JP2009262523A - Original plate of lithographic printing plate and plate-making method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an original plate of a lithographic printing plate, onto which an image can be recorded by laser, in which a dotty stain is suppressed, which can maintains excellent level both in plate wear and in storage stability. <P>SOLUTION: In the original plate of the lithographic printing plate having at least a polymerizable image recording layer on an aluminum support with an anodically oxidized film thereon, the average diameter of micropores of the anodically oxidized film is set to be ≥30 nm and ≤200 nm and, at the same time, the total sum of halide ions included in all the layers provided on the support is set to be ≤5 μmol/m<SP>2</SP>under the preferable condition that the image recording layer includes (A) sensitizing coloring matter, (B) polymerization initiator and (C) a polymerizable compound. As the plate-making method of the original plate of the lithographic printing plate, on press development or gum development is preferable. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a lithographic printing plate precursor. More specifically, the present invention relates to a lithographic printing plate precursor capable of image recording with a laser and capable of on-press development or gum development.

In general, a lithographic printing plate precursor comprises an oleophilic image portion that receives ink in the printing process and a hydrophilic non-image portion that receives dampening water. Lithographic printing utilizes the property that water and oil-based inks repel each other, so that the oleophilic image area of the lithographic printing plate is the ink receiving area and the hydrophilic non-image area is dampened with the water receiving area (ink non-receiving area). As described above, a difference in ink adhesion is caused on the surface of a lithographic printing plate, and after ink is applied only to an image portion, the ink is transferred to a printing medium such as paper and printed.
In order to produce this lithographic printing plate, conventionally, a lithographic printing plate precursor (PS plate) in which an oleophilic photosensitive resin layer (image recording layer) is provided on a hydrophilic support has been widely used. Usually, after exposing the lithographic printing plate precursor through an original image such as a lithographic film, the image recording layer to be an image portion is left, and the other unnecessary image recording layer is removed with an alkaline developer or an organic solvent. Plate making is performed by a method of exposing the surface of the hydrophilic support by dissolving and removing to obtain a lithographic printing plate precursor.

  In the conventional plate making process of a lithographic printing plate precursor, after exposure, a step of dissolving and removing unnecessary image recording layers with a developer or the like is necessary, but such additional wet processing is made unnecessary or Simplification is cited as one of the issues. In particular, in recent years, disposal of waste liquids discharged with wet processing has become a major concern for the entire industry due to consideration for the global environment, and therefore, the demand for solving the above-mentioned problems has become stronger.

On the other hand, as one simple plate-making method, an image recording layer that can remove the image recording layer of a lithographic printing plate precursor in a normal printing process is used. A method called on-press development has been proposed in which an image recording layer corresponding to a portion is removed to obtain a lithographic printing plate.
As a specific method for on-press development, for example, a method using a lithographic printing plate precursor having an image recording layer that can be dissolved or dispersed in a dampening water, an ink solvent, or an emulsion of a dampening water and an ink. , A method of mechanically removing the image recording layer by contact with rollers or a blanket cylinder of a printing press, cohesion of the image recording layer by penetration of dampening water, ink solvent, etc., or between the image recording layer and the support. There is a method in which the image recording layer is mechanically removed by weakening the adhesive force and then contacting with rollers or a blanket cylinder.
Further, as another simple plate-making method, the removal of the unnecessary portion of the image recording layer in the development processing step is replaced with a conventional highly alkaline developer, and a finishing gum conventionally applied after alkali development. A method called gum development performed with a solution has also been proposed.
In the present invention, unless otherwise specified, the “development process step” means using a device other than a printing press (usually an automatic developing machine) and contacting a liquid (usually an alkaline developer). Refers to the step of removing the infrared laser unexposed portion of the lithographic printing plate precursor to expose the surface of the hydrophilic support, and “on-press development” refers to a liquid (usually printing ink and / or Or a dampening solution) to remove the infrared laser unexposed portion of the lithographic printing plate precursor and expose the surface of the hydrophilic support.
Of the processes through the “development process step”, development using a gum solution as a developer is particularly referred to as “gum development”.

On the other hand, in recent years, digitization techniques for electronically processing, storing, and outputting image information by a computer have become widespread, and various new image output methods corresponding to such digitization techniques are put into practical use. It is becoming. Along with this, digitized image information is carried by high-convergence radiation such as laser light, and the lithographic printing plate precursor is scanned and exposed with that light, directly without using a lithographic film. Computer-to-plate (CTP) technology has been attracting attention. Therefore, obtaining a lithographic printing plate precursor adapted to such a technique is one of the important technical issues.
As described above, in recent years, the simplification, drying, and no processing of plate making operations have become more desirable than ever in terms of both consideration for the global environment and adaptation to digitalization. It is coming.

  As a lithographic printing plate precursor adapted to the above-mentioned demand, an on-press development type lithographic printing plate precursor having a photo- or heat-polymerizable image recording layer is used. In these lithographic printing plate precursors, unexposed areas are completely removed because mild areas such as on-machine development using printing ink or fountain solution or gum development are removed without using an alkaline developer. In some cases, a fine image recording layer remained without being completely removed. The remaining of the minute image recording layer results in the occurrence of minute dot-like stains on the printed matter, which is a serious problem in practical use. This improvement is one of the important technical issues.

  The surface of an aluminum support used for a lithographic printing plate (hereinafter also simply referred to as a “lithographic printing plate support”) has excellent hydrophilicity and water retention because it is used to carry a non-image area. Various contradictory performances are required, such as excellent adhesion to the image recording layer formed thereon. If the surface of the lithographic printing plate support is too low in hydrophilicity, ink will adhere to the non-image area during printing, and stains on the blanket cylinder, and so-called background stains, will occur. That is, the stain resistance is deteriorated. Also, if the surface water retention is too low, there will be inconveniences such as the occurrence of clogging in the shadow area unless the amount of water shown during printing is increased. On the other hand, if the adhesiveness with the image recording layer is too low, the image recording layer is easily peeled off, and the durability (printing durability) is deteriorated when the number of printed sheets is large.

Therefore, in order to improve various performances such as stain resistance and printing durability, for example, a method of forming an anodized film by anodizing a roughened aluminum plate has been proposed. (See Patent Document 1).
Here, the invention described in the above-mentioned patent document 1 supports the lithographic printing plate by an anchor effect that is manifested by increasing the opening diameter of the micropores, increasing the number thereof, and slightly incorporating the image recording layer into the micropores. The aim is to improve the adhesion between the body surface and the image recording layer.
However, when such an anchor effect is used, although the printing durability is improved, the image recording layer is difficult to remove from the micropores even in the non-exposed area. The recording layer may remain, particularly when the lithographic printing plate precursor is stored for a long period of time under high temperature and high humidity conditions, the above-mentioned fine spot-like stains are likely to occur, and the stain resistance of the product may deteriorate. there were.

In order to improve this problem, for example, the addition of a compound having a development promoting action has been proposed. (For example, refer to Patent Document 2) Although this technology can suppress the remaining of a minute image recording layer to some extent by improving developability, the performance when stored for a long time under high temperature and high humidity conditions is Depending on the conditions, there were cases where it was insufficient. Increasing the amount of the compound having a development promoting action improves the effect of suppressing the remaining of the minute image recording layer, but there is a problem that the printing durability is lowered. As described above, in reality, it is still insufficient to maintain both the printing durability and the storage stability at an excellent level with respect to the problem of suppressing the remaining of the minute image recording layer. It was desired.
JP 2000-263959 A JP 2001-171250 A

  An object of the present invention is to provide both printing durability and storability with respect to the problem of remaining a fine image recording layer in a lithographic printing plate precursor having at least an image recording layer on an aluminum support having an anodized film. It is an object of the present invention to provide a new lithographic printing plate precursor that can be maintained at an excellent level, and a plate making method using the same.

As a result of intensive studies to achieve the above object, the present inventors have conducted an anodic oxidation treatment with an aqueous solution containing phosphoric acid in a lithographic printing plate precursor having at least an image recording layer on an aluminum support having an anodized film. by controlling the total of halide ions contained in each layer on the decorated aluminum support 0μmol / m ² or more 5 [mu] mol / m ² or less, with respect to a problem that the residual inhibition of the image recording layer of the small, printing durability The present invention has been completed by finding that a lithographic printing plate precursor capable of maintaining both excellent storage stability and storability can be obtained. That is, the present invention is as follows.

1. A lithographic printing plate precursor having at least a polymerizable image recording layer on an aluminum support having an anodized film, all of which is provided on an aluminum support that has been anodized with an aqueous solution containing phosphoric acid A lithographic printing plate precursor wherein the total of halide ions contained in the layer is 5 μmol / m ² or less.
2. 2. The lithographic printing plate precursor as described in 1 above, wherein the average diameter of micropores of the anodized film on the aluminum support is from 30 nm to 200 nm.
3. The lithographic printing plate precursor as described in 1 or 2 above, wherein the image recording layer contains (A) a sensitizing dye, (B) a polymerization initiator, and (C) a polymerizable compound.
4). The lithographic printing plate precursor as described in any one of 1 to 3 above, wherein the image recording layer further contains a binder polymer. 5. The lithographic printing plate precursor as described in any one of 1 to 4 above, wherein the (A) sensitizing dye is an infrared absorber.
6). The lithographic printing plate precursor as described in any one of 1 to 5 above, wherein the image recording layer can be removed with printing ink and / or fountain solution or with a gum solution.
7). The lithographic printing plate precursor according to any one of 1 to 6 above, is image-exposed with an infrared laser and then attached to a printing press, or image-exposed with an infrared laser after being attached to a printing press, and printing ink and fountain solution Is subjected to on-press development processing, and printing is performed.
8). A step of imagewise exposing the lithographic printing plate precursor according to any one of 1 to 6 above, and a development for removing an unexposed portion of the lithographic printing plate precursor by developing the exposed lithographic printing plate precursor with a gum solution And a process for making a lithographic printing plate precursor.

  In the present invention, by keeping the total of halide ions contained in each layer on the aluminum support that has been anodized with an aqueous solution containing phosphoric acid within the above range, the remaining of the minute image recording layer is suppressed. The problem of maintaining both printing durability and storage stability at an excellent level was achieved. The details of this mechanism of action are not clear, but the following is presumed to be one of the factors.

  When halide ions are present above a certain amount on a lithographic printing plate precursor, the halide ions generally accelerate the corrosion of the metal, so that corrosion of the substrate becomes prominent at high temperatures and high humidity. The surface state of the substrate may change, such as pitting corrosion. When such a change occurs, the image recording layer is more likely to remain than immediately after manufacture, and is detected as a stain during printing. In the lithographic printing plate precursor for on-press development or gum development, which is a preferred embodiment of the present invention, since an alkali developer is not used, the removability of the non-exposed image recording layer is higher than that of a conventional lithographic printing plate precursor. Therefore, the influence of such a change with time tends to be particularly remarkable. In the present invention, it is presumed that by controlling the amount of halide ions contained in each layer on the support, the progress of such deterioration is delayed, and as a result, the remaining of the minute image recording layer can be suppressed. Is done. Further, in the present invention, the above-described effect of suppressing the remaining of the minute image recording layer under high temperature and high humidity conditions by reducing the amount of halide ions is that the average diameter of the micropores in the anodized film is In the case of being in a specific range defined in the invention, it is remarkably improved. Furthermore, surprisingly, by using an aluminum support that has been anodized with an aqueous solution containing phosphoric acid, it is possible to further suppress the remaining of a minute image recording layer. The inventor found a surprising effect that could not be expected from conventional knowledge, and completed the present invention.

  According to the present invention, it is possible to obtain a lithographic printing plate precursor capable of suppressing spot-like stains due to the remaining of the minute image recording layer and maintaining both excellent storability.

[Lithographic printing plate precursor]
The lithographic printing plate precursor of the present invention, controls the total halide ions contained in each layer on the aluminum support having been subjected to anodic oxidation treatment with an aqueous solution containing phosphoric acid 0μmol / m ² or more 5 [mu] mol / m ² or less It is characterized by doing.
Hereinafter, the present invention will be described in detail.

[Aluminum support]
The aluminum support used in the present invention is characterized by having an anodized film that has been anodized with an aqueous solution containing phosphoric acid.
The aluminum plate as the most preferable support in the present invention is a metal plate mainly composed of dimensionally stable aluminum, and contains pure aluminum plate, aluminum as a main component, and a trace amount of foreign elements. An alloy plate or a plastic film or paper on which aluminum (alloy) is laminated or deposited is selected. In the following description, the above-mentioned support made of aluminum or aluminum alloy is used generically as an aluminum support. Examples of the foreign element contained in the aluminum alloy include silicon, iron, manganese, copper, magnesium, chromium, zinc, bismuth, nickel, and titanium. The content of the foreign element in the alloy is 10% by mass or less. In the present invention, a pure aluminum plate is suitable, but completely pure aluminum is difficult to manufacture in terms of refining technology, and therefore may contain a slightly different element. Thus, the composition of the aluminum plate applied to the present invention is not specified, and it is a conventionally known material such as JIS A 1050, JIS A 1100, JIS A 3103, JIS A 3005, etc. Can be used as appropriate.
Moreover, the thickness of the aluminum support body used for this invention is about 0.1 mm-about 0.6 mm. This thickness can be appropriately changed according to the size of the printing press, the size of the printing plate, and the user's desire. Such an aluminum support is subjected to a support surface treatment described below.

(Mechanical roughening)
As the mechanical roughening treatment, the surface of the aluminum support is mechanically roughened by a slurry liquid containing a rotating nylon brush roll having a desired bristle diameter and an abrasive supplied to the support surface. be able to. Although a well-known thing can be used as an abrasive | polishing agent, quartz sand, quartz, aluminum hydroxide, or a mixture thereof is preferable. This processing method is described in detail in JP-A-6-135175 and JP-B-50-40047. In addition to this, a method of spraying a slurry liquid, a method using a wire brush, a method of transferring the surface shape of an uneven rolling roll to the surface of a metal substrate, and the like may be used. Among these, as a method for transferring the surface shape, for example, the method described in paragraph [0004] of JP-A-7-205565 can be used. These mechanical surface roughening treatments can be used alone or in combination. The centerline average roughness Ra after the mechanical surface roughening treatment is preferably controlled in the range of 0.1 to 1 μm.
In addition, in the case of performing an electropolishing process or a chemical etching process after the mechanical surface roughening, in the case of performing an electrochemical surface roughening process, the surface roughening state changes. The center line average roughness Ra is preferably controlled in consideration of the change.

(Electropolishing treatment in acidic aqueous solution or chemical etching treatment in acid or alkaline aqueous solution)
This is performed for the purpose of obtaining a printing plate with good soiling performance by dissolving the uneven edge portion generated by the above-mentioned mechanical roughening to obtain a surface having smooth waviness. The dissolution amount of the metal substrate at this time is preferably 3 to ²⁰ g / m ² .
The etching method may be immersion, or may be sprayed with an etching solution. Etching agents suitably used are caustic soda, sodium carbonate, sodium aluminate, sodium metasilicate, sodium phosphate, potassium hydroxide, lithium hydroxide, and the like. Preferred ranges of concentration and temperature are 1 to 50% and 20%, respectively. ~ 100 ° C.
After the electropolishing or chemical etching process is completed, do not bring the treatment liquid into the next process, and remove the liquid with a nip roller and clean it with a spray to remove the dirt (smut) remaining on the surface. Preferably it is done. For cleaning by spraying, acids such as nitric acid, sulfuric acid, phosphoric acid, chromic acid, hydrofluoric acid, and borohydrofluoric acid are used.

(Electrochemical roughening treatment using direct current or alternating current in an aqueous solution mainly composed of nitric acid or hydrochloric acid)
It is carried out for the purpose of generating a crater or honeycomb-shaped bit having an average diameter of about 0.5 to 20 μm on the surface of the metal substrate at an area ratio of 30 to 100%. Such a process has the effect of improving the printing durability and resistance to stains on the non-image area of the printing plate.
The anode time electricity suitable for this method is in the range of ^{50C / dm 2 ~400C / dm 2} . More specifically, in the electrolytic solution containing from 0.1 to 50% by weight hydrochloric acid or nitric acid, the temperature 20 to 80 ° C., for 1 second to 30 minutes, at a current density of 100C / dm ² ~400C / dm ² It is preferable to perform alternating current and / or direct current electrolysis. In the electrochemical surface roughening treatment, the center line average roughness Ra of the support surface can also be controlled by adjusting the amount of electricity used.

(Electropolishing treatment in acidic aqueous solution or chemical etching treatment in acid or alkali aqueous solution)
This is performed for the purpose of removing the smut component generated by the above-described electrochemical surface roughening and smoothing the edge portion of the generated bit to improve the stain performance when the printing plate is formed. Preferably, a method of contacting with 15 to 65% by mass of sulfuric acid at a temperature of 50 to 90 ° C. as described in JP-A-53-12739, and JP-B-48-28123. The method of carrying out the alkali etching is mentioned. The dissolution amount of the support is preferably in the range of 0.05-5 g / m ^2, and more preferably in the range of 0.1 to 3 g / m ^2.

  The lithographic printing plate precursor according to the invention is characterized in that the following anodizing treatment is performed.

(Anodizing treatment)
In the present invention, an electrolytic bath mainly composed of phosphoric acid is used. The anodizing treatment using the electrolytic bath mainly composed of phosphoric acid may contain sulfuric acid, phosphoric acid, oxalic acid or boric acid / sodium borate. In this case, the electrolyte solution may of course contain at least components normally contained in at least an Al alloy plate, an electrode, tap water, groundwater, and the like. Further, the second and third components may be added. Examples of the second and third components herein include metal ions such as Na, K, Mg, Li, Ca, Ti, Al, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn, and ammonium. Examples of the ions include cations, nitrate ions, carbonate ions, chloride ions, phosphate ions, fluorine ions, sulfite ions, titanate ions, silicate ions, borate ions, and the like, and the concentration is 0 to About 10,000 ppm is preferable.
The conditions for the anodizing treatment are not particularly limited, but the concentration of the treatment liquid is preferably 30 to 500 g / liter, more preferably 50 to 300 g / liter, and the treatment liquid temperature is 10 to 70 ° C., preferably 25 to 25 ° C. At 40 ° C., the current density is 0.1 to 40 A / m ² , preferably 5 to 10 A / m ² , and the treatment time is 2 to 300 seconds, more preferably 5 to 60 seconds, by direct current or alternating current electrolysis. It is processed. The amount of the anodized film formed is preferably in the range of 0.5 to 5.0 g / m ² , more preferably in the range of 1.0 to 2.5 g / m ² , and particularly preferably 1. The range is ^{2 to} 1.8 g / m ² .
The pore diameter of the micropore formed on the anodized film is determined by the above processing conditions. In the present invention, the pore diameter of the micropore is preferably 30 nm to 200 nm, more preferably 40 nm to 150 nm. Hereinafter, the treatment conditions are particularly preferably selected so as to fall within the range of 50 nm to 100 nm. When the pore diameter of the micropore is 200 nm or less, the printing ink does not adhere to the portion corresponding to the non-image portion of the blanket during printing, and the non-image portion is not stained at all. A printed matter can be obtained. When the pore diameter of the micropore is 30 nm or more, sufficient printing durability is exhibited.

As the hydrophilization treatment of the support surface, widely known methods can be applied. As a particularly preferable treatment, a hydrophilic treatment with silicate or polyvinylphosphonic acid is performed. The film is formed with a Si or P element amount of ^{2 to} 40 mg / m ² , more preferably 4 to 30 mg / m ² . The coating amount can be measured by fluorescent X-ray analysis.

  The hydrophilization treatment is carried out by applying an anodized film to an aqueous solution containing 1 to 30% by weight, preferably 2 to 15% by weight of alkali metal silicate or polyvinylphosphonic acid, and having a pH of 10 to 13 at 25 ° C. This is carried out by immersing the aluminum support on which is formed, for example, at 15 to 80 ° C. for 0.5 to 120 seconds.

  As the alkali metal silicate used for the hydrophilization treatment, sodium silicate, potassium silicate, lithium silicate, or the like is used. Examples of the hydroxide used for increasing the pH of the aqueous alkali metal silicate solution include sodium hydroxide, potassium hydroxide, and lithium hydroxide. In addition, you may mix | blend alkaline-earth metal salt or Group IVB metal salt with said process liquid. Alkaline earth metal salts include nitrates such as calcium nitrate, strontium nitrate, magnesium nitrate, and barium nitrate, and water-soluble substances such as sulfate, hydrochloride, phosphate, acetate, oxalate, and borate. Salt. 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.

  Alkaline earth metal salts or Group IVB metal salts can be used alone or in combination of two or more. A preferable range of these metal salts is 0.01 to 10% by mass, and a more preferable range is 0.05 to 5.0% by mass. Silicate electrodeposition as described in US Pat. No. 3,658,662 is also effective. A surface obtained by combining a support subjected to electrolytic grain as disclosed in JP-B-46-27481, JP-A-52-58602, and JP-A-52-30503 with the above-described anodizing treatment and hydrophilization treatment. Processing is also useful.

[Halide ion]
The lithographic printing plate precursor according to the invention has, as an essential component, at least an image recording layer on a support and, if necessary, any other layer (for example, an undercoat layer, a protective layer, etc.) other than the image recording layer. The total of halide ions contained in each layer on the support is 0 to 5.0 μmol / m ² .

Here, the total of halide ions contained in each layer on the support means fluoride ions (F ⁻ ), chloride ions (Cl ⁻ ), bromide ions (Br ⁻ ) contained in all layers on the support. ), And the total number of moles of iodide ion (I ⁻ ).
The total halide ions contained in each layer on the support, preferably 0 to 4.0μmol / ^{m 2,} more preferably 0 to 3 [mu] mol / ^{m 2,} particularly preferably 0 to 2.0μmol / ^{m 2.}

  As a method for setting the halide ion concentration within the above range, (1) a compound having a structure not containing halide ions is used, and (2) each compound or a solvent for preparation is contained as an impurity or counter ion. Examples thereof include reducing the halide ions as much as possible and (3) sufficiently washing the halide ions attached to the substrate surface.

More specifically, the method (1) includes a binder polymer, a sensitizing dye, a polymerization initiator, a sensitizer, a development accelerator, a polymerizable compound, an undercoat compound, a surfactant, a colorant, and a protective layer binder. With regard to additives such as layered compounds, low molecular weight hydrophilic compounds, and specific compounds of the present invention, halide ions can be eliminated, for example, by the following method.
When a halide ion is included as a counter ion, a counter ion other than the halide ion is used in advance, or after producing a compound having a halide ion as a counter ion once, by a method such as salt exchange or ion exchange, Substitution can be made with ions other than halide ions. Alternatively, ionic type compounds such as onium type (ammonium, sulfonium, azinium, iodonium, phosphonium) (for example, polymerization initiator, sensitizing dye, sensitizer, low molecular weight hydrophilic compound having a salt structure (development accelerator) , Etc.) may be used instead of nonionic alternative compounds.

More specifically, in the method (2), when halide ions are contained as impurities, by-products, or catalyst residues during production, recrystallization, reprecipitation, ion exchange, salt exchange, Removal methods such as ion exchange, dialysis, reverse osmosis, column chromatography, size exclusion chromatography, adsorption (silica gel, alumina, zeolite, hydrotalcite, other adsorbents), washing, sublimation, distillation, etc. Besides being preferably used, it is also effective to reduce the amount of halide ions resulting from the solvent, raw materials, equipment, etc. during the reaction.
A method of precipitating halide ions as a hardly soluble salt by a method such as adding a silver nitrate solution and removing it is also preferably used.

The concentration of halide ions in the present invention can be measured by a conventionally known method. Specifically, for example, the purpose is to use a measurement method such as a method of quantifying by ion chromatography or a method of titrating with an aqueous silver nitrate solution. It may be selected by.
When the halide ion concentration detected by such a measurement method is in the above range, the lithographic printing plate precursor according to the invention is used. Moreover, the lithographic printing plate precursor according to the present invention has a plurality of layers coated on a support, and the halide ion concentration as a whole of the plurality of layers needs to be in the above range.
Measurement of the halide ion concentration of the individual material and the whole layer can be performed as follows.

(Measurement method of halide ion concentration)
(1) Preparation of halide ion measurement sample in material (for example, ionic surfactant and binder polymer) A sample of 3.0 g was placed in a 100 ml beaker, 60 ml of solvent was added, and then ultrasonic waves were applied for 30 minutes. The solvent is selected from ion-exchanged water or a mixed solvent obtained by adding an organic solvent such as methanol, MFG (2-methoxy-1-propanol) or the like to ion-exchanged water so that the sample is completely dissolved.
(2) Preparation of halide ion measurement samples from all layers on the lithographic printing plate precursor substrate After immersing 1500 m ^{2 of the} lithographic printing plate precursor in 1 L of methanol to elute halide ions from each layer on the substrate, the pressure was reduced. The solvent was removed with, and 8 ml of ion exchange water was further added, followed by irradiation with ultrasonic waves for 30 minutes.
After passing through the ODS pretreatment disk, ion exchange water was added to make the total volume 10 ml.
(3) Ion Chromatography Samples prepared by the methods described in (1) and (2) above were prepared using a Tosoh LC-8020 ion chromatography device (column: IC-Anion-PW manufactured by Tosoh, moving layer: anion standard manufactured by Tosoh). The eluent, temperature: 35 ° C., flow rate: 1.2 ml / min) was used to quantify halide ions. The sample extracted from the lithographic printing plate precursor was converted per 1 m ² .

  By making the total of halide ions in each layer coated on the specific aluminum support of the present invention within the above range, excellent printing durability, and even when stored under high-sound and high-humidity conditions, contamination occurs. A lithographic printing plate precursor excellent in stability over time is obtained.

[Specific acid compound]
In the present invention, at least one of the undercoat layer and the image recording layer may contain a compound represented by the following general formula (1) (hereinafter also referred to as a specific acid compound).

In the formula, X is an aliphatic or aromatic hydrocarbon containing 1 to 30 carbon atoms, an aliphatic amine containing 1 to 30 carbon atoms and 1 to 8 nitrogen atoms, 1 to 30 carbon atoms and an oxygen atom. It represents an n-valent group obtained by removing n hydrogen atoms from a compound selected from aliphatic ethers of 1 to 10 and heterocyclic compounds containing 1 to 30 carbon atoms. The group represented by X may further have a substituent. Y represents —COOM, —OP═O (OM) ₂ , or —P═O (OM) ₂ , and M represents a hydrogen atom or a counter cation. n represents an integer of 1 to 20.

When X represents a group derived from an aliphatic hydrocarbon, the number of carbon atoms is more preferably from 1 to 20, and particularly preferably from 1 to 16.
Preferred examples of the aliphatic hydrocarbon include methane, ethane, propane, butane, pentane, hexane, cyclohexane, octane, 2-ethylhexane, decane, dodecane, tetradecane, hexadecane, octadecane, ethylene, propylene, and 2-methylpropylene. Acetylene, methylacetylene and the like.

When X represents a group derived from an aromatic hydrocarbon, the number of carbon atoms is preferably 6-20, more preferably 6-18, and particularly preferably 6-12.
Preferable examples of the aromatic hydrocarbon include benzene and naphthalene. Among them, preferred X is a phenyl group or a naphthyl group.

When X represents a group from an aliphatic amine containing 1 to 30 carbon atoms and 1 to 8 nitrogen atoms, the number of carbon atoms is more preferably 1 to 20 and 1 to 5 nitrogen atoms.
Preferred examples of the aliphatic amine include methylamine, ethylamine, propylamine, dimethylamine, diethylamine, dipropylamine, N, N-dimethylethylamine, N, N-dimethylpropylamine, trimethylamine, triethylamine, 1,2-bis. (Dimethylamino) cyclohexane, N, N, N ′, N′-tetramethylethylenediamine, N, N-bis (2-dimethylaminoethyl) methylamine, N, N, N ′, N′-tetramethyl-1, 2-diaminopropane, N, N, N ′, N′-tetramethyl-1,3-diaminopropane, N, N, N ′, N′-tetramethyl-1,6-hexamethylenediamine, N, N ′ -Bis (2-dimethylaminoethyl) -N, N'-dimethylethylenediamine, 1,2-bis [(2-dimethylaminoethyl) oxy] ethylene, and the like.
Among them, preferred X is a residue obtained by removing one hydrogen atom from each methyl group in the amine molecule.

When X represents a group derived from an aliphatic ether having 1 to 30 carbon atoms and 1 to 10 oxygen atoms, the aliphatic ether is preferably a compound having an oxyethylene group. Preferred examples of such ether include alkyl methyl ether or alkyl ethyl ether of ethylene glycol or polyethylene glycol, saturated or unsaturated fatty acid ester of polyethylene glycol monoalkyl ether, and the like.
Among them, preferred X is a monovalent group obtained by removing one hydrogen atom from the methyl group or ethyl group of the above alkyl methyl ether or alkyl ethyl ether.

When X represents a group (heterocyclic group) from a heterocyclic compound, it is preferably a 3- to 8-membered ring, more preferably a 3- to 6-membered ring, and particularly preferably a 5- to 6-membered ring. preferable. Moreover, as a kind of hetero atom which comprises a heterocyclic ring, it is preferable that a nitrogen atom, an oxygen atom, or a sulfur atom is included.
Examples of preferred heterocyclic groups include pyrrolinyl, furanyl, thiophenyl, benzopyrrolinyl, benzofuranyl, benzothiophenyl, pyrazolinyl, isoxazolinyl, isothiazolinyl, indazolinyl, benzisoxazolinyl, benzisothiazolinyl, imidazolinyl, oxazolinyl, thiazolinyl , Benzimidazolinyl, benzoxazolinyl, benzothiazolinyl, pyridinyl, quinolinyl, isoquinolinyl, pyridazinyl, pyrimidinyl, pyrazinyl, phthalazinyl, quinazolinyl, quinoxalinyl, acylidinyl, phenanthridinyl, carbazolinyl, purinyl, pyranidinyl, pyranyl, piperidinyl , Morpholinyl, indolinyl, indolizinyl, cinnolinyl, acridinyl, phenothiazinyl, tetrazo Cycloalkenyl, triazinyl, and the like.

The group represented by X can further have one or more substituents.
Examples of substituents include carboxylic acid ester groups (for example, carboxylic acid alkyl ester groups such as methoxycarbonyl, ethoxycarbonyl, propyloxycarbonyl, isopropyloxycarbonyl, butyloxycarbonyl, hexyloxycarbonyl, octyloxycarbonyl, cyclohexyloxy Phenoxy as carboxylic acid aryl ester groups such as carbonyl, 2-ethylhexyloxycarbonyl, benzyloxycarbonyl, 2-hydroxyethoxycarbonyl, 2-methoxyethoxycarbonyl, alkoxypoly (ethyleneoxy) carbonyl, acylaminopoly (ethyleneoxy) carbonyl, etc. Carbonyl), linear, branched or cyclic alkyl groups (methyl, ethyl, propyl, isopropyl, butyl, hexyl) Cyclohexyl, octyl, dodecyl, etc.), aryl groups (eg, phenyl), alkynyl groups, heterocyclic groups, halogen atoms (—F, —Br, —Cl, —I, etc.), hydroxy groups, alkoxy groups, aryloxy groups, mercapto groups , Alkylthio group, arylthio group, alkyldithio group, aryldithio group, sulfo group, sulfonate group,

Amino group, N-alkylamino group, N, N-diarylamino group, N-alkyl-N-arylamino group, carbamoyloxy group, Ν-alkylcarbamoyloxy group, N-arylcarbamoyloxy group, N, N-dialkyl Carbamoyloxy group, N, N-diarylcarbamoyloxy group, N-alkyl-N-arylcarbamoyloxy group, alkylsulfoxy group, arylsulfoxy group, acylthio group, acylamino group, N-alkylacylamino group, N-aryl Acylamino group, ureido group, N′-alkylureido group, N ′, N′-dialkylureido group, N′-arylureido group, N ′, N′-diarylureido group, N′-alkyl-N′-aryl Ureido group, N-alkylureido group, N-arylureido group, '-Alkyl-N-alkylureido group, N'-alkyl-N-arylureido group, N', N'-dialkyl-N-alkylureido group, N ', N'-dialkyl-N-arylureido group, N′-aryl-Ν-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, 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, alkoxysulfonyl group, aryloxysulfonyl group, sulfinamoyl group, N-alkylsulfinamoyl group, N, N-dialkylsulfinamoyl group, N-arylsulfinamoy Group, N, N-diarylsulfinamoyl group, N-alkyl-N-arylsulfinamoyl group, sulfamoyl group, N-alkylsulfamoyl group, N, N-dialkylsulfamoyl group, N-arylsulfa A moyl group, an N, N-diarylsulfamoyl group, an N-alkyl-N-arylsulfamoyl group,

Dialkyl phosphono group (—PO ₃ (alkyl) ₂ ), diaryl phosphono group (—PO ₃ (aryl) ₂ ), alkylaryl phosphono group (—PO ₃ (alkyl) (aryl)), monoalkyl phosphono group (—PO ₃ H (alkyl)) and its conjugate base group (hereinafter referred to as alkylphosphonate group), monoarylphosphono group (—PO ₃ H (aryl)) and its conjugate base group (hereinafter referred to as arylphosphonate) Group), phosphonooxy group (—OPO ₃ H ₂ ) and its conjugate base group (hereinafter referred to as phosphonatooxy group), dialkyl phosphonooxy group (—OPO ₃ (alkyl) ₂ ), diaryl phosphono oxy group _{(-OPO 3 (aryl) 2)} , alkylaryl phosphonooxy group (-OPO alkyl) (aryl)), monoalkyl phosphonooxy group _(-OPO 3 H (alkyl)) and its conjugated base group (hereinafter referred to as alkyl phosphonophenyl group), monoaryl phosphonooxy group (-OPO ₃ H (Aryl)) and its conjugate base group (hereinafter referred to as arylphosphonatooxy group),

Alkoxysilyl group, cyano group, nitro group, onium group [preferably an onium group consisting of atoms of Group V or VI of the periodic table, more preferably ammonium, phosphonium or sulfonium, particularly preferably ammonium It is. Any onium counter cation can be selected, but preferred examples include halide ions (fluoride ions, chloride ions, bromide ions, iodide ions, etc.), sulfate ions, sulfonate ions (methanesulfonic acid). Ions, benzenesulfonate ions, p-toluenesulfonate ions, etc.), tetrafluoroborate ions, hexafluorophosphate ions, borate ions, phosphate ions, hydrogen phosphate ions, dihydrogen phosphate ions, etc. Can do. And the like. These groups may be combined to form a composite substituent.

Y in the general formula (1) represents -COOM, -OP = O (OM) ₂ , or -P = O (OM) ₂ , and M represents a hydrogen atom or a counter cation. n represents an integer of 1 to 20. More preferably, n is 2-10. n being 2 or more indicates that a plurality of groups represented by Y are present in one molecule. M represents a hydrogen atom or a counter ion necessary for neutralizing the electric charge. M may be a cation species having a valence other than monovalent, or may be a double salt having a plurality of counter cations. Particularly preferred is a compound in which Y is —COOM and M is a hydrogen atom.

  As M, a hydrogen atom or any cation species can be selected. Preferred examples include a hydrogen atom, an alkali metal ion (lithium, sodium, potassium, etc.), a group 2 metal ion (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, tetramethyl) Ammonium, tetrabutylammonium, pyridinium, morpholinium, guanidinium, etc.), phosphonium ions, sulfonium ions, and the like. More preferred are hydrogen atoms, alkali metal ions, ammonium ions, or organic ammonium ions, and particularly preferred are hydrogen atoms, sodium ions, and potassium ions.

  Although the preferable example of a compound represented by General formula (1) below is shown, this invention is not limited to these.

Various methods can be selected as a method for incorporating the specific compound in the present invention into at least one of the undercoat layer and the image recording layer.
That is, the specific compound in the present invention is added to water, methanol, ethanol, methyl ethyl ketone, acetonitrile, an organic solvent such as N-methyl-2-pyrrolidone, dimethyl sulfoxide, a mixed solvent thereof, or a mixed solvent of these organic solvent and water. As a preferred example, a method in which a solution dissolved so as to contain at least an undercoat layer or an image recording layer is applied and dried.
Further, the support is immersed in a solution prepared by dissolving at least the specific compound in the present invention in an organic solvent such as water, methanol, ethanol, methyl ethyl ketone, a mixed solvent thereof, or a mixed solvent of these organic solvent and water. In addition, a method of drying and providing an undercoat layer after washing with an appropriate solvent, if necessary, can be selected.

In the former method, a solution having a specific compound 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 is applied by various methods. it can. 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 specific compound is preferably 0.01 to 20% by mass, more preferably 0.05 to 5% by mass. The immersion temperature is preferably 20 to 90 ° C, more preferably 25 to 50 ° C, and the immersion time is preferably 0.1 second to 20 minutes, more preferably 2 seconds to 1 minute.

  The solution used in the above method is a basic substance such as ammonia, triethylamine, triethanolamine, sodium carbonate, sodium bicarbonate, sodium hydroxide, potassium hydroxide, or an inorganic acid such as phosphoric acid, sulfuric acid, nitric acid. PH is adjusted by various organic acidic substances such as organic sulfonic acids such as nitrobenzenesulfonic acid and naphthalenesulfonic acid, organic phosphonic acids such as phenylsulfonic acid, benzoic acid, fumaric acid, malic acid, salicylic acid and other organic carboxylic acids. May be. In this case, the pH of the solution is preferably from 0 to 12, more preferably from pH = 1 to 10.

  In the lithographic printing plate precursor according to the invention, the specific compound in the invention may be used alone or in combination of two or more. Further, the specific compound in the present invention may be contained in at least one of the undercoat layer and the image recording layer, but the addition amount and type thereof can be appropriately selected in any combination.

Amount after drying of the specific compound in the present invention is preferably from 1 to 100 mg / ^{m 2,} more preferably from 2 to 50 mg / ^{m 2,} particularly preferably from 4 to 30 mg / ^{m 2.} If the coating amount is less than 1 mg / m ² , the effects of the present invention may not be sufficiently obtained. Moreover, even if it exceeds 100 mg / m < ² >, it is the same.

(Image recording layer)
The image recording layer of the present invention may contain the specific compound of the present invention as described above. Hereinafter, components other than the specific compound will be described.
The image recording layer of the present invention preferably contains (A) a sensitizing dye, (B) a polymerization initiator, and (C) a polymerizable compound, more preferably a binder polymer, and further a micro It is particularly preferred to contain capsules or microgels. Furthermore, other components can be contained as necessary.
The image recording layer of the present invention is preferably an image recording layer composed of the above components and capable of on-press development or gum development.

<(A) Sensitizing dye>
The sensitizing dye used in the image recording layer of the present invention is appropriately selected according to the wavelength, use, etc. of the light source used for image exposure, and is not particularly limited. For example, an infrared absorber and a sensitizing dye that absorbs light of 350 nm to 450 nm are preferable.
When the sensitizing dye used in the present invention is a cationic compound, it is preferable to use one having no halide ion as a counter ion.

(Infrared absorber)
An infrared absorber is a component used to increase sensitivity to an infrared laser. The infrared absorber has a function of converting absorbed infrared rays into heat. The infrared absorbent used in the present invention is preferably a dye or pigment having an absorption maximum at a wavelength of 760 to 1200 nm.

  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.

  Examples of preferable dyes include cyanine dyes described in JP-A-58-125246, JP-A-59-84356, JP-A-60-78787, JP-A-58-173696, 58-181690, JP-A-58-194595, etc., methine dyes, JP-A-58-112793, JP-A-58-224793, JP-A-59-48187, JP-A-59- No. 73996, JP-A-60-52940, JP-A-60-63744 and the like, Naphthoquinone dyes described in JP-A-58-112792, etc., British Patent 434,875 And cyanine dyes described in 1).

  Further, near infrared absorption sensitizers described in US Pat. No. 5,156,938 are also preferably used, and substituted arylbenzo (thio) pyrylium described in US Pat. No. 3,881,924. Salt, trimethine thiapyrylium salt described in JP-A-57-142645 (US Pat. No. 4,327,169), JP-A-58-181051, 58-220143, 59-41363, 59-84248, 59-84249, 59-146063, 59-146061, pyrylium compounds described in JP-A-59-216146, cyanine dyes described in U.S. Pat. No. 4,283,475 The pentamethine thiopyrylium salt described in No. 5 and the pyrylium compounds described in JP-B 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 preferable examples of the infrared absorbing dye include specific indolenine cyanine dyes described in JP-A-2002-278057 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 preferable, and one particularly preferable example is a cyanine dye represented by the following general formula (i).

In formula (i), X ¹ represents a hydrogen atom, a halogen atom, -NPh _2, X ² -L ¹ or a group represented by the following structural formula (ia). 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 group having a hetero atom or a hetero atom having 1 to 12 carbon atoms. A hydrocarbon group is shown. Here, the hetero atom represents N, S, O, a halogen atom, or Se. Xa ⁻ has the same meaning as Za ⁻ described later. R ^a represents a hydrogen atom, an alkyl group, an aryl group, an amino group, or a halogen atom.

R ¹ and R ² each independently represents a hydrocarbon group having 1 to 12 carbon atoms. From the storage stability of the image recording 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. 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. Preferred aromatic hydrocarbon groups include a benzene ring group and a naphthalene ring group. 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. 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 (i) has an anionic substituent in its structure and neutralization of charge is not necessary. Preferred Za ⁻ is a halide ion, a perchlorate ion, a tetrafluoroborate ion, a hexafluorophosphate ion, and a sulfonate ion, particularly preferably a perchlorate ion, in view of the storage stability of the image recording layer coating solution. , Hexafluorophosphate ions, and aryl sulfonate ions.

  Specific examples of the cyanine dye represented by the general formula (i) 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 JP-A-2002-278057 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 Roso pigments, nitro pigments, natural materials, 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 Application 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 to 10 μm, more preferably in the range of 0.05 to 1 μm, and particularly preferably in the range of 0.1 to 1 μm. Within this range, good stability and uniformity of the pigment dispersion in the image recording layer can be obtained.

  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 infrared absorbing agent can be added by being encapsulated in microcapsules.

The addition amount is preferably such that the absorbance at the maximum absorption wavelength in the wavelength range of 760 nm to 1200 nm of the image recording layer is in the range of 0.1 to 1.5 by reflection measurement. , 0.2 to 1.2, and more preferably 0.3 to 1.0. Within this range, a uniform polymerization reaction in the depth direction of the image recording layer proceeds, and good film strength of the image area and adhesion to the support can be obtained.
The absorbance of the image recording layer can be adjusted by the amount of infrared absorber added to the image recording layer and the thickness of the image recording layer. Absorbance can be measured by a conventional method. As a measuring method, for example, on a reflective support such as aluminum, an image recording layer having a thickness appropriately determined in a range in which the coating amount after drying is necessary as a lithographic printing plate is formed, and the reflection density is set to the optical density. And a method of measuring with a spectrophotometer by a reflection method using an integrating sphere.

(Sensitizing dye that absorbs light of 350 nm to 450 nm)
As the sensitizing dye that absorbs light of 350 nm to 450 nm, a sensitizing dye having a maximum absorption in the wavelength range of 350 to 450 nm is preferable. Examples of such sensitizing dyes include merocyanine dyes represented by the following general formula (I), benzopyrans and coumarins represented by the following general formula (II), and aromatics represented by the following general formula (III). Examples include ketones and anthracenes represented by the following general formula (IV).

In the formula (I), A represents an S atom or NR ₆ , R ₆ represents a monovalent non-metallic atomic group, and Y forms a basic nucleus of the dye together with the adjacent A and the adjacent carbon atom. Represents a non-metallic atomic group, X ₁ and X ₂ each independently represent a monovalent non-metallic atomic group, or X ₁ and X ₂ may combine with each other to form an acidic nucleus of the dye.

In formula (II), = Z represents an oxo group, a thioxo group, an imino group or an alkylidene group represented by the partial structural formula (I ′), and X ₁ and X ₂ have the same meanings as in general formula (I) , R _{7 to} R ₁₂ each independently represents a monovalent nonmetallic atomic group.

In the formula (III), Ar ₃ represents an aromatic group or a heteroaromatic group, and R ₁₃ represents a monovalent nonmetallic atomic group. Preferred R ₁₃ is an aromatic group or a heteroaromatic group. Ar ₃ and R ₁₃ may be bonded to each other to form a ring.

In the formula (IV), X ₃ , X ₄ and R _{14 to} R ₂₁ each independently represents a monovalent nonmetallic atomic group. Preferred X ₃ and X ₄ are electron donating groups having a negative Hammett's substituent constant.

In the general formulas (I) to (IV), preferred examples of the monovalent nonmetallic atomic group represented by X ₁ to X ₄ and R ₆ to R ₂₁ include a hydrogen atom, an alkyl group (for example, a methyl group, Ethyl group, propyl group, t-butyl group, cyclohexyl group, etc.), aryl group (eg, phenyl group, biphenyl group, etc.), heteroaryl group (eg, thiophene, pyrrole, furan, etc.), alkenyl group (eg, vinyl group, 1-propenyl group etc.), alkynyl group (eg ethynyl group, 1-propynyl group etc.), halogen atom (—F, —Br, —Cl, —I), hydroxy group, alkoxy group, aryloxy group, amino group, Nitrogen atom-containing groups such as cyano group, nitro group, acyl group, N-alkylamino group, N, N-diarylamino group, mercapto group, alkylthio group, arylthio group, Kirujichio group, an aryl dithio group, alkylsulfinyl group, a sulfo group (-SO ₃ H) and its conjugated base group (a sulfonato group), alkoxycarbonyl sulfur atom containing groups such alkoxy sulfonyl group, a phosphono group (-PO ₃ H ₂₎ and its Examples thereof include phosphorus atom-containing groups such as conjugated base groups (phosphonate groups) and dialkylphosphono groups (—PO ₃ (alkyl) ₂ ). Among monovalent nonmetallic atomic groups, a hydrogen atom, an alkyl group, and an aryl group , A halogen atom, an alkoxy group, and an acyl group are particularly preferable.

  Examples of the basic nucleus of the dye formed by Y in the general formula (I) together with the adjacent A and adjacent carbon atoms include 5, 6 and 7-membered nitrogen-containing or sulfur-containing heterocycles. A membered heterocycle is preferred.

  Examples of nitrogen-containing heterocycles include L.I. G. Brooker et al. , J .; Am. Chem. Soc. 73, 5326-5358 (1951) and those known to constitute basic nuclei in the merocyanine dyes described in References can be suitably used. Specific examples include thiazoles, benzothiazoles, naphthothiazoles, thianaphtheno-7 ′, 6 ′, 4,5-thiazoles, oxazoles, benzoxazoles, naphthoxazoles, selenazoles, benzoselenazoles, Naphthoselenazoles, thiazolines, 2-quinolines, 4-quinolines, 1-isoquinolines, 3-isoquinolines, benzimidazoles, 3,3-dialkylindolenines, 2-pyridines, 4-pyridines Etc.

  Examples of the sulfur-containing heterocycle include a dithiol partial structure in dyes described in JP-A-3-296759. Specific examples include benzodithiols, naphthodithiols, dithiols and the like.

  For the sake of convenience, the description of the heterocyclic ring described above used the name of the heterocyclic mother skeleton for the sake of convenience. However, in the case of forming the basic skeleton partial structure of the sensitizing dye, for example, 3 for the benzothiazole skeleton. -Introduced in the form of an alkylidene-type substituent with one degree of unsaturation, such as a substituted-2 (3H) -benzothiazolidene group.

  Furthermore, sensitizing dyes represented by the following general formulas (V) to (XI) can also be used.

In formula (V), R ^{1 to} R ¹⁴ each independently represents a hydrogen atom, an alkyl group, an alkoxy group, a cyano group or a halogen atom. However, at least one of R ^{1 to} R ¹⁰ represents an alkoxy group having 2 or more carbon atoms.
In the formula (VI), R ^{15 to} R ³² each independently represents a hydrogen atom, an alkyl group, an alkoxy group, a cyano group, or a halogen atom. However, at least one of R ^{15 to} R ²⁴ represents an alkoxy group having 2 or more carbon atoms.

In formula (VII), R ¹ , R ² and R ³ each independently represents a halogen atom, an alkyl group, an aryl group, an aralkyl group, a —NR ⁴ R ⁵ group or a —OR ⁶ group, and R ⁴ , R ⁵ And R ⁶ each independently represents a hydrogen atom, an alkyl group, an aryl group or an aralkyl group, and k, m and n each represents an integer of 0 to 5.

In formula (VIII), X ₁ and X ₂ each independently represent an oxygen atom, a sulfur atom, —CR ₁₁ R ₁₂ — or N R ₁₃ —. Provided that at least one is an oxygen atom, a sulfur atom or NR ₁₃ - a. Y represents an oxygen atom, a sulfur atom or = NR _14. R _{1 to} R ₁₄ each independently represents a hydrogen atom or a monovalent nonmetallic atomic group. Alternatively, R _{1 to} R ₁₄ may be bonded to each other to form an aliphatic or aromatic ring.

In formula (IX), A ¹ And A ² each represents a carbon atom or a hetero atom. Q ¹ represents a nonmetallic atomic group necessary for forming a heterocyclic ring together with A ¹ , A ² and the carbon atoms adjacent to them. X ¹ and X ² each represent a cyano group or a substituted carbonyl group, or X ¹ and X ² may be bonded to each other to form a ring.

In the formula (X), each X independently represents an oxygen atom or a sulfur atom, and R ₁ , R ₂ , R ₃ , R ₄ , R ₅ , R ₆ , R ₇ and R ₈ are each independently a hydrogen atom or a single atom. Represents a valent nonmetallic atomic group.

In the formula (XI), X represents an oxygen atom or a sulfur atom, and R ₁ , R ₂ , R ₃ , R ₄ , R ₅ , R ₆ , R ₇ , and R ₈ are each independently a hydrogen atom or a monovalent Represents a non-metallic atomic group, and A represents an aryl group or heteroaryl group having 20 or less carbon atoms.

  Of the sensitizing dyes having an absorption maximum in the wavelength range of 350 nm to 450 nm, a dye more preferable from the viewpoint of high sensitivity is a dye represented by the following general formula (XII).

In the formula (XII), A represents an aromatic ring group or a heterocyclic group, and X represents an oxygen atom, a sulfur atom or N—R ₃ . R ₁ , R ₂ and R ₃ each independently represent a monovalent nonmetallic atomic group, or A and R ₁ or R ₂ and R ₃ are bonded to each other to form an aliphatic or aromatic ring. It may be formed. )

The general formula (XII) will be described in more detail. R ₁ , R ₂ and R ₃ each independently represent a monovalent nonmetallic atomic group, preferably an alkyl group, an alkenyl group, an aryl group, an aromatic heterocyclic residue, an alkoxy group, an alkylthio group, a hydroxy group Represents a halogen atom.

Preferable examples of R ₁ , R ₂ and R ₃ will be specifically described.
Preferred alkyl groups as R ₁ , R ₂ and R ₃ are preferably linear, branched or cyclic alkyl groups having up to 20 carbon atoms, and specific examples thereof include a methyl group, an ethyl group, a propyl group, A t-butyl group, an isopentyl group, etc. can be mentioned. Of these, linear alkyl groups having 1 to 12 carbon atoms, branched alkyl groups having 3 to 12 carbon atoms, and cyclic alkyl groups having 5 to 10 carbon atoms are more preferable.

As the substituent of the substituted alkyl group preferable as R ₁ , R ₂ and R ₃ , a monovalent nonmetallic atomic group excluding hydrogen is used, and preferable examples include halogen atoms (—F, —Br, —Cl, -I), nitrogen group-containing groups such as hydroxy group, alkoxy group, aryloxy group, acyl group, cyano group, nitro group, amino group, N-alkylamino group, N, N-diarylamino group, mercapto group, alkylthio group , Arylthio group, alkyldithio group, aryldithio group, alkylsulfinyl group, sulfo group (—SO ₃ H) and its conjugate base group (sulfonate group), alkoxysulfonyl group and other sulfur atom-containing groups, phosphono group (—PO ₃ H ₂ ) and its conjugate base group (phosphonate group), a phosphorus atom-containing group such as a dialkylphosphono group (—PO ₃ (alkyl) ₂ ), An aryl group, a heteroaryl group, an alkenyl group, and an alkynyl group are mentioned.

  Examples of the alkyl group in these substituents include the same alkyl groups as described above. Specific examples of the aryl group in these substituents include a phenyl group, a methoxyphenyl group, and a chlorophenyl group.

  Examples of heteroaryl groups in these substituents include monocyclic or polycyclic aromatic ring groups containing at least one of nitrogen, oxygen and sulfur atoms. Examples of preferred heteroaryl groups include, for example, thienyl. Group, furyl group, pyryl group, carbazolyl group, acridyl group and the like. These may be further benzo-fused or may have a substituent.

Examples of alkenyl groups in these substituents include vinyl groups and 1-propenyl groups, and examples of alkynyl groups include ethynyl groups, 1-propynyl groups, and 1-butynyl groups. Examples of G ₁ in the acyl group (G ₁ CO—) include hydrogen, the above alkyl group, and the following aryl group.
Among the substituents of these substituted alkyl groups, more preferred are a halogen atom (—F, —Br, —Cl, —I), an alkoxy group, an aryloxy group, an alkylthio group, an arylthio group, an aryl group, an alkenyl group, N - alkylamino group, N, N-nitrogen atom-containing groups such as diarylamino group, alkylsulfinyl group, a sulfo group (-SO ₃ H) and its conjugated base group (a sulfonato group), a sulfur atom-containing group such as alkoxysulfonyl And phosphorus atom-containing groups such as a phosphono group (—PO ₃ H ₂ ) and its conjugated base group (phosphonate group) and a dialkylphosphono group (—PO ₃ (alkyl) ₂ ).

  On the other hand, the alkylene group in the substituted alkyl group includes a divalent residue obtained by removing any one of the hydrogen atoms on the alkyl group having up to 20 carbon atoms, preferably a carbon atom. A linear alkylene group having 1 to 12 carbon atoms, a branched chain having 3 to 12 carbon atoms, and a cyclic alkylene group having 5 to 10 carbon atoms can be exemplified.

Preferable specific examples of the substituted alkyl group represented by R ₁ , R ₂ and R ₃ obtained by combining the above substituent and an alkylene group include a chloromethyl group, a trifluoromethyl group, a methoxymethyl group, and a phenoxymethyl group. Methylthiomethyl group, diethylaminopropyl group, morpholinopropyl group, acetyloxymethyl group, N-cyclohexylcarbamoyloxyethyl group, 2-oxoethyl group, carboxypropyl group, methoxycarbonylethyl group, chlorophenoxycarbonylmethyl group, carbamoylmethyl group, N-methylcarbamoylethyl group, phosphonobutyl group, benzyl group and the like can be mentioned.

Preferred alkenyl groups as R ₁ , R ₂ and R ₃ are preferably straight-chain, branched or cyclic alkenyl groups having up to 20 carbon atoms. Specific examples thereof include vinyl groups, 1-propenyl groups, 2- A propenyl group etc. are mentioned.
Preferred substituted alkenyl groups for R ₁ , R ₂ and R ₃ include those having a monovalent nonmetallic atomic group excluding hydrogen as a substituent on the carbon atom of the alkenyl group. Examples of preferred substituents include the alkyl groups, substituted alkyl groups, and substituents shown in the substituted alkyl groups described above. Preferable specific examples of the substituted alkenyl group include a styryl group and a cinnamyl group.

Preferred aryl groups for R ₁ , R ₂ and R ₃ include those in which 1 to 3 benzene rings form a condensed ring, and those in which a benzene ring and a 5-membered unsaturated ring form a condensed ring. Can do. Specific examples include a phenyl group, a naphthyl group, an anthryl group, a phenanthryl group, an indenyl group, an acenaphthenyl group, and a fluorenyl group, and a phenyl group and a naphthyl group are preferable.

Preferred substituted aryl groups for R ₁ , R ₂ and R ₃ include those having a monovalent nonmetallic atomic group excluding hydrogen as a substituent on the ring-forming carbon atom of the aryl group. Examples of preferred substituents include the alkyl groups, substituted alkyl groups, and substituents shown in the substituted alkyl groups described above. Preferred specific examples of the substituted aryl group include a biphenyl group, a tolyl group, a chlorophenyl group, a hydroxyphenyl group, a methoxyphenyl group, a methylthiophenyl group, an ethylaminophenyl group, a benzoyloxyphenyl group, an acetylaminophenyl group, a carboxyphenyl group, A sulfophenyl group, a sulfonatophenyl group, a phosphonophenyl group, a phosphonatophenyl group, etc. can be mentioned.

Preferred aromatic heterocyclic residues as R ₁ , R ₂ and R ₃ include monocyclic or polycyclic aromatic heterocyclic groups containing at least one of nitrogen, oxygen and sulfur atoms. Examples of aromatic heterocyclic groups include thiophene, thiathrene, furan, pyran, isobenzofuran, chromene, xanthene, phenoxazine, pyrrole, pyrazole, isothiazole, isoxazole, pyrazine, pyrimidine, pyridazine, indolizine, isoindolizine , Indoel, Indazole, Purine, Quinolidine, Isoquinoline, Phthalazine, Naphthyridine, Quinazoline, Cinoline, Pteridine, Carbazole, Carboline, Phenanthrin, Acridine, Perimidine, Phenanthrolin, Phthalazine, Phenalzazine, Phenoxazine, Furazane, Phenoxazine, etc. Examples thereof include a group derived from a heterocyclic ring, and these may be further benzo-condensed.
Preferred substituted aromatic heterocyclic residues as R ₁ , R ₂ and R ₃ have a monovalent nonmetallic atomic group excluding hydrogen as a substituent on the ring-forming atom of the aromatic heterocyclic residue. Is mentioned. Examples of preferred substituents include the alkyl groups, substituted alkyl groups, and substituents shown in the substituted alkyl groups described above.

Alkyl group in Preferred alkoxy groups and alkylthio groups as R _1, R ₂ and R ₃ are the same as those described for preferred alkyl groups as the R _1, R ₂ and R _3.
Preferred substituted alkoxy groups for R ₁ , R ₂ and R ₃ and substituted alkyl groups in substituted alkylthio groups are the same as those described for the substituted alkyl groups preferred as R ₁ , R ₂ and R ₃ .

The aromatic ring group and heterocyclic group represented by A in the general formula (XII) are the same as those described for the aryl group and aromatic heterocyclic residue described for R ₁ , R ₂ and R ₃ , respectively. Including things.

  The sensitizing dye represented by the general formula (XII) can be obtained by a condensation reaction between the above-described acidic nucleus or acidic nucleus having an active methylene group and an aromatic ring or a heterocyclic ring. Specifically, it can be synthesized with reference to the description of JP-B-59-28329.

  Although the preferable specific example of a compound represented by general formula (XII) is shown below, this invention is not limited to these. Further, the isomer by the double bond connecting the acidic nucleus and the basic nucleus is not limited to either isomer.

About the sensitizing dye, the structure, whether it is used alone or in combination, and details of usage such as addition amount can be appropriately set according to the performance design of the lithographic printing plate precursor.
For example, compatibility in the composition constituting the image recording layer can be enhanced by using two or more sensitizing dyes in combination. In selecting a sensitizing dye, in addition to photosensitivity, the molar extinction coefficient at the emission wavelength of the light source used is an important factor. By using a dye having a large molar extinction coefficient, the amount of the dye added can be made relatively small, which is economical and advantageous from the viewpoint of film physical properties of the image recording layer. The photosensitivity of the image recording layer, the resolution, and the physical properties of the exposure film are greatly affected by the absorbance at the light source wavelength, and thus the addition amount of the sensitizing dye is appropriately selected in consideration of these.

  However, for example, for the purpose of curing a thick film having a thickness of 5 μm or more, the degree of curing may be increased by lower absorbance. In the case of a lithographic printing plate precursor having a relatively thin film thickness, the addition amount of the sensitizing dye is such that the absorbance at the maximum absorption wavelength of the image recording layer is preferably 0.1 to 1.5 by a reflection measurement method. The range is set, more preferably in the range of 0.2 to 1.2, and still more preferably in the range of 0.3 to 1.0. Usually, it is preferably 0.05 to 30 parts by mass, more preferably 0.1 to 20 parts by mass, and further preferably 0.2 to 10 parts by mass with respect to 100 parts by mass of the total solid content of the image recording layer. .

<(B) Polymerization initiator>
The polymerization initiator used in the present invention is a compound that generates radicals by light, heat, or both, and initiates and accelerates polymerization of a compound having a polymerizable unsaturated group. As the polymerization initiator that can be used in the present invention, a known thermal polymerization initiator, a compound having a bond with a small bond dissociation energy, a photopolymerization initiator, or the like can be used, and a radical that is suitably used in the present invention is generated. The compound to be used refers to a compound that initiates and accelerates polymerization of a compound having a polymerizable unsaturated group by generating radicals by thermal energy. As the thermal radical generator according to the present invention, a known polymerization initiator, a compound having a bond with a small bond dissociation energy, or the like can be appropriately selected and used. Moreover, the compound which generate | occur | produces a radical can be used individually or in combination of 2 or more types. When an ionic compound is used as the polymerization initiator, it is necessary to use a compound having no halide ion.

  Examples of the radical generating compound include organic halides, carbonyl compounds, organic peroxides, azo polymerization initiators, azide compounds, metallocene compounds, hexaarylbiimidazole compounds, organic borate compounds, disulfone compounds, oximes. Examples thereof include ester compounds and onium salt compounds.

  Specific examples of the organic halide include Wakabayashi et al., “Bull Chem. Soc Japan” 42, 2924 (1969), US Pat. No. 3,905,815, Japanese Examined Patent Publication No. 46-4605, JP 48-36281, JP 55-3070, JP 60-239736, JP 61-169835, JP 61-169837, JP 62-58241, JP 62 -212401, JP-A-63-70243, JP-A-63-298339, M.S. P. Examples include compounds described in Hutt “Journal of Heterocyclic Chemistry” 1 (No 3), (1970) ”, and particularly preferable examples include oxazole compounds substituted with a trihalomethyl group and s-triazine compounds.

  More preferred examples include s-triazine derivatives and oxadiazole derivatives to which at least one mono, di, or trihalogen-substituted methyl group is bonded. Specifically, for example, 2,4,6-tris (monochloromethyl) -s-triazine, 2,4,6-tris (dichloromethyl) -s-triazine, 2,4,6-tris (trichloromethyl) -S-triazine, 2-methyl-4,6-bis (trichloromethyl) -s-triazine, 2-n-propyl-4,6-bis (trichloromethyl) -s-triazine, 2- (α, α, β-trichloroethyl) -4,6-bis (trichloromethyl) -s-triazine, 2-phenyl-4,6-bis (trichloromethyl) -s-triazine, 2- (p-methoxyphenyl) -4,6 -Bis (trichloromethyl) -s-triazine, 2- (3,4-epoxyphenyl) -4,6-bis (trichloromethyl) -s-triazine, 2- (p-chlorophenyl) -4,6- (Trichloromethyl) -s-triazine, 2- (p-bromophenyl) -4,6-bis (trichloromethyl) -s-triazine, 2- (p-fluorophenyl) -4,6-bis (trichloromethyl) ) -S-triazine, 2- (p-trifluoromethylphenyl) -4,6-bis (trichloromethyl) -s-triazine, 2- (2,6-dichlorophenyl) -4,6-bis (trichloromethyl) -S-triazine, 2- (2,6-difluorophenyl) -4,6-bis (trichloromethyl) -s-triazine, 2- (2,6-dibromophenyl) -4,6-bis (trichloromethyl) -S-triazine, 2- (4-biphenylyl) -4,6-bis (trichloromethyl) -s-triazine, 2- (4'-chloro-4-biphenylyl) -4,6 Bis (trichloromethyl) -s-triazine, 2- (p-cyanophenyl) -4,6-bis (trichloromethyl) -s-triazine, 2- (p-acetylphenyl) -4,6-bis (trichloromethyl) ) -S-triazine, 2- (p-ethoxycarbonylphenyl) -4,6-bis (trichloromethyl) -s-triazine, 2- (p-phenoxycarbonylphenyl) -4,6-bis (trichloromethyl)- s-triazine, 2- (p-methylsulfonylphenyl) -4,6-bis (trichloromethyl) -s-triazine, 2- (p-dimethylsulfoniumphenyl) -4,6-bis (trichloromethyl) -s- Triazine tetrafluoroborate, 2- (2,4-difluorophenyl) -4,6-bis (trichloromethyl) -s-tria Gin, 2- (p-diethoxyphosphorylphenyl) -4,6-bis (trichloromethyl) -s-triazine, 2- [4- (4-hydroxyphenylcarbonylamino) phenyl] -4,6-bis (trichloro) Methyl) -s-triazine, 2- [4- (p-methoxyphenyl) -1,3-butadienyl] -4,6-bis (trichloromethyl) -s-triazine, 2-styryl-4,6-bis ( Trichloromethyl) -s-triazine, 2- (p-methoxystyryl) -4,6-bis (trichloromethyl) -s-triazine, 2- (pi-propyloxystyryl) -4, 6-bis (trichloro) Methyl) -s-triazine, 2- (p-tolyl) -4,6-bis (trichloromethyl) -s-triazine, 2- (4-methoxynaphthyl) -4,6-bi (Trichloromethyl) -s-triazine, 2-phenylthio-4,6-bis (trichloromethyl) -s-triazine, 2-benzylthio-4,6-bis (trichloromethyl) -s-triazine, 2,4,6 -Tris (dibromomethyl) -s-triazine, 2,4,6-tris (tribromomethyl) -s-triazine, 2-methyl-4,6-bis (tribromomethyl) -s-triazine, 2-methoxy -4,6-bis (tribromomethyl) -s-triazine, 2- (o-methoxystyryl) -5-trichloromethyl-1,3,4-oxadiazole, 2- (3,4-epoxystyryl) -5-trichloromethyl-1,3,4-oxadiazole, 2- [1-phenyl-2- (4-methoxyphenyl) vinyl] -5-trichloromethyl-1,3 4-oxadiazole, 2- (p-hydroxystyryl) -5-trichloromethyl-1,3,4-oxadiazole, 2- (3,4-dihydroxystyryl) -5-trichloromethyl-1,3 4-oxadiazole, 2- (pt-butoxystyryl) -5-trichloromethyl-1,3,4-oxadiazole and the like.

  Examples of the carbonyl compound include benzophenone, Michler ketone, 2-methylbenzophenone, 3-methylbenzophenone, 4-methylbenzophenone, 2-chlorobenzophenone, 4-bromobenzophenone, 2-carboxybenzophenone and other benzophenone derivatives, 2,2-dimethoxy- 2-phenylacetophenone, 2,2-diethoxyacetophenone, 1-hydroxycyclohexyl phenyl ketone, α-hydroxy-2-methylphenylpropanone, 1-hydroxy-1-methylethyl- (p-isopropylphenyl) ketone, 1- Hydroxy-1- (p-dodecylphenyl) ketone, 2-methyl- (4 ′-(methylthio) phenyl) -2-morpholino-1-propanone, 1,1,1-trichloromethyl- (p-butylpheny ) Acetophenone derivatives such as ketones, thioxanthone derivatives such as thioxanthone, 2-ethylthioxanthone, 2-isopropylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2,4-diisopropylthioxanthone, p And benzoic acid ester derivatives such as ethyl dimethylaminobenzoate and ethyl p-diethylaminobenzoate.

  As the azo compound, for example, an azo compound described in JP-A-8-108621 can be used.

  Examples of the organic peroxide include trimethylcyclohexanone peroxide, acetylacetone peroxide, 1,1-bis (tert-butylperoxy) -3,3,5-trimethylcyclohexane, 1,1-bis (tert-butyl). Peroxy) cyclohexane, 2,2-bis (tert-butylperoxy) butane, tert-butyl hydroperoxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide, 2,5-dimethylhexane-2,5-dihydro Peroxide, 1,1,3,3-tetramethylbutyl hydroperoxide, tert-butylcumyl peroxide, dicumyl peroxide, 2,5-dimethyl-2,5-di (tert-butylperoxy) hexane, 2, -Oxanoyl peroxide, succinic peroxide, benzoyl peroxide, 2,4-dichlorobenzoyl peroxide, diisopropyl peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate, di-2-ethoxyethyl peroxydicarbonate , Dimethoxyisopropyl peroxycarbonate, di (3-methyl-3-methoxybutyl) peroxydicarbonate, tert-butyl peroxyacetate, tert-butyl peroxypivalate, tert-butyl peroxyneodecanoate, tert- Butyl peroxyoctanoate, tert-butyl peroxylaurate, tersyl carbonate, 3,3 ′, 4,4′-tetra- (t-butylperoxycarbonyl) benzophenone, 3,3 ′, 4 '-Tetra- (t-hexylperoxycarbonyl) benzophenone, 3,3', 4,4'-tetra- (p-isopropylcumylperoxycarbonyl) benzophenone, carbonyldi (t-butylperoxydihydrogen diphthalate) , Carbonyldi (t-hexylperoxydihydrogen diphthalate) and the like.

  Examples of the metallocene compound include JP-A-59-152396, JP-A-61-151197, JP-A-63-41484, JP-A-2-249, JP-A-2-4705, Various titanocene compounds described in JP-A-5-83588, such as di-cyclopentadienyl-Ti-bis-phenyl, di-cyclopentadienyl-Ti-bis-2,6-difluorophen-1-yl, Di-cyclopentadienyl-Ti-bis-2,4-di-fluorophen-1-yl, di-cyclopentadienyl-Ti-bis-2,4,6-trifluorophen-1-yl, di- -Cyclopentadienyl-Ti-bis-2,3,5,6-tetrafluorophen-1-yl, di-cyclopentadienyl-Ti-bis-2,3,4,5,6-penta Fluorophen-1-yl, di-methylcyclopentadienyl-Ti-bis-2,6-difluorophen-1-yl, di-methylcyclopentadienyl-Ti-bis-2,4,6-trifluoropheny -1-yl, di-methylcyclopentadienyl-Ti-bis-2,3,5,6-tetrafluorophen-1-yl, di-methylcyclopentadienyl-Ti-bis-2,3,4 , 5,6-pentafluorophen-1-yl, di-cyclopentadienyl-Ti-bis-2,6-difluoro-3- (pyrrol-1-yl) phen-1-yl, JP-A-1-304453 And iron-arene complexes described in JP-A-1-152109.

  Examples of the hexaarylbiimidazole compound include, for example, Japanese Patent Publication No. 6-29285, U.S. Pat. Nos. 3,479,185, 4,311,783, and 4,622,286. And, specifically, 2,2′-bis (o-chlorophenyl) -4,4 ′, 5,5′-tetraphenylbiimidazole, 2,2′-bis (o-bromophenyl) )) 4,4 ′, 5,5′-tetraphenylbiimidazole, 2,2′-bis (o, p-dichlorophenyl) -4,4 ′, 5,5′-tetraphenylbiimidazole, 2,2 ′ -Bis (o-chlorophenyl) -4,4 ', 5,5'-tetrakis (m-methoxyphenyl) biidazole, 2,2'-bis (o, o'-dichlorophenyl) -4,4', 5,5 '-Tetrafeni Biimidazole, 2,2′-bis (o-nitrophenyl) -4,4 ′, 5,5′-tetraphenylbiimidazole, 2,2′-bis (o-methylphenyl) -4,4 ′, 5 , 5′-tetraphenylbiimidazole, 2,2′-bis (o-trifluorophenyl) -4,4 ′, 5,5′-tetraphenylbiimidazole, and the like.

  Examples of the organic borate compounds include JP-A-62-143044, JP-A-62-1050242, JP-A-9-188585, JP-A-9-188686, JP-A-9-188710, and JP-A-9-188710. 2000-131837, Japanese Patent Application Laid-Open No. 2002-107916, Japanese Patent No. 2764769, Japanese Patent Application Laid-Open No. 2002-116539, and Kunz, Martin “Rad Tech'98. Proceeding April 19-22, 1998, Chicago”, etc. The organic borate described in JP-A-6-157623, JP-A-6-175564, JP-A-6-175561, or organic boron oxosulfonium complex, JP-A-6-175554 No. 6, JP-A-6-17555 Organoboron iodonium complex described in JP-A-9-188, organoboron phosphonium complex described in JP-A-9-188710, JP-A-6-34811, JP-A-7-128785, JP-A-7-140589, Specific examples include organoboron transition metal coordination complexes such as Kaihei 7-306527 and JP-A-7-292014.

  Examples of the disulfone compound include compounds described in JP-A Nos. 61-166544 and 2003-328465.

  Examples of the oxime ester compound include JCS Perkin II (1979) 1653-1660), JCS Perkin II (1979) 156-162, Journal of Photopolymer Science and Technology (1995) 202-232, and JP-A No. 2000-66385. And compounds described in JP 2000-80068 A. Specific examples thereof include compounds represented by the following structural formula.

  Examples of the onium salt compound include S.I. I. Schlesinger, Photogr. Sci. Eng. 18, 387 (1974), T .; S. Diazonium salts described in Bal et al, Polymer, 21, 423 (1980), ammonium salts described in US Pat. No. 4,069,055, JP-A-4-365049, etc., US Pat. No. 4,069 , 055 and 4,069,056, phosphonium salts described in European Patent Nos. 104 and 143, U.S. Pat. Nos. 339,049 and 410,201, 2-150848, JP-A-2-296514, iodonium salts, European Patent Nos. 370,693, 390,214, 233,567, 297,443, and 297,442 U.S. Pat. Nos. 4,933,377, 161,811, 410,201, 339,049, 4,760,013, 4,73 No. 4,444, 2,833,827, German Patent Nos. 2,904,626, 3,604,580, and 3,604,581, the sulfonium salts described in J . 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), and onium salts such as arsonium salts.

In particular, the oxime ester compound, diazonium salt, iodonium salt, and sulfonium salt are preferable from the viewpoint of reactivity and stability.
Preferred onium salts for the present invention are onium salts represented by the following general formulas (RI-I) to (RI-III).

In the formula (RI-I), Ar ¹¹ represents an aryl group having 20 or less carbon atoms which may have 1 to 6 substituents, and preferred substituents include an alkyl group having 1 to 12 carbon atoms and 1 carbon atom. -12 alkenyl group, C1-C12 alkynyl group, C1-C12 aryl group, C1-C12 alkoxy group, C1-C12 aryloxy group, halogen atom, C1-C12 An alkylamino group, a dialkylamino group having 1 to 12 carbon atoms, an alkylamide group or arylamide group having 1 to 12 carbon atoms, a carbonyl group, a carboxyl group, a cyano group, a sulfonyl group, a thioalkyl group having 1 to 12 carbon atoms, A C1-C12 thioaryl group is mentioned. Z ^11- represents a monovalent anion, which is a hexafluorophosphate ion, a tetrafluoroborate ion, a sulfonate ion, a sulfinate ion, a thiosulfonate ion, or a sulfate ion, and has stability and visibility of a printed image. To hexafluorophosphate ions, tetrafluoroborate ions, sulfonate ions, and sulfinate ions.

In formula (RI-II), Ar ²¹ and Ar ²² each independently represent an aryl group having 20 or less carbon atoms which may have 1 to 6 substituents, and preferred substituents have 1 to 12 carbon atoms. An alkyl group, an alkenyl group having 1 to 12 carbon atoms, an alkynyl group having 1 to 12 carbon atoms, an aryl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an aryloxy group having 1 to 12 carbon atoms, a halogen atom An alkylamino group having 1 to 12 carbon atoms, a dialkylamino group having 1 to 12 carbon atoms, an alkylamide group or arylamide group having 1 to 12 carbon atoms, a carbonyl group, a carboxyl group, a cyano group, a sulfonyl group, and 1 carbon atom -12 thioalkyl group and C1-C12 thioaryl group are mentioned. Z ^21- represents a monovalent anion, which is a hexafluorophosphate ion, a tetrafluoroborate ion, a sulfonate ion, a sulfinate ion, a thiosulfonate ion, or a sulfate ion. Hexafluorophosphate from the viewpoint of stability and visibility Ions, tetrafluoroborate ions, sulfonate ions, sulfinate ions, and carboxylate ions are preferred.

In the formula (RI-III), R ³¹ , R ³² and R ³³ each independently represents an aryl group having 20 or less carbon atoms, an alkyl group, an alkenyl group or an alkynyl group which may have 1 to 6 substituents. In view of reactivity and stability, an aryl group is desirable. Preferred substituents are alkyl groups having 1 to 12 carbon atoms, alkenyl groups having 1 to 12 carbon atoms, alkynyl groups having 1 to 12 carbon atoms, aryl groups having 1 to 12 carbon atoms, alkoxy groups having 1 to 12 carbon atoms, Aryloxy group having 1 to 12 carbon atoms, halogen atom, alkylamino group having 1 to 12 carbon atoms, dialkylamino group having 1 to 12 carbon atoms, alkylamide group or arylamide group having 1 to 12 carbon atoms, carbonyl group, carboxyl Group, a cyano group, a sulfonyl group, a thioalkyl group having 1 to 12 carbon atoms, and a thioaryl group having 1 to 12 carbon atoms. Z ^31- represents a monovalent anion, which is a hexafluorophosphate ion, a tetrafluoroborate ion, a sulfonate ion, a sulfinate ion, a thiosulfonate ion, or a sulfate ion. From the viewpoint of stability and visibility, hexafluorophosphate Phosphate ions, tetrafluoroborate ions, sulfonate ions, sulfinate ions, and carboxylate ions are preferable, and carboxylate ions described in JP-A No. 2001-343742 are more preferable, and JP-A No. 2002-148790 is particularly preferable. Of the carboxylate ions. Examples of onium salts that can be suitably used as a polymerization initiator in the present invention will be given below, but the present invention is not limited thereto.

Moreover, you may use the polymerization initiator of the following general formula (RI-IV) of the azinium structure. In the formula, R ¹ , R ² , R ³ , R ⁴ , R ⁵ , and R ⁶ each independently represent a hydrogen atom, a halogen atom, or a monovalent substituent. X ⁻ represents an ion.

  Examples of the monovalent substituent include, for example, a halogen atom, amino group, substituted amino group, substituted carbonyl tomb, hydroxy group, substituted oxy group, thiol group, thioether group, silyl group, nitro group, cyano group, alkyl group, Alkenyl group, aryl group, heterocyclic group, sulfo group, substituted sulfonyl group, sulfonate group, substituted sulfinyl group, phosphono group, substituted phosphono group, phosphonate group, substituted phosphonate group, etc. It may have a substituent.

In addition, as the compound represented by the general formula (RI-IV), a skeleton (cation part) having a specific structure in the compound represented by the general formula (RI-IV) is bonded via R ¹ to form a cation part. Are included in the molecule (multimeric form), and such compounds are also preferably used.
Furthermore, the compound represented by the general formula (RI-IV) may be a compound (polymer type) introduced into the polymer side chain via any of R ^{1 to} R ⁶ , and is listed as one of preferred embodiments. It is done.

  Specific examples of the compound represented by the general formula (RI-IV) [Exemplary Compounds A-1 to A-34] are listed below, but the scope of the present invention is not limited thereto.

The polymerization initiator is not limited to the above, but a triazine-based initiator, an organic halogen compound, an oxime ester compound, a diazonium salt, an iodonium salt, and a sulfonium salt are more preferable from the viewpoints of reactivity and stability. Among these, from the viewpoint of improving the visibility of the printout image in combination with an infrared absorber, the onium salt has an inorganic ion such as PF ₆ ⁻ or BF ₄ ⁻ as a counter ion. Those are preferred. Furthermore, diaryliodonium is preferred as the onium because of its excellent color development.

  These polymerization initiators are each preferably 0.1 to 50% by mass, more preferably 0.5 to 30% by mass, and particularly preferably 0.8 to 20% by mass with respect to the total solid content constituting the image recording layer. Can be added at a ratio of Within this range, good sensitivity and good stain resistance of the non-image area during printing can be obtained. These polymerization initiators may be used alone or in combination of two or more. Moreover, these polymerization initiators may be added to the same layer as other components, or another layer may be provided and added thereto.

<(C) Polymerizable compound>
The polymerizable compound that can be used in the present invention is an addition polymerizable compound having at least one ethylenically unsaturated double bond, and is a compound having at least one terminal ethylenically unsaturated bond, preferably two or more. To be elected. 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, ie 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, an addition reaction product of an unsaturated carboxylic acid ester or amide having a nucleophilic substituent such as a hydroxy group, amino group or mercapto group with a monofunctional or polyfunctional isocyanate or epoxy, and a monofunctional or polyfunctional compound. A dehydration condensation reaction product with a functional carboxylic acid is also preferably used. Further, an addition reaction product of an unsaturated carboxylic acid ester or amide having an electrophilic substituent such as an epoxy group or an epoxy group with a monofunctional or polyfunctional alcohol, amine or thiol, a halogen group or Also suitable are substitution reaction products of unsaturated carboxylic acid esters or amides having a leaving substituent such as a tosyloxy group with monofunctional or polyfunctional alcohols, amines or thiols. As another example, it is also possible to use a group of compounds substituted with unsaturated phosphonic acid, styrene, vinyl ether or the like instead of the unsaturated carboxylic acid.

  Specific examples of the monomer of an ester of an aliphatic polyhydric alcohol compound and an unsaturated carboxylic acid include acrylic acid esters such as ethylene glycol diacrylate, triethylene glycol diacrylate, 1,3-butanediol diacrylate, and tetramethylene glycol. Diacrylate, propylene glycol diacrylate, neopentyl glycol diacrylate, trimethylolpropane triacrylate, trimethylolpropane tri (acryloyloxypropyl) ether, trimethylolethane triacrylate, hexanediol diacrylate, 1,4-cyclohexanediol diacrylate , Tetraethylene glycol diacrylate, pentaerythritol diacrylate, pentaerythritol triacrylate , Pentaerythritol tetraacrylate, dipentaerythritol diacrylate, dipentaerythritol hexaacrylate, sorbitol triacrylate, sorbitol tetraacrylate, sorbitol pentaacrylate, sorbitol hexaacrylate, tri (acryloyloxyethyl) isocyanurate, polyester acrylate oligomer, isocyanuric acid There are EO-modified triacrylate and the like.

  Methacrylic acid esters include tetramethylene glycol dimethacrylate, triethylene glycol dimethacrylate, neopentyl glycol dimethacrylate, trimethylolpropane trimethacrylate, trimethylolethane trimethacrylate, ethylene glycol dimethacrylate, 1,3-butanediol dimethacrylate, Hexanediol dimethacrylate, pentaerythritol dimethacrylate, pentaerythritol trimethacrylate, pentaerythritol tetramethacrylate, dipentaerythritol dimethacrylate, dipentaerythritol hexamethacrylate, sorbitol trimethacrylate, sorbitol tetramethacrylate, bis [p- (3-methacryloxy- 2-hydroxypro ) Phenyl] dimethyl methane, bis - [p- (methacryloxyethoxy) phenyl] dimethyl methane.

  Itaconic acid esters include ethylene glycol diitaconate, propylene glycol diitaconate, 1,3-butanediol diitaconate, 1,4-butanediol diitaconate, tetramethylene glycol diitaconate, pentaerythritol diitaconate And sorbitol tetritaconate. Examples of crotonic acid esters include ethylene glycol dicrotonate, tetramethylene glycol dicrotonate, pentaerythritol dicrotonate, and sorbitol tetradicrotonate. Examples of isocrotonic acid esters include ethylene glycol diisocrotonate, pentaerythritol diisocrotonate, and sorbitol tetraisocrotonate. Examples of maleic acid esters include ethylene glycol dimaleate, triethylene glycol dimaleate, pentaerythritol dimaleate, and sorbitol tetramaleate.

  Examples of other esters include, for example, aliphatic alcohol esters described in JP-B-51-47334 and JP-A-57-196231, JP-A-59-5240, and JP-A-59-5241. And those having an aromatic skeleton described in JP-A-2-226149 and those containing an amino group described in JP-A-1-165613. Furthermore, the ester monomers described above can also be used as a mixture.

  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.

  Further, urethane-based addition polymerizable compounds produced by using an addition reaction of isocyanate and hydroxy group are also suitable. Specific examples of such compounds are described in, for example, Japanese Patent Publication No. 48-41708. Containing two or more polymerizable vinyl groups in one molecule obtained by adding a vinyl monomer containing a hydroxy group represented by the following general formula (2) to a polyisocyanate compound having two or more isocyanate groups in the molecule A vinyl urethane compound etc. are mentioned.

^{_{CH 2 = C (R 4)}} COOCH 2 CH (R 5) OH (2)
(However, R ⁴ and R ⁵ represent H or CH _3. )

  Further, urethane acrylates as described in JP-A-51-37193, JP-B-2-32293, JP-B-2-16765, JP-B-58-49860, JP-B-56-17654 And urethane compounds having an ethylene oxide skeleton described in JP-B-62-39417 and JP-B-62-39418. Furthermore, addition 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 are used. Depending on the case, it is possible to obtain a photopolymerizable composition excellent in the photosensitive speed.

  Other examples include polyester acrylates, epoxy resins and acrylic acid or methacrylic acid described in JP-A-48-64183, JP-B-49-43191, JP-B-52-30490, and JP-B-52-30490. Mention may be made of polyfunctional acrylates and methacrylates such as reacted epoxy acrylates. In addition, JP-B-46-43946, JP-B-1-40337, JP-B-1-40336, specific unsaturated compounds described in each gazette, vinylphosphonic acid compounds described in JP-A-2-25493, and the like are also included. Can 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.

About these polymerizable compounds, the details of usage such as the structure, single use or combination, addition amount and the like can be arbitrarily set according to the performance design of the final lithographic printing plate precursor. For example, it is selected from the following viewpoints.
From the viewpoint of sensitivity, a structure having a large 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 area, that is, the cured film, those having three or more functionalities are preferable, and furthermore, different functional numbers and different polymerizable groups (for example, acrylic acid ester, methacrylic acid ester, styrenic compound, vinyl ether type). A method of adjusting both sensitivity and strength by using a compound) is also effective.
Further, the selection and use method of the addition 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 recording layer. In some cases, the compatibility can be improved by using a low-purity compound or by using two or more kinds in combination. In addition, a specific structure may be selected for the purpose of improving the adhesion of the substrate and the protective layer described later.
The polymerizable compound is preferably used in the range of 5 to 80% by mass, more preferably 25 to 75% by mass with respect to the nonvolatile component in the image recording layer. These may be used alone or in combination of two or more. In addition, the use method of the addition polymerizable compound can be arbitrarily selected from the viewpoint of polymerization inhibition with respect to oxygen, resolution, fogging, refractive index change, surface adhesiveness, etc. Depending on the case, a layer configuration and coating method such as undercoating and overcoating can be performed.

<Other image recording layer components>
The image recording layer of the present invention can further contain various additives as required. These will be described below.

<1> Microcapsules and Microgels In the present invention, several modes may be used as a method for incorporating the above-mentioned image recording layer constituent components (A) to (C) and other constituent components described later into the image recording layer. it can. One is a molecular dispersion type image recording layer in which the constituent components are dissolved and applied in an appropriate solvent as described in, for example, JP-A-2002-287334. In another embodiment, for example, as described in JP-A Nos. 2001-277740 and 2001-277742, all or a part of the constituent components are encapsulated in microcapsules and contained in the image recording layer. It is a microcapsule type image recording layer. Further, in the microcapsule type image recording layer, the constituent component can be contained outside the microcapsule. Here, it is preferable that the microcapsule-type image recording layer includes a hydrophobic constituent component in the microcapsule and a hydrophilic constituent component outside the microcapsule.
As still another embodiment, an embodiment in which the image recording layer contains crosslinked resin particles, that is, microgel, can be mentioned. The microgel can contain a part of the constituent components (A) to (C) in and / or on the surface thereof. In particular, an embodiment in which (C) a reactive microgel is formed by having a polymerizable compound on the surface thereof is particularly preferable from the viewpoint of image forming sensitivity and printing durability.
In order to obtain better on-press developability, the image recording layer is preferably a microcapsule type or microgel type image recording layer.

  As a method for microencapsulating or microgelling the components of the image recording layer, known methods can be applied.

  For example, as a method for producing microcapsules, a method using coacervation found in U.S. Pat. Nos. 2,800,547 and 2,800,498, U.S. Pat. No. 3,287,154, JP-B-38-19574, 42-446 by the interfacial polymerization method, US Pat. No. 3,418,250, US Pat. No. 3,660,304 by polymer precipitation method, US Pat. No. 3,796,669, isocyanate polyol A method using a wall material, a method using an isocyanate wall material found in US Pat. No. 3,914,511, and a urea-formaldehyde system found in US Pat. Nos. 4,001,140, 4,087,376 and 4,089,802. Or urea formaldehyde-resorcino A method using a wall forming material, a method using a wall material such as melamine-formaldehyde resin and hydroxycellulose, as shown in US Pat. No. 4,025,445, and Japanese Patent Publication Nos. 36-9163 and 51-9079. In situ method using monomer polymerization, spray drying method found in British Patent No. 930422, US Pat. No. 3,111,407, electrolytic dispersion cooling method seen in British Patent Nos. 952807 and 967074, etc. However, it is not limited to these.

  A preferable microcapsule wall used in the present invention 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, and a mixture thereof, and particularly preferably polyurea and polyurethane. Moreover, you may introduce | transduce into the microcapsule wall the compound which has crosslinkable functional groups, such as an ethylenically unsaturated bond which can be introduce | transduced into the below-mentioned binder polymer.

On the other hand, as a method for preparing the microgel, granulation by interfacial polymerization described in JP-B-38-19574 and JP-A-42-446, as described in JP-A-5-61214, etc. It is possible to utilize granulation by non-aqueous dispersion polymerization. However, it is not limited to these methods.
As the method using the interfacial polymerization, the above-described known microcapsule production method can be applied.

  Preferred microgels used in the present invention are those granulated by interfacial polymerization and having three-dimensional crosslinking. From such a viewpoint, the material to be used is preferably polyurea, polyurethane, polyester, polycarbonate, polyamide, and a mixture thereof, and polyurea and polyurethane are particularly preferable.

  The average particle size of the microcapsules or microgel is preferably 0.01 to 3.0 μm. 0.05-2.0 micrometers is further more preferable, and 0.10-1.0 micrometer is especially preferable. Within this range, good resolution and stability over time can be obtained.

<2> Binder polymer In the image recording layer of the present invention, a binder polymer can be used in order to improve the film strength of the image recording layer. As the binder polymer that can be used in the present invention, conventionally known binder polymers can be used without limitation, and polymers having film properties are preferred. Examples of such binder polymers include acrylic resins, polyvinyl acetal resins, polyurethane resins, polyurea resins, polyimide resins, polyamide resins, epoxy resins, methacrylic resins, polystyrene resins, novolac phenolic resins, polyester resins, and synthetic rubbers. And natural rubber.
The binder polymer may have crosslinkability in order to improve the film strength of the image area. In order to impart crosslinkability to the binder polymer, a crosslinkable functional group such as an ethylenically unsaturated bond may be introduced into the main chain or side chain of the polymer. The crosslinkable functional group may be introduced by copolymerization.
Examples of the polymer having an ethylenically unsaturated bond in the main chain of the molecule include poly-1,4-butadiene and poly-1,4-isoprene.
Examples of polymers having an ethylenically unsaturated bond in the side chain of the molecule are polymers of esters or amides of acrylic acid or methacrylic acid where the ester or amide residue (R of -COOR or -CONHR) is Mention may be made of polymers having an ethylenically unsaturated bond.

Examples of the residue (the R) having an ethylenically unsaturated _{bond, -CH = CH 2, -C (} CH 3) = CH 2, - (CH 2) n CR 1 = CR 2 R 3, - ( _{CH 2 O) n CH 2 CR} 1 = CR 2 R 3, - (CH 2 CH 2 O) n CH 2 CR 1 = CR 2 R 3, - (CH 2) n NH-CO-O-CH 2 CR 1 ^{= CR 2 R 3, - (} CH 2) n -O-CO-CR 1 = CR 2 R 3 and _{(CH 2 CH 2 O) 2} -X ( wherein, R ¹ to R ³ are each a hydrogen atom, Represents a halogen atom or an alkyl group having 1 to 20 carbon atoms, an aryl group, an alkoxy group or an aryloxy group, and R ¹ and R ² or R ³ may be bonded to each other to form a ring. Represents an integer of from 10 to 10. X represents a dicyclopentadienyl residue.
Specific examples of the ester residue include —CH═CH ₂ , —C (CH ₃ ) ═CH ₂ , —CH ₂ CH═CH ₂ (described in Japanese Patent Publication No. 7-21633), —CH. _{2 CH 2 O-CH 2 CH} = CH 2, -CH 2 C (CH 3) = CH 2, -CH 2 CH = CH-C 6 H 5, -CH 2 CH 2 OCOCH = CH-C 6 H 5, (wherein, X represents a dicyclopentadienyl _{residue.) -CH 2 CH 2 -NHCOO-} CH 2 CH = CH 2 and CH ₂ CH ₂ O-X and the like.
Specific examples of the amide residue include —CH═CH ₂ , —C (CH ₃ ) ═CH ₂ , —CH ₂ CH═CH ₂ , —CH ₂ CH ₂ —Y (wherein Y represents a cyclohexene residue. _{represented), -. CH 2 CH 2} -OCO-CH = CH 2 and the like.

  In the case of a binder polymer having crosslinkability, for example, free radicals (polymerization initiation radicals or growth radicals in the polymerization process of a polymerizable compound) are added to the crosslinkable functional group, and a polymerization chain of a polymerizable compound is formed directly between polymers. Through addition polymerization, a cross-link is formed between the polymer molecules and cured. Alternatively, atoms in the polymer (eg, hydrogen atoms on carbon atoms adjacent to the functional bridging group) are abstracted by free radicals to form polymer radicals that are bonded to each other so that crosslinking between the polymer molecules occurs. Forms and cures.

  The content of the crosslinkable group in the binder polymer (content of unsaturated double bond capable of radical polymerization by iodometric titration) is preferably 0.1 to 10.0 mmol, more preferably 1 to 7 per gram of the binder polymer. 0.0 mmol, particularly preferably 2.0 to 5.5 mmol. Within this range, good sensitivity and good storage stability can be obtained.

The content of halide ions in the binder polymer is preferably 50 × 10 ⁻⁶ mol / g, more preferably 20 × 10 ⁻⁶ mol / g, particularly preferably 10 × 10 ⁻⁶ mol / g, or less. . About a minimum, it is so preferable that content is small.
The amount of halide ions in the binder can be reduced by using an ion exchange resin, a specific mineral, or performing purification by reprecipitation.

  Further, from the viewpoint of improving the on-press developability of the image recording layer unexposed portion, the binder polymer preferably has high solubility or dispersibility in ink and / or fountain solution. In order to improve the solubility or dispersibility in ink, the binder polymer is preferably lipophilic, and in order to improve the solubility or dispersibility in dampening water, the binder polymer is hydrophilic. Is preferred. For this reason, in the present invention, it is also effective to use a lipophilic binder polymer and a hydrophilic binder polymer in combination.

  Examples of hydrophilic binder polymers include hydroxy groups, carboxyl groups, carboxylate groups, hydroxyethyl groups, polyoxyethyl groups, hydroxypropyl groups, polyoxypropyl groups, amino groups, aminoethyl groups, aminopropyl groups, and ammonium. Preferred examples include those having a hydrophilic group such as a group, an amide group, a carboxymethyl group, a sulfo group, or a phosphoric acid group.

  Specific examples 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 their salts, Polymethacrylic acids and their salts, homopolymers and copolymers of hydroxyethyl methacrylate, homopolymers and copolymers of hydroxyethyl acrylate, homopolymers and copolymers of hydroxypropyl methacrylate, homopolymers and copolymers of hydroxypropyl acrylate, homopolymers of hydroxybutyl methacrylate Polymers and copolymers, homopolymers and copolymers of hydroxybutyl acrylate Polyethylene glycols, hydroxypropylene polymers, polyvinyl alcohols, hydrolyzed polyvinyl acetate, polyvinyl formal, polyvinyl butyral, polyvinyl pyrrolidone, acrylamide homopolymers and copolymers having a hydrolysis degree of 60 mol% or more, preferably 80 mol% or more , Homopolymers and polymers of methacrylamide, homopolymers and copolymers of N-methylolacrylamide, polyvinylpyrrolidone, alcohol-soluble nylon, polyether of 2,2-bis- (4-hydroxyphenyl) -propane and epichlorohydrin, etc. Is mentioned.

  The binder polymer preferably has a mass average molar mass of 5000 or more, more preferably 10,000 to 300,000, and a number average molar mass of 1000 or more, preferably 2000 to 250,000. Is more preferable. The polydispersity (mass average molar mass / number average molar mass) is preferably 1.1 to 10.

  The binder polymer can be obtained by purchasing a commercial product or synthesizing it by a known method.

The content of the binder polymer is 5 to 90% by mass, preferably 5 to 80% by mass, and more preferably 10 to 70% by mass with respect to the total solid content of the image recording layer. Within this range, good image area strength and image formability can be obtained.
Further, (C) the polymerizable compound and the binder polymer are preferably used in a mass ratio of 0.5 / 1 to 4/1.
These binder polymers can reduce halide ions remaining as impurities by removing halides remaining as a reaction catalyst or the like using an ion exchange resin.

<3> Surfactant In the image recording layer of the present invention, a surfactant can be used in order to promote on-press developability and improve the coated surface state. Examples of the surfactant include nonionic surfactants, ionic surfactants, cationic surfactants, amphoteric surfactants, and fluorosurfactants. Surfactant may be used independently and may be used in combination of 2 or more type. When halide ions are contained as impurities or counter ions in the surfactant, it is preferable to remove or exchange with other anions by a method such as desalting or ion exchange.

  The nonionic surfactant used for this invention is not specifically limited, A conventionally well-known thing can be used. For example, polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenyl ethers, polyoxyethylene polystyryl phenyl ethers, polyoxyethylene polyoxypropylene alkyl ethers, glycerin fatty acid partial esters, sorbitan fatty acid partial esters, pentaerythritol Fatty acid partial esters, propylene glycol mono fatty acid esters, sucrose fatty acid partial esters, polyoxyethylene sorbitan fatty acid partial esters, polyoxyethylene sorbitol fatty acid partial esters, polyethylene glycol fatty acid esters, polyglycerin fatty acid partial esters, Polyoxyethylenated castor oil, polyoxyethylene glycerin fatty acid partial esters, fatty acid diethanolamides, N N- bis-2-hydroxyalkylamines, polyoxyethylene alkylamines, triethanolamine fatty acid ester, trialkylamine oxide, polyethylene glycol, copolymers of polyethylene glycol and polypropylene glycol.

  The ionic surfactant used in the present invention is not particularly limited, and conventionally known ionic surfactants can be used. For example, fatty acid salts, abietic acid salts, hydroxyalkane sulfonates, alkane sulfonates, dialkyl sulfosuccinate esters, linear alkyl benzene sulfonates, branched alkyl benzene sulfonates, alkyl naphthalene sulfonates, alkyl phenoxy poly Oxyethylene propyl sulfonates, polyoxyethylene alkyl sulfophenyl ether salts, N-methyl-N-oleyl taurine sodium salt, N-alkyl sulfosuccinic acid monoamide disodium salt, petroleum sulfonates, sulfated beef oil, fatty acid alkyl esters Sulfates, alkyl sulfates, polyoxyethylene alkyl ether sulfates, fatty acid monoglyceride sulfates, polyoxyethylene alcohol Ruphenyl ether sulfates, polyoxyethylene styryl phenyl ether sulfates, alkyl phosphates, polyoxyethylene alkyl ether phosphates, polyoxyethylene alkyl phenyl ether phosphates, styrene / maleic anhydride Examples thereof include partial saponification products of polymers, partial saponification products of olefin / maleic anhydride copolymers, and naphthalene sulfonate formalin condensates.

The cationic surfactant used in the present invention is not particularly limited, and conventionally known cationic surfactants can be used. Examples thereof include alkylamine salts, quaternary ammonium salts, polyoxyethylene alkylamine salts, and polyethylene polyamine derivatives. As the counter anion of the cationic surfactant, it is preferable to select one other than halide ions (sulfate ion, hydrogen sulfate ion, hydroxide ion, phosphate ion, alkyl sulfonate ion, aryl sulfonate ion, etc.). .
The amphoteric surfactant used in the present invention is not particularly limited, and conventionally known amphoteric surfactants can be used. Examples thereof include carboxybetaines, aminocarboxylic acids, sulfobetaines, aminosulfuric esters, and imidazolines.

  Of the above surfactants, the term “polyoxyethylene” can be read as “polyoxyalkylene” such as polyoxymethylene, polyoxypropylene, polyoxybutylene, etc. These surfactants can also be used.

  More preferable surfactants include fluorine-based surfactants containing a perfluoroalkyl group in the molecule. Examples of such fluorosurfactants include ionic types such as perfluoroalkyl carboxylates, perfluoroalkyl sulfonates, and perfluoroalkyl phosphates; amphoteric types such as perfluoroalkyl betaines; Cation type such as trimethylammonium salt; perfluoroalkylamine oxide, perfluoroalkylethylene oxide adduct, oligomer containing perfluoroalkyl group and hydrophilic group, oligomer containing perfluoroalkyl group and lipophilic group, perfluoroalkyl Nonionic types such as an oligomer containing a group, a hydrophilic group and a lipophilic group, and a urethane containing a perfluoroalkyl group and a lipophilic group. Moreover, the fluorine-type surfactant described in each gazette of Unexamined-Japanese-Patent No. 62-170950, 62-226143, and 60-168144 is also mentioned suitably.

Surfactant can be used individually or in combination of 2 or more types.
The content of the surfactant is preferably 0.001 to 10% by mass and more preferably 0.01 to 5% by mass with respect to the total solid content of the image recording layer.

<4> Colorant In the image recording layer of the present invention, a dye having a large absorption in the visible light region can be used as an image colorant. 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 (orientated chemistry) Kogyo Co., Ltd.), Victoria Pure Blue, Crystal Violet (CI42555), Methyl Violet (CI42535), Ethyl Violet, Rhodamine B (CI145170B), Malachite Green (CI42000), Methylene Blue (CI522015), etc., and JP-A-62-2 And dyes described in No. 293247. Also, pigments such as phthalocyanine pigments, azo pigments, carbon black, titanium oxide, etc. can be suitably used.
When these colorants are used, it is easy to distinguish between an image area after image formation and a non-image area, so it is preferable to add them. The addition amount is 0.01 to 10% by mass with respect to the total solid content of the image recording material.

<5> Print-out agent To the image-recording layer of the invention, a compound that changes color by an acid or a radical can be added in order to produce a print-out image. As such a compound, for example, various dyes such as diphenylmethane, triphenylmethane, thiazine, oxazine, xanthene, anthraquinone, iminoquinone, azo, and azomethine are effectively used.

  Specific examples include brilliant green, ethyl violet, methyl green, crystal violet, basic fuchsin, methyl violet 2B, quinaldine red, rose bengal, methanyl yellow, thymol sulfophthalein, xylenol blue, methyl orange, paramethyl red, Congo Fred, Benzopurpurin 4B, α-Naphthyl Red, Nile Blue 2B, Nile Blue A, Methyl Violet, Malachite Green, Parafuchsin, Victoria Pure Blue BOH [manufactured by Hodogaya Chemical Co., Ltd.], Oil Blue # 603 [Orient Chemical Industry Co., Ltd.], Oil Pink # 312 [Made by Orient Chemical Co., Ltd.], Oil Red 5B [Made by Orient Chemical Co., Ltd.], Oil Scarlet # 308 [Orient Gaku Kogyo Co., Ltd.], Oil Red OG [Orient Chemical Co., Ltd.], Oil Red RR [Orient Chemical Co., Ltd.], Oil Green # 502 [Orient Chemical Co., Ltd.], Spiron Red BEH Special [made by Hodogaya Chemical Co., Ltd.], m-cresol purple, cresol red, rhodamine B, rhodamine 6G, sulforhodamine B, auramine, 4-p-diethylaminophenyliminonaphthoquinone, 2-carboxyanilino-4-p- Diethylaminophenyliminonaphthoquinone, 2-carboxystearylamino-4-pN, N-bis (hydroxyethyl) amino-phenyliminonaphthoquinone, 1-phenyl-3-methyl-4-p-diethylaminophenylimino-5-pyrazolone, 1-β-naphthyl-4- - dyes and p of diethylamino phenyl imino-5-pyrazolone, p ', p "- hexamethyl triamnotriphenylmethane (leuco crystal violet), and a leuco dye such as Pergascript Blue SRB (manufactured by Ciba-Geigy).

  In addition to the above, a leuco dye known as a material for thermal paper or pressure-sensitive paper is also suitable. Specific examples include crystal violet lactone, malachite green lactone, benzoylleucomethylene blue, 2- (N-phenyl-N-methylamino) -6- (Np-tolyl-N-ethyl) amino-fluorane, 2-anilino. -3-methyl-6- (N-ethyl-p-toluidino) fluorane, 3,6-dimethoxyfluorane, 3- (N, N-diethylamino) -5-methyl-7- (N, N-dibenzylamino) ) -Fluorane, 3- (N-cyclohexyl-N-methylamino) -6-methyl-7-anilinofluorane, 3- (N, N-diethylamino) -6-methyl-7-anilinofluorane, 3 -(N, N-diethylamino) -6-methyl-7-xylidinofluorane, 3- (N, N-diethylamino) -6-methyl-7-chloro Fluorane, 3- (N, N-diethylamino) -6-methoxy-7-aminofluorane, 3- (N, N-diethylamino) -7- (4-chloroanilino) fluorane, 3- (N, N-diethylamino) -7-chlorofluorane, 3- (N, N-diethylamino) -7-benzylaminofluorane, 3- (N, N-diethylamino) -7,8-benzofluorane, 3- (N, N-dibutyl) Amino) -6-methyl-7-anilinofluorane, 3- (N, N-dibutylamino) -6-methyl-7-xylidinofluorane, 3-piperidino-6-methyl-7-anilinofluorane 3-pyrrolidino-6-methyl-7-anilinofluorane, 3,3-bis (1-ethyl-2-methylindol-3-yl) phthalide, 3,3-bis (1-n-butyl- -Methylindol-3-yl) phthalide, 3,3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide, 3- (4-diethylamino-2-ethoxyphenyl) -3- (1-ethyl- 2-methylindol-3-yl) -4-zaphthalide, 3- (4-diethylaminophenyl) -3- (1-ethyl-2-methylindol-3-yl) phthalide, and the like.

  A suitable addition amount of the dye that changes color by an acid or radical is 0.01 to 10% by mass with respect to the solid content of the image recording layer.

<6> Polymerization inhibitor A small amount of a thermal polymerization inhibitor is added to the image recording layer of the present invention in order to prevent unnecessary thermal polymerization of the polymerizable compound (C) during the production or storage of the image recording layer. It is preferable to do this.
Examples of the thermal polymerization inhibitor 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 are preferred. The addition amount of the thermal polymerization inhibitor is preferably about 0.01 to about 5% by mass with respect to the total solid content of the image recording layer.

<7> Higher fatty acid derivatives and the like In the image recording layer of the present invention, a higher fatty acid derivative such as behenic acid and behenic acid amide is added to prevent polymerization inhibition due to oxygen, and a drying process after coating. May be unevenly distributed on the surface of the image recording layer. The amount of the higher fatty acid derivative added is preferably about 0.1 to about 10% by mass with respect to the total solid content of the image recording layer.

<8> Plasticizer The image recording layer of the present invention may contain a plasticizer in order to improve the on-press developability.
Examples of the plasticizer include phthalates such as dimethyl phthalate, diethyl phthalate, dibutyl phthalate, diisobutyl phthalate, dioctyl phthalate, octyl capryl phthalate, dicyclohexyl phthalate, ditridecyl phthalate, butyl benzyl phthalate, diisodecyl phthalate, diallyl phthalate; Glycol esters such as glycol phthalate, ethyl phthalyl ethyl glycolate, methyl phthalyl ethyl glycolate, butyl phthalyl butyl glycolate, triethylene glycol dicaprylate; Phosphate esters such as tricresyl phosphate and triphenyl phosphate Diisobutyl adipate, dioctyl adipate, dimethyl sebacate, dibutyl sebacate, dioct Ruazereto, aliphatic dibasic acid esters such as dibutyl maleate; polyglycidyl methacrylate, triethyl citrate, glycerin triacetyl ester, butyl laurate in.
The plasticizer content is preferably about 30% by mass or less based on the total solid content of the image recording layer.

<9> Inorganic fine particles The image recording layer of the present invention may contain inorganic fine particles in order to improve the cured film strength and on-press developability.
As the inorganic fine particles, for example, silica, alumina, magnesium oxide, titanium oxide, magnesium carbonate, calcium alginate, or a mixture thereof is preferably exemplified. These can be used for strengthening the film, strengthening the interfacial adhesion by surface roughening, and the like.
The inorganic fine particles preferably have an average particle size of 5 nm to 10 μm, and more preferably 0.5 μm to 3 μm. Within the above range, it is possible to form a non-image portion having excellent hydrophilicity, which is stably dispersed in the image recording layer, sufficiently retains the film strength of the image recording layer, and hardly causes stains during printing.
The inorganic fine particles as described above can be easily obtained as a commercial product such as a colloidal silica dispersion.
The content of the inorganic fine particles is preferably 40% by mass or less, and more preferably 30% by mass or less, based on the total solid content of the image recording layer.

<10> Hydrophilic low molecular weight compound The image-recording layer of the invention may contain a hydrophilic low molecular weight compound in order to improve the on-press developability. Examples of the hydrophilic low-molecular compound include water-soluble organic compounds such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol and the like, and ether or ester derivatives thereof, glycerin, Polyhydroxys such as pentaerythritol, organic amines such as triethanolamine and diethanolamine monoethanolamine and salts thereof, quaternary ammonium salts, organic sulfonic acids such as alkylsulfonic acid, toluenesulfonic acid and benzenesulfonic acid and salts thereof Organic sulfamic acids such as alkylsulfamic acids and their salts, organic sulfuric acids such as alkylsulfuric acid and alkylethersulfuric acid and their salts, and organic phosphates such as phenylphosphonic acid. Emissions acids and salts thereof, tartaric acid, oxalic acid, citric acid, malic acid, lactic acid, gluconic acid, organic carboxylic acids and salts thereof such as amino acids and the like.

  Among these, organic sulfonic acid, organic sulfamic acid, and sodium salt or lithium salt of organic sulfuric acid are preferably used. By containing these compounds in the image recording layer, it is possible to improve the on-press developability without reducing the printing durability.

  Specific examples of organic sulfonates include sodium normal butyl sulfonate, sodium isobutyl sulfonate, sodium sec-butyl sulfonate, sodium tert-butyl sulfonate, sodium normal pentyl sulfonate, and sodium 1-ethylpropyl sulfonate. Sodium hexyl sulfonate, sodium 1,2-dimethylpropyl sulfonate, sodium 2-ethylbutyl sulfonate, sodium cyclohexyl sulfonate, sodium normal heptyl sulfonate, sodium normal octyl sulfonate, sodium tert-octyl sulfonate, normal Sodium nonyl sulfonate, sodium allyl sulfonate, sodium 2-methylallyl sulfonate, sodium benzene sulfonate Sodium p-toluenesulfonate, sodium p-hydroxybenzenesulfonate, sodium p-styrenesulfonate, dimethyl-5-sulfonate sodium isophthalate, disodium 1,3-benzenedisulfonate, 1,3,5-benzenetri Trisodium sulfonate, sodium p-chlorobenzenesulfonate, sodium 3,4-dichlorobenzenesulfonate, sodium 1-naphthylsulfonate, sodium 2-naphthylsulfonate, sodium 4-hydroxynaphthylsulfonate, 1,5-naphthyldisulfone Examples thereof include disodium acid, disodium 2,6-naphthyldisulfonate, trisodium 1,3,6-naphthyltrisulfonate, and lithium salt exchangers thereof.

  Specific examples of the organic sulfamate include sodium normal butyl sulfamate, sodium isobutyl sulfamate, sodium tert-butyl sulfamate, sodium normal pentyl sulfamate, sodium 1-ethylpropyl sulfamate, sodium normal hexyl sulfamate, Examples include sodium 1,2-dimethylpropylsulfamate, sodium 2-ethylbutylsulfamate, sodium cyclohexylsulfamate, and lithium salt exchangers thereof.

  These compounds have a small hydrophobic part structure and almost no surface-active action, and are clearly distinguished from the above-mentioned surfactants in which long-chain alkyl sulfonates and long-chain alkyl benzene sulfonates are used favorably. .

  As the organic sulfate, a compound represented by the general formula (3) is particularly preferably used.

  In the general formula (3), R represents a substituted or unsubstituted alkyl group, alkenyl group, alkynyl group, aryl group or heterocyclic group, m represents an integer of 1 to 4, and n represents 0 to 4 X represents a counter ion (for example, alkali metal ion (sodium ion, potassium ion, lithium ion), group 2 metal ion, ammonium ion, organic ammonium ion, etc.) necessary for neutralizing the charge. To express. Y represents a hydrogen atom or a substituent. When Y represents a substituent, preferred examples include an alkyl group, an alkenyl group, a hydroxy group, a halogen atom (fluorine, chlorine, bromine) and the like. When n is 2 or more, Y may be one type or two or more types may be combined.

  R is preferably a substituted or unsubstituted, linear, branched or cyclic alkyl group having 1 to 12 carbon atoms, alkenyl group having 1 to 12 carbon atoms, alkynyl group having 1 to 12 carbon atoms, carbon number Examples include 20 or less aryl groups. Examples of the substituent include a linear, branched or cyclic alkyl group having 1 to 12 carbon atoms, an alkenyl group having 1 to 12 carbon atoms, an alkynyl group having 1 to 12 carbon atoms, a halogen atom, and an aryl having 20 or less carbon atoms. Groups.

  Preferred examples of the compound represented by the general formula (3) include sodium oxyethylene-2-ethylhexyl ether sulfate, sodium dioxyethylene-2-ethylhexyl ether sulfate, potassium dioxyethylene-2-ethylhexyl ether sulfate, dioxy Ethylene-2-ethylhexyl ether lithium sulfate, sodium trioxyethylene-2-ethylhexyl ether sulfate, sodium tetraoxyethylene-2-ethylhexyl ether sulfate, sodium dioxyethylene hexyl ether sulfate, sodium dioxyethylene octyl ether sulfate, dioxyethylene Examples include sodium lauryl ether sulfate. The most preferred compounds include sodium dioxyethylene-2-ethylhexyl ether sulfate, potassium dioxyethylene-2-ethylhexyl ether sulfate, lithium dioxyethylene-2-ethylhexyl ether sulfate, sulfoalkyl ether of polyalkyleneoxy monoalkyl ether ( For example, sodium 4- (2-ethylhexyloxy (ethoxy (ethoxy))) butanesulfonate, sodium 4- (2-ethylhexyloxy (ethoxy (ethoxy (ethoxy (ethoxy)))) butanesulfonate, 4- (octyl) Oxy (ethoxy (ethoxy))) butanesulfonate sodium, and the like.

The amount of these low molecular weight hydrophilic compounds added to the image recording layer is preferably 0.5% by mass or more and 20% by mass or less of the total solid content of the image recording layer. More preferably, they are 1 mass% or more and 10 mass% or less, More preferably, they are 2 mass% or more and 8 mass% or less. In this range, good on-press developability and printing durability can be obtained.
These compounds may be used alone or in combination of two or more.

<11> Grease-sensitizing agent In the present invention, a phosphonium compound may be used in combination in order to improve the inking property. The phosphonium compound functions as a surface coating agent (grease sensitizing agent) for the inorganic stratiform compound, and prevents deterioration of the inking property during printing by the inorganic stratiform compound. Suitable phosphonium compounds include phosphonium compounds described in JP-A-2006-297907 and compounds represented by the following general formula (4).

In formula (4), Ar _{1 to} Ar ₆ each independently represents an aryl group or a heterocyclic group, L represents a divalent linking group, X ⁿ⁻ represents an n-valent counter ion, and n represents 1 Represents an integer of ˜3, and m represents a number satisfying nx m = 2.

  Here, as the aryl group, phenyl group, naphthyl group, tolyl group, xylyl group, fluorophenyl group, chlorophenyl group, bromophenyl group, methoxyphenyl group, ethoxyphenyl group, dimethoxyphenyl group, methoxycarbonylphenyl group, dimethylaminophenyl A group and the like are preferable. Examples of the heterocyclic group include a pyridyl group, a quinolyl group, a pyrimidinyl group, a thienyl group, and a furyl group. L is preferably a linking group having 6 to 15 carbon atoms, more preferably a linking group having 6 to 12 carbon atoms.

Preferred examples of X ^n- include sulfonate ion, carboxylate ion, sulfate ion, PF ₆ ⁻ , BF ₄ ⁻ , and the like. Of these, sulfonate ions, carboxylate ions, PF ₆ ⁻ and BF ₄ ⁻ are particularly preferable.

  Specific examples of the phosphonium compound represented by the general formula (4) are shown below.

The amount of the phosphonium compound added to the image recording layer is preferably 0.01 to 20% by mass, more preferably 0.05 to 10% by mass, and most preferably 0.1 to 5% by mass based on the solid content of the image recording layer. . Within these ranges, good ink fillability during printing can be obtained.
The present sensitizer can be added not only to the image recording layer but also to the protective layer.

  In the present invention, a polymer having a repeating unit represented by the following general formula (5) (hereinafter referred to as a specific polymer) can be used as a sensitizer.

In the general formula (5), R ¹¹ represents a hydrogen atom or a substituent. L ¹ represents a divalent linking group, and R ¹² , R ¹³ and R ¹⁴ each independently represents a hydrogen atom or a substituent. X ⁻ represents a counter ion necessary for neutralizing the electric charge.

R ¹¹ represents a hydrogen atom or a substituent. Preferably, it represents a hydrogen atom, an alkyl group, an aryl group, a substituted carbonyl group, a substituted oxy group, a heterocyclic group or a halogen atom, more preferably a hydrogen atom, an alkyl group or a halogen atom, particularly preferably a hydrogen atom or Represents an alkyl group. Most preferred as R ¹¹ is a hydrogen atom or a methyl group.

R ¹² , R ¹³ and R ¹⁴ will be described. R ¹² , R ¹³ and R ¹⁴ each independently represents a hydrogen atom, an alkyl group, an aryl group, a heterocyclic group or an alkylidene group, more preferably a hydrogen atom or an alkyl group, particularly preferably Represents an alkyl group. Provided that one of R ¹² , R ¹³ and R ¹⁴ is an alkylidene group (ie, a divalent group derived by removing one hydrogen atom from a carbon atom having a free valence of a monovalent hydrocarbon group). ) Represents one remaining group that can be substituted for N, and therefore one of R ¹² , R ^13, and R ¹⁴ does not exist. R ¹² , R ¹³ and R ¹⁴ may be bonded to each other to form a ring.

L ¹ represents a single bond or a divalent linking group. When L ¹ is a divalent linking group, 1 to 60 carbon atoms, 0 to 10 nitrogen atoms, 0 to 50 oxygen atoms, 1 to 100 hydrogen atoms , And 0 to 20 sulfur atoms.
More specifically, the following divalent groups or groups formed by appropriately combining these groups can be exemplified.

X ⁻ represents a counter ion necessary for neutralizing the electric charge. As particularly preferred X ⁻ , a carboxylate ion having 1 to 50 carbon atoms, an alkyl sulfonate ion having 1 to 50 carbon atoms, an aryl sulfonate ion having 6 to 50 carbon atoms, an alkyl sulfate ion having 1 to 50 carbon atoms, sulfuric acid Ions, phosphate ions, alkyl phosphate ions having 1 to 50 carbon atoms, alkyl phosphonate ions having 1 to 50 carbon atoms, aryl phosphonate ions having 6 to 50 carbon atoms, PF ₆ ⁻ , BF ₄ ⁻ , and these Combinations are mentioned.

  The specific polymer used for this invention may have copolymerization component units other than the structural unit of General formula (5).

  The specific polymer is contained in at least one of the image recording layer and the protective layer. Further, it may be contained in both the image recording layer and the protective layer. Furthermore, it may be contained in the undercoat layer in addition to the image recording layer and / or the protective layer.

  The content of the specific polymer of the present invention is preferably 0.0005% by mass to 30.0% by mass, more preferably 0.001% by mass to 20.0% by mass with respect to the total solid content of the layer to be contained. 0.002% by mass to 15.0% by mass is most preferable. Within this range, good inking properties can be obtained.

  Although the specific example of a specific polymer is shown below, a specific polymer is not limited to the following example.

<12> Co-sensitizer In the image recording layer of the present invention, a known compound called a chain transfer agent or a co-sensitizer having an action such as further improving sensitivity or suppressing inhibition of polymerization by oxygen is contained. May be added.

  Examples of such compounds include amines such as MR Sander et al., “Journal of Polymer Society”, Vol. 10, page 3173 (1972), Japanese Patent Publication No. 44-20189, Japanese Patent Publication No. 51-82102, Japanese Patent Publication No. 52-134692, JP-A-59-138205, JP-A-60-84305, JP-A-62-18537, JP-A-64-33104, Research Disclosure 33825, and the like, and the like. Specifically, N, N-dialkylaniline derivatives such as triethanolamine, N-phenylglycine, N-phenylaspartic acid, and p-dimethylaminobenzoic acid ethyl ester, p-formyldimethylaniline, p-methylthiodimethylaniline, etc. , Etc.

  Another example of acting as a chain transfer agent is a group of compounds having SH, PH, SiH, GeH in the molecule. These can donate hydrogen to low activity radical species to generate radicals, or can be oxidized and then deprotonated to generate radicals.

  In the image recording layer of the present invention, in particular, thiol compounds (for example, 2-mercaptobenzimidazoles, 2-mercaptobenzthiazoles, 2-mercaptobenzoxazoles, 3-mercaptotriazoles, 5-mercaptotetrazoles, etc.) ) Can be preferably used as a chain transfer agent.

  Especially, the thiol compound represented by following General formula (6) as described in Unexamined-Japanese-Patent No. 2006-091479 etc. is used especially suitably. By using this thiol compound as a chain transfer agent, it avoids odor problems and sensitivity reduction due to evaporation from the image recording layer and diffusion to other layers, and it has excellent storage stability and high sensitivity and high printing durability. A lithographic printing plate precursor is obtained.

  In general formula (6), R represents a hydrogen atom, an alkyl group which may have a substituent, or an aryl group which may have a substituent, and A has a carbon atom together with an N = CN moiety. It represents an atomic group that forms a 5-membered or 6-membered heterocyclic ring, and A may further have a substituent.

  More preferably, those represented by the following general formula (6A) or general formula (6B) are used.

  In general formula (6A) and formula (6B), R represents a hydrogen atom, an alkyl group which may have a substituent, or an aryl group which may have a substituent, X represents a halogen atom, an alkoxyl group, An alkyl group which may have a substituent or an aryl group which may have a substituent is represented.

  Specific examples include 1-methyl-2-mercaptobenzimidazole, 1-propyl-2-mercaptobenzimidazole, 1-hexyl-2-mercaptobenzimidazole, 1-hexyl-2-mercapto-5-chlorobenzimidazole. 1-pentyl-2-mercaptobenzimidazole, 1-octyl-2-mercaptobenzimidazole, 1-octyl-2-mercapto-5-methoxybenzimidazole, 1-cyclohexyl-2-mercaptobenzimidazole, 1-phenyl-2 -Mercaptobenzimidazole, 1-phenyl-2-mercapto-5-methylsulfonylbenzimidazole, 1- (p-tolyl) -2-mercaptobenzimidazole, 1-methoxyethyl-2-mercaptobenzimidazole, 1- Til-2-mercaptonaphthimidazole, 1-methyl-2-mercapto-5-phenyl-1,3,5-triazole, 1-butyl-2-mercapto-5-phenyl-1,3,5-triazole, 1- Heptyl-2-mercapto-5-phenyl-1,3,5-triazole, 1-phenyl-2-mercapto-5-phenyl-1,3,5-triazole, 1-benzyl-2-mercapto-5-phenyl- 1,3,5-triazole, 1-phenethyl-2-mercapto-5-phenyl-1,3,5-triazole, 1-cyclohexyl-2-mercapto-5-phenyl-1,3,5-triazole, 1 -Phenethyl-2-mercapto-5- (3-fluorophenyl) -1,3,5-triazole, 1-phenethyl-2-mercapto-5- (3 Trifluoromethylphenyl) -1,3,5-triazole, 1-benzyl-2-mercapto-5- (p-tolyl) -1,3,5-triazole, 1-benzyl-2-mercapto-5- (4 -Methoxyphenyl) -1,3,5-triazole, 1-benzyl-2-mercapto-5- (p-trifluoromethylphenyl) -1,3,5-triazole, 1-benzyl-2-mercapto-5 (3,5-dichlorophenyl) -1,3,5-triazole, 1-phenyl-2-mercapto-5- (p-tolyl) -1,3,5-triazole, 1-phenyl-2-mercapto-5 (4-methoxyphenyl) -1,3,5-triazole, 1- (1-naphthyl) -2-mercapto-5-phenyl-1,3,5-triazole, 1- (4-bromopheny ) -2-mercapto-5-phenyl-1,3,5-triazole, 1- (4-trifluorophenyl) -2-mercapto-5-phenyl-1,3,5-triazole, 6-bromo-2 -Mercapto-benzimidazole, etc.

  The amount of these chain transfer agents used is preferably 0.01 to 20% by mass, more preferably 0.1 to 15% by mass, based on the total solid content of the image recording layer. More preferably, it is 1.0-10 mass%.

<Formation of image recording layer>
The image recording layer of the present invention is applied by preparing a coating solution by dispersing or dissolving each of the necessary components in a solvent. 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 Examples include ethane, methyl lactate, ethyl lactate, N, N-dimethylacetamide, N, N-dimethylformamide, tetramethylurea, N-methylpyrrolidone, dimethyl sulfoxide, sulfolane, γ-butyllactone, toluene, water, and the like. However, the present invention is not limited to this. These solvents are used alone or in combination. The solid content concentration of the coating solution is preferably 1 to 50% by mass.
The image recording layer of the present invention can be formed by preparing a plurality of coating solutions in which the same or different components are dispersed or dissolved in the same or different solvents, and repeating a plurality of coatings and dryings.

Further, the coating amount (solid content) of the image recording layer on the support obtained after coating and drying varies depending on the use, but generally 0.3 to 3.0 g / m ² is preferable. Within this range, good sensitivity and good film properties of the image recording layer can be obtained.
Various methods can be used as a coating method. Examples thereof include bar coater coating, spin coating, spray coating, curtain coating, dip coating, air knife coating, blade coating, and roll coating.

[Protective layer]
The lithographic printing plate precursor according to the invention has a protective layer containing a layered compound on the image recording layer. The protective layer (also referred to as an overcoat layer) has a function of suppressing an image formation inhibition reaction by blocking oxygen, and also has a function of preventing scratches in the image recording layer and preventing ablation at the time of high-illuminance laser exposure. Hereinafter, the protective layer components and the like will be described.

  Usually, the exposure processing of a lithographic printing plate is carried out in the atmosphere. The image forming reaction in the image recording layer caused by the exposure process can be inhibited by low molecular compounds such as oxygen and basic substances present in the atmosphere. The protective layer prevents low molecular compounds such as oxygen and basic substances from entering the image recording layer, and as a result, suppresses image formation inhibition reaction in the air. Therefore, the property desired for the protective layer is to reduce the permeability of low-molecular compounds such as oxygen, and furthermore, the transparency of light used for exposure is good, and the adhesiveness with the image recording layer is excellent. And it can be easily removed in an on-press development process after exposure. The protective layer having such characteristics is described in, for example, US Pat. No. 3,458,311 and JP-B-55-49729.

The layered compound of the present invention is a particle having a thin flat plate shape, and enables oxygen barrier in a thin layer by gas barrier property by controlling the path length of gas diffusion. As the layer compound, an inorganic compound is preferable. For example, the following general formula
A (B, C) _2-5 D ₄ O ₁₀ (OH, F, O) ₂
[However, A is any of Li, K, Na, Ca, Mg, organic cation, B and C are any of Fe (II), Fe (III), Mn, Al, Mg, V, and D is Si or Al. And mica groups such as natural mica and synthetic mica, talc, teniolite, montmorillonite, saponite, hectorite, zirconium phosphate and the like represented by the formula 3MgO.4SiO.H ₂ O.
Examples of the natural mica include muscovite, soda mica, phlogopite, biotite and sericite. In addition, examples of the synthetic mica include non-swelling mica such as fluorine phlogopite mica ₃ (AlSi ₃ O ₁₀ ) F ₂ , potassium tetrasilicon mica KMg _2.5 Si ₄ O ₁₀ ) F ₂ , and Na tetrasilicic mica NaMg _2.5 (Si ₄ O ₁₀ ) F ₂ , Na or Li Teniolite (Na, Li) Mg ₂ Li (Si ₄ O ₁₀ ) F ₂ , Montmorillonite-based Na or Li Hectorite (Na, Li) _1/8 Mg Swellable mica such as _2/5 Li _1/8 (Si ₄ O ₁₀ ) F ₂ can be used. Synthetic smectite is also useful.

Of the above layered compounds, fluorine-based swellable mica, which is a synthetic layered compound, is particularly useful. That is, swellable clay minerals such as mica, montmorillonite, saponite, hectorite, bentonite, etc. have a laminated structure composed of unit crystal lattice layers with a thickness of about 10 to 15 mm, and metal atom substitution in the lattice is other than Significantly greater than viscous minerals. As a result, the lattice layer is deficient in positive charge, and in order to compensate for it, organic cations such as Li ⁺ , Na ⁺ , Ca ²⁺ , Mg ²⁺ , amine salts, quaternary ammonium salts, phosphonium salts and sulfonium salts are used between Adsorbs cations. These layered compounds swell with water. If shear is applied in this state, it will easily cleave and form a stable sol in water. Bentonite and swelling synthetic mica have this tendency.

As the shape of the layered compound, from the viewpoint of diffusion control, the thinner the better, the better the plane size as long as the smoothness of the coated surface and the transmittance of actinic rays are not impaired. Accordingly, the aspect ratio is 20 or more, preferably 100 or more, particularly preferably 200 or more. The aspect ratio is the ratio of the thickness to the major axis of the particle, and can be measured, for example, from a projected view of the particle by a micrograph. The larger the aspect ratio, the greater the effect that can be obtained.
As for the particle diameter of the layered compound, the average major axis is 0.3 to 20 μm, preferably 0.5 to 10 μm, particularly preferably 1 to 5 μm. When the particle diameter is smaller than 0.3 μm, the suppression of permeation of oxygen and moisture is insufficient, and the effect cannot be sufficiently exhibited. On the other hand, if it is larger than 20 μm, the dispersion stability in the coating solution is insufficient, resulting in a problem that stable coating cannot be performed. The average thickness of the particles is 0.1 μm or less, preferably 0.05 μm or less, and particularly preferably 0.01 μm or less. For example, among the inorganic layered compounds, the size of the swellable synthetic mica that is a representative compound is about 1 to 50 nm in thickness and about 1 to 20 μm in surface size.

  When the inorganic layered compound particles having such a large aspect ratio are contained in the protective layer, the coating film strength is improved, and the permeation of oxygen and moisture can be effectively prevented. Deterioration is prevented, and even when stored for a long time under high-humidity conditions, the storage stability of the planographic printing plate precursor does not deteriorate due to changes in humidity, and the storage stability is excellent.

  Next, an example of a general dispersion method when a layered compound is used for the protective layer will be described. First, 5 to 10 parts by mass of the swellable laminar compound mentioned above as a preferred laminar compound is added to 100 parts by mass of water, and the mixture is thoroughly swelled and swollen. Examples of the disperser used here include various mills that disperse mechanically by applying a direct force, a high-speed stirring disperser having a large shearing force, and a disperser that provides high-intensity ultrasonic energy. Specifically, ball mill, sand grinder mill, visco mill, colloid mill, homogenizer, tisol bar, polytron, homomixer, homo blender, ketdy mill, jet agitator, capillary emulsifier, liquid siren, electrostrictive ultrasonic generator, An emulsifying device having a Paulman whistle can be used. A dispersion of 5 to 10% by mass of the inorganic stratiform compound dispersed by the above method is highly viscous or gelled and has very good storage stability. When preparing a protective layer coating solution using this dispersion, it is preferably prepared by diluting with water and stirring sufficiently, and then blending with a binder solution.

  It is preferable that content of the inorganic stratiform compound in a protective layer is 5/1-1/100 by mass ratio with respect to the quantity of the binder used for a protective layer. Even when a plurality of types of inorganic layered compounds are used in combination, the total amount of these inorganic layered compounds is preferably the above-described mass ratio.

The inorganic layered compound can be added not only to the protective layer but also to the image recording layer. Addition of an inorganic layered compound to the image recording layer is useful for improving printing durability, polymerization efficiency (sensitivity), and stability over time.
The amount of the inorganic stratiform compound added to the image recording layer is preferably from 0.1 to 50 mass%, more preferably from 0.3 to 30 mass%, most preferably from 1 to 10 mass%, based on the solid content of the image recording layer. preferable.

  As the binder used in the protective layer, any of water-soluble polymers and water-insoluble polymers can be appropriately selected and used. Specifically, for example, polyvinyl alcohol, modified polyvinyl alcohol, polyvinyl pyrrolidone, polyvinyl imidazole, polyacrylic acid, polyacrylamide, partially saponified product of polyvinyl acetate, ethylene-vinyl alcohol copolymer, water-soluble cellulose derivative, gelatin, starch Examples thereof include water-soluble polymers such as derivatives and gum arabic, and polymers such as polyvinylidene chloride, poly (meth) acrylonitrile, polysulfone, polyvinyl chloride, polyethylene, polycarbonate, polystyrene, polyamide, and cellophane. These may be used in combination of two or more as required.

  A relatively useful material among the above is a water-soluble polymer compound having excellent crystallinity. Specifically, water-soluble acrylic resins such as polyvinyl alcohol, polyvinyl pyrrolidone, polyvinyl imidazole, and polyacrylic acid, gelatin, gum arabic, and the like are suitable. Among these, water can be applied as a solvent, and at the time of printing Polyvinyl alcohol, polyvinyl pyrrolidone, and polyvinyl imidazole are preferable from the viewpoint that they are easily removed by the fountain solution. Among them, polyvinyl alcohol (PVA) gives the best results for basic properties such as oxygen barrier properties and development removability.

  The polyvinyl alcohol that can be used in the protective layer may be partially substituted with esters, ethers, and acetals as long as they contain a substantial amount of unsubstituted vinyl alcohol units having the required water solubility. Similarly, a part may contain other copolymerization components. For example, various hydrophilic modification sites such as ion modification sites modified with ions such as carboxyl groups and sulfo groups, cation modification sites modified with cations such as amino groups and ammonium groups, silanol modification sites, and thiol modification sites are randomly selected. Polyvinyl alcohol having various degrees of polymerization, the above-mentioned ion-modified site, the above-mentioned cation-modified site, the silanol-modified site, the thiol-modified site, the alkoxyl-modified site, the sulfide-modified site, and the ester modification of vinyl alcohol and various organic acids. Polyvinyl alcohol having various degrees of polymerization having various modified sites such as a site, an ester-modified site of the ion-modified site and alcohols, an epoxy-modified site, and the like are preferably used.

  Preferred examples of the polyvinyl alcohol include compounds having a hydrolysis degree of 71 to 100 mol% and a polymerization degree of 300 to 2400. Specifically, Kuraray Co., Ltd. PVA-105, PVA-110, PVA-117, PVA-117H, PVA-120, PVA-124, PVA-124H, PVA-CS, PVA-CST, PVA-HC, PVA-203, PVA-204, PVA-205, PVA-210, PVA-217, PVA-220, PVA-224, PVA-217EE, PVA-217E, PVA-220E, PVA-224E, PVA-405, PVA- 420, PVA-613, L-8 and the like. Examples of the modified polyvinyl alcohol include KL-318, KL-118, KM-618, KM-118, SK-5102 having an ion-modified site, C-318, C-118, and CM-318 having a cation-modified site. M-205 and M-115 having terminal thiol modification sites, MP-103, MP-203, MP-102, MP-202 having terminal sulfide modification sites, and ester modification sites with higher fatty acids HL-12E, HL-1203, and other reactive silane-modified R-1130, R-2105, R-2130, and the like.

  As other additives for the protective layer, glycerin, dipropylene glycol and the like can be added in an amount corresponding to several mass% with respect to the water-soluble or water-insoluble polymer to give flexibility. An ionic surfactant such as sodium alkyl sulfonate; an amphoteric surfactant such as alkylaminocarboxylate and alkylaminodicarboxylate; and a nonionic surfactant such as polyoxyethylene alkylphenyl ether can be added. These active agents can be added in an amount of 0.1 to 100% by mass with respect to the water-soluble or water-insoluble polymer.

  In order to improve the adhesion to the image area, for example, JP-A-49-70702 and British Patent Application No. 1303578 include an acrylic polymer in a hydrophilic polymer mainly composed of polyvinyl alcohol. It is described that sufficient adhesion can be obtained by mixing 20 to 60% by mass of a water-based emulsion, a water-insoluble vinylpyrrolidone-vinyl acetate copolymer and the like, and laminating the mixture on an image recording layer. Any of these known techniques can be used in the present invention.

  Furthermore, other functions can be imparted to the protective layer. For example, by adding a colorant (for example, a water-soluble dye) that is excellent in the transparency of infrared rays used for exposure and that can efficiently absorb light of other wavelengths, safe light is not caused. Suitability can be improved.

The protective layer is formed by applying and drying a protective layer coating solution prepared by dispersing or dissolving the protective layer component in a solvent on the image recording layer. The coating solvent can be appropriately selected in relation to the binder, but when a water-soluble polymer is used, it is preferable to use distilled water or purified water.
This protective layer coating solution includes known ionic surfactants for improving coating properties, nonionic surfactants, cationic surfactants, fluorine-based surfactants and water-soluble plasticizers for improving physical properties of films. Additives can be added. Examples of the water-soluble plasticizer include propionamide, cyclohexanediol, glycerin, sorbitol and the like. A water-soluble (meth) acrylic polymer can also be added. Furthermore, a known additive for improving the adhesion with the image recording layer and the temporal stability of the coating solution may be added to the coating solution.
The method for applying the protective layer is not particularly limited, and a known method such as the method described in US Pat. No. 3,458,311 or Japanese Patent Publication No. 55-49729 can be applied. . Specific examples of the protective layer include blade coating, air knife coating, gravure coating, roll coating coating, spray coating, dip coating, and bar coating.

The coating amount of the protective layer, the coating amount after drying is preferably in the range of 0.02 to 3 g / ^{m 2,} more preferably in the range of 0.05 to 1 g / ^{m 2,} and most preferably 0. The range is 1 to 0.4 g / m ² .

(Undercoat layer)
In the lithographic printing plate precursor according to the invention, particularly in the case of an on-press development type lithographic printing plate precursor, an undercoat layer is provided between the image recording layer and the support, if necessary. The undercoat layer may contain a specific development accelerator.
Since the undercoat layer tends to cause the image recording layer to peel off from the support in the unexposed area, the on-press developability is improved. In addition, in the case of infrared laser exposure, since the undercoat layer functions as a heat insulating layer, the heat generated by exposure does not diffuse to the support and can be used efficiently, so that the sensitivity can be increased. is there.
Specific examples of the undercoat layer compound (undercoat compound) include silane coupling agents having an addition-polymerizable ethylenic double bond reactive group described in JP-A-10-282679, Preferable examples include phosphorus compounds having an ethylenic double bond reactive group described in Kaihei 2-304441.
The most preferable undercoat compound includes a polymer resin obtained by copolymerizing a monomer having an adsorptive group, a monomer having a hydrophilic group, and a monomer having a crosslinkable group.

An essential component of the undercoat polymer resin is an adsorptive group on the hydrophilic support surface. The presence or absence of adsorptivity on the surface of the hydrophilic support can be determined by the following method, for example.
A coating night is prepared by dissolving the test compound in a readily soluble solvent, and the coating night is coated and dried on the support so that the coating amount after drying is 30 mg / m ² . Next, the support on which the test compound is applied is sufficiently washed with an easily soluble solvent, and then the residual amount of the test compound that has not been removed by washing is measured to calculate the amount of adsorption of the support. Here, the measurement of the remaining amount may be performed by directly quantifying the amount of the remaining compound or by quantifying the amount of the test compound dissolved in the cleaning liquid. The compound can be quantified by, for example, fluorescent X-ray measurement, reflection spectral absorbance measurement, liquid chromatography measurement and the like. The compound having support adsorptivity is a compound that remains at 1 mg / m ² or more even after the above-described washing treatment.

The adsorptive group on the surface of the hydrophilic support is a substance (for example, metal, metal oxide) or a functional group (for example, hydroxy group) existing on the surface of the hydrophilic support, and a chemical bond (for example, ionic bond, hydrogen). Bond, coordination bond, bond by intermolecular force). The adsorptive group is preferably an acid group or a cationic group.
The acid group preferably has an acid dissociation constant (pKa) of 7 or less. Examples of the acid group include a phenolic hydroxy group, a carboxyl _{group, -SO 3 H, -OSO 3 H} , -PO 3 H 2, -OPO 3 H 2, -CONHSO 2 -, - SO 2 NHSO 2 - and -COCH ₂ COCH ₃ is included. Among them -OPO ₃ H ₂ and _-PO 3 _{H 2} are particularly preferred. These acid groups may be metal salts.
The cationic group is preferably an onium group. Examples of the onium group include an ammonium group, a phosphonium group, an arsonium group, a stibonium group, an oxonium group, a sulfonium group, a selenonium group, a stannonium group, and an iodonium group. An ammonium group, a phosphonium group and a sulfonium group are preferred, an ammonium group and a phosphonium group are more preferred, and an ammonium group is most preferred.

  Particularly preferable examples of the monomer having an adsorptive group include compounds represented by the following formula (U1) or (U2).

In the above formula, R ¹ , R ² and R ³ are each independently a hydrogen atom, a halogen atom or an alkyl group having 1 to 6 carbon atoms. R ¹ , R ² and R ³ are each independently preferably a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. More preferred is a hydrogen atom or a methyl group. R ² and R ³ are particularly preferably a hydrogen atom. Z is a functional group that adsorbs to the surface of the hydrophilic support.
In the formula (U1), X is an oxygen atom (—O—) or imino (—NH—). X is more preferably an oxygen atom. In the formula (U1), L is a divalent linking group. L is a divalent aliphatic group (alkylene group, substituted alkylene group, alkenylene group, substituted alkenylene group, alkynylene group, substituted alkynylene group), divalent aromatic group (arylene group, substituted arylene group) or divalent Or an oxygen atom (—O—), a sulfur atom (—S—), an imino (—NH—), a substituted imino (—NR—, where R is an aliphatic group, an aromatic group. Or a combination with a heterocyclic group) or carbonyl (—CO—).
The aliphatic group may have a cyclic structure or a branched structure. The number of carbon atoms in the aliphatic group is preferably 1 to 20, more preferably 1 to 15, and most preferably 1 to 10. The aliphatic group is preferably a saturated aliphatic group rather than an unsaturated aliphatic group. The aliphatic group may have a substituent. Examples of the substituent include a halogen atom, a hydroxy group, an aromatic group, and a heterocyclic group.
The number of carbon atoms in the aromatic group is preferably 6 to 20, more preferably 6 to 15, and most preferably 6 to 10. The aromatic group may have a substituent. Examples of the substituent include a halogen atom, a hydroxy group, an aliphatic group, an aromatic group, and a heterocyclic group.
The heterocyclic group preferably has a 5-membered or 6-membered ring as the heterocycle. The heterocycle may be condensed with another heterocycle, aliphatic ring or aromatic ring. The heterocyclic group may have a substituent. Examples of the substituent include a halogen atom, a hydroxy group, an oxo group (═O), a thioxo group (═S), an imino group (═NH), a substituted imino group (═N—R, R is an aliphatic group, aromatic Group or heterocyclic group), aliphatic group, aromatic group and heterocyclic group.
L is preferably a divalent linking group containing a plurality of polyoxyalkylene structures. The polyoxyalkylene structure is more preferably a polyoxyethylene structure. In other words, L preferably contains — (OCH ₂ CH ₂ ) _n — (n is an integer of 2 or more).
In the formula (U2), Y is a carbon atom or a nitrogen atom. When Y is a nitrogen atom and L is connected to Y to form a quaternary pyridinium group, Z itself is adsorbable, so Z is not essential, and Z may be a hydrogen atom. L represents the same divalent linking group or single bond as in formula (U1).

The adsorptive functional group is as described above.
Examples of typical compounds represented by formula (U1) or (U2) are shown below.

  Examples of the hydrophilic group of the undercoat polymer resin that can be used in the present invention include a hydroxy group, a carboxyl group, a carboxylate group, a hydroxyethyl group, a polyoxyethyl group, a hydroxypropyl group, a polyoxypropyl group, and an amino group. Preferred examples include a group, aminoethyl group, aminopropyl group, ammonium group, amide group, carboxymethyl group, sulfo group, and phosphate group. Among these, a monomer having a sulfo group exhibiting high hydrophilicity is preferable. Specific examples of the monomer having a sulfo group include methallyloxybenzenesulfonic acid, allyloxybenzenesulfonic acid, allylsulfonic acid, vinylsulfonic acid, p-styrenesulfonic acid, methallylsulfonic acid, acrylamide t-butylsulfonic acid, Examples include 2-acrylamido-2-methylpropanesulfonic acid, (3-acryloyloxypropyl) butylsulfonic acid sodium salt, and amine salt. Of these, 2-acrylamido-2-methylpropanesulfonic acid sodium salt is preferred in view of hydrophilic performance and handling of synthesis.

  The water-soluble polymer resin for the undercoat layer of the present invention preferably has a crosslinkable group. The crosslinkable group can improve the adhesion with the image area. In order to make the polymer resin for the undercoat layer crosslinkable, a crosslinkable functional group such as an ethylenically unsaturated bond is introduced into the side chain of the polymer, or the polar substituent of the polymer resin is countercharged. Or a compound having an ethylenically unsaturated bond may be introduced by forming a salt structure.

  Examples of polymers having an ethylenically unsaturated bond in the side chain of the molecule are polymers of esters or amides of acrylic acid or methacrylic acid where the ester or amide residue (R of -COOR or -CONHR) is Mention may be made of polymers having an ethylenically unsaturated bond.

Examples of the residue (the R) having an ethylenically unsaturated _{bond, -CH = CH 2, -C (} CH 3) = CH 2, - (CH 2) n CR 1 = CR 2 R 3, - ( _{CH 2 O) n CH 2 CR} 1 = CR 2 R 3, - (CH 2 CH 2 O) n CH 2 CR 1 = CR 2 R 3, - (CH 2) n NH-CO-O-CH 2 CR 1 = CR ₂ R ₃ ,-(CH ₂ ) _n -O-CO-CR ₁ = CR ₂ R ₃ and (CH ₂ CH ₂ O) ₂ -X (wherein R _{1 to} R ₃ are each a hydrogen atom Represents a halogen atom or an alkyl group having 1 to 20 carbon atoms, an aryl group, an alkoxy group or an aryloxy group, and R ₁ and R ₂ or R ₃ may be bonded to each other to form a ring. Represents an integer of 1 to 10. X represents a dicyclopentadienyl residue. it can.
Specific examples of the ester residue include —CH═CH ₂ , —C (CH ₃ ) ═CH ₂ , —CH ₂ CH═CH ₂ (described in Japanese Patent Publication No. 7-21633), —CH. _{2 CH 2 O-CH 2 CH} = CH 2, -CH 2 C (CH 3) = CH 2, -CH 2 CH = CH-C 6 H 5, -CH 2 CH 2 OCOCH = CH-C 6 H 5, _{-CH 2 CH 2 NHCOO-CH 2} CH = CH 2, and _CH 2 _CH (wherein, X represents a dicyclopentadienyl residue.) 2 O-X and the like.
Specific examples of the amide residue include —CH═CH ₂ , —C (CH ₃ ) ═CH ₂ , —CH ₂ CH═CH ₂ , —CH ₂ CH ₂ O—Y (wherein Y is a cyclohexene residue) the _{represented), -. CH 2 CH 2} OCO-CH = CH 2 and the like.
As the monomer having a crosslinkable group of the polymer resin for the undercoat layer, an ester or amide of acrylic acid or methacrylic acid having the crosslinkable group is preferable.

  The content of the crosslinkable group in the polymer resin for the undercoat layer (content of unsaturated double bond capable of radical polymerization by iodine titration) is preferably 0.1 to 10.0 mmol per 1 g of the polymer resin. Preferably it is 1.0-7.0 mmol, Most preferably, it is 2.0-5.5 mmol. Within this range, both good sensitivity and dirtiness and good storage stability can be obtained.

The polymer resin for the undercoat layer preferably has a mass average molar mass of 5000 or more, more preferably 10,000 to 300,000, and a number average molar mass of 1000 or more is preferable. More preferably, it is ˜250,000. The polydispersity (mass average molar mass / number average molar mass) is preferably 1.1 to 10.
The polymer resin for the undercoat layer may be any of a random polymer, a block polymer, a graft polymer, and the like, but is preferably a random polymer.

The undercoat polymer resin may be used alone or in combination of two or more. The undercoat layer coating solution is obtained by dissolving the undercoat polymer resin in an organic solvent (for example, methanol, ethanol, acetone, methyl ethyl ketone, etc.) and / or water. The undercoat layer coating solution may contain an infrared absorber.
Various known methods can be used as a method of applying the undercoat layer coating solution to the support. Examples thereof include bar coater coating, spin coating, spray coating, curtain coating, dip coating, air knife coating, blade coating, and roll coating.
The coating amount (solid content) of the undercoat layer is preferably from 0.1-100 mg / ^{m 2,} and more preferably 1 to 30 mg / ^{m 2.}

[Back coat layer]
After the surface treatment is performed on the support or after the undercoat layer is formed, a backcoat layer can be provided on the back surface of the support, if necessary.
Examples of the back coat layer include hydrolysis and polycondensation of organic polymer compounds described in JP-A-5-45885, organic metal compounds or inorganic metal compounds described in JP-A-6-35174, and the like. Preferable examples include a coating layer made of a metal oxide. Of these, the use of silicon alkoxy compounds such as Si (OCH ₃ ) ₄ , Si (OC ₂ H ₅ ) ₄ , Si (OC ₃ H ₇ ) ₄ , Si (OC ₄ H ₉ ) ₄ is inexpensive. It is preferable in that it is easily available.

[Plate making method]
The lithographic printing plate precursor according to the invention is preferably made by on-press development or gum development after image exposure.

(Image exposure)
Examples of the exposure light source of the lithographic printing plate precursor according to the present invention include carbon arc, high-pressure mercury lamp, xenon lamp, metal halide lamp, fluorescent lamp, tungsten lamp, halogen lamp, ultraviolet laser, visible light laser, and infrared light laser. It is done. A laser is particularly preferable, and examples thereof include a solid-state laser and a semiconductor laser that emit infrared light of 760 to 1200 nm, and a semiconductor laser that emits light of 250 to 420 nm. When a laser is used, it is preferable to perform imagewise scanning exposure according to digital data. In order to shorten the exposure time, it is preferable to use a multi-beam laser device.
When an infrared laser is used, the exposure time per pixel is preferably within 20 μs. Moreover, it is preferable that irradiation energy amount is 10-300 mJ / cm < ² >.
When an ultraviolet laser is used, the pixel residence time is preferably as short as possible in order to minimize the competitive reaction with oxygen, and is preferably 1 millisecond or less. More preferably, it is 500 μs or less, and most preferably 100 μs or less. The amount of energy is preferably 0.1 to 10 mJ / cm ² .

(On-press development method)
A step of performing image exposure of the lithographic printing plate precursor, and a printing step of printing by supplying printing ink and dampening water without performing any development treatment on the exposed lithographic printing plate precursor, An unexposed portion of the lithographic printing plate precursor is removed during the printing process. The imagewise exposure may be performed by first mounting the lithographic printing plate precursor on a printing machine, or the exposed lithographic printing plate precursor may be mounted on a printing machine, and then printing using the printing machine. By supplying ink and fountain solution and printing as it is, on-machine development processing at the initial stage of printing, that is, the image recording layer in the unexposed area is removed, and accordingly the hydrophilic support surface is formed. Exposed to become dampening water receiving area and can be printed.
This will be described in more detail below.

  The exposed lithographic printing plate precursor is mounted on a plate cylinder of a printing press. In the case of a printing press equipped with a laser exposure device, image exposure is performed after a lithographic printing plate precursor is mounted on a plate cylinder of the printing press. From the viewpoint of ease of work in a bright room, it is preferable to use an infrared-sensitive lithographic printing plate precursor and expose with an infrared laser.

  After exposing the lithographic printing plate precursor imagewise with an infrared laser and supplying it with dampening water and printing ink without going through a development process such as a wet development process, the exposed part of the image recording layer The image recording layer cured by exposure forms a printing ink receiving portion having an oleophilic surface. On the other hand, in the unexposed area, the uncured image recording layer is removed by dissolution or dispersion by the supplied dampening water and / or printing ink, and a hydrophilic surface is exposed in that area. As a result, the fountain solution adheres to the exposed hydrophilic surface, and the printing ink is deposited on the image recording layer in the exposed area and printing is started.

Here, dampening water or printing ink may be supplied to the printing plate first, but printing is first performed in order to prevent the dampening water from being contaminated by the removed image recording layer components. It is preferable to supply ink. As the fountain solution and printing ink, normal lithographic fountain solution and printing ink are used.
In this way, the lithographic printing plate precursor is subjected to on-press development on an offset printing machine and used as it is for printing a large number of sheets.

(Gum development method)
After the lithographic printing plate precursor is exposed imagewise with a laser, the unexposed portion of the image recording layer may be removed using a gum solution. It is then used for printing. In the present invention, the gum solution means an aqueous solution containing a water-soluble resin. By including a hydrophilic resin, it is possible to protect the hydrophilic support that has been exposed by removing the non-image area, or to protect the image area.
Generally gum arabic with a strong desensitizing action is often used for the gum solution, and an aqueous solution of about 15 to 20% by mass of gum arabic is often used as the gum solution. In addition to gum arabic, various water-soluble resins are used as a desensitizing agent. For example, water-soluble polysaccharides extracted from dextrin, steravic, structan, alginates, polyacrylates, hydroxyethylcellulose, polyvinylpyrrolidone, polyacrylamide, methylcellulose, hydroxypropylcellulose, hydroxymethylcellulose, carboxyalkylcellulose salts, soybean okara In addition, pullulan or pullulan derivatives and polyvinyl alcohol are also preferable.

  Further, as modified starch derivatives, roasted starch such as British gum, enzyme modified dextrins such as enzyme dextrin and shardinger dextrin, oxidized starch shown in solubilized starch, modified starch pregelatinized and unmodified gelatinized starch , Phosphate starch, fat starch, sulfate starch, nitrate starch, xanthate starch, carbamic acid starch and other esterified starch, carboxyalkyl starch, hydroxyalkyl starch, sulfoalkyl starch, cyanoethyl starch, allyl starch, benzyl starch, carbamyl Etherified starch such as ethyl starch and dialkylamino starch, methylol cross-linked starch, hydroxyalkyl cross-linked starch, cross-linked starch such as phosphoric acid cross-linked starch and dicarboxylic acid cross-linked starch, starch polyacrylamide copolymer, starch polyacrylic acid copolymer Starch polyvinyl acetate copolymer, starch polyacrylonitrile copolymer, chaotic starch polyacrylate copolymer, chaotic starch vinyl polymer copolymer, starch polystyrene maleic acid copolymer, starch polyethylene oxide copolymer, Starch graft polymers such as starch polypropylene copolymers are preferred.

  Natural polymers include starches such as candy starch, potato starch, tapioca starch, wheat starch and corn starch, carrageenan, laminaran, seaweed mannan, funari, Irish moss, agar and algae such as sodium alginate. , Plant mucilage such as troroaoy, mannan, quince seed, pectin, tragacanth gum, karaya gum, xanthine gum, guar bin gum, locust bin gum, carob gum, benzoin gum, homopolysaccharides such as dextran, glucan, levan and succinoglucan and santangum Preferred are microbial mucilages such as hetropolysaccharides, proteins such as glue, gelatin, casein and collagen.

  These water-soluble resins can be used in combination of two or more, and can be contained in the gum solution in an amount of preferably 1 to 50% by mass, more preferably 3 to 30% by mass.

  The gum solution used in the present invention contains a pH adjuster, surfactant, preservative, antifungal agent, lipophilic substance, wetting agent, chelating agent, antifoaming agent, etc. in addition to the above desensitizing agent. It can be contained.

  The gum solution is advantageously used in a pH range of 3 to 12, and therefore a pH adjuster is generally added. In order to adjust the pH to 3 to 12, generally, a mineral acid, an organic acid, an inorganic salt or the like is added to the gum solution and adjusted. The addition amount is 0.01-2 mass%. For example, the mineral acid includes nitric acid, sulfuric acid, phosphoric acid, metaphosphoric acid, and the like. Examples of the organic acid include acetic acid, succinic acid, malonic acid, p-toluenesulfonic acid, levulinic acid, phytic acid, organic phosphonic acid, and amino acids such as glycine, α-alanine, and β-alanine. Examples of inorganic salts include magnesium nitrate, primary sodium phosphate, secondary sodium phosphate, primary ammonium phosphate, nickel sulfate, sodium hexametaphosphate, sodium tripolyphosphate, and the like. You may use together at least 1 sort (s) or 2 or more types, such as a mineral acid, an organic acid, or an inorganic salt.

  Examples of the surfactant contained in the gum solution include an anionic surfactant, a cationic surfactant, an amphoteric surfactant, and a nonionic surfactant. Anionic surfactants include fatty acid salts, abietic acid salts, hydroxyalkane sulfonates, alkane sulfonates, α-olefin sulfonates, dialkyl sulfosuccinates, alkyl diphenyl ether disulfonates, linear alkyl benzene sulfonates, branched Chain alkylbenzene sulfonates, alkylnaphthalene sulfonates, alkylphenoxy polyoxyethylene propyl sulfonates, polyoxyethylene alkyl sulfophenyl ether salts, sodium N-methyl-N-oleyl taurate, disodium N-alkylsulfosuccinate monoamide Salts, petroleum sulfonates, sulfated castor oil, sulfated beef tallow oil, fatty acid alkyl ester sulfate esters, alkyl sulfate esters, polyoxy Ethylene alkyl ether sulfates, fatty acid monoglyceride sulfates, polyoxyethylene alkylphenyl ether sulfates, polyoxyethylene styryl phenyl ether sulfates, alkyl phosphates, polyoxyethylene alkyl ether phosphates, polyoxyethylene Examples thereof include alkyl phenyl ether phosphate esters, saponification products of styrene-maleic anhydride copolymers, partial saponification products of olefin-maleic anhydride copolymers, and naphthalene sulfonate formalin condensates. Among these, dialkyl sulfosuccinates, alkyl sulfate esters, alkyl naphthalene sulfonates, α-olefin sulfonates, and alkyl diphenyl ether disulfonates are particularly preferably used.

As the cationic surfactant, alkylamine salts, quaternary ammonium salts and the like are used.
As the amphoteric surfactant, alkyl carboxybetaines, alkyl imidazolines, alkylaminocarboxylic acids and the like are used.

  Nonionic surfactants include polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenyl ethers, polyoxyethylene polystyryl phenyl ether, polyoxyethylene polyoxypropylene alkyl ether, glycerin fatty acid partial esters, sorbitan fatty acid partial esters , Pentaerythritol fatty acid partial esters, propylene glycol monofatty acid esters, sucrose fatty acid partial esters, polyoxyethylene sorbitan fatty acid partial esters, polyoxyethylene sorbitol fatty acid partial esters, polyethylene glycol fatty acid esters, polyglycerin fatty acid partial esters , Polyoxyethylenated castor oil, polyoxyethylene glycerin fatty acid partial esters, fatty acid diethanol Mido, N, N-bis-2-hydroxyalkylamines, polyoxyethylene alkylamine, triethanolamine fatty acid ester, trialkylamine oxide, polypropylene glycol molecular weight 200-5000, trimethylolpropane, glycerin or sorbitol poly Examples include adducts of oxyethylene or polyoxypropylene, and acetylene glycols. Fluorine-based and silicon-based nonionic surfactants can also be used in the same manner.

  Two or more surfactants can be used in combination. The amount used is not particularly limited, but a preferable range is 0.01 to 20% by mass, preferably 0.05 to 10% by mass based on the total mass of the gum solution.

  As the preservative, known materials used in the fields of fiber, wood processing, food, medicine, cosmetics, agricultural chemicals and the like can be used. For example, quaternary ammonium salts, monohydric phenol derivatives, dihydric phenol derivatives, polyhydric phenol derivatives, imidazole derivatives, pyrazolopyrimidine derivatives, monovalent naphthols, carbonates, sulfone derivatives, organotin compounds, cyclopentane derivatives, phenyl derivatives , Phenol ether derivatives, phenol ester derivatives, hydroxylamine derivatives, nitrile derivatives, naphthalenes, pyrrole derivatives, quinoline derivatives, benzothiazole derivatives, secondary amines, 1,3,5 triazine derivatives, thiadiazole derivatives, anilide derivatives, pyrrole derivatives , Halogen derivatives, dihydric alcohol derivatives, dithiols, cyanic acid derivatives, thiocarbamic acid derivatives, diamine derivatives, isothiazole derivatives, monohydric alcohols, saturated aldehydes, Japanese monocarboxylic acid, saturated ether, unsaturated ether, lactone, amino acid derivative, hydantoin, cyanuric acid derivative, guanidine derivative, pyridine derivative, saturated monocarboxylic acid, benzenecarboxylic acid derivative, hydroxycarboxylic acid derivative, biphenyl, hydroxamic acid derivative , Aromatic alcohols, halogenophenol derivatives, benzenecarboxylic acid derivatives, mercaptocarboxylic acid derivatives, quaternary ammonium salt derivatives, triphenylmethane derivatives, hinokitiol, furan derivatives, benzofuran derivatives, acridine derivatives, isoquinoline derivatives, arsine derivatives, thiocarbamine Acid derivatives, phosphate esters, halogenobenzene derivatives, quinone derivatives, benzenesulfonic acid derivatives, monoamine derivatives, organophosphate esters, piperazine derivatives , Phenazine derivatives, pyrimidine derivatives, thiophanate derivatives, imidazoline derivatives, isoxazole derivatives, known preservatives such as ammonium salt derivatives can be used. Particularly preferred preservatives include pyridinethiol-1-oxide salts, salicylic acid and its salts, 1,3,5-trishydroxyethylhexahydro-S-triazine, 1,3,5-trishydroxymethylhexahydro-S- Examples include triazine, 1,2-benzisothiazolin-3-one, 5-chloro-2-methyl-4-isothiazolin-3-one, and 2-bromo-2-nitro-1,3-propanediol. The preferred addition amount is an amount that exerts stability against bacteria, molds, yeasts, etc., and varies depending on the types of bacteria, molds, yeasts, but 0.01 to The range of 4% by mass is preferable, and it is preferable to use two or more preservatives in combination so as to be effective against various molds and bacteria.

  The gum solution can also contain a lipophilic substance. Preferred lipophilic substances include organic carboxylic acids having 5 to 25 carbon atoms such as oleic acid, lanolinic acid, valeric acid, nonylic acid, capric acid, myristic acid, palmitic acid, castor oil and the like. These lipophilic substances can be used alone or in combination of two or more. The lipophilic substance contained in the gum solution is in the range of 0.005 to 10% by mass, more preferably 0.05 to 5% by mass, based on the total mass.

  In addition, glycerin, ethylene glycol, propylene glycol, triethylene glycol, butylene glycol, hexylene glycol, diethylene glycol, dipropylene glycol, glycerin, trimethylolpropane, diglycerin, etc. may be added as a wetting agent to the gum solution as necessary. it can. These wetting agents may be used alone or in combination of two or more. The preferred use amount of these wetting agents is 0.1 to 5% by mass.

  A chelate compound may be added to the gum solution. Usually, the gum solution is usually marketed as a concentrated solution, and is used after being diluted by adding tap water, well water or the like at the time of use. Calcium ions contained in the diluted tap water and well water may adversely affect printing and may cause the printed matter to become dirty. Therefore, the above disadvantages can be eliminated by adding a chelate compound. . Preferred chelate compounds include, for example, ethylenediaminetetraacetic acid, its potassium salt, its sodium salt; diethylenetriaminepentaacetic acid, its potassium salt, its sodium salt; triethylenetetraminehexaacetic acid, its potassium salt, its sodium salt, hydroxyethylethylenediaminetrimethyl Acetic acid, potassium salt, sodium salt; nitrilotriacetic acid, sodium salt; 1-hydroxyethane-1,1-diphosphonic acid, potassium salt, sodium salt; aminotri (methylenephosphonic acid), potassium salt, sodium Examples thereof include organic phosphonic acids such as salts and phosphonoalkanetricarboxylic acids. Organic amine salts are also effective in place of the sodium and potassium salts of the chelating agents. These chelating agents are selected so that they are stably present in the gum solution composition and do not impair the printability. The addition amount is suitably 0.001 to 1.0 mass% with respect to the gum solution at the time of use.

  An antifoaming agent can be added to the gum solution, and a silicon antifoaming agent is particularly preferable. Among them, an emulsified dispersion type and a solubilized type can be used. Preferably, the range of 0.001 to 1.0 mass% is optimal with respect to the gum solution at the time of use.

  The remaining component of the gum solution is water. It is advantageous in terms of transportation that the gum solution is a concentrated solution in which the water content is less than at the time of use, and is diluted with water at the time of use. In this case, the degree of concentration is appropriate such that each component does not cause separation or precipitation. The gum solution may be prepared as an emulsified dispersion type, an organic solvent is used as its oil phase, and it may be made into a solubilized type (emulsified type) with the aid of a surfactant as described above. .

  The organic solvent is preferably an organic solvent having a solubility in water at 20 ° C. of 5% by mass or less and a boiling point of 160 ° C. or more. For example, phthalic acid diester agents such as dibutyl phthalate, diheptyl phthalate, di-n-octyl phthalate, di (2-ethylhexyl) phthalate, dinonyl phthalate, didecyl phthalate, dilauryl phthalate, butyl benzyl phthalate, etc. , Aliphatic dibasic esters such as butyl glycol adipate, dioctyl azelate, dibutyl sebacate, di (2-ethylhexyl) sebacate, dioctyl sebacate, for example, epoxidized triglycerides such as epoxidized soybean oil, The freezing point of phosphoric acid esters such as cresyl phosphate, trioctyl phosphate, trischlor ethyl phosphate, for example, benzoic acid esters such as benzyl benzoate is 15 ° C. or less, Boiling point at atmospheric pressure include 300 ° C. or more plasticizers.

  Examples of other alcohols include 2-octanol, 2-ethylhexanol, nonanol, n-decanol, undecanol, n-dodecanol, trimethylnonyl alcohol, tetradecanol, and benzyl alcohol. Examples of glycols include ethylene glycol isoamyl ether, ethylene glycol monophenyl ether, ethylene glycol benzyl ether, ethylene glycol hexyl ether, and octylene glycol.

  Odor is particularly mentioned as a condition when selecting the compound. A preferable range of the amount of these solvents used is 0.1 to 5% by mass of the gum solution, and a more preferable range is 0.5 to 3% by mass. These solvents can be used alone or in combination of two or more.

  The gum solution used in the present invention is prepared by preparing an aqueous phase at a temperature of 40 ° C. ± 5 ° C., stirring at a high speed, slowly dropping the prepared oil phase into the aqueous phase, stirring sufficiently, and then emulsifying and dispersing through a pressure type homogenizer. It is produced by doing.

  In the present invention, following the step of removing the unexposed portion of the image recording layer using the above-mentioned gum solution, a water washing step and further a step of desensitizing the non-image portion with the gum solution can be appropriately performed. .

  The gum development processing in the present invention can be suitably carried out by an automatic processor equipped with a supply means such as a gum solution and a rubbing member. Examples of the automatic processor include an automatic processor described in Japanese Patent Application Laid-Open No. 2006-235227 that performs rubbing while conveying a lithographic printing plate precursor after image recording. Among these, an automatic processor using a rotating brush roll as the rubbing member is particularly preferable.

The rotating brush roll that can be preferably used in the present invention can be appropriately selected in consideration of the difficulty of scratching the image area and the stiffness of the lithographic printing plate precursor support. As the rotating brush roll, a known one formed by planting a brush material on a plastic or metal roll can be used. For example, as described in Japanese Patent Application Laid-Open No. 58-159533, Japanese Patent Application Laid-Open No. 3-100554, or Japanese Utility Model Publication No. 62-167253, metal or plastic in which brush materials are implanted in rows. A brush roll can be used in which the groove mold material is radially wound around a plastic or metal roll as a core without a gap. The brush material includes plastic fibers (for example, polyesters such as polyethylene terephthalate and polybutylene terephthalate, polyamides such as nylon 6.6 and nylon 6.10, polyacrylonitrile, poly (meth) acrylate, etc. Acrylic and polyolefin synthetic fibers such as polypropylene and polystyrene) can be used. For example, the fiber has a hair diameter of 20 to 400 μm and a hair length of 5 to 30 mm. Can be used.
Furthermore, the outer diameter of the rotating brush roll is preferably 30 to 200 mm, and the peripheral speed at the tip of the brush rubbing the plate surface is preferably 0.1 to 5 m / sec.

  The rotating direction of the rotating brush roll used in the present invention may be the same or opposite to the conveying direction of the planographic printing plate precursor of the present invention. Thus, when two or more rotating brush rolls are used, it is preferable that at least one rotating brush roll rotates in the same direction and at least one rotating brush roll rotates in the opposite direction. This further ensures the removal of the image recording layer in the non-image area. Furthermore, it is also effective to swing the rotating brush roll in the direction of the rotation axis of the brush roll.

In the present invention, development and desensitization are performed in a developing tank. Thereafter, a drying treatment may be performed continuously, but after the development, a water washing treatment or a further desensitization treatment may be performed before the drying treatment. In the present invention, the temperature of the gum solution used for gum development and the washing water in the post-process can be used separately at any temperature, but is preferably 10 ° C to 50 ° C.
In the gum development method of the present invention, it is possible to provide a drying step at any place after gum development. The drying step is generally performed by blowing a drying air having an arbitrary temperature after most of the processing liquid is removed by a roller nip.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to these.

(Method of measuring the amount of halide ions in the material)
Samples were prepared as described above, and the amount of halide ions was quantified by titration with an aqueous silver nitrate solution (0.01 mol / L) (automatic titrator AT-30 manufactured by Kyoto Electronics Industry).

(Removal of halide ions)
(1) Ionic surfactant (a) Desalting and purification of commercially available surfactant Surfactant A [Pionine A-24-EA (40% by mass aqueous solution) manufactured by Takemoto Yushi Co., Ltd., halide ion concentration 160 × 10 ^-6 mol / g] was desalted and purified with a desalting apparatus (ASTOM Corp., Micro Alyzer S3), and a sample of surfactant B [halide ion concentration 80 × 10 ^-6 mol / g (40 mass%) Aqueous solution)] and surfactant C [sample with a halide ion concentration of 10 × 10 ⁻⁶ mol / g (40 mass% aqueous solution)].

(B) Synthesis of Surfactant D Substantially Not Containing Halide Ion Diethylene glycol mono (2-ethylhexyl) ether 500 parts by mass Sodium hydroxide 92 parts by mass, toluene 1490 parts by mass in a reaction vessel, 1 at 90 ° C. Stir for hours. 312 parts by mass of 1,4-butanesultone was added dropwise while keeping the internal temperature at 100 ° C. or lower. After completion of the dropwise addition, the mixture was further stirred for 5 hours while maintaining the internal temperature at 90 ° C. After cooling the reaction vessel, 11200 parts by mass of acetonitrile was added with stirring to perform crystallization. After separating the crystals by centrifugal filtration, the crystals are washed with acetonitrile, and further dried under vacuum to obtain a surfactant D: Sodium 4- (2- (2- (2- (ethylhexyloxy) ethoxy) ethoxy) butane- 720 parts by mass of sodium 1-sulfonate was obtained. Halide ions were below the detection limit.

(2) Binder polymer <Synthesis of binder polymer A-1>
1-Methoxy-2-propanol: 156.28 g was placed in a 500 ml flask equipped with a condenser and a stirrer, and heated to 70 ° C. under a nitrogen stream. Methyl methacrylate: 50.06 g, diethylene glycol monomethyl ether: 75.29 g, methacrylic acid: 8.61 g, V-601: 1.382 g of 1-methoxy-2-propanol: 156.28 g solution over 2.5 hours It was dripped. After completion of dropping, the mixture was stirred for 2 hours at 70 ° C., V-601: 1.151 g was added, the temperature was raised to 90 ° C., and the mixture was further stirred for 2 hours. After cooling the reaction solution to room temperature, glycidyl methacrylate: 15.64 g, p-methoxyphenol: 0.2992 g, tetraethylammonium bromide: 1.496 g were added, heated again to 90 ° C., stirred for 8 hours, and binder polymer A -1 (24 mass% MFG solution) was obtained. The halide concentration of the obtained binder polymer A-1 (24% by mass MFG solution) was 9.6 × 10 ⁻⁶ mol / g.

<Synthesis of Binder Polymer A-2>
1-Methoxy-2-propanol: 156.28 g was placed in a 500 ml flask equipped with a condenser and a stirrer, and heated to 70 ° C. under a nitrogen stream. Methyl methacrylate: 50.06 g, diethylene glycol monomethyl ether: 75.29 g, methacrylic acid: 8.61 g, V-601: 1.382 g of 1-methoxy-2-propanol: 156.28 g solution over 2.5 hours It was dripped. After completion of dropping, the mixture was stirred for 2 hours at 70 ° C., V-601: 1.151 g was added, the temperature was raised to 90 ° C., and the mixture was further stirred for 2 hours. After cooling the reaction solution to room temperature, glycidyl methacrylate: 15.64 g, p-methoxyphenol: 0.2992 g, tetraethylammonium bromide: 0.748 g were added, heated again to 90 ° C., stirred for 8 hours, and binder polymer A -2 (24 mass% MFG solution) was obtained. The resulting binder polymer A-2 (24% by mass MFG solution) had a halide concentration of 3.8 × 10 ⁻⁶ mol / g.

  As a result of measuring the mass average molar mass of the obtained binder polymers A-1 and A-2 by gel permeation chromatography method (GPC) using polystyrene as a standard substance, both were 200,000, It was confirmed that polymerization was taking place. Further, as a result of acid value titration, it was confirmed that no carboxyl group remained.

(1) Purification by reprecipitation method (binder polymer B)
100 parts by mass of the binder polymer A-2 (24% by mass MFG solution) was added to 1000 parts by mass of water, and reprecipitation was performed. The obtained solid was drained and then dissolved in 200 parts by mass of acetone. This solution was added to 1000 parts by mass of water for reprecipitation, and then the obtained solid was drained. Reprecipitation from the acetone solution was performed again, and the resulting solid was drained and then vacuum dried to obtain binder polymer B. Halide ions were below the detection limit.

(2) Purification by ion exchange resin (binder polymer C)
10 parts by mass of an anion exchange resin (Amberlyst A-26 OH type) was added to 100 parts by mass of the binder polymer A-2 (24% by mass MFG solution), and the mixture was stirred at room temperature for 1 hour, and then the ion exchange resin was removed by filtration. . To this solution was further added 10 parts by mass of a cation exchange resin (Amberlyst 15 H type), and the mixture was stirred at room temperature for 1 hour, and then the ion exchange resin was removed by filtration to obtain a binder polymer solution C. Halide ions were below the detection limit.

[Examples 1 to 15 and Comparative Examples 1 and 2]
1. Production of lithographic printing plate precursors (1) to (13) and (R1) (1) Production of support 10% by mass for removing rolling oil on the surface of a 0.3 mm thick aluminum plate (material: JIS A1050) After degreasing treatment with sodium aluminate aqueous solution at 50 ° C. for 30 seconds, three bundled nylon brushes having a bristle diameter of 0.3 mm and a pumice-water suspension having a median diameter of 25 μm (specific gravity 1.1 g / cm) ³ ), the aluminum surface was grained and washed thoroughly with water. This plate was etched by being immersed in a 25 mass% sodium hydroxide aqueous solution at 45 ° C for 9 seconds, washed with water, further immersed in 20 mass% nitric acid at 60 ° C for 20 seconds, and washed with water. At this time, the etching amount of the grained surface was about 3 g / m ² .
Next, an electrochemical roughening treatment was performed continuously using an alternating voltage of 60 Hz. The electrolytic solution at this time was a 1% by mass aqueous nitric acid solution (containing 0.5% by mass aluminum ions), and the liquid temperature was 50 ° C. The AC power source waveform is electrochemical roughening treatment using a trapezoidal rectangular wave alternating current with a time ratio TP of 0.8 msec until the current value reaches a peak from zero, a duty ratio of 1: 1, and a trapezoidal rectangular wave alternating current. Went. Ferrite was used for the auxiliary anode. The current density was 30 A / dm ² at the peak current value, and 5% of the current flowing from the power source was shunted to the auxiliary anode. The amount of electricity in nitric acid electrolysis was 175 C / dm ² when the aluminum plate was the anode. Then, water washing by spraying was performed.

Furthermore, as in the case of nitric acid electrolysis, a 0.5% by mass aqueous solution of hydrochloric acid (containing 0.5% by mass of aluminum ions) and a liquid temperature of 50 ° C. is used as the electrolyte, and the aluminum plate serves as an electric quantity of 50 C / dm ² when the anode is used. An electrochemical surface roughening treatment was carried out by the method described above, followed by washing with water by spraying.

This plate was provided with a DC anodized film of 1.5 g / m ² at a voltage of 50 V and a maximum current density of 2 A / dm ² using 2.5 M phosphoric acid as an electrolytic solution, and then washed and dried. When the obtained substrate was observed with an SEM, the average diameter of the micropores was 80 nm. Furthermore, the silicate process was performed using 2.5 mass% sodium silicate aqueous solution. The amount of silicate at this time was 8 mg / m ² in terms of Si.

Further, the following undercoat layer coating solution 1 was applied so that the dry coating amount was 12 mg / m ² to obtain a support 1 of the present invention.

Separately, to an aluminum substrate subjected to up to electrochemical roughening treatment in the same manner as the support 1, a 0.3M sulfuric acid as the electrolyte at a current density of 0.5A / dm ² of 1.5 g / ^{m 2} After providing the direct current anodized film, it was washed with water and dried. When the obtained substrate was observed with an SEM, the average diameter of the micropores was 12 nm. Furthermore, the silicate process was performed using 2.5 mass% sodium silicate aqueous solution. The amount of silicate at this time was 8 mg / m ² in terms of Si. Furthermore, the following undercoat layer coating solution 1 was applied so that the dry coating amount was 12 mg / m ² to obtain a support 5.
Further, by providing a direct current anodic oxide film having an average diameter of micropores of 35 nm, 180 nm, and 220 nm by changing the maximum current density at a voltage of 50 V using 2.5 M phosphoric acid as an electrolyte, It processed similarly and obtained the support body 2, the support body 3, and the support body 4 of this invention.

-Undercoat layer coating solution 1-
・ Undercoat compound (1) (Mw: 60,000) 0.017 g
Specific acid compound (N-hydroxyethyliminodiacetic acid) 0.018 g
・ Methanol 9.00 g
・ Water 1.00g

(2) Formation of Image Recording Layer and Protective Layer An image recording layer coating solution having the following composition was bar-coated on the support 1 on which the undercoat layer had been formed, followed by oven drying at 100 ° C. for 60 seconds, and a dry coating amount of 1 An image recording layer of 0.0 g / m ² was formed. Subsequently, a protective layer coating solution having the following composition is bar-coated on the image recording layer and oven-dried at 120 ° C. for 60 seconds to form a protective layer having a dry coating amount of 0.160 g / m ² . Lithographic printing plate precursors (1) to (13) and a comparative lithographic printing plate precursor (R1) were obtained.
The image recording layer coating solution was obtained by mixing the following photosensitive solution and microgel solution immediately before coating and stirring.

-Sensitive solution-
Binder polymer (types listed in Table 1) 0.177 g
(B) Polymerization initiator (Exemplary Compound I-28) 0.142 g
(A) Infrared absorber (1) 0.0308 g
(C) Polymerizable compound (Aronix M-215 (manufactured by Toa Gosei Co., Ltd.)) 0.319 g
Fluorosurfactant (1) 0.004g
Ionic surfactant (type listed in Table 1) 0.125 g
Methyl ethyl ketone 2.554g
1-methoxy-2-propanol 7.023 g

-Microgel solution-
Microgel dispersion (1) 1.800 g
1.678g of water

  The synthesis method of the microgel dispersion (1) used in the microgel solution and the structure of the compound used in the photosensitive solution are shown below.

(Synthesis of microgel dispersion (1))
As an oil phase component, trimethylolpropane and xylene diisocyanate adduct (manufactured by Mitsui Takeda Chemical Co., Ltd., Takenate D-110N, 75% by mass ethyl acetate solution) 10.0 g, as a polymerizable compound Aronix M-215 (Toa Synthesis Co., Ltd.) 6.00 g and Piionin A-41C (Takemoto Yushi Co., Ltd.) 0.12 g were dissolved in ethyl acetate 16.67 g. As an aqueous phase component, 37.5 g of a 4 mass% aqueous solution of PVA-205 was prepared. The oil phase component and the aqueous phase component were mixed and emulsified for 10 minutes at 12,000 rpm using a homogenizer. The obtained emulsion was added to 25 g of distilled water, stirred at room temperature for 30 minutes, and then stirred at 40 ° C. for 2 hours. The microgel dispersion thus obtained was diluted with distilled water so that the solid content concentration was 21% by mass to obtain a microgel dispersion (1). The average particle size was 0.23 μm.

-Protective layer coating solution-
-1.5 g of the following layered compound dispersion (1)
・ Polyvinyl alcohol 0.06g
(PVA105, manufactured by Kuraray Co., Ltd., saponification degree 98.5 mol%, polymerization degree 500)
・ Polyvinylpyrrolidone 0.01g
(Polyvinylpyrrolidone K30, manufactured by Tokyo Chemical Industry Co., Ltd., Mw = 40,000)
・ Vinyl pyrrolidone / vinyl acetate copolymer 0.01g
(LUVITEC VA64W, manufactured by ISP, copolymerization ratio = 6/4)
・ Nonionic surfactant 0.013g
(Emalex 710, manufactured by Nippon Emulsion Co., Ltd.)
・ Ion-exchanged water 6.0g

(Preparation of layered compound dispersion (1))
6.4 g of synthetic mica Somasif ME-100 (manufactured by Coop Chemical Co., Ltd.) was added to 193.6 g of ion-exchanged water, and dispersed using an homogenizer until the average particle size (laser scattering method) became 3 μm. The aspect ratio of the obtained dispersed inorganic particles was 100 or more.

2. Preparation of lithographic printing plate precursors (14), (15) and (R2) For the purpose of comparing the effect of the average diameter of the anodic oxide coating micropores, the support 5 is used, and the binder polymer in the photosensitive solution and the ionic surface activity are used. The lithographic printing plate precursors (14) and (15) of the present invention and a comparative lithographic printing plate precursor (R2) were prepared using the agents as described in Table 1.

3. Measurement of halide ion amount The obtained lithographic printing plate precursor was measured for the total of halide ions of each layer on the support by the method described above. The results are shown in Table 1.

4). Evaluation of planographic printing plate precursors The obtained planographic printing plate precursors (1) to (15), and (R1) and (R2) were output by a Trendsetter 3244VX manufactured by Creo equipped with a water-cooled 40 W infrared semiconductor laser, and the output was 11.7 W. After exposure under the conditions of an outer drum rotational speed of 250 rpm and a resolution of 2400 dpi, on-machine developability, thickness setting and printing durability were evaluated as follows. The results are shown in Table 1.

(Evaluation of on-press developability)
The exposed lithographic printing plate precursor is attached to a cylinder of a printing machine SOR-M manufactured by Heidelberg without developing, and is dampened with water (EU-3 (Effect manufactured by FUJIFILM Corporation) / water / isopropyl alcohol = 1/89/10 (volume ratio)) and TRANS-G (N) black ink (Dainippon Ink Chemical Co., Ltd.) were used, and after supplying dampening water and ink, 6,000 sheets per hour Printing was performed at a printing speed. At this time, the number of print sheets required until the ink was not transferred to the unexposed portion (non-image portion) of the image recording layer was evaluated as on-press developability. The smaller the number, the better the on-press developability.

(Evaluation of printing durability)
When printing is continued and the number of printed sheets is increased, the image recording layer is gradually worn and the ink acceptability is lowered, so that the ink density on the printing paper is lowered. Printing durability was evaluated by the number of printed sheets when the ink density (reflection density) was reduced by 0.1 from the start of printing. The larger the number of sheets, the better the printing durability.

(Evaluation of minute spot stains)
After the prepared lithographic printing plate precursor is stored for 10 days under conditions of a temperature of 60 ° C. and a relative humidity of 70%, a printed material is produced by using a printing machine, and a minute image generated in a non-image portion (unexposed portion of the printing plate) of the printed material. The number of spot-like stains per 80 cm ² was counted. It is evaluated that the smaller the number, the better the prevention of minute spot-like stains.
(Evaluation of blanket dirt)
After 6000 sheets were printed at the time of on-press developability evaluation, the degree of adhesion of the printing ink and the smear of the printed matter were examined at the portion of the blanket plate that was in contact with the non-image portion.
○: There is almost no ink on the blanket, and the printed matter is not soiled.
Δ: The blanket has ink, but the printed matter is not soiled (acceptable limit level).
X: The blanket has ink and the printed matter is dirty.

Table 1 shows the following. In Comparative Examples 1 and 2 in which the content of halide ions is outside the range of the present invention, the number of minute spot-like stains is very large.
On the other hand, in the planographic printing plate precursors (1) to (15) according to the present invention, by controlling the average diameter of the micropores of the support within the preferred range of the present invention, not only the printing durability is improved, Surprisingly, it can be seen that an unexpected effect of improving to a very good level also appears with respect to fine spot-like stains.
The lithographic printing plate precursor according to the present invention can maintain both the printing durability and the storage stability at an excellent level with respect to the problem of remaining minute image recording layers. The plate precursor is also good in terms of printing durability and on-press development. From the above, the effect of the present invention is clear.

[Example 21]
1. Preparation of planographic printing plate precursors (21) and (R21) for gum developer (1) Aluminum support 21 and comparative support 21
In the same manner as in the production of the aluminum support 1, a direct current anodic oxide film is provided using 2.5M phosphoric acid as an electrolytic solution, followed by washing with water and drying. The average diameter of micropores was used in the following experiment. Further, in the same manner as the preparation of the comparative support 1, the substrate before the sodium silicate treatment obtained by providing a direct current anodic oxide film with 0.3M sulfuric acid as an electrolytic solution, washing with water and drying is used as a comparative support. The body 21 (average diameter of micropores 12 nm) was used in the following experiment.

(2) Formation of undercoat layer An undercoat layer coating solution 2 having the following composition was applied onto the aluminum support 21 and the comparative support 21 and dried at 100 ° C for 3 minutes. The coating amount of the obtained undercoat layer was 19 mg / m ² .

-Undercoat layer coating solution 2-
・ Undercoat compound (1) (Mw: 60000) 2.5 g
・ Specific acid compound (N-hydroxyethyliminodiacetic acid) 2.5 g
・ N-methylpyrrolidone 49.0g
・ Methanol 450.0g
・ Water 1.5g

(3) Formation of Image Recording Layer On the undercoat layer obtained as described above, an image recording layer coating solution 2 having the following composition was applied and dried at 80 ° C. for 1 minute. The coating amount of the obtained image recording layer was 1.25 g / m ² .

-Image recording layer coating solution 2-
・ The following binder polymer (1) 0.54 g
・ Polymerizable compound (1) 0.48 g
Isocyanuric acid EO-modified triacrylate (Aronix M-315, manufactured by Toa Gosei Co., Ltd.)
・ The following sensitizing dye (1) 0.07 g
・ The following polymerization initiator (1) 0.11 g
・ The following co-sensitizer (1) 0.07 g
・ 0.40 g of ε-phthalocyanine pigment dispersion
[Pigment: 15 parts by mass, allyl methacrylate / methacrylic acid (80/20) copolymer as dispersant: 10 parts by mass, cyclohexanone /
Methoxypropyl acetate / 1-methoxy-2-propanol = 15
Part by mass / 20 parts by mass / 40 parts by mass]
・ Methyl ethyl ketone 4.80g
・ Dimethyl sulfoxide 4.80g

(4) Formation of protective layer A protective layer coating solution 2 having the following composition was coated on the image recording layer using a bar, and then dried at 125 ° C for 70 seconds to give a coating amount of 0.70 g / m ^2. A lithographic printing plate precursor was prepared.

-Protective layer coating solution2-
Polyvinyl alcohol (saponification degree: 98 mol%, polymerization degree: 500) 40 g
・ Polyvinylpyrrolidone (Mw: 50,000) 5g
・ Poly [vinyl pyrrolidone / vinyl acetate (1/1)] (Mw: 70,000) 0.5 g
・ Surfactant (Emalex 710, manufactured by Nippon Emulsion Co., Ltd.) 0.5g
・ 950g of water

  With respect to the obtained lithographic printing plate precursor, the total of halide ions in each layer on the support was measured in the same manner as in Example 1. The results are shown in Table 2.

2. Evaluation of lithographic printing plate precursors <Exposure / Development / Printing>
The lithographic printing plate precursor was subjected to imagewise exposure using a 405 nm semiconductor laser with an output of 100 mW while changing the energy density.
Thereafter, using the following aqueous solution A as a developer, and using an automatic developing processor having the structure shown in FIG. The lithographic printing plate was prepared by performing a drying treatment at 20 in the figure without performing the water washing and desensitization treatments of 16 and 18 in the figure. The automatic processor has two rotating brush rolls, and the first rotating brush roll is a brush roll having an outer diameter of 90 mm in which fibers made of polybutylene terephthalate (hair diameter: 200 μm, hair length: 17 mm) are implanted. The second rotating brush roll was made of polybutylene terephthalate fiber (hair diameter 200 μm, hair length), with 200 rotations per minute in the same direction as the transport direction (peripheral speed 0.94 m / sec at the tip of the brush). 17 mm) was implanted with a 60 mm outer diameter brush roll at 200 revolutions per minute (peripheral speed of the brush tip of 0.63 m / sec) in the direction opposite to the conveying direction. The transportation of the planographic printing plate precursor was carried out at a transportation speed of 100 cm / min.

  The aqueous solution A was showered from the spray pipe with a circulation pump and supplied to the plate surface. The tank capacity of the aqueous solution A was 10 liters.

-Aqueous solution A-
・ Water 100.00g
・ Benzyl alcohol 1.00g
・ Polyoxyethylene naphthyl ether 1.00g
(Average number of oxyethylene n = 13)
・ Dioctylsulfosuccinate sodium salt 0.50 g
・ Ethylene glycol 0.50g
・ Primary ammonium phosphate 0.05g
・ Citric acid 0.05g

  Next, the planographic printing plate is attached to a printing machine SOR-M manufactured by Heidelberg, and dampening water (EU-3 (Etchi solution manufactured by FUJIFILM Corporation) / water / isopropyl alcohol = 1/89/10 (volume ratio). ) And TRANS-G (N) black ink (manufactured by Dainippon Ink & Chemicals, Inc.), and printing was performed at a printing speed of 6000 sheets per hour.

<Evaluation>
Printing durability and stain resistance were evaluated as follows. The results are shown in Table 2.
(A) Printing durability When the above-mentioned printing was performed and the number of printed sheets increased, the image recording layer was gradually worn out and the ink receptivity was lowered, so that the ink density in the printed material was lowered. In a printing plate exposed at the same exposure amount (energy density), the printing durability was relatively evaluated based on the number of printed sheets when the ink density (reflection density) was reduced by 0.1 from the start of printing. That is, the lithographic printing plate 21 was used as a reference (100), and calculation was performed according to the following formula. Large numbers indicate high printing durability.
Printing durability = (Number of printing durability of target lithographic printing plate) / (Number of printing durability of standard lithographic printing plate) × 100

(B) Fine dot-like stain The obtained lithographic printing plate precursor was left in a constant temperature and humidity chamber set at 60 ° C. and a relative humidity of 75% for 10 days, and then developed in the same manner as described above. The number of minute spot-like stains within the range of 80 cm ² on the printing paper surface was counted. These results are shown in Table 2.

  As can be seen from Table 2, the lithographic printing plate precursor according to the present invention has high printing durability and is excellent in that it has few minute spot-like stains after storage. Further, when the non-image portion of the lithographic printing plate was visually confirmed after the development treatment, no residual image recording layer was observed in the lithographic printing plate precursor of the present invention.

[Example 31]
1. Preparation of lithographic printing plate precursor 31 The same as lithographic printing plate precursor 21 except that the image recording layer coating solution 2 is changed to the following image recording layer coating solution 3 and the protective layer coating solution 2 is changed to the following protective layer coating solution 3. A lithographic printing plate precursor 31 was prepared.

-Image recording layer coating solution 3-
・ The following binder polymer (2) 0.54 g
-0.48 g of the following polymerizable compound (2)
-0.07 g of the above sensitizing dye (1)
・ The above polymerization initiator (1) 0.19 g
・ Cosensitizer (1) 0.07g
・ 0.40 g of ε-phthalocyanine pigment dispersion
[Pigment: 15 parts by mass, allyl methacrylate / methacrylic acid (80/20) copolymer as dispersant: 10 parts by mass, cyclohexanone /
Methoxypropyl acetate / 1-methoxy-2-propanol = 15
Part by mass / 20 parts by mass / 40 parts by mass]
・ Thermal polymerization inhibitor 0.01g
N-nitrosophenylhydroxylamine aluminum salt / fluorine surfactant (1) 0.001 g
・ Polyoxyethylene-polyoxypropylene condensate 0.04g
(Asahi Denka Kogyo Co., Ltd., Pluronic L44)
・ Tetraethylammonium sulfonate 0.01g
・ Sensitizer (Exemplified specific polymer (11)) 0.035 g
・ 3.5 g of 1-methoxy-2-propanol
・ Methyl ethyl ketone 8.0g

-Protective layer coating solution 3-
-The following layered compound dispersion (2) 13.00 g
Polyvinyl alcohol (saponification degree 98 mol%, polymerization degree 500) 1.30 g
-Sodium 2-ethylhexyl sulfosuccinate 0.20 g
・ Poly (vinyl pyrrolidone / vinyl acetate = 1/1) (Mw 70,000) 0.05g
・ Surfactant (Emalex 710, manufactured by Nippon Emulsion Co., Ltd.) 0.05g
・ Water 133.00g

(Preparation of layered compound dispersion (2))
To 368 g of water, 32 g of synthetic mica (“Somasif ME-100” manufactured by Co-op Chemical Co., Ltd., aspect ratio: 1000 or more) is added and dispersed using an homogenizer until the average particle size (laser scattering method) is 0.5 μm. As a result, a mica dispersion (1) was obtained.

2. Evaluation of Lithographic Printing Plate Precursor 31 The measurement result of halide ions of the obtained lithographic printing plate precursor 31 was 1.5 μmol / m ² , respectively.
The obtained lithographic printing plate precursor 31 was exposed, developed and printed in the same manner as in Example 21 and evaluated in the same manner. The planographic printing plate precursor 31 of the present invention has a preferable result that the number of minute spot-like stains after storage is one and the occurrence of minute dot-like stains is small.

[Example 41]
The planographic printing plate precursor (1) was exposed by the method described in Example 1 and developed under the same development conditions as in Example 21. When evaluated in the same manner as in Example 1, the lithographic printing plate precursor (1) of the present invention gave a favorable result that the number of minute spot-like stains after storage was two and the occurrence of minute spot-like stains was small. .

1 is a schematic structure of an example of an automatic developing apparatus that can be used for development with a gum solution.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Automatic developing device 10 Development processing part 12 Printing plate 14 Developing part 16 Washing part 18 Desensitizing treatment part 20 Drying part 24 Developing tank 141, 142 Brush roller (rubbing member)
200 Pre-processing section

Claims (8)

A lithographic printing plate precursor having at least a polymerizable image recording layer on an aluminum support having an anodized film, all of which is provided on an aluminum support that has been anodized with an aqueous solution containing phosphoric acid A lithographic printing plate precursor wherein the total of halide ions contained in the layer is 5 μmol / m ² or less.   The lithographic printing plate precursor as claimed in claim 1, wherein the average diameter of the micropores of the anodized film on the aluminum support is from 30 nm to 200 nm.   The lithographic printing plate precursor as claimed in claim 1 or 2, wherein the image recording layer comprises (A) a sensitizing dye, (B) a polymerization initiator, and (C) a polymerizable compound.   The lithographic printing plate precursor as claimed in any one of claims 1 to 3, wherein the image recording layer further contains a binder polymer.   The lithographic printing plate precursor as claimed in any one of claims 1 to 4, wherein the (A) sensitizing dye is an infrared absorber.   The lithographic printing plate according to any one of claims 1 to 5, wherein the image recording layer is removable with a printing ink and / or fountain solution, or is removable with a gum solution. Original edition.   The lithographic printing plate precursor according to any one of claims 1 to 6 is image-exposed with an infrared laser and then mounted on a printing press, or image-exposed with an infrared laser after being mounted on a printing press, and printing ink and wet A plate-making method characterized in that it is supplied with sewage water, subjected to on-press development, and printed.   An imagewise exposure of the lithographic printing plate precursor according to any one of claims 1 to 6, and an unexposed portion of the lithographic printing plate precursor by developing the exposed lithographic printing plate precursor with a gum solution And a development process for removing the lithographic printing plate precursor.

Images