aromatic sulfonic acids such as p-toluenesulfonic acid and naphthalenesulfonic acid, and aliphatic sulfonic acids.

In addition, for the purpose of further improving sensitivity, cyclic acid anhydrides, phenols, and organic acids can be used in combination. Examples of cyclic acid anhydrides include phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, 3,6-endooxy-Δ4-tetrahydrophthalic anhydride described in US Pat. No. 4,115,128, Tetrachlorophthalic anhydride, maleic anhydride, chloromaleic anhydride, α-phenylmaleic anhydride, succinic anhydride, pyromellitic anhydride and the like can be used. As phenols, bisphenol A, p-nitrophenol, p-ethoxyphenol, 2,4,4′-trihydroxybenzophenone, 2,3,4-trihydroxybenzophenone, 4-hydroxybenzophenone, 4,4 ′, 4 “-Trihydroxytriphenylmethane, 4,4 ′, 3”, 4 ”-tetrahydroxy-3,5,3 ′, 5′-tetramethyltriphenylmethane and the like. There are sulfonic acids, sulfinic acids, alkylsulfuric acids, phosphonic acids, phosphoric acid esters, carboxylic acids, and the like, which are described in Japanese Laid-Open Patent Publication No. 60-88942 and Japanese Patent Application Laid-Open No. 2-96755. P-toluenesulfonic acid, dodecylbenzenesulfonic acid, p-toluenesulfinic acid, ethyl sulfate, Phosphonic acid, phenylphosphinic acid, phenyl phosphate, diphenyl phosphate, benzoic acid, isophthalic acid, adipic acid, p-toluic acid, 3,4-dimethoxybenzoic acid, phthalic acid, terephthalic acid, 4-cyclohexene-1,2 -Dicarboxylic acid, erucic acid, lauric acid, n-undecanoic acid, ascorbic acid, etc. are mentioned.
When the above cyclic acid anhydride, phenols and organic acids are added to the image forming layer, the proportion in the image forming layer is preferably 0.05 to 20% by mass, more preferably 0.1 to 15% by mass. Especially preferably, it is 0.1-10 mass%.

  Further, when preparing a coating solution for an image forming layer according to the present invention, it is described in Japanese Patent Application Laid-Open Nos. 62-251740 and 3-208514 in order to broaden the stability of processing with respect to development conditions. Nonionic surfactants, amphoteric surfactants as described in JP-A-59-121044, JP-A-4-13149, siloxane compounds as described in EP950517, A fluorine-containing monomer copolymer as described in JP-A-11-288093 can be added.

Specific examples of the nonionic surfactant include sorbitan tristearate, sorbitan monopalmitate, sorbitan trioleate, stearic acid monoglyceride, polyoxyethylene nonylphenyl ether and the like. Specific examples of the double-sided activator include alkyldi (aminoethyl) glycine, alkylpolyaminoethylglycine hydrochloride, 2-alkyl-N-carboxyethyl-N-hydroxyethylimidazolinium betaine and N-tetradecyl-N, N-betaine. Type (for example, trade name “Amorgen K” manufactured by Daiichi Kogyo Seiyaku Co., Ltd.).
The siloxane compound is preferably a block copolymer of dimethylsiloxane and polyalkylene oxide. Specific examples include DBE-224, DBE-621, DBE-712, DBP-732, DBP-534, manufactured by Chisso Corporation. And polyalkylene oxide-modified silicones such as Tego Glide 100 manufactured by Tego, Germany.
The proportion of the nonionic surfactant and amphoteric surfactant in the image forming layer is preferably 0.05 to 15% by mass, more preferably 0.1 to 5% by mass.

In the image forming layer of the lithographic printing plate precursor according to the invention, a printing-out agent for obtaining a visible image immediately after heating by exposure, or a dye or pigment as an image colorant can be added.
Typical examples of the printing-out agent include a combination of a compound that releases an acid by heating by exposure (photoacid releasing agent) and an organic dye that can form a salt. Specifically, combinations of o-naphthoquinonediazide-4-sulfonic acid halides and salt-forming organic dyes described in JP-A-50-36209 and JP-A-53-8128, 36223, 54-74728, 60-3626, 61-143748, 61-151644 and 63-58440, and trihalomethyl compounds and salt-forming organic dyes Can be mentioned. Such trihalomethyl compounds include oxazole compounds and triazine compounds, both of which have excellent temporal stability and give clear printout images.

  As the image colorant, other dyes can be used in addition to the above-mentioned salt-forming organic dyes. Examples of suitable dyes including salt-forming organic dyes include oil-soluble dyes and basic dyes. Specifically, Oil Yellow # 101, Oil Yellow # 103, Oil Pink # 312, Oil Green BG, Oil Blue BOS, Oil Blue # 603, Oil Black BY, Oil Black BS, Oil Black T-505 (oriental chemical industry) Manufactured by Co., Ltd.), Victoria Pure Blue, Crystal Violet (CI42555), Methyl Violet (CI42535), Ethyl Violet, Rhodamine B (CI145170B), Malachite Green (CI42000), Methylene Blue (CI522015), and the like. The dyes described in JP-A-62-293247 are particularly preferred. These dyes can be added in a proportion of 0.01 to 10% by mass, preferably 0.1 to 3% by mass, based on the total solid content of the image forming layer. Furthermore, a plasticizer is added to the image forming layer coating solution according to the present invention, if necessary, in order to impart flexibility of the coating film. For example, butylphthalyl, polyethylene glycol, tributyl citrate, diethyl phthalate, dibutyl phthalate, dihexyl phthalate, dioctyl phthalate, tricresyl phosphate, tributyl phosphate, trioctyl phosphate, tetrahydrofurfuryl oleate, acrylic acid or methacrylic acid These oligomers and polymers are used.

In addition to these, epoxy compounds, vinyl ethers, phenol compounds having a hydroxymethyl group, phenol compounds having an alkoxymethyl group, and JP-A No. 11-160860 described in JP-A-8-276558. A crosslinkable compound having an alkali dissolution inhibiting action described in the publication can be appropriately added depending on the purpose.
The image forming layer in the image recording material of the present invention obtained as described above is excellent in film formability and film strength, and the exposed area exhibits high alkali solubility upon infrared exposure.

2. Negative type image forming layer 2-1. Polymerized and cured layer As one of the negative type image forming layers, a polymerized and cured layer is exemplified. This polymerization hardened layer contains (A) an infrared absorber, (B) a radical generator (radical polymerization initiator), and a radical polymerizable compound that is cured by causing a polymerization reaction with the generated radical (C), Preferably (D) a binder polymer is contained. The infrared rays absorbed by the infrared absorbent are converted into heat, and the heat generated at this time decomposes a radical polymerization initiator such as an onium salt to generate radicals. The radically polymerizable compound is selected from compounds having at least one ethylenically unsaturated double bond and having at least one terminal ethylenically unsaturated bond, preferably two or more, and polymerizes in a chain manner by the generated radicals. A reaction takes place and cures.

2-2. Acid cross-linked layer Another embodiment of the image forming layer is an acid cross-linked layer. The acid cross-linking layer contains (E) a compound that generates an acid by light or heat (hereinafter referred to as an acid generator) and (F) a compound that cross-links by the generated acid (hereinafter referred to as a cross-linking agent). And (G) an alkali-soluble polymer capable of reacting with a crosslinking agent in the presence of an acid to form a layer containing them. In this acid cross-linking layer, the acid generated by decomposition of the acid generator by light irradiation or heating promotes the action of the cross-linking agent, and a strong cross-linking structure between the cross-linking agents or between the cross-linking agent and the binder polymer. As a result, the alkali solubility is lowered and the developer becomes insoluble. At this time, in order to efficiently use the energy of the infrared laser, (A) an infrared absorber is blended in the image forming layer.

[(A) Infrared absorber]
The image forming layer capable of forming an image with an infrared laser contains an infrared absorber. As an infrared absorber, any material that absorbs light energy used for recording and generates heat can be used without any limitation on the absorption wavelength range, but it is compatible with readily available high-power lasers. From the viewpoint, an infrared-absorbing dye or pigment having an absorption maximum at a wavelength of 800 nm to 1200 nm is preferable.

As the dye, commercially available dyes and known dyes described in documents such as “Dye Handbook” (edited by the Society for Synthetic Organic Chemistry, published in 1970) can be used. Specifically, dyes such as azo dyes, metal complex azo dyes, pyrazolone azo dyes, naphthoquinone dyes, anthraquinone dyes, phthalocyanine dyes, carbonium dyes, quinoneimine dyes, methine dyes, cyanine dyes, squarylium dyes, pyrylium salts, metal thiolate complexes, etc. Is mentioned.
Preferred dyes include, for example, cyanine dyes described in JP-A-58-125246, JP-A-59-84356, JP-A-59-202829, JP-A-60-78787, and the like. Methine dyes described in JP-A-58-173696, JP-A-58-181690, JP-A-58-194595, JP-A-58-112793, JP-A-58-224793, JP-A-59- 48187, JP-A-59-73996, JP-A-60-52940, JP-A-60-63744, etc., naphthoquinone dyes, JP-A-58-112792, etc. And cyanine dyes described in British Patent 434,875.

Also, a near infrared absorption sensitizer described in US Pat. No. 5,156,938 is preferably used, and a substituted arylbenzo (thio) pyrylium salt described in US Pat. No. 3,881,924, Trimethine thiapyrylium salts described in JP-A-57-142645 (US Pat. No. 4,327,169), JP-A-58-181051, 58-220143, 59-41363, 59-84248 Nos. 59-84249, 59-146063, 59-146061, pyranlium compounds, cyanine dyes described in JP-A-59-216146, US Pat. No. 4,283,475 The pentamethine thiopyrylium salts described above and the pyrylium compounds disclosed in Japanese Patent Publication Nos. 5-13514 and 5-19702 are also preferably used. . Another example of a preferable dye is a near-infrared absorbing dye described in US Pat. No. 4,756,993 as formulas (I) and (II).
Other preferred examples of the infrared absorbing dye of the present invention include specific indolenine cyanine dyes described in Japanese Patent Application Nos. 2001-6326 and 2001-237840 as exemplified below.

  Particularly preferred among these dyes are cyanine dyes, squarylium dyes, pyrylium salts, nickel thiolate complexes, and indolenine cyanine dyes. Further, cyanine dyes and indolenine cyanine dyes are preferred, and one particularly preferred example is a cyanine dye represented by the following general formula (A).

In the general formula (A), ^{X 1} represents a hydrogen atom, a halogen _atom, -NPh ^2, X 2 -L ¹ or a group shown below. Here, X ² represents an oxygen atom, a nitrogen atom, or a sulfur atom, and L ¹ represents a hydrocarbon group having 1 to 12 carbon atoms, an aromatic ring having a hetero atom, or 1 to 1 carbon atom including a hetero atom. 12 hydrocarbon groups are shown. In addition, a hetero atom here shows N, S, O, a halogen atom, and Se. Xa ^- the Za described later ^- is defined as for, R ^a represents a hydrogen atom, an alkyl group, an aryl group, a substituted or unsubstituted amino group, substituted or unsubstituted amino group and a halogen atom.

R ¹ and R ² each independently represent a hydrocarbon group having 1 to 12 carbon atoms. From the storage stability of the image forming layer coating solution, R ¹ and R ² are preferably hydrocarbon groups having 2 or more carbon atoms, and R ¹ and R ² are bonded to each other to form a 5-membered ring. Alternatively, it is particularly preferable that a 6-membered ring is formed.

Ar ¹ and Ar ² may be the same or different and each represents an aromatic hydrocarbon group which may have a substituent. Preferred aromatic hydrocarbon groups include a benzene ring and a naphthalene ring. Moreover, as a preferable substituent, a C12 or less hydrocarbon group, a halogen atom, and a C12 or less alkoxy group are mentioned. Y ¹ and Y ² may be the same or different and each represents a sulfur atom or a dialkylmethylene group having 12 or less carbon atoms. R ³ and R ⁴ may be the same or different and each represents a hydrocarbon group having 20 or less carbon atoms which may have a substituent. Preferred substituents include alkoxy groups having 12 or less carbon atoms, carboxyl groups, and sulfo groups. R ⁵ , R ⁶ , R ⁷ and R ⁸ may be the same or different and each represents a hydrogen atom or a hydrocarbon group having 12 or less carbon atoms. From the availability of raw materials, a hydrogen atom is preferred. Za ⁻ represents a counter anion. However, Za ⁻ is not necessary when the cyanine dye represented by formula (A) has an anionic substituent in its structure and neutralization of charge is not necessary. Preferred Za ⁻ is a halogen ion, a perchlorate ion, a tetrafluoroborate ion, a hexafluorophosphate ion, and a sulfonate ion, particularly preferably a perchlorate ion, from the storage stability of the image forming layer coating solution. Hexafluorophosphate ions and aryl sulfonate ions.

Specific examples of the cyanine dye represented by formula (A) that can be suitably used in the present invention include those described in paragraph numbers [0017] to [0019] of JP-A No. 2001-133969. Can do.
Further, other particularly preferable examples include specific indolenine cyanine dyes described in Japanese Patent Application Nos. 2001-6326 and 2001-237840 described above.

  Examples of the pigment used in the present invention include commercially available pigments and color index (CI) manual, “Latest Pigment Handbook” (edited by Japan Pigment Technology Association, published in 1977), “Latest Pigment Application Technology” (CMC Publishing, 1986), “Printing Ink Technology”, CMC Publishing, 1984) can be used.

  Examples of the pigment include black pigments, yellow pigments, orange pigments, brown pigments, red pigments, purple pigments, blue pigments, green pigments, fluorescent pigments, metal powder pigments, and other polymer-bonded dyes. Specifically, insoluble azo pigments, azo lake pigments, condensed azo pigments, chelate azo pigments, phthalocyanine pigments, anthraquinone pigments, perylene and perinone pigments, thioindigo pigments, quinacridone pigments, dioxazine pigments, isoindolinone pigments In addition, quinophthalone pigments, dyed lake pigments, azine pigments, nitroso pigments, nitro pigments, natural pigments, fluorescent pigments, inorganic pigments, carbon black, and the like can be used. Among these pigments, carbon black is preferable.

  These pigments may be used without surface treatment, or may be used after surface treatment. The surface treatment method includes a method of surface coating with a resin or wax, a method of attaching a surfactant, a method of bonding a reactive substance (eg, silane coupling agent, epoxy compound, polyisocyanate, etc.) to the pigment surface, etc. Can be considered. The above-mentioned surface treatment methods are described in “Characteristics and Applications of Metal Soap” (Shobobo), “Printing Ink Technology” (CMC Publishing, 1984) and “Latest Pigment Application Technology” (CMC Publishing, 1986). Yes.

  The particle diameter of the pigment is preferably in the range of 0.01 μm to 10 μm, preferably in the range of 0.05 μm to 1 μm, from the viewpoint of the stability of the dispersion in the image forming layer coating solution and the uniformity of the image forming layer. More preferably, the thickness is preferably in the range of 0.1 μm to 1 μm.

  As a method for dispersing the pigment, a known dispersion technique used in ink production, toner production, or the like can be used. Examples of the disperser include an ultrasonic disperser, a sand mill, an attritor, a pearl mill, a super mill, a ball mill, an impeller, a disperser, a KD mill, a colloid mill, a dynatron, a three-roll mill, and a pressure kneader. Details are described in "Latest Pigment Applied Technology" (CMC Publishing, 1986).

  The content of the infrared absorber in the image forming layer is preferably 0.01 to 50% by mass, more preferably 0.1 to 10% by mass, and more preferably 0.5 to 10% by mass relative to the total solid mass of the image forming layer. 10 mass% is most preferable. Within this range, high-sensitivity recording is possible, and high-quality image formation is possible without the occurrence of contamination in non-image areas.

[(B) Compound generating radicals]
The radical generator refers to a compound that initiates and accelerates polymerization of a compound having a polymerizable unsaturated group by generating radicals by energy of light, heat, or both. As a radical generator applicable to the present invention, a known thermal polymerization initiator or a compound having a bond with a small bond dissociation energy can be selected and used. For example, an onium salt, an s having a trihalomethyl group can be used. -Organic halogen compounds such as triazine compounds and oxazole compounds, peroxides, azo polymerization initiators, arylazide compounds, benzophenones, acetophenones, carbonyl compounds such as thioxanthones, metallocene compounds, hexaarylbiimidazole compounds, organic boron Examples thereof include salt compounds and dizulphone compounds.

  In the present invention, particularly preferable radical generators include onium salts, and among them, onium salts represented by the following general formulas (B-1) to (B-3) are preferably used.

In formula (B-1), Ar ¹¹ and Ar ¹² each independently represent an aryl group having 20 or less carbon atoms, which may have a substituent. Preferred substituents when this aryl group has a substituent include a halogen atom, a nitro group, an alkyl group having 12 or less carbon atoms, an alkoxy group having 12 or less carbon atoms, or a carbon atom having 12 or less carbon atoms. An aryloxy group is mentioned. Z ^11- represents an inorganic anion or an organic anion.

In the formula (B-2), Ar ²¹ represents an aryl group having 20 or less carbon atoms which may have a substituent. Preferred examples of the substituent include a halogen atom, a nitro group, an alkyl group having 12 or less carbon atoms, an alkoxy group having 12 or less carbon atoms, an aryloxy group having 12 or less carbon atoms, and 12 or less carbon atoms. Examples thereof include an alkylamino group, a dialkylamino group having 12 or less carbon atoms, an arylamino group having 12 or less carbon atoms, or a diarylamino group having 12 or less carbon atoms. Z ^21- represents a counter ion having the same ^meaning as Z ^11- .

In formula (B-3), R ³¹ , R ³² and R ³³ may be the same or different and each represents a hydrocarbon group having 20 or less carbon atoms which may have a substituent. Preferable substituents include a halogen atom, a nitro group, an alkyl group having 12 or less carbon atoms, an alkoxy group having 12 or less carbon atoms, or an aryloxy group having 12 or less carbon atoms. Z ^31- represents a counter ion having the same ^meaning as Z ^11- .
In the general formulas (B-1) to (B-3), Z ¹¹⁻ , Z ²¹⁻ , and Z ³¹⁻ represent an inorganic anion or an organic anion. As the inorganic anion, a halogen ion (F ⁻ , Cl ^{-, Br -, I -)} , perchlorate ion (ClO ₄ ^-), perborate ion (BrO ₄ ^-), tetrafluoroborate ion _{^{(BF 4 -), SbF 6}} -, PF 6 - , and the like As organic anions, organic borate anions, sulfonate ions, phosphonate ions, carboxylate ions, R ⁴⁰ —SO ₃ H ⁻ , R ⁴⁰ —SO ₂ ^— , R ⁴⁰ —SO ₂ S ⁻ , R ⁴⁰ —SO _{2 are used.} N ^{- -Y-R 40} ion ^{(wherein, R 40} is an alkyl group having 1 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms, Y is a single bond, -CO -, - SO -, and represented) and the like a..

  In the present invention, specific examples of onium salts that can be suitably used include those described in paragraph numbers [0030] to [0033] of JP-A No. 2001-133696.

  The onium salt used in the present invention preferably has a maximum absorption wavelength of 400 nm or less, and more preferably 360 nm or less. By making the absorption wavelength in the ultraviolet region in this way, the lithographic printing plate precursor can be handled under white light.

These onium salts may be used alone or in combination of two or more.
These onium salts may be added in a proportion of 0.1 to 50% by mass, preferably 0.5 to 30% by mass, particularly preferably 1 to 20% by mass, based on the total solid content of the image forming layer coating solution. it can. When the addition amount is in the above range, highly sensitive recording is achieved, and the occurrence of smudges in the non-image area during printing is suppressed.
These onium salts are not necessarily added to the image forming layer, and may be added to another layer provided adjacent to the image forming layer.

[(C) Radical polymerizable compound]
The radically polymerizable compound used in the image forming layer in this embodiment is a radically polymerizable compound having at least one ethylenically unsaturated double bond, and has at least one terminal ethylenically unsaturated bond, preferably two. It is selected from the compounds having the above. Such a compound group is widely known in the industrial field, and can be used without any particular limitation in the present invention. These have chemical forms such as monomers, prepolymers, i.e. dimers, trimers and oligomers, or mixtures thereof and copolymers thereof. Examples of monomers and copolymers thereof include unsaturated carboxylic acids (for example, acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid, maleic acid, etc.), and esters and amides thereof. In this case, an ester of an unsaturated carboxylic acid and an aliphatic polyhydric alcohol compound, or an amide of an unsaturated carboxylic acid and an aliphatic polyvalent amine compound is used. In addition, unsaturated carboxylic acid esters having nucleophilic substituents such as hydroxyl groups, amino groups, mercapto groups, amides and monofunctional or polyfunctional isocyanates, addition reaction products of epoxies, monofunctional or polyfunctional A dehydration condensation reaction product with a functional carboxylic acid is also preferably used. In addition, an addition reaction product of an unsaturated carboxylic acid ester or amide having an electrophilic substituent such as an isocyanate group or an epoxy group with a monofunctional or polyfunctional alcohol, amine or thiol, halogen A substitution reaction product of an unsaturated carboxylic acid ester or amide having a leaving substituent such as a group or a tosyloxy group with a monofunctional or polyfunctional alcohol, amine or thiol is also suitable. As another example, it is also possible to use a group of compounds substituted with unsaturated phosphonic acid, styrene or the like instead of the unsaturated carboxylic acid.

  Specific examples of acrylic acid ester, methacrylic acid ester, itaconic acid ester, crotonic acid ester, isocrotonic acid ester, maleic acid ester, which are radical polymerizable compounds that are esters of aliphatic polyhydric alcohol compounds and unsaturated carboxylic acids, It describes in paragraph number [0037]-[0042] of Unexamined-Japanese-Patent No. 2001-133696, and these are applicable also to this invention.

  Examples of other esters include aliphatic alcohol esters described in JP-B-46-27926, JP-B-51-47334, JP-A-57-196231, JP-A-59-5240, JP-A-59-5241. Those having an aromatic skeleton described in JP-A-2-226149 and those containing an amino group described in JP-A-1-165613 are also preferably used.

Specific examples of amide monomers of aliphatic polyvalent amine compounds and unsaturated carboxylic acids include methylene bis-acrylamide, methylene bis-methacrylamide, 1,6-hexamethylene bis-acrylamide, 1,6-hexamethylene bis. -Methacrylamide, diethylenetriamine trisacrylamide, xylylene bisacrylamide, xylylene bismethacrylamide and the like.
Examples of other preferable amide monomers include those having a cyclohexylene structure described in JP-B-54-21726.

  In addition, urethane-based addition polymerizable compounds produced by using an addition reaction of isocyanate and hydroxyl group are also suitable, and specific examples thereof include, for example, one molecule described in JP-B-48-41708. A vinylurethane compound containing two or more polymerizable vinyl groups in one molecule obtained by adding a vinyl monomer containing a hydroxyl group represented by the following formula (VI) to a polyisocyanate compound having two or more isocyanate groups. Etc.

Formula (VI)
^{_{CH 2 = C (R 41)}} COOCH 2 CH (R 42) OH
^{(Wherein, R 41} and ^{R 42} represent H or CH _3.)

  Also, urethane acrylates such as those described in JP-A-51-37193, JP-B-2-32293, and JP-B-2-16765, JP-B-58-49860, JP-B-56-17654, Urethane compounds having an ethylene oxide skeleton described in JP-B-62-39417 and JP-B-62-39418 are also suitable.

  Furthermore, radical polymerizable compounds having an amino structure or a sulfide structure in the molecule described in JP-A-63-277653, JP-A-63-260909, and JP-A-1-105238 may be used.

  Other examples include polyester acrylates, epoxy resins and (meth) acrylic acid as described in JP-A-48-64183, JP-B-49-43191, JP-B-52-30490, and JP-B-52-30490. Examples thereof include polyfunctional acrylates and methacrylates such as reacted epoxy acrylates. Further, specific unsaturated compounds described in JP-B-46-43946, JP-B-1-40337, and JP-B-1-40336, vinylphosphonic acid compounds described in JP-A-2-25493, and the like can also be mentioned. . In some cases, a structure containing a perfluoroalkyl group described in JP-A-61-22048 is preferably used. Furthermore, Journal of Japan Adhesion Association vol. 20, no. 7, pages 300 to 308 (1984), which are introduced as photocurable monomers and oligomers, can also be used.

For these radically polymerizable compounds, the details of how to use them, such as what structure to use, whether they are used alone or in combination, and how much they are added, can be selected according to the performance design of the final recording material. Can be set. For example, it is selected from the following viewpoints. From the viewpoint of sensitivity, a structure having a high unsaturated group content per molecule is preferable, and in many cases, a bifunctional or higher functionality is preferable. Further, in order to increase the strength of the image portion, that is, the cured film, those having three or more functionalities are preferable, and compounds having different functional numbers and different polymerizable groups (for example, acrylate ester compounds, methacrylate esters). It is also effective to adjust both photosensitivity and strength by using a combination of a compound, a styrene compound, and the like. A compound having a large molecular weight or a compound having high hydrophobicity is excellent in sensitivity and film strength, but may not be preferable in terms of development speed and precipitation in a developer. Further, the selection and use method of the radical polymerization compound is also an important factor for the compatibility and dispersibility with other components (for example, binder polymer, initiator, colorant, etc.) in the image forming layer. The compatibility may be improved by using a low-purity compound or using a combination of two or more compounds. In addition, a specific structure may be selected for the purpose of improving the adhesion of the support, overcoat layer and the like. As for the compounding ratio of the radically polymerizable compound in the image forming layer, a larger amount is advantageous in terms of sensitivity. However, when the amount is too large, undesirable phase separation may occur or the manufacturing process due to the adhesiveness of the image forming layer may occur. Problems (for example, transfer of image forming layer components, manufacturing defects due to adhesion) and precipitation from the developer may occur.
From these viewpoints, the preferred blending ratio of the radical polymerizable compound is often 5 to 80% by mass, preferably 20 to 75% by mass, based on the total components of the composition. These may be used alone or in combination of two or more. In addition, the usage of the radical polymerizable compound can be arbitrarily selected from the viewpoint of polymerization inhibition with respect to oxygen, resolution, fogging, refractive index change, surface tackiness, etc. Depending on the case, a layer configuration and coating method such as undercoating and overcoating can be performed.

[(D) Binder polymer]
In such an image forming layer, it is preferable to further use a binder polymer from the viewpoint of improving the film properties of the image forming layer, and it is preferable to use a linear organic polymer as the binder. Any such “linear organic polymer” may be used. Preferably, a linear organic polymer that is soluble or swellable in water or weak alkaline water is selected to enable water development or weak alkaline water development. The linear organic polymer is selected and used not only as a film-forming agent for forming an image forming layer, but also according to the use as water, weak alkaline water or an organic solvent developer.
For example, when a water-soluble organic polymer is used, water development becomes possible. Examples of such linear organic polymers include radical polymers having a carboxylic acid group in the side chain, such as JP-A-59-44615, JP-B-54-34327, JP-B-58-12777, and JP-B-54-25957. , JP 54-92723, JP 59-53836, JP 59-71048, that is, methacrylic acid copolymer, acrylic acid copolymer, itaconic acid copolymer. Examples thereof include a polymer, a crotonic acid copolymer, a maleic acid copolymer, and a partially esterified maleic acid copolymer. Similarly, there is an acidic cellulose derivative having a carboxylic acid group in the side chain. In addition, those obtained by adding a cyclic acid anhydride to a polymer having a hydroxyl group are useful.
Among these, a (meth) acrylic resin having a benzyl group or an allyl group and a carboxyl group in the side chain is particularly preferable because of excellent balance of film strength, sensitivity, and developability.

In addition, Japanese Patent Publication No. 7-2004, Japanese Patent Publication No. 7-120041, Japanese Patent Publication No. 7-120042, Japanese Patent Publication No. 8-12424, Japanese Patent Laid-Open No. 63-287944, Japanese Patent Laid-Open No. 63-287947, Japanese Patent Laid-Open No. Urethane-based binder polymers containing acid groups described in No. 271741, JP-A-11-352691 and the like are very excellent in strength, and are advantageous in terms of printing durability and suitability for low exposure.
In addition, polyvinyl pyrrolidone, polyethylene oxide, and the like are useful as the water-soluble linear organic polymer. In order to increase the strength of the cured film, alcohol-soluble nylon, polyether of 2,2-bis- (4-hydroxyphenyl) -propane and epichlorohydrin, and the like are also useful.

The weight average molecular weight of the polymer used in the present invention is preferably 5000 or more, more preferably in the range of 10,000 to 300,000, and the number average molecular weight is preferably 1000 or more, more preferably 2000 to 2000. The range is 250,000. The polydispersity (weight average molecular weight / number average molecular weight) is preferably 1 or more, and more preferably 1.1 to 10.
These polymers may be random polymers, block polymers, graft polymers or the like, but are preferably random polymers.

  The binder polymer used in the present invention may be used alone or in combination. These polymers are added to the image forming layer in a proportion of 20 to 95% by mass, preferably 30 to 90% by mass, based on the total solid content of the image forming layer coating solution. When the addition amount is less than 20% by mass, the strength of the image portion is insufficient when an image is formed. If the amount added exceeds 95% by mass, no image is formed. Moreover, it is preferable that the compound which has an ethylenically unsaturated double bond which can be radically polymerized, and a linear organic polymer shall be 1 / 9-7 / 3 by mass ratio.

Next, the components of the acid cross-linking layer will be described. The infrared absorber used here can be the same as that used in the polymerization curable image forming layer.
The content is preferably 0.01 to 50% by mass, more preferably 0.1 to 10% by mass, and most preferably 0.5 to 10% by mass with respect to the total solid mass of the image forming layer.
In the range of the content, highly sensitive recording can be achieved, and the occurrence of stains in the obtained non-image portion for lithographic printing can be suppressed.

[(E) Acid generator]
In the present embodiment, an acid generator that generates an acid by being decomposed by heat refers to a compound that generates an acid when irradiated with light in a wavelength region of 200 to 500 nm or heated to 100 ° C. or higher.
Examples of the acid generator include a photoinitiator for photocationic polymerization, a photoinitiator for radical photopolymerization, a photodecolorant for dyes, a photochromic agent, or a known acid generator used for a microresist And the like, and known compounds and mixtures thereof that can generate an acid upon thermal decomposition.
Of the acid generators described above, compounds represented by the following general formulas (E-1) to (E-5) are preferred.

In the general formulas (E-1) to (E-5), R ¹ , R ² , R ^4, and R ⁵ may be the same or different and may have a substituent and have 20 or less carbon atoms. Represents a hydrocarbon group. R ³ represents a halogen atom, an optionally substituted hydrocarbon group having 10 or less carbon atoms or an alkoxy group having 10 or less carbon atoms. Ar ¹ and Ar ² may be the same or different and each represents an aryl group having 20 or less carbon atoms which may have a substituent. R ⁶ represents a divalent hydrocarbon group having 20 or less carbon atoms which may have a substituent. n represents an integer of 0 to 4.
In the above formula, R ¹ , R ² , R ⁴ and R ⁵ are preferably hydrocarbon groups having 1 to 14 carbon atoms.

  The preferable aspect of the acid generator represented by the general formulas (E-1) to (E-5) is described in paragraphs [0197] to [0222] of JP-A No. 2001-142230. It is described in detail as a compound of (V). These compounds can be synthesized, for example, by the method described in JP-A-2-100054 and JP-A-2-100055.

  Examples of the acid generator (E) include onium salts having a halide, sulfonic acid, or the like as a counter ion. Among them, iodonium represented by the following general formulas (E-6) to (E-8): Preferred examples include salts having any structural formula of salts, sulfonium salts and diazonium salts.

In the general formulas (E-6) to (E-8), X ⁻ represents a halide ion, ClO ₄ ⁻ , PF ₆ ⁻ , SbF ₆ ⁻ , BF ₄ ⁻ or R ⁷ SO ₃ ⁻ , , R ⁷ represents a hydrocarbon group having 20 or less carbon atoms which may have a substituent. Ar ³ and Ar ⁴ each independently represent an aryl group having 20 or less carbon atoms, which may have a substituent. R ⁸ , R ⁹ and R ¹⁰ represent a hydrocarbon group having 18 or less carbon atoms which may have a substituent.
Such onium salts are described as compounds of general formulas (I) to (III) in paragraph numbers [0010] to [0035] of JP-A-10-39509.

The addition amount of the acid generator is preferably 0.01 to 50% by mass, more preferably 0.1 to 25% by mass, and most preferably 0.5 to 20% by mass with respect to the total solid mass of the image forming layer. .
When the addition amount is less than 0.01% by mass, an image may not be obtained. When the addition amount exceeds 50% by mass, the non-image area is smeared during printing when used as a lithographic printing original plate. Sometimes.
The above acid generators may be used alone or in combination of two or more.

[(F) Crosslinking agent]
Next, the crosslinking agent will be described. The following are mentioned as a crosslinking agent.
(I) Aromatic compound substituted with hydroxymethyl group or alkoxymethyl group (ii) Compound having N-hydroxymethyl group, N-alkoxymethyl group or N-acyloxymethyl group (iii) Epoxy compound

Hereinafter, the compounds (i) to (iii) will be described in detail.
Examples of the aromatic compound substituted with the hydroxymethyl group or alkoxymethyl group (i) include an aromatic compound or a heterocyclic compound polysubstituted with a hydroxymethyl group, an acetoxymethyl group or an alkoxymethyl group. . However, resinous compounds obtained by condensation polymerization of phenols and aldehydes known as resol resins under basic conditions are also included.
Of the aromatic compounds or heterocyclic compounds poly-substituted with a hydroxymethyl group or an alkoxymethyl group, among them, a compound having a hydroxymethyl group or an alkoxymethyl group at a position adjacent to the hydroxy group is preferable.
Of the aromatic compounds or heterocyclic compounds poly-substituted with an alkoxymethyl group, compounds having an alkoxymethyl group of 18 or less carbon atoms are preferred, represented by the following general formulas (F-1) to (F-4). More preferred is a compound.

In the general formulas (F-1) to (F-4), L ^{1 to} L ⁸ are each independently a hydroxymethyl group substituted with an alkoxy group having 18 or less carbon atoms such as methoxymethyl or ethoxymethyl, or Represents an alkoxymethyl group.
These crosslinking agents are preferable in that they have high crosslinking efficiency and can improve printing durability.

(Ii) As a compound having an N-hydroxymethyl group, an N-alkoxymethyl group or an N-acyloxymethyl group, European Patent Publication (hereinafter referred to as “EP-A”) No. 0,133,216, West Germany Monomer and oligomer-melamine-formaldehyde condensate and urea-formaldehyde condensate described in Patent Nos. 3,634,671 and 3,711,264, EP-A 0,212,482 And alkoxy-substituted compounds described in the book.
Among these, for example, melamine-formaldehyde derivatives having at least two free N-hydroxymethyl groups, N-alkoxymethyl groups or N-acyloxymethyl groups are preferable, and N-alkoxymethyl derivatives are most preferable.

(Iii) Examples of the epoxy compound include monomers, dimers, oligomers, and polymeric epoxy compounds having one or more epoxy groups. For example, a reaction product of bisphenol A and epichlorohydrin, a low molecular weight phenol-formaldehyde resin, and Examples include reaction products with epichlorohydrin.
In addition, there can be mentioned epoxy resins described and used in US Pat. No. 4,026,705 and British Patent 1,539,192.

The amount of addition when the compounds (i) to (iii) are used as the crosslinking agent is preferably 5 to 80% by mass, more preferably 10 to 75% by mass, based on the total solid content of the image forming layer. 20-70 mass% is the most preferable.
When the addition amount is less than 5% by mass, the durability of the image forming layer of the resulting image recording material may be reduced, and when it exceeds 80% by mass, stability during storage may be reduced. .

  In the present invention, (iv) a phenol derivative represented by the following general formula (F-5) can also be suitably used as the crosslinking agent.

In the general formula (F-5), Ar ¹ represents an aromatic hydrocarbon ring which may have a substituent, and R ¹ , R ² and R ³ are a hydrogen atom or a carbon atom having 12 or less carbon atoms. Represents a hydrogen group. m represents an integer of 2 to 4, and n represents an integer of 1 to 3.
From the viewpoint of availability of raw materials, the aromatic hydrocarbon ring is preferably a benzene ring, a naphthalene ring or an anthracene ring. As the substituent, a halogen atom, a hydrocarbon group having 12 or less carbon atoms, an alkoxy group having 12 or less carbon atoms, an alkylthio group having 12 or less carbon atoms, a cyano group, a nitro group, a trifluoromethyl group, or the like is preferable.
Among the above, Ar ¹ is a benzene ring, naphthalene ring, halogen atom, hydrocarbon group having 6 or less carbon atoms, or 6 or less carbon atoms, which has no substituent, in that sensitivity can be increased. And a benzene ring or a naphthalene ring having, as a substituent, an alkoxy group having a carbon number of 6 or less, an alkylcarbamoyl group having a carbon number of 12 or less, or a nitro group.

As the hydrocarbon group represented by R ¹ or R ² , a methyl group is preferable because synthesis is easy. The hydrocarbon group represented by R ³ is preferably a hydrocarbon group having 7 or less carbon atoms such as a methyl group and a benzyl group because of its high sensitivity. Furthermore, m is preferably 2 or 3 and n is preferably 1 or 2 for ease of synthesis.

[(G) Alkali water soluble polymer compound]
Examples of the alkaline water-soluble polymer compound that can be used in the crosslinked layer applicable to the present invention include novolak resins and polymers having a hydroxyaryl group in the side chain. Examples of the novolak resin include resins obtained by condensing phenols and aldehydes under acidic conditions.

Among them, for example, novolak resin obtained from phenol and formaldehyde, novolak resin obtained from m-cresol and formaldehyde, novolak resin obtained from p-cresol and formaldehyde, novolak resin obtained from o-cresol and formaldehyde, octylphenol and formaldehyde Novolak resin obtained, novolak resin obtained from m- / p-mixed cresol and formaldehyde, phenol / cresol (m-, p-, o- or m- / p-, m- / o-, o- / p- A high molecular weight polymer having a high ortho bond rate obtained by reacting under no pressure using a catalyst and using a novolac resin obtained from formaldehyde and phenol and paraformaldehyde in a sealed state under high pressure without using a catalyst. Rack resin and the like are preferable.
The novolak resin may be selected from those having a weight average molecular weight of 800 to 300,000 and a number average molecular weight of 400 to 60,000 depending on the purpose.

A polymer having a hydroxyaryl group in the side chain is also preferred, and examples of the hydroxyaryl group in the polymer include an aryl group having one or more OH groups bonded thereto.
Examples of the aryl group include a phenyl group, a naphthyl group, an anthracenyl group, and a phenanthrenyl group, and among them, a phenyl group or a naphthyl group is preferable from the viewpoint of availability and physical properties.
Examples of the polymer having a hydroxyaryl group in the side chain that can be used in the present embodiment include any one of the structural units represented by the following general formulas (G-1) to (G-4). The polymer containing can be mentioned. However, the present invention is not limited to these.

In General Formulas (G-1) to (G-4), R ¹¹ represents a hydrogen atom or a methyl group. R ¹² and R ¹³ may be the same or different and each represents a hydrogen atom, a halogen atom, a hydrocarbon group having 10 or less carbon atoms, an alkoxy group having 10 or less carbon atoms, or an aryloxy group having 10 or less carbon atoms. R ¹² and R ¹³ may be bonded and condensed to form a benzene ring or a cyclohexane ring. R ¹⁴ represents a single bond or a divalent hydrocarbon group having 20 or less carbon atoms. R ¹⁵ represents a single bond or a divalent hydrocarbon group having 20 or less carbon atoms. R ¹⁶ represents a single bond or a divalent hydrocarbon group having 10 or less carbon atoms. X ¹ represents a single bond, an ether bond, a thioether bond, an ester bond or an amide bond. p represents an integer of 1 to 4. q and r each independently represents an integer of 0 to 3.

These alkali-soluble polymers are described in detail in paragraph numbers [0130] to [0163] of JP-A No. 2001-142230.
The alkaline water-soluble polymer compound that can be used in this embodiment may be used alone or in combination of two or more.

The addition amount of the alkaline water-soluble polymer compound is preferably 5 to 95% by mass, more preferably 10 to 95% by mass, and most preferably 20 to 90% by mass with respect to the total solid content of the image forming layer.
When the addition amount of the alkali water-soluble resin is less than 5% by mass, the durability of the image forming layer may be deteriorated, and when it exceeds 95% by mass, image formation may not be performed.

  Further, as a known recording material applicable to the image forming layer according to the present invention, a negative type image recording material containing a phenol derivative described in JP-A-8-276558, or described in JP-A-7-306528 is disclosed. Negative recording material containing a diazonium compound, negative type using an acid-catalyzed crosslinking reaction using a polymer having a heterocyclic group having an unsaturated bond in the ring described in JP-A-10-203037 Examples thereof include image forming materials, and the image forming layer described in these materials can be applied to the acid crosslinking layer as the negative image forming layer in the present invention.

[Other ingredients]
In addition to these, various compounds other than these may be added to such a negative type image forming layer. For example, a dye having a large absorption in the visible light region can be used as an image colorant. In addition, pigments such as phthalocyanine pigments, azo pigments, carbon black, and titanium oxide can also be suitably used.
Further, in the present invention, when the image forming layer is a polymerization hardened layer, in order to prevent unnecessary thermal polymerization of a compound having an ethylenically unsaturated double bond capable of radical polymerization during preparation or storage of a coating solution. It is desirable to add a small amount of a thermal polymerization inhibitor. Suitable thermal polymerization inhibitors include hydroquinone, p-methoxyphenol, di-t-butyl-p-cresol, pyrogallol, t-butylcatechol, benzoquinone, 4,4'-thiobis (3-methyl-6-t-butylphenol ), 2,2′-methylenebis (4-methyl-6-tert-butylphenol), N-nitroso-N-phenylhydroxylamine aluminum salt and the like. The addition amount of the thermal polymerization inhibitor is preferably about 0.01% by mass to about 5% by mass with respect to the mass of the entire composition. If necessary, higher fatty acid derivatives such as behenic acid and behenic acid amide may be added to prevent polymerization inhibition due to oxygen and unevenly distributed on the surface of the image forming layer in the drying process after coating. Good. The amount of the higher fatty acid derivative added is preferably about 0.1% by mass to about 10% by mass of the total composition.

Further, in the image forming layer coating solution of the present invention, nonionic surface activity as described in JP-A Nos. 62-251740 and 3-208514 is used in order to broaden the processing stability against development conditions. An amphoteric surfactant as described in JP-A-59-121044 and JP-A-4-13149 can be added.
Specific examples of the nonionic surfactant include sorbitan tristearate, sorbitan monopalmitate, sorbitan trioleate, stearic acid monoglyceride, polyoxyethylene nonylphenyl ether and the like.

Specific examples of amphoteric surfactants include alkyldi (aminoethyl) glycine, alkylpolyaminoethylglycine hydrochloride, 2-alkyl-N-carboxyethyl-N-hydroxyethylimidazolinium betaine, N-tetradecyl-N, N- Examples include betaine type (for example, trade name Amorgen K, manufactured by Dai-ichi Kogyo Co., Ltd.).
The proportion of the nonionic surfactant and amphoteric surfactant in the image forming layer coating solution is preferably 0.05 to 15% by mass, more preferably 0.1 to 5% by mass.

  Furthermore, a plasticizer is added to the image forming layer coating solution in the present invention, if necessary, in order to impart flexibility of the coating film. For example, polyethylene glycol, tributyl citrate, diethyl phthalate, dibutyl phthalate, dihexyl phthalate, dioctyl phthalate, tricresyl phosphate, tributyl phosphate, trioctyl phosphate, tetrahydrofurfuryl oleate and the like are used.

3. Hydrophobized precursor-containing image forming layer As a further image forming layer that can be applied to the lithographic printing plate support of the present invention, a compound capable of forming a hydrophobic region by heating or irradiation with radiation (hereinafter, appropriately hydrophobized precursor) Heat-sensitive image-forming layer containing the body). Such an image-forming layer is fused to each other by heating, such as (a) a fine particle polymer having a heat-reactive functional group, or (b) a microcapsule containing a compound having a heat-reactive functional group. For example, if it is a microcapsule, it contains a compound that forms an image area region, that is, a hydrophobic region (parent ink region) by causing a chemical reaction of the inclusion by heat, and these are preferably Since it is dispersed in a hydrophilic binder, after image formation (exposure), a lithographic printing plate precursor is mounted on a printing machine cylinder, and a dampening solution and / or ink is supplied to perform special development processing. It is characterized in that it can be developed on the machine without performing it.

Such an image forming layer contains (a) a fine particle polymer having a thermoreactive functional group, or (b) a microcapsule encapsulating a compound having a thermoreactive functional group.
Examples of the heat-reactive functional group common to the above (a) and (b) include, for example, an ethylenically unsaturated group (for example, acryloyl group, methacryloyl group, vinyl group, allyl group) that undergoes a polymerization reaction, and an addition reaction. Isocyanate group or block thereof, functional group having an active hydrogen atom that is a reaction partner (for example, amino group, hydroxyl group, carboxyl group), epoxy group that similarly performs an addition reaction, amino group that is a reaction partner, carboxyl group Or a hydroxyl group, the carboxyl group and hydroxyl group or amino group which perform a condensation reaction, the acid anhydride and amino group or hydroxyl group which perform a ring-opening addition reaction are mentioned. The thermoreactive functional group used in the present invention is not limited to these, and may be any functional group that performs any reaction as long as a chemical bond is formed.

[(A) Fine particle polymer having a thermally reactive functional group]
(A) Thermally reactive functional groups suitable for the fine particle polymer include, for example, acryloyl group, methacryloyl group, vinyl group, allyl group, epoxy group, amino group, hydroxyl group, carboxyl group, isocyanate group, and acid anhydride group. And groups protecting them. The introduction of the thermally reactive functional group into the polymer fine particles may be performed at the time of polymerizing the polymer, or may be performed by utilizing a polymer reaction after the polymerization.

When a thermoreactive functional group is introduced during the polymerization of the polymer, it is preferable to perform emulsion polymerization or suspension polymerization using a monomer having a thermoreactive functional group.
Specific examples of the monomer having a heat-reactive functional group include allyl methacrylate, allyl acrylate, vinyl methacrylate, vinyl acrylate, glycidyl methacrylate, glycidyl acrylate, 2-isocyanate ethyl methacrylate, and its blocked alcohol, 2-isocyanate ethyl acrylate. Block isocyanates with alcohol, 2-aminoethyl methacrylate, 2-aminoethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxyethyl acrylate, acrylic acid, methacrylic acid, maleic anhydride, difunctional acrylate, difunctional methacrylate Can be mentioned. The monomer having a heat-reactive functional group used in the present invention is not limited to these.
Examples of the monomer having no thermally reactive functional group that can be copolymerized with these monomers include styrene, alkyl acrylate, alkyl methacrylate, acrylonitrile, and vinyl acetate. The monomer having no heat-reactive functional group used in the present invention is not limited to these.

  Examples of the polymer reaction used when the thermally reactive functional group is introduced after polymerization of the polymer include the polymer reaction described in International Publication No. 96/34316.

Among the above-mentioned (a) fine-particle polymers having a heat-reactive functional group, those in which the fine-particle polymers are easily fused and coalesced by heat are preferable from the viewpoint of image formability, and from the viewpoint of on-press developability. Particularly preferred are those having a hydrophilic surface and being dispersed in water. In addition, the film contact angle (water droplets in the film) when it is prepared by applying only the fine particle polymer and drying at a temperature lower than the solidification temperature is the contact of the film when it is prepared by drying at a temperature higher than the solidification temperature. It is preferable to be lower than the corner (water droplet in the air).
In order to make the hydrophilicity of the surface of the fine particle polymer in such a preferable state, a hydrophilic polymer or oligomer such as polyvinyl alcohol or polyethylene glycol, or a hydrophilic low molecular weight compound may be adsorbed on the surface of the fine particle polymer. The surface hydrophilization method is not limited to these, and various known surface hydrophilization methods can be applied.

(A) The thermal fusing temperature of the fine particle polymer having a heat-reactive functional group is preferably 70 ° C. or higher, but more preferably 80 ° C. or higher in view of the temporal stability. However, if the heat fusion temperature is too high, it is not preferable from the viewpoint of sensitivity, so the range of 80 to 250 ° C is preferable, and the range of 100 to 150 ° C is more preferable.
(A) The average particle diameter of the fine particle polymer is preferably 0.01 to 20 μm, more preferably 0.05 to 2.0 μm, and more preferably 0.1 to 1.0 μm. preferable. Within this range, good resolution and stability over time can be obtained.
(A) The addition amount of the fine particle polymer is preferably 50 to 98% by mass, more preferably 60 to 95% by mass, based on the solid content of the image forming layer.

[(B) Microcapsules encapsulating a compound having a thermally reactive functional group]
(B) Thermally reactive functional groups suitable for microcapsules include, for example, polymerizable unsaturated groups, hydroxyl groups, carboxyl groups in addition to the functional groups previously mentioned as common to (a) and (b). , Carboxylate groups, acid anhydride groups, amino groups, epoxy groups, isocyanate groups, isocyanate block bodies, and the like.

  The compound having a polymerizable unsaturated group is preferably a compound having at least one, preferably two or more ethylenically unsaturated bonds such as acryloyl group, methacryloyl group, vinyl group and allyl group. Such a compound group is widely known in the said industrial field | area, and in this invention, these can be used without being specifically limited. These are monomers, prepolymers, that is, dimers, trimers and oligomers, or mixtures thereof, and copolymers thereof in chemical form.

Specific examples include unsaturated carboxylic acids (for example, acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid, maleic acid), esters thereof, and unsaturated carboxylic acid amides. Of these, esters of unsaturated carboxylic acids and aliphatic polyhydric alcohols and amides of unsaturated carboxylic acids and aliphatic polyvalent amines are preferred.
Further, an addition reaction product of unsaturated carboxylic acid ester or unsaturated carboxylic acid amide having a nucleophilic substituent such as hydroxyl group, amino group, mercapto group and the like with monofunctional or polyfunctional isocyanate or epoxide, and monofunctional Alternatively, a dehydration condensation reaction product with a polyfunctional carboxylic acid is also preferably used.
In addition, an addition reaction product of an unsaturated carboxylic acid ester or amide having an electrophilic substituent such as an isocyanate group or an epoxy group with a monofunctional or polyfunctional alcohol, amine or thiol, and a halogen group or a tosyloxy group Also suitable are substitution reaction products of unsaturated carboxylic acid esters or amides having a leaving substituent with monofunctional or polyfunctional alcohols, amines or thiols.
Another preferred example is a compound in which the unsaturated carboxylic acid is replaced with unsaturated phosphonic acid or chloromethylstyrene.

  Specific examples of these compounds include the paragraphs [0014] to [0035] of JP-A No. 2001-27742 previously proposed by the applicant of the present invention, and detailed production of microcapsules containing these compounds. The method is described in [0036] to [0039], and these descriptions can also be applied to the present invention.

(B) The microcapsule wall preferably used for the microcapsule has a three-dimensional cross-linking and has a property of swelling with a solvent. From such a viewpoint, the wall material of the microcapsule is preferably polyurea, polyurethane, polyester, polycarbonate, polyamide, or a mixture thereof, and polyurea and polyurethane are particularly preferable. Further, a compound having a thermally reactive functional group may be introduced into the microcapsule wall.
(B) The average particle size of the microcapsules is preferably 0.01 to 20 μm, more preferably 0.05 to 2.0 μm, and particularly preferably 0.10 to 1.0 μm. Within the above range, good resolution and stability over time can be obtained.

(B) In an image forming mechanism using a microcapsule having a heat-reactive functional group, a microcapsule material, a compound encapsulated in the microcapsule material, and other image forming layers in which the microcapsule is dispersed Any component that reacts to form an image area, that is, a hydrophobic area (parent ink area) may be used. For example, a type in which microcapsules are fused together by heat, a microcapsule inclusion Of these, compounds that ooze out from the capsule surface or outside the microcapsule during application, or a compound that enters the microcapsule wall from the outside causes a chemical reaction by heat, or those microcapsule materials or encapsulated compounds A type that reacts with a hydrophilic resin to which is added, or a low molecular compound to which it is added. The capsule wall material or its inclusions, by using those to have a functional group such as thermally react with each other in different functional groups each, such as the type of reacting microcapsules each other and the like.
Therefore, although it is preferable for image formation that the microcapsules are fused together by heat, it is not essential.

  (B) The addition amount of the microcapsules to the image forming layer is preferably 10 to 60% by mass, and more preferably 15 to 40% by mass in terms of solid content. Within the above range, good on-press developability as well as good sensitivity and printing durability can be obtained.

(B) When microcapsules are added to the image forming layer, a solvent that dissolves the inclusions and swells the wall material can be added to the microcapsule dispersion medium. By such a solvent, diffusion of the encapsulated compound having a heat-reactive functional group to the outside of the microcapsule is promoted.
Such a solvent depends on the microcapsule dispersion medium, the material of the microcapsule wall, the wall thickness, and the inclusions, but can be easily selected from many commercially available solvents. For example, in the case of water-dispersible microcapsules composed of crosslinked polyurea and polyurethane walls, alcohols, ethers, acetals, esters, ketones, polyhydric alcohols, amides, amines, fatty acids and the like are preferable.

  A solvent that does not dissolve in the microcapsule dispersion but dissolves when the solvent is mixed can also be used. The amount of addition is determined by the combination of materials. When the amount is less than the appropriate value, image formation is insufficient, and when the amount is large, the stability of the dispersion deteriorates. Usually, it is preferably 5 to 95% by mass of the coating solution, more preferably 10 to 90% by mass, and particularly preferably 15 to 85% by mass.

[Other ingredients]
In the heat-sensitive image forming layer in this embodiment, in addition to (a) a fine particle polymer having a heat-reactive functional group having the image-forming property, or (b) a microcapsule encapsulating a compound having a heat-reactive functional group, Various additives can be used in combination depending on the purpose.
(Reaction initiator, reaction accelerator)
In the heat-sensitive image forming layer, a compound that initiates or accelerates these reactions may be added as necessary. Examples of the compound that initiates or accelerates the reaction include compounds that generate radicals or cations by heat. Specific examples include lophine dimers, trihalomethyl compounds, peroxides, azo compounds, diazonium salts, diphenyliodonium salts, onium salts, acyl phosphines, and imide sulfonates.
These compounds are preferably added in the range of 1 to 20% by mass of the solid content of the image forming layer, and more preferably in the range of 3 to 10% by mass. When it is within the above range, good onset reaction reaction effect or reaction promoting effect can be obtained without impairing on-press developability.

(Hydrophilic resin)
A hydrophilic resin may be added to such a heat-sensitive image forming layer in the present invention. Addition of the hydrophilic resin not only improves the on-press developability, but also improves the film strength of the thermal image forming layer itself.
As the hydrophilic resin, those having a hydrophilic group such as hydroxyl, carboxyl, hydroxyethyl, hydroxypropyl, amino, aminoethyl, aminopropyl, carboxymethyl and the like are preferable.

Specific examples of hydrophilic resins include gum arabic, casein, gelatin, starch derivatives, carboxymethylcellulose and its sodium salt, cellulose acetate, sodium alginate, vinyl acetate-maleic acid copolymers, styrene-maleic acid copolymers, polyacrylic acids and Salts thereof, polymethacrylic acids and salts thereof, homopolymers and copolymers of hydroxyethyl methacrylate, homopolymers and copolymers of hydroxyethyl acrylate, homopolymers and copolymers of hydroxypropyl methacrylate, homopolymers and copolymers of hydroxypropyl acrylate, hydroxybutyl Methacrylate homopolymers and copolymers, hydroxybutyl acrylate homopolymers and copolymers, polyethylene Glycols, hydroxypropylene polymers, polyvinyl alcohols, and hydrolyzed polyvinyl acetate, polyvinyl formal, polyvinyl butyral, polyvinyl pyrrolidone, acrylamide homopolymers and copolymers having a degree of hydrolysis of at least 60% by weight, preferably at least 80% by weight Methacrylamide homopolymers and polymers, N-methylolacrylamide homopolymers and copolymers, and the like.
The addition amount of the hydrophilic resin to the heat-sensitive image forming layer is preferably 5 to 40% by mass, more preferably 10 to 30% by mass, based on the solid content of the image forming layer. Within this range, good on-press developability and film strength can be obtained.

  In order to form an image of such a heat-responsive image forming layer (heat-sensitive image forming layer) by scanning exposure with infrared laser light or the like, (A) an infrared absorber is contained in the image forming layer. A preferable addition amount is preferably 1 to 30% by mass and more preferably 5 to 25% by mass in the total solid content of the image forming layer coating solution. When the content is in the above range, an image forming layer excellent in both sensitivity and image formability is obtained.

  The image forming layer containing the hydrophobizing precursor is coated on the hydrophilic surface of the support by dissolving or dispersing the necessary components in a solvent to prepare a coating solution. The solid content concentration of the coating solution is preferably 1 to 50% by mass.

(Other lithographic printing plate precursors)
The present invention can be preferably used for lithographic printing plate precursors other than infrared laser exposure. Hereinafter, examples of the planographic printing plate precursor and the image forming layer other than the infrared laser exposure will be described in detail.

  Preferable examples of the positive type image forming layer include conventionally known positive type image forming layers [(a) to (b)] shown below.

(A) Conventionally used conventional positive image forming layer comprising naphthoquinonediazide and novolak resin.
(B) A chemically amplified positive image-forming layer comprising a combination of an alkali-soluble compound protected with an acid-decomposable group and an acid generator.

  The above (a) and (b) are well known in the art, but are more preferably used in combination with the following positive type image forming layers ((c) to (f)). It is.

(C) A laser-sensitive positive image-forming layer comprising a sulfonate polymer and an infrared absorber, which can produce a lithographic printing plate that does not require development processing as described in JP-A-10-282672.
(D) Laser sensitivity comprising a carboxylic acid ester polymer and an acid generator or an infrared absorber capable of producing a lithographic printing plate that does not require development processing as described in EP 652483 and JP-A-6-502260. Positive image forming layer.
(E) a laser-sensitive positive type comprising an alkali-soluble compound described in JP-A-11-095421 and a substance that is thermally decomposable and substantially reduces the solubility of the alkali-soluble compound in a state where it is not decomposed. Image forming layer.
(F) An alkali development elution positive image forming layer comprising an infrared absorber, a novolak resin, and a dissolution inhibitor, which can produce an alkali development elution type positive lithographic printing plate.

  On the lithographic printing plate support of the present invention, an image forming layer is formed by dissolving a coating liquid component of the desired layer such as the image recording coating liquid in a solvent and coating it, and a lithographic printing plate precursor is produced. can do. In the lithographic printing plate precursor, in addition to the image forming layer, a protective layer, a resin intermediate layer, an undercoat layer, a backcoat layer, and the like can be formed in the same manner depending on the purpose.

Solvents used here include ethylene dichloride, cyclohexanone, methyl ethyl ketone, methanol, ethanol, propanol, ethylene glycol monomethyl ether, 1-methoxy-2-propanol, 2-methoxyethyl acetate, 1-methoxy-2-propyl acetate, dimethoxy Ethane, methyl lactate, ethyl lactate, N, N-dimethylacetamide, N, N-dimethylformamide, tetramethylurea, N-methylpyrrolidone, dimethyl sulfoxide, sulfolane, γ-butyrolactone, toluene, etc., and water-soluble images In the case of using the formation layer, water or an aqueous solvent such as alcohol can be exemplified, but the present invention is not limited to this, and may be appropriately selected according to the physical properties of the image formation layer. These solvents are used alone or in combination.
The concentration of the above components (total solid content including additives) in the solvent is preferably 1 to 50% by mass.
The coating amount (solid content) on the support obtained after coating and drying varies depending on the use, but generally 0.5 to 5.0 g / m ² is preferable for the photosensitive printing plate. As the coating amount decreases, the apparent sensitivity increases, but the film properties of the photosensitive film deteriorate.
Various methods can be used as the coating method, and examples thereof include bar coater coating, spin coating, spray coating, curtain coating, dip coating, air knife coating, blade coating, and roll coating.

  The lithographic printing plate precursor according to the present invention has excellent adhesion between the support and the image forming layer, and the hydrophilic support surface is quickly exposed by development, thereby improving the anti-printing property of non-image areas. A large number of high-quality printed materials can be obtained even under severe printing conditions.

The lithographic printing plate precursor according to the invention can be obtained by applying a known plate making method according to the image forming layer.
Thereafter, the obtained lithographic printing plate is put on a printing machine and used for printing a large number of sheets.

(Erase processing)
In the lithographic printing plate precursor according to the present invention, when the image forming layer is a positive type that is solubilized by exposure, an unnecessary image portion (for example, an original film) is obtained after the image exposure and development processing. If there is a film edge trace, etc., an unnecessary image portion can be erased.
Specifically, for example, when a part of an original image is erased and an undesired residual film is generated in a non-image area, the erasing process exposes the boundary surface between images in continuous processing. It is used when remaining without being used, and has a great influence on the image quality of the formed image.

  In the lithographic printing plate precursor according to the invention, the intermediate layer containing the specific polymer compound has a structural unit having a relatively high polarity and is excellent in solubility in a polar solvent. Since the erasing liquid used in the erasing process has a highly polar component, the specific polymer compound of the present invention has an excellent affinity for the erasing liquid, and is easily removed by the erasing process, and the non-image area is stained. An excellent image is not formed. That is, when the lithographic printing plate precursor according to the invention has an embodiment having a positive image forming layer, it further has an effect of excellent erasability.

  The erasing process is preferably performed by, for example, applying an erasing solution as described in Japanese Patent Publication No. 2-13293 to an unnecessary image portion, leaving it for a predetermined time, and then washing with water. A method of developing after irradiating an unnecessary image portion with an actinic ray guided by an optical fiber as described in JP-A-59-174842 can also be used.

Hereinafter, the general composition of the erasing liquid used in the erasing process will be described.
In general, the erasing liquid preferably contains an organic solvent for dissolving the image forming layer, an acidic substance for preventing contamination, and a fluorosurfactant. Further, the erasing liquid further contains water, printing ink, a solvent for removing developing ink such as image portion protection, a wetting agent, a viscosity modifier, a colorant, and a surfactant other than the above-mentioned fluorosurfactant as necessary. can do.

Examples of organic solvents for dissolving the image forming layer include lactones such as propiolactone, butyrolactone, valerolactone, and hexanolactone (common names: cyclic intramolecular esters), glycols such as methoxy glycol and ethoxy glycol, and methyl. -Ketones such as isobutyl ketone, ethyl-isobutyl ketone, cyclohexanone, esters such as 2-methoxyethyl acetate, 2-ethoxyethyl acetate, ethyl acetate and butyl acetate, ethers such as diethylene glycol dimethyl ether and diethylene glycol diethyl ether, and other dimethyl Special solvents such as sulfoxide and dimethylformamide can be mentioned.
These organic solvents can be used alone or in combination of two or more, but it is preferable to add 25 to 99.89% by mass with respect to all components of the erasing solution.

Examples of the acidic substance for preventing dirt include fluorine-containing compounds such as phosphoric acid, hydrogen fluoride, and zirconic fluoride, citric acid, and lactic acid. Among these, phosphoric acid and fluorine-containing compounds are preferable, Especially, it is especially preferable to use phosphoric acid from the ease of drainage treatment.
These acidic substances can also be used alone or in combination of two or more. The addition amount is preferably 0.1 to 20% by mass, and in the case of phosphoric acid, 0.5 to 15% by mass is preferable.

  In addition, when 1 to 20% by mass of water is added to the erasing solution, the acidity increases, and the antifouling effect is improved. It has the advantage that it can be erased without being removed in advance with water.

As the fluorosurfactant used in the erasing solution, an anionic or nonionic fluorosurfactant is preferable, but a nonionic fluorosurfactant is particularly preferable. Particularly preferred examples of the nonionic fluorosurfactant include fluoroaliphatic oligomers having a fluoroaliphatic group and a polyoxyalkylene group represented by the following general formula (i) or (ii).
(R _f ) _m Q [(OR) _x Q′A] _n (i)
[(R _f ) _m Q {(OR) _x Q′A ′} _n ] ₂ (ii)
Here, R _f represents a fluoroaliphatic group, Q represents a linking group for covalently bonding R and OR, OR represents a polyoxyalkylene group, A represents a monovalent terminal organic group such as an acyl group, An alkyl group, an aryl group, etc., A ′ represents A or a single bond, provided that at least one R bonded to Q binds to another Q, and Q ′ represents A or A ′ and R , M represents an integer of 2 or more, n represents an integer of 2 or more, and x represents an integer of 5 or more.

The fluorosurfactant used in the erasing solution suitably used in the present invention can be obtained as a commercial product. Specific examples include FC-430, FC-431 (manufactured by 3M), Megafuck F-141, F-142, F-142D, F-143, F-144, F-144D, F-528, F-170, F-171, F-172 F-173, F-177, F-183, F-184 (manufactured by Dainippon Ink & Chemicals, Inc.).
The addition amount of the fluorosurfactant varies depending on the solvent used and other additives, but is preferably 0.01 to 5% by mass, particularly preferably 0.05 to 2% by mass in the total composition of the erasing liquid.

  As a preferred type of wetting agent which is an optional component contained in the erasing solution, water-soluble polyhydric alcohols such as glycerin, glycol and polyglycol are useful. By adding a wetting agent, it is possible to help prevent drying due to evaporation of the organic solvent in the erased portion, or to maintain hydrophilicity until the eraser is removed with water or a developer.

Viscosity modifiers can be used to assist in reducing bleeding of the erasing liquid by reducing the fluidity of the erasing liquid when applying the erasing liquid to the area to be erased, or for applying tools such as brushes when coating. It can be added in order to suppress sagging and improve handling properties. Such a viscosity modifier is preferably one that can be completely removed with running water after treatment, and is preferably a water-soluble resin that is soluble in other erasing liquid components.
Specifically, for example, modified cellulose such as polyvinyl pyrrolidone, polyethylene oxide, carboxymethyl cellulose, methyl cellulose, polyvinyl acetate / maleic anhydride copolymer, polyvinyl methyl ether / maleic anhydride copolymer, etc. A substance having the trade name of Aerosil with fine silicon powder can also be used as a viscosity modifier.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, the scope of the present invention is not limited by these.

[Examples 1 to 10, Comparative Examples 1 to 3]
(Thermal positive lithographic printing plate precursor)
-Fabrication of aluminum substrate-
A molten metal was prepared using an aluminum material of JIS A 1050, and after performing the molten metal treatment and filtration, an ingot having a thickness of 500 mm and a width of 1200 mm was produced by a DC casting method. After the surface was shaved with a chamfering machine with an average thickness of 10 mm, it was kept soaked at 550 ° C. for about 5 hours, and when the temperature dropped to 400 ° C., rolling with a thickness of 2.7 mm using a hot rolling mill A board was used. Furthermore, heat treatment was performed at 500 ° C. using a continuous annealing machine. Subsequently, cold rolling was performed to finish the aluminum sheet AL-1 with a thickness of 0.3 mm and a width of 1060 mm.

<Surface roughening treatment>
Each obtained aluminum plate was subjected to the surface roughening treatment shown below to obtain lithographic printing plate supports P-1 to P-2.
The surface treatment was performed by continuously performing the following treatments (a) to (e) (as described in Table 1).

(A) Mechanical surface roughening treatment using a brush and an abrasive A suspension of pumiston (average particle size 30 μm) having a specific gravity of 1.13 suspended in water is used as a polishing slurry, and one rotating brush is used. Then, mechanical surface roughening was performed at a brush rotational speed of 250 rpm so that Ra after roughening was 0.58 μm.

As the roller-shaped brush, use is made of 6/10 nylon bristles with a bristles length of 50 mm and bristles diameter of 0.295 mm, which are planted so as to be dense by making holes on the surface of a 300 mm diameter stainless steel roller. It was.
As the two supporting rollers under the brush, a stainless steel roller having a diameter of 200 mm was used at a distance of 300 mm between the centers.

  The roller-like brush is pressed with a pressure of 7 kW plus against the load before the brush motor is pressed against the aluminum plate, and the rotation direction on the roughened surface is the conveyance direction of the aluminum web W. It was rotated to be in the same direction.

  The concentration of the abrasive was continuously obtained from the temperature and specific gravity of the abrasive slurry, and mechanical surface roughening was performed while replenishing the slurry recovery tank with water and pumiston so that the concentration was constant. Further, the pumicestone pulverized and refined in the mechanical surface roughening was removed by a classifier in the particle diameter adjusting unit so that the particle size distribution of the pamiston in the abrasive slurry was substantially constant. A cyclone was used as the classifier.

(B) Etching treatment in alkaline aqueous solution An aluminum plate was sprayed with an aqueous solution having a caustic soda concentration of 370 g / L, an aluminum ion concentration of 100 g / L, and a temperature of 60 ° C. to perform an etching treatment. The etching amount of the surface subjected to the electrochemical roughening after the aluminum plate was 3 g / m ² . Thereafter, the liquid is drained with a nip roller, washed with water using a free-falling curtain-like liquid film, and further sprayed with a spray tube having a structure having spray tips spread in a fan shape at intervals of 80 mm. After washing with water for 2 seconds, the liquid was drained with a nip roller.

(C) Electrochemical roughening treatment An electrochemical roughening treatment was carried out by the method described in JP-A-2005-35034, pages 35 (b) to 36 (h).

(D) Anodizing treatment Anodizing treatment was performed using an anodizing apparatus shown in FIG. 4 of JP-A-2005-35034. As the electrolytic solution, an electrolytic solution (temperature 33 ° C.) in which aluminum sulfate was dissolved in a 170 g / L sulfuric acid aqueous solution to make the aluminum ion concentration 5 g / L was used. The anodizing treatment was performed so that the average current density during the anodic reaction of the aluminum plate (about 16 seconds) was 15 A / dm ² , and the final oxide film amount was 2.4 g / m ² . The time for the aluminum plate to participate in the anodic reaction was 16 seconds.
Thereafter, the liquid was drained with a nip roller, washed with water, and further drained with a nip roller.

(E) Silicate treatment The aluminum plate was immersed in a 2.5% by mass aqueous solution of sodium silicate (liquid temperature 20 ° C.) for 10 seconds. Si content of the aluminum plate surface was measured by a fluorescent X-ray analyzer, it was 3.5 mg / ^{m 2.} Thereafter, the liquid was drained with a nip roller, washed with water, and further drained with a nip roller. Furthermore, 90 degreeC wind was blown for 10 seconds and it was made to dry.

-Formation of intermediate layer-
First, the specific polymer compound or comparative compound described in Table 2 below was dissolved in methanol so that the concentration was 0.31% by mass. In addition, about the compound with low solubility to methanol, the mixed solution which mixed N-methylpyrrolidone with methanol was used until the solution of the said density | concentration was prepared.
Next, the prepared solution was applied on an aluminum support described in Table 2 below so that the solid content was 17 mg / m ² and dried by heating at 120 ° C. for 1 minute to form an intermediate layer.
Specific polymer compounds I-2, I-3, I-7, I-8, and I-74 described in Table 2 below show the specific examples described above. Comparative compounds C-1 and C-2 are random copolymer compounds having the following structures.

-Formation of image forming layer-
On the intermediate layer formed as described above, an image forming layer was formed by the following method to obtain positive type lithographic printing plate precursors of Examples 1 to 10 and Comparative Examples 1 to 3.
That is, the following coating solution 1 for image forming layer was applied with a bar coater, dried with PERBECT OVEN PH200 manufactured by TABAI at 130 ° C. for 50 seconds, and the coating amount after drying was 1.3 g / m ² ( Lower layer) was provided. Thereafter, the following coating solution 2 for image forming layer was applied with a bar coater, dried at 130 ° C. for 60 seconds using a TARFAI PERFECT OVEN PH200, and the coating amount after drying was 0.26 / m ^2. Upper layer) was provided.

(Positive type image forming layer coating solution 1)
N- (4-aminosulfonylphenyl) methacrylamide /
Acrylonitrile / methyl methacrylate copolymer 1.9 g
(36/34/30% by mass: weight average molecular weight 50000, acid value 2.65)
・ 0.3 g of m / p cresol novolak
(M / p = 6/4, weight average molecular weight 4500, containing 0.8% by mass of unreacted cresol)
・ Cyanine dye A (the following structure) 0.13g
・ 4,4'-bishydroxyphenylsulfone 0.14g
・ Tetrahydrophthalic anhydride 0.20g
・ 0.008 g of p-toluenesulfonic acid
・ 3-methoxy-4-diazodiphenylamine hexafluorophosphate 0.032 g
・ The counter ion of ethyl violet is 6-hydroxy-2-
0.078 g changed to naphthalene sulfonate ion
・ Fluorine surfactant 0.2g
(Megafac F780, 30% methyl ethyl ketone manufactured by Dainippon Ink & Chemicals, Inc.)
・ Methyl ethyl ketone 16.0g
1-methoxy-2-propanol 8.0g
・ Γ-Butyrolactone 8.0g

(Positive type image forming layer coating solution 2)
・ Phenol / m / p cresol novolak 0.27g
(Phenol / m / p = 5/3/2, mass average molecular weight 5000, unreacted cresol 0.8% by mass)
・ Acrylic resin B (the following structure) 0.042g
・ Cyanine dye A (the above structure) 0.019 g
・ Long chain alkyl group-containing polymer A 0.042 g
・ Sulphonium salt compound C (the following structure) 0.065g
-Ammonium compound D (the following structure) 0.004 g
・ Fluorine surfactant 0.02g
(Megafac F780, 30% methyl ethyl ketone manufactured by Dainippon Ink & Chemicals, Inc.)
・ Fluorosurfactant E (the following structure)
(Methyl ethyl ketone 60%) 0.032 g
・ Methyl ethyl ketone 13.0g
・ 1-methoxy-2-propanol 7.0g

[Synthesis Example: Synthesis of Polymer A Containing Long Chain Alkyl Group]
A 1000 ml three-necked flask equipped with a condenser and a stirrer was charged with 59 g of 1-methoxy-2-propanol and heated to 80 ° C. Under a nitrogen stream, a solution consisting of 42.0 g of n-stearyl methacrylate, 16.0 g of methacrylic acid, 0.714 g of a polymerization initiator V-601 (manufactured by Wako Pure Chemical Industries), and 59 g of 1-methoxy-2-propanol was used for 2 hours. It was dripped over half. Furthermore, it was made to react at 80 degreeC for 2 hours. The reaction mixture was cooled to room temperature and poured into 1000 ml of water. After decantation, the product was washed with methanol, and the obtained liquid product was dried under reduced pressure to obtain 73.5 g of a long-chain alkyl group-containing polymer A shown below. The mass average molecular weight measured by gel permeation chromatography (GPC) using polystyrene as a standard substance was 66,000.

-Evaluation of lithographic printing plate precursors-
The resulting lithographic printing plate precursor was exposed with a TrendSetter 3244VFS manufactured by Creo under the conditions of a drum rotation speed of 150 rpm and a plate surface energy of 100 mJ / cm ² . Then, Fujifilm Corporation's automatic processor LP-940H was loaded with Fujifilm Corporation developer DT-2 (diluted 1: 8) and Fujifilm Corporation Finisher FG-1 (1: 1) and developed with a developer temperature of 32 ° C. and a development time of 12 seconds. The electric conductivity of the developer at this time was 43 mS / cm. The developed lithographic printing plate was printed using a printing machine Lithlon 226 manufactured by Komori Corporation.
The printing durability of the image area, the anti-staining property of the non-image area, and the erasability were evaluated by the following methods. The results are shown in Table 2.

(1) Evaluation of printing durability of image area Using the printing as described above, it was visually evaluated how many sheets could be printed while maintaining a sufficient ink density. The larger this number, the better the printing durability.

(2) Evaluation of stain resistance of non-image area Blanket after printing with DIC-GEOS (s) red ink on a Mitsubishi diamond F2 printing machine (Mitsubishi Heavy Industries, Ltd.) and printing 10,000 sheets Dirt was evaluated visually.
The anti-smudge property was evaluated in four grades: ◎, ○, Δ, and × from the side where the degree of dirt on the blanket was small.
◎: No dirt at all ○: No dirt can be visually confirmed (to the extent that it can be confirmed with a magnifying glass)
Δ: Partially dirty ×: Completely dirty

(3) Evaluation of erasability A part of the image portion of the lithographic printing plate after development was treated with an erasing solution RP-1K manufactured by Fuji Film Co., Ltd., and printed as described above to obtain a non-image portion. The presence or absence of soiling was visually confirmed.
The evaluation was made in four grades, ◎, ○, Δ, and ×, from the direction with less contamination.
◎: No dirt at all ○: No dirt can be visually confirmed (to the extent that it can be confirmed with a magnifying glass)
Δ: Partially dirty ×: Completely dirty

From the results in Table 2, the following can be understood.
The lithographic printing plate precursors of Examples 1 to 4 and 7 to 10 and Comparative Examples 1 and 2 use an aluminum support that has been subjected to a silicate treatment. Among them, the lithographic printing plate precursors of Examples 1 to 4 and 7 to 10 are those in which a specific polymer compound (block copolymer) is used as a polymer compound contained in the intermediate layer. Excellent performance in terms of prevention and erasability, especially in terms of printing durability. In contrast, Comparative Example 1 using Comparative Compound C-1 (Random Copolymer) as the polymer compound contained in the intermediate layer is inferior in terms of printing durability, antifouling properties, and erasability. . Further, Comparative Example 2 using Comparative Compound C-2 (Random Copolymer) as the polymer compound contained in the intermediate layer is inferior in terms of printing durability.

  The lithographic printing plate precursors of Examples 5 to 6 and Comparative Example 3 are those using an aluminum support that was not subjected to silicate treatment. Among them, the lithographic printing plate precursors of Examples 5 to 6 are obtained by using a specific polymer compound (block copolymer) as the polymer compound contained in the intermediate layer, and the comparative compound C-2 (random copolymer). Compared to Comparative Example 3 using a polymer), it is found that the printing durability is excellent and the antifouling property is also good.

  As described above, in the present invention, the properties of the intermediate layer are changed by controlling the precise structure of the polymer, and the lithographic printing is superior in printing durability and stain resistance as compared with the intermediate layer using a conventionally known polymer compound. It can be seen that there is an unexpected effect that the material can be produced.

  Further, as in Examples 6 to 8, when the specific polymer compound in which Z in the general formula (2) is an unsubstituted alkyl group is used for the intermediate layer, both printing durability, antifouling properties and erasability are achieved. Good results could be obtained.

[Example 11, Comparative Example 4]
-Thermal negative lithographic printing plate precursor-
-Formation of intermediate layer-
The specific polymer compounds or comparative compounds described in Table 3 below were dissolved in methanol so that the concentration was 0.31% by mass. Next, the prepared solution was applied on an aluminum support described in Table 3 below so that the solid content was 10 mg / m ² and dried by heating at 120 ° C. for 1 minute to form an intermediate layer.
In addition, the specific polymer compound I-84 described in Table 3 below shows the specific examples described above. Comparative compound C-3 is a random copolymer compound having the following structure.

-Formation of image forming layer-
A negative type image forming layer coating solution having the following composition was prepared, and the coating amount after drying the image forming layer coating solution on the intermediate layer formed as described above (image forming layer coating amount) was 1.3 g / m. ² was applied and dried to form a thermal negative type image forming layer to obtain a thermal negative lithographic printing plate precursor.

<Negative image forming layer coating solution>
Infrared absorber: Cyanine dye A (the above structure) 0.07 g
・ Acid generator [SH-1] (the following structure) 0.3 g
・ Crosslinking agent [KZ-1] (the following structure) 0.5g
・ Alkali-soluble polymer 1.7g
(Marcalinker MS-4P, manufactured by Maruzen Petrochemical Co., Ltd.)
・ Victoria Pure Blue Naphthalenesulfonate 0.035g
(Hokamigaya Chemical Co., Ltd.)
・ Fluorine-based surfactant 0.01g
(Megafuck F-177, manufactured by Dainippon Ink & Chemicals, Inc.)
・ Phthalic anhydride 0.05g
・ Methyl ethyl ketone 12g
・ Methyl alcohol 10g
・ 4g of 1-methoxy-2-propanol
・ 4 g of 3-methoxy-1-propanol

[Exposure and development processing]
The obtained thermal negative lithographic printing plate precursor was exposed with a Trend setter 3244VFS manufactured by Creo equipped with a water-cooled 40 W infrared semiconductor laser under the conditions of an output of 9 W, an outer drum rotation speed of 210 rpm, a plate surface energy of 100 mJ / cm ² , and a resolution of 2400 dpi. . After the exposure, it was heated at 288 ° F. for 75 seconds in an oven manufactured by Wisconsin, and then developed using an automatic developing machine LP940H manufactured by Fuji Photo Film Co., Ltd. The negative type of Example 11 and Comparative Example 4 A lithographic printing plate was obtained. The developer used was 1: 4 water diluted water of DP-4 made by the company, the temperature of the developing bath was 30 ° C., and the 1: 1 water diluted solution of FP-2W made by the company was used as the finisher. The developed lithographic printing plate was printed using a printing machine Lithron manufactured by Komori Corporation.

[Printing and evaluation]
The negative lithographic printing plate obtained above was evaluated for printing durability and antifouling property in the same manner as in Example 1. The results are shown in Table 3.

  From the results of Table 3, even when the image forming layer is replaced with a thermal negative type, a specific polymer compound (block copolymer) is used as the polymer compound contained in the intermediate layer, as in the thermal positive type image forming layer. In Example 11 using), it was confirmed that both the printing durability and the antifouling property were good. On the other hand, Comparative Example 4 using Comparative Compound C-3 (Random Copolymer) was inferior to Example 11 in terms of printing durability and stain resistance.

As described above, the lithographic printing plate precursor according to the invention is excellent in printing durability and antifouling property and can exhibit good printing performance.

Claims (9)

An intermediate layer containing a structural unit represented by the following general formula (1) and a block copolymer containing a structural unit represented by the following general formula (2) on an aluminum support, and an image forming layer A lithographic printing plate precursor characterized by having in order.

[In General Formula (1), R ¹ represents a hydrogen atom, a substituent having 1 to 30 carbon atoms, or a halogen atom. L ¹ represents a single bond or a (n + 1) -valent linking group. Y represents an acidic group or a salt thereof. n represents an integer of 1 to 6. ]

[In General Formula (2), R ² represents a hydrogen atom, a substituent having 1 to 30 carbon atoms, or a halogen atom. L ² represents a single bond or a divalent linking group. Z represents a substituent having 0 to 30 carbon atoms. However, the general formula (2) does not contain an acidic group. ] _2. The lithographic printing according to claim 1, wherein Y in the general formula (1) is a CO ₂ H group, a phosphonic acid group, a phosphoric acid group, a sulfonic acid group, a phenolic hydroxyl group, or a salt thereof. Version original edition.   The lithographic printing plate precursor as claimed in claim 1 or 2, wherein Z in the general formula (2) is an onium group.   The lithographic printing plate precursor as claimed in claim 1 or 2, wherein Z in the general formula (2) is an alkyl group.   The content of the structural unit represented by the general formula (1) is 15 to 95 mol%, and the content of the structural unit represented by the general formula (2) is 5 to 85 mol%. The lithographic printing plate precursor as claimed in any one of claims 1 to 4, wherein:   The content of the structural unit represented by the general formula (1) is 30 to 80 mol%, and the content of the structural unit represented by the general formula (2) is 20 to 70 mol%. The lithographic printing plate precursor as claimed in any one of claims 1 to 5, wherein:   The lithographic printing plate precursor as claimed in any one of claims 1 to 6, wherein the image forming layer is recordable with an infrared laser.   The lithographic printing plate precursor as claimed in any one of claims 1 to 7, wherein the image forming layer contains an infrared absorber.   The lithographic printing plate precursor as claimed in any one of claims 1 to 8, wherein the image forming layer has a laminate structure of two or more layers.