JP2008256743A - Method for making lithographic printing plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for making a lithographic printing plate superior in printing durability by using a preferable developer of pH2-10 in an environment and working safety, having strong image intensity, and obtaining excellent development. <P>SOLUTION: The method for making the lithographic printing plate removes the non-exposure part of an image recording layer while rubbing a lithographic printing original plate having the image recording layer on a support by a rubbing member under the existence of the developer of pH2-10 after curing the image recording layer of an exposure part by image exposure. The rubbing force F of the rubbing member is in a range of 5 (g/mm)≤F≤100 (g/mm). <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for producing a lithographic printing plate.

  In general, a lithographic printing plate comprises an oleophilic image area that receives ink in the printing process and a hydrophilic non-image area that receives dampening water. Lithographic printing utilizes the property that water and printing ink 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, the lithographic printing plate precursor is exposed through an original image such as a lithographic film, and then the image portion of the image recording layer is left, and the other unnecessary image recording layer is removed with an alkaline developer or organic A lithographic printing plate is obtained by dissolving and removing with a solvent and exposing the surface of the hydrophilic support to form a non-image area.

  In the conventional plate making process of a lithographic printing plate precursor, a step of dissolving and removing unnecessary image recording layers with a developer after the exposure is necessary. However, the developer is closer to the neutral range for environmental and occupational safety. Treatment and low waste liquid are cited as 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.

  Lower alkalinity of the developing solution and simplification of the processing process have been more strongly demanded than ever in terms of consideration of the global environment, adaptation to a small space, and low running cost. However, as described above, the development process generally comprises three steps: development with an alkaline aqueous solution having a pH of 10 or more, then pouring an alkaline agent in a washing bath, and then processing with a hydrophilic resin as a main gum solution. As a result, the automatic developing machine itself takes up a large space, and developing waste liquid, washing waste liquid, and gum waste liquid are produced, leaving problems in terms of environment and running cost.

  On the other hand, for example, Patent Document 1 proposes a developing method using an alkaline solution containing a nonionic surfactant having a pH of 10 to 12.5, but the photosensitive composition contains an alkali-soluble polymer. However, there is a problem that development becomes impossible if the pH is lower than that. For example, Patent Document 2 describes a lithographic printing plate precursor in which an image forming layer in which hydrophobic thermoplastic polymer particles are dispersed in a hydrophilic binder is provided on a hydrophilic support. This lithographic printing plate precursor is formed by image exposure using an infrared laser to form an image by coalescence of hydrophobic thermoplastic polymer particles by heat, and is then mounted on a cylinder of a printing machine, fountain solution and / or On-press development is possible with ink. However, the method of forming an image by merging the fine particles by simple thermal fusion exhibits good on-press developability, but the image strength (adhesion with the support) is extremely weak, and the printing durability is poor. Had the problem of being sufficient.

Therefore, as a method for solving the above problems, an image is recorded on a lithographic printing plate precursor having a heat-sensitive layer containing a fine particle polymer having a heat-reactive group on a support, and then an automatic processor equipped with a rubbing member is used. A method for producing a lithographic printing plate has been proposed by removing the image recording layer in the unexposed area by rubbing the recording surface of the lithographic printing plate precursor with a rubbing member in the presence of a developing solution (see Patent Document 3). ). Further, a lithographic printing plate preparation method including a developing step of using a developer having a pH of 2 to 10 and removing an image recording layer in an unexposed portion by rubbing with a rubbing member is known (see Patent Document 4). However, these documents do not mention anything about the rubbing force of the rubbing member.
JP 2002-91016 A Japanese Patent No. 2938397 Japanese Patent Laid-Open No. 2003-316021 JP 2006-39468 A

  The present invention has been made in view of the above circumstances, and a developer having a pH of 2 to 10 that is preferable from the viewpoint of environment and occupational safety is used. Good developability is obtained, and the image strength is high and the printing durability is excellent. An object is to provide a method for producing a lithographic printing plate.

The above problem has been solved by the following means.
1. The lithographic printing plate precursor having the image recording layer on the support is cured by imagewise exposure after the image recording layer in the exposed portion is cured, and then the image recording layer is rubbed with a rubbing member in the presence of a developer having a pH of 2 to 10. In the method for producing a lithographic printing plate in which an unexposed portion is removed, the rubbing force F of the rubbing member is in the following range.
5 (g / mm) ≦ F ≦ 100 (g / mm)
2. 2. The method for producing a lithographic printing plate as described in 1 above, wherein when the image recording layer unexposed portion is removed, the amount of the rubbing member pushed into the lithographic printing plate precursor is 0.2 to 6 mm.
3. 3. The method of preparing a lithographic printing plate as described in 1 or 2 above, wherein a developing processor having two or more rubbing members is used.
4). The lithographic printing plate as described in any one of 1 to 3 above, wherein the image recording layer in the previous period contains a polymerization initiator, a polymerizable compound, and a binder polymer having an acid value of 0.3 meq / g or less. Manufacturing method.
5. 5. The method for preparing a lithographic printing plate as described in 4 above, wherein the binder polymer having an acid value of 0.3 meq / g or less is a polyurethane resin.
6). 6. The developer according to any one of 1 to 5, wherein the developer contains at least one compound selected from the group consisting of compounds represented by the following formula <1>, <2> or <3>. A method for producing a lithographic printing plate as described in 1. above.

In the formula <1>, R1 represents a hydrogen atom or an alkyl group, and A is a group containing a hydrogen atom, an ethylene oxide group, a carboxylic acid group, or a carboxylate. B is a group containing an ethylene oxide group, a carboxylic acid group, or a carboxylate. In formula <2>, R2 and R3 represent H or an alkyl group, C is an alkyl group or an ethylene oxide group, and D is a group containing a carboxylate anion. In formula <3>, R 4, R 5, R 6 and R 7 each independently represent H or an alkyl group, and Z ⁻ represents a counter anion. The alkyl group of R1 to R7 may have a substituent.

  According to the present invention, there is provided a method for producing a lithographic printing plate which uses a developer having a pH of 2 to 10 which is preferable for the environment and occupational safety, has good developability, and has high image strength and excellent printing durability. Can be provided.

[Preparation method of planographic printing plate]
The method for producing a lithographic printing plate according to the present invention comprises: a lithographic printing plate precursor having an image recording layer on a support; the image recording layer in an exposed area is cured by imagewise exposure; When removing the unexposed portion of the image recording layer while rubbing with a rubbing member, the rubbing force F of the rubbing member is in the range of 5 (g / mm) ≦ F ≦ 100 (g / mm). Features. Further, when the unexposed portion of the image recording layer is removed, it is preferable that the pushing amount of the rubbing member against the planographic printing plate precursor is 0.2 to 6 mm.

  In the method for producing a lithographic printing plate of the present invention, the rubbing force F of the rubbing member is 5 to 100 g / mm. More preferably, it is 10-100 g / mm, Most preferably, it is 20-80 g / mm. When the rubbing force F is less than 5 g / mm, the removal of the unexposed portion of the image recording layer is incomplete, resulting in poor development. On the other hand, if the rubbing force F exceeds 100 g / mm, the image area is scratched, so that the printing durability is deteriorated.

  The lithographic printing plate production method of the present invention can be applied to any automatic processor provided with a developer supply means and a rubbing member. As an automatic processor, it is sufficient that a rubbing member can be attached to the developing unit.

  The rubbing member used in the present invention may be any member as long as it can rub the image recording surface of the lithographic printing plate precursor, but the member can rub the image recording surface by rotating around the rotation axis. It is particularly preferred to use (eg, known channel brushes, twisting brushes, implantation brushes, carpet brushes, and Morton rollers).

As channel brushes, long so-called channel brushes as disclosed in Japanese Utility Model Laid-Open Nos. 62-167253, 4-63447, 4-64128, and JP-A-6-186751. A (band-like brush) that is spirally wound around the surface of the roller body is used.

  As the torsion brush, the one in which a torsion brush is inserted into a spiral groove provided on the shaft as disclosed in JP-A-3-87832 and spirally wound around the shaft is used.

  As an implantation brush, what is produced by the method of making a small hole in a shaft roller and implanting a brush material is used.

  As a carpet brush, an elongated belt in which a hair material is woven into a woven fabric is wound around the shaft roller as disclosed in JP 2001-5193 A and JP 2001-66788 A. Is used.

  As the Molton roller, a roller part disclosed in JP-A-10-198044 is covered with a cylindrical sliding contact material made of a fiber knitted fabric, and the end on the mounting side is tightened. it can.

  Among them, an automatic processor using a rotating brush roll as a rubbing member is particularly preferable.

Below, the measuring method of the rubbing force F of the rubbing member in this invention and the means to achieve the rubbing force of this invention are demonstrated.
<Measurement method of rubbing force>
A brush roll is attached to a rotating shaft and rotated. At the same time, the force (rubbing force) received from the brush hair is measured with a force gauge. The number of rotations of the brush was 1500 rpm, and the pressing distance was adjusted by changing the relative distance between the force gauge and the brush. As the force gauge, FGC-0.5B manufactured by Nidec Sympo Co., Ltd. was used.
FIG. 1 shows a simple measurement configuration diagram.

<Means for achieving rubbing force>
As for the rubbing member, the material, thickness, and hair length are factors that affect the rubbing conditions described here, and further, as the rubbing conditions, the pressing amount of the brush and the number of rotations influence.
However, the rubbing force is particularly affected by the brush material, thickness, bristle length, and brush pressing amount.
As the material of the brush, natural fibers such as horse hair and pig hair, artificial fibers, metal fibers, and the like can be used. However, artificial fibers are preferable in terms of chemical resistance. Man-made fibers include nylons such as nylon 6, nylon 6,6, nylon 6,10, nylon 6,12 and nylon 12, polyesters such as polyethylene terephthalate and polybutylene terephthalate (PBT), polyacrylonitrile, poly (meta ) Polyacrylics such as alkyl acrylate, polyolefins such as polyethylene, polypropylene, polystyrene, polyvinyl chloride and polyvinylidene chloride, celluloses such as acetyl cellulose, polyurethanes such as polyurethane, polyphenylene sulfite, ethylene tetrafluoride Fluorine resins such as ethylene copolymers and polyvinylidene fluoride are used, but considering elasticity, rigidity, wear resistance, heat resistance, chemical resistance, water supply, moisture absorption, etc., nylon 6, nylon 6, 6, Nylon 6 · 10, Nai 6/12, nylon 12, polypropylene, polybutylene terephthalate and polyethylene terephthalate are preferable, and nylon nylon 6/6, nylon 6.10, 6.12, nylon 12, polybutylene terephthalate (PBT) and polypropylene are more preferable. It is done. Of the polyesters, polybutylene terephthalate (PBT) is particularly preferable. Of the polyolefins, polypropylene is particularly preferred. In particular, polyesters can be used without being hydrolyzed when the treatment liquid has a pH value of 2 to 10 described later, and are more suitably used because they are stronger than nylons and have high rubbing properties. it can.
Regarding the thickness of the brush hair, the thickness of the hair is preferably in the range of 25 to 500 μm, and when it is less than 25 μm, the rubbing force falls within the target range even if the length of the hair and the pushing amount are changed. There is nothing, and it is hard to say that the platemaking image quality is good. On the other hand, if the thickness exceeds 500 μm, there may be a tendency that the image portion is scratched or the printing durability is deteriorated.
If the length of the brush bristles is too short, the amount of change in the rubbing force when the indentation amount is increased becomes large, and therefore the length is usually in the range of 2 to 50 mm, more preferably 4 to 25 mm.

The pushing amount of the brush is an effective apparatus condition for applying the rubbing force, and although it depends on the material and length of the brush, it is usually preferably 0.2 to 6 mm, more preferably 0.5 to 4 mm. is there.
Here, the pushing amount with the rubbing member is a distance in which the bristles provided on the rubbing member surface are just in contact with the planographic printing plate precursor surface and the rubbing member is pushed into the planographic printing plate precursor surface side. Say.
Finally, the amount of pushing of the rubbing member is used in accordance with the effective rubbing force. If the amount of pressing is too small, there is a high possibility that a portion that will not be rubbed will come out, which tends to cause uneven halftone dots. Moreover, if the target rubbing force is applied, it is not necessary to push in more than necessary, and if it is pushed too much, it becomes easy to cause a rotation failure of the brush.

  When a rotating member is used as the rubbing member, the number of rotations of the rubbing member is preferably as fast as possible in order to improve the removability of the image recording layer unexposed portion of the lithographic printing plate precursor. From the viewpoints of durability, production cost, scattering of the developer and damage to the exposed portion of the lithographic printing plate precursor, 30 to 1000 rpm, more preferably 50 to 500 rpm is preferable.

  When using a brush as a rubbing member, the number of the brush should just be one or more, and may have two or more. In the case of two or more, one or more may be rotated in the direction opposite to the processing direction of the planographic printing plate precursor. Further, when a rotating rubbing member is used, the developing process may be performed while swinging the rubbing member in the direction of the rotation axis. By swinging the rubbing member in the rotation axis direction, the non-image portion of the lithographic printing plate precursor can be more effectively removed, and a higher quality lithographic printing plate can be produced.

Development methods include a method of rubbing in a state immersed in a developer and a method of conveying horizontally. Bubbles may be generated depending on the developer even when transported horizontally, but in the case of a strong rubbing condition by the immersion method, when the majority of the rubbing member is out of the liquid surface, the rubbing member The entrained air generates a large amount of bubbles on the liquid surface and enters the circulation system (hose, motor), leading to poor circulation of the developer. In severe cases, the bubbles are generated in large amounts on the liquid surface. An image defect may occur.
Therefore, when the developing method is an immersion method, the brush is preferably provided in the vicinity of the liquid surface on the side where the plate is fed from the liquid surface, with more than half of the brush immersed in the developer.

FIG. 2 is a diagram showing a schematic configuration example of an automatic developing processor for realizing the method of preparing a lithographic printing plate according to the present invention.
The automatic developing processor shown in FIG. 2 includes a developing tank 106 and two transport roller pairs 108 provided at both ends of the developing tank 106. The developer tank 106 is filled with a developer 107, and a rubbing member 112 is provided in the developer 107. In order to produce a lithographic printing plate, first, an image recording layer of the lithographic printing plate precursor 104 having an image recording layer on a support is imagewise exposed by an exposure device (not shown), and the lithographic printing plate precursor after imagewise exposure is obtained. 104 is developed by an automatic development processor. In the automatic developing processor, the image recording surface of the lithographic printing plate precursor 104 that has passed through the pair of conveying rollers 108 on the right side in FIG. 2 is rubbed by the rubbing member 112 in a state where the image recording surface is immersed in the developer 107, Development is performed by removing an unexposed portion of the image recording layer of the printing plate precursor 104.

  FIG. 3 is a diagram illustrating a schematic configuration example of a horizontal conveyance type automatic developing processor. A rubbing member 112 and a developer spray pipe 126 are provided between two conveying roller pairs 108 provided at both ends of the developing tank 106. The developer 107 is sprayed from the developer spray pipe 126 onto the exposed lithographic printing plate precursor 104 conveyed along the conveyance guide plate 127 and is rubbed by the rubbing member 112, so that the image recording layer of the lithographic printing plate precursor 104 is Unexposed areas are removed.

  In the present invention, the lithographic printing plate precursor after development (hereinafter referred to as lithographic printing plate) can be optionally washed with water, dried and desensitized. Moreover, you may perform a desensitization process simultaneously with image development. Although the temperature of the developer can be used at any temperature, it is preferably 10 ° C to 50 ° C.

  When using an automatic developing machine, for example, a method in which a developer charged in a developer tank is pumped up and sprayed from a spray nozzle (see Patent Document 3), a submerged guide roll in a tank filled with the developer, etc. Either a method for immersing and transporting a lithographic printing plate precursor by the above method, or a so-called disposable processing method for supplying and processing a substantially unused developer for each plate as required, can be applied. In any system, a rubbing member such as the above-described brush or molton is provided. Further, a lithographic printing plate can be produced by an apparatus in which an exposure apparatus and an automatic developing processor are integrated.

  In the exposure processing by the exposure apparatus, the lithographic printing plate precursor is exposed through a transparent original image having a line image, a halftone dot image or the like, or is exposed imagewise by laser beam scanning or the like using digital data. Examples of light sources suitable for exposure include carbon arc lamps, mercury lamps, xeno lamps, metal hydrado lamps, strobes, ultraviolet rays, infrared rays, and laser beams. A laser beam is particularly preferable, and examples include a solid-state laser and a semiconductor laser that emit infrared rays with a wavelength of 760 to 1200 nm, an ultraviolet semiconductor laser that emits light with a wavelength of 250 to 420 nm, an argon ion laser that emits visible light, and an FD-YAG laser. . Among these, from the viewpoint of simplification of plate making, a laser that emits infrared rays or ultraviolet rays that can be operated under white light or yellow light is preferable. In order to shorten the exposure time, it is preferable to use a multi-beam laser device.

In the present invention, the development process may be performed immediately after the exposure process, but a heat treatment process (preheat) may be provided between the exposure process and the development process. This heat treatment has the effect of improving the printing durability and further improving the uniformity of the image curing degree within the plate surface, and the conditions can be appropriately set within the range where these effects are present. Examples of the heating means include a conventional convection oven, an IR irradiation device, an IR laser, a microwave device, a Wisconsin oven, and the like. Specifically, it can be carried out by holding the plate surface temperature in the range of 70 to 150 ° C. for 1 second to 5 minutes. Preferably, the temperature is 80 ° C to 140 ° C for 5 to 1 minute, more preferably 90 ° C to 130 ° C for 10 to 30 seconds. This range is preferable in that the above effect can be obtained efficiently and there is no adverse effect such as deformation of the printing plate due to heat.
At this time, it is preferable that the heat treatment means used in the heat treatment process and the developing device used in the development process are connected to each other and automatically continuously processed. Specifically, it is a plate making line in which a plate setter and a developing device are coupled by a conveying means such as a conveyor. A heat treatment unit may be provided between the plate setter and the developing device, and the heating unit and the developing device may be integrated.

When the printing plate to be used is easily affected by ambient light in the work environment, it is preferable that the plate making line is shielded by a filter or a cover. Of course, when there is no heat treatment, the exposure means is directly connected to the development processing means, and continuous processing is automatically performed.
In the present invention, after the exposure step, development may be carried out immediately, but a water washing step (pre-water washing) for the purpose of removing the protective layer described above between the exposure step and the development step. There may be a process.
Both of the above two steps may be included, or one of them may be introduced.
After finishing the development process and forming an image as described above, the entire surface may be exposed with an actinic ray such as ultraviolet light to accelerate the curing of the image portion. Examples of the light source for the entire surface exposure include a carbon arc lamp, a mercury lamp, a gallium lamp, a metal halide lamp, a xenon lamp, a tungsten lamp, and various laser lights. Further, in order to obtain a sufficient printing durability, the overall exposure is preferably at least 10 mJ / cm ² or more, more preferably 100 mJ / cm ² or more.

  Furthermore, heating may be performed simultaneously with the entire surface exposure, and further improvement in printing durability is recognized by heating. Examples of the heating device include a conventional convection oven, an IR irradiation device, an IR laser, a microwave device, a Wisconsin oven, and the like. At this time, the plate surface temperature is preferably 30 ° C to 150 ° C, more preferably 35 ° C to 130 ° C, and still more preferably 40 ° C to 120 ° C.

  In the present invention, it is preferable to dry the lithographic printing plate precursor on which an image is formed by performing the above-described development process and additionally a preheating or pre-water washing process in order to facilitate subsequent handling. Examples of the drying method include natural drying in a room, hot air drying, and using a dryer attached to a gum coater or an automatic processor.

<Developer>
In the present invention, an aqueous solution having a pH of 2 to 10 can be used as a developer. For example, water alone or an aqueous solution containing water as a main component (containing 60% by mass or more of water) is preferable. An aqueous solution containing (anionic, nonionic, cationic, etc.) is preferred. The pH of the developer is more preferably from 3 to 9, and further preferably from 4 to 8.

  Examples of the anionic surfactant used in the present invention include fatty acid salts, abietic acid salts, hydroxyalkane sulfonic acid salts, alkane sulfonic acid salts, dialkyl sulfosuccinic acid salts, linear alkyl benzene sulfonic acid salts, branched alkyl benzene sulfonic acid salts, Alkylnaphthalene sulfonates, alkylphenoxy polyoxyethylene propyl sulfonates, polyoxyethylene alkyl sulfophenyl ether salts, N-methyl-N-oleyl taurine sodium, N-alkyl sulfosuccinic acid monoamide disodium salts, petroleum sulfonates , Sulfated castor oil, sulfated beef tallow oil, fatty acid alkyl ester sulfates, alkyl sulfates, polyoxyethylene alkyl ether sulfates, fatty acid compounds Glyceryl sulfate ester salt, polyoxyethylene alkylphenyl ether sulfate ester salt, polyoxyethylene styryl phenyl ether sulfate ester salt, alkyl phosphate ester salt, polyoxyethylene alkyl ether phosphate ester salt, polyoxyethylene alkylphenyl ether phosphate ester salt, styrene -Partially saponified products of maleic anhydride copolymer, partial saponified products of olefin-maleic anhydride copolymer, naphthalene sulfonate formalin condensate and the like. Among these, dialkyl sulfosuccinates, alkyl sulfate esters and alkyl naphthalene sulfonates are particularly preferably used.

  It does not specifically limit as a cationic surfactant used for this invention, A conventionally well-known thing can be used. Examples thereof include alkylamine salts, quaternary ammonium salts, polyoxyethylene alkylamine salts, and polyethylene polyamine derivatives.

  Nonionic surfactants used in the present invention include polyethylene glycol type higher alcohol ethylene oxide adduct, alkylphenol ethylene oxide adduct, fatty acid ethylene oxide adduct, polyhydric alcohol fatty acid ester ethylene oxide adduct, higher alkylamine ethylene. Oxide adduct, fatty acid amide ethylene oxide adduct, fat and oil ethylene oxide adduct, polypropylene glycol ethylene oxide adduct, dimethylsiloxane-ethylene oxide block copolymer, dimethylsiloxane- (propylene oxide-ethylene oxide) block copolymer, etc. Alcohol-type glycerol fatty acid ester, pentaerythritol fatty acid ester, sorbitol and sorbita Fatty acid esters of fatty acid esters of sucrose, alkyl ethers of polyhydric alcohols, fatty acid amides of alkanolamines.

  These nonionic surfactants may be used alone or in combination of two or more. In the present invention, ethylene oxide adduct of sorbitol and / or sorbitan fatty acid ester, polypropylene glycol ethylene oxide adduct, dimethylsiloxane-ethylene oxide block copolymer, dimethylsiloxane- (propylene oxide-ethylene oxide) block copolymer, polyhydric alcohol Fatty acid esters are more preferred.

  Further, from the viewpoint of stable solubility or turbidity in water, the nonionic surfactant used in the developer of the present invention preferably has an HLB (Hydrophile-Lipophile Balance) value of 6 or more. More preferably. Furthermore, the ratio of the nonionic surfactant contained in the developer is preferably 0.01 to 10% by mass, and more preferably 0.01 to 5% by mass. Further, acetylene glycol-based and acetylene alcohol-based oxyethylene adducts, fluorine-based and silicon-based surfactants can be used in the same manner.

  As the surfactant used in the developer of the present invention, a nonionic surfactant is particularly suitable from the viewpoint of foam suppression.

The developer of the present invention further preferably contains at least one selected from the group consisting of compounds represented by the following formula <1>, <2> or <3>.

In the formula <1>, R1 represents a hydrogen atom or an alkyl group, and A is a group containing a hydrogen atom, an ethylene oxide group, a carboxylic acid group, or a carboxylate. B is a group containing an ethylene oxide group, a carboxylic acid group, or a carboxylate. In formula <2>, R2 and R3 represent H or an alkyl group, C is an alkyl group or an ethylene oxide group, and D is a group containing a carboxylate anion. In formula <3>, R 4, R 5, R 6 and R 7 each represent H or an alkyl group, and Z ⁻ is a counter anion. The alkyl group of R1 to R7 may have a substituent.

  Although it does not specifically limit as a compound (henceforth a surfactant) represented by said formula <1>, <2> or <3>, A typical thing is shown below.

  (In the formula, R11 to R13, R15, R16, R18, R19, R21, R24 to R27 each represent H or an alkyl group. R14, R17, R19, R20, R22, R23 may be an alkylene group or may be omitted. .)

In the compound corresponding to the formula (I), R11 to R13 in the formula are H or an alkyl group, and R14 is an alkylene group. However, N and a carboxyl group may be directly connected, and in this case, R14 does not exist. In compound (I), when the total carbon number is increased, the hydrophobic portion is increased, and it becomes difficult to dissolve in an aqueous developer. In this case, it can be improved by mixing an organic solvent, alcohol or other solubilizing aid in water, but if the total carbon number becomes too large, dissolve the surfactant within the proper mixing range. I can't. The total number of carbon atoms of R11 to R14 is preferably 10 to 40, more preferably 12 to 30.
Here, when R11 to R14 described above are alkyl groups, the structure may be linear or branched.
The carbon number of R11 to R14 in the compound (I) is influenced by the material used for the image recording layer, particularly the binder polymer. In the case of a binder polymer having a high degree of hydrophilicity, those having a relatively small number of carbon atoms in R11 to R14 tend to be preferable, and those having a low degree of hydrophilicity in the binder polymer used preferably have a large number of carbon atoms in R11 to R14.
Typical compounds include those shown below.

In the compound of formula (II), R15 to R16 in the formula are H or an alkyl group, and R17 is an alkylene group. However, N and a carboxyl group may be directly connected, and in this case, R17 does not exist. Similar to the compound (I), in the compound (II), when the total carbon number is increased, the hydrophobic portion is increased and it is difficult to dissolve in the aqueous developer. In this case, it can be improved by mixing an organic solvent, alcohol or other solubilizing aid in water, but if the total carbon number becomes too large, dissolve the surfactant within the proper mixing range. I can't. Here, the total number of carbon atoms of R15 to R17 is preferably 10 to 30, and more preferably 12 to 25.
Here, when R11 to R14 described above are alkyl groups, the structure may be linear or branched.
The carbon number of R15 to R17 in the compound (II) is affected by the material used for the image recording layer, particularly the binder polymer. In the case of a binder polymer having a high degree of hydrophilicity, those having a relatively small carbon number of R15 to R17 tend to be preferable, and those having a low hydrophilicity are preferably those having a large number of carbon atoms of R15 to R17.
Further, in the above compounds, X ⁺ includes divalent metal ions such as calcium ions and magnesium ions, ammonium ions, hydrogen ions, etc., in addition to monovalent metal ions such as potassium ions and sodium ions. In compound (II), sodium ion and potassium are particularly preferred. Typical compounds include those shown below.

In the compound corresponding to the above formula (III), R18 in the formula is H or an alkyl group, and R19 and R20 are alkylene groups. However, N and a carboxyl group may be directly connected, and in this case, R19 and 20 do not exist. Similarly to the compounds (I) and (II), in the compound (III), when the total carbon number is increased, the hydrophobic portion is increased and it is difficult to dissolve in the aqueous developer. In this case, it can be improved by mixing an organic solvent, alcohol or other solubilizing aid in water, but if the total carbon number becomes too large, dissolve the surfactant within the proper mixing range. I can't. Here, the total number of carbon atoms of R18 to R20 is preferably 10 to 30, more preferably 12 to 28.
Here, when R18 to R20 described above are alkyl groups, the structure may be linear or branched.
The carbon number of R18 to R20 in the compound (III) is affected by the material used for the image recording layer, particularly the binder polymer. In the case of a binder polymer having a high degree of hydrophilicity, those having a relatively small carbon number of R15 to R17 tend to be preferable, and those having a low hydrophilicity are preferably those having a large number of carbon atoms of R15 to R17.
Further, in the above compounds, for X ⁺ and Y ⁺ , in addition to monovalent metal ions such as potassium ion and sodium ion, divalent metal ions such as calcium ion and magnesium ion, ammonium ion and hydrogen ion are used. It is done. In compound (III), sodium ion and potassium are particularly preferred. Typical compounds include those shown below.

In the compound corresponding to the above formula (IV), R21 in the formula is H or an alkyl group, and R22 and R23 are alkylene groups. However, N and ethylene oxide may be directly connected, and in this case, R22 and 23 do not exist. Also in the compound (IV), when the total carbon number is increased, the hydrophobic portion is increased and it is difficult to dissolve in the aqueous developer. In this case, it can be improved by mixing an organic solvent, alcohol or other solubilizing aid in water, but if the total carbon number becomes too large, dissolve the surfactant within the proper mixing range. I can't. Here, the total number of carbon atoms of R21 to R23 is preferably 8 to 50, and more preferably 12 to 40.
Here, when R21 to R23 described above are alkyl groups, the structure may be linear or branched.
The carbon number of R21 to R23 in the compound (IV) is affected by the material used for the image recording layer, particularly the binder polymer. In the case of a binder polymer having a high degree of hydrophilicity, those having a relatively small number of carbon atoms in R21 to R23 tend to be preferable, and those having a low hydrophilicity in the binder polymer used preferably have a large number of carbon atoms in R21 to R23. About m and n showing the number of ethylene oxide, if it becomes large, a hydrophilic degree will increase and stability in water will increase. m and n may be the same number or different numbers. Typical compounds include those shown below.

In the compound corresponding to the above formula (V), R24 to R27 in the formula are H or an alkyl group.
Also in the compound (V), when the total carbon number is increased, the hydrophobic portion is increased and it is difficult to dissolve in the aqueous developer. In this case, it can be improved by mixing an organic solvent, alcohol or other solubilizing aid in water, but if the total carbon number becomes too large, dissolve the surfactant within the proper mixing range. I can't. Here, the total number of carbon atoms of R24 to R27 is preferably 10 to 30, and more preferably 12 to 28.
Here, when R24 to R27 described above are alkyl groups, the structure thereof may be linear or branched.
The carbon number of R24 to R27 in these compounds (surfactants) is influenced by the material used for the image recording layer, particularly the binder polymer. In the case of a binder polymer having a high degree of hydrophilicity, those having a relatively low carbon number of R24 to R27 tend to be preferable, and those having a low hydrophilicity are preferably those having a high carbon number of R24 to R27.
Z ⁻ represents a counter anion. Although these are not limited, Cl ⁻ , Br ⁻ , I ^{− and the} like are often used. Typical compounds include those shown below.

  The above surfactants usually exhibit an effect when the total amount is 2% by mass in the developing solution of the present invention, but depending on the type of the surfactant, it may be an acceptable level and may not be a satisfactory level. Preferably, an addition amount of 5% by mass or more is necessary. Further, when the surfactant concentration (active ingredient concentration) exceeds 20% by mass and used in the developing bath, the member may be eroded and cause failure of the apparatus. Therefore, the active ingredient concentration is preferably 20% or less.

Further, the developer of the present invention may contain an organic solvent. Examples of the organic solvent that can be contained include aliphatic hydrocarbons (hexane, heptane, “Isopar E, H, G” (manufactured by Esso Chemical Co., Ltd.) or gasoline, kerosene, etc.), and aromatic hydrocarbons (toluene). And xylene), halogenated hydrocarbons (methylene dichloride, ethylene dichloride, trichlene, monochlorobenzene, etc.) and the following polar solvents.
Examples of polar solvents include alcohols (methanol, ethanol, propanol, isopropanol, benzyl alcohol, ethylene glycol monomethyl ether, 2-ethoxyethanol, diethylene glycol monoethyl ether, diethylene glycol monohexyl ether, triethylene glycol monomethyl ether, propylene glycol mono Ethyl ether, dipropylene glycol monomethyl ether, polyethylene glycol monomethyl ether, polypropylene glycol, tetraethylene glycol, ethylene glycol monobutyl ether, ethylene glycol monobenzyl ether, ethylene glycol monophenyl ether, methylphenyl carbinol, n-amyl alcohol, methyl amyl Alcoa Etc.), ketones (acetone, methyl ethyl ketone, ethyl butyl ketone, methyl isobutyl ketone, cyclohexanone, etc.), esters (ethyl acetate, propyl acetate, butyl acetate, amyl acetate, benzyl acetate, methyl lactate, butyl lactate, ethylene glycol monobutyl) Acetate, propylene glycol monomethyl ether acetate, diethylene glycol acetate, diethyl phthalate, butyl levulinate, etc.) and others (triethyl phosphate, tricresyl phosphate, N-phenylethanolamine, N-phenyldiethanolamine, etc.). If the organic solvent is insoluble in water, it can be used after being solubilized in water using a surfactant or the like. If the developer contains an organic solvent, safety, ignition, From the viewpoint of property, the concentration of the solvent is preferably less than 40% by mass.

  Further, the developer of the present invention may contain a water-soluble polymer compound. Examples of water-soluble polymer compounds include soybean polysaccharides, modified starches, gum arabic, dextrin, fiber derivatives (eg carboxymethylcellulose, carboxyethylcellulose, methylcellulose, etc.) and modified products thereof, pullulan, polyvinyl alcohol and derivatives thereof, polyvinylpyrrolidone, Examples include polyacrylamide and acrylamide copolymers, vinyl methyl ether / maleic anhydride copolymers, vinyl acetate / maleic anhydride copolymers, styrene / maleic anhydride copolymers, and the like.

  A well-known thing can be used for the said soybean polysaccharide, for example, there exists a brand name Soya Five (made by Fuji Oil Co., Ltd.) as a commercial item, and the thing of various grades can be used. What can be preferably used is one in which the viscosity of a 10% by mass aqueous solution is in the range of 10 to 100 mPa / sec.

As the modified starch, known ones can be used. Starch such as corn, potato, tapioca, rice, wheat is decomposed with acid or enzyme in the range of 5 to 30 glucose residues per molecule, and further in an alkali. It can be made by a method of adding oxypropylene or the like.
Two or more water-soluble polymer compounds can be used in combination. The content of the water-soluble polymer compound in the developer is preferably from 0.1 to 20% by mass, more preferably from 0.5 to 10% by mass.

  In addition to the above, the developer of the present invention may contain a preservative, a chelate compound, an antifoaming agent, an organic acid, an inorganic acid, an inorganic salt, and the like.

  Preservatives include phenol or derivatives thereof, formalin, imidazole derivatives, sodium dehydroacetate, 4-isothiazolin-3-one derivatives, benzisothiazolin-3-one, benztriazole derivatives, amiding anidine derivatives, quaternary ammonium salts, pyridine, Derivatives such as quinoline and guanidine, diazine, triazole derivatives, oxazole, oxazine derivatives, nitrobromoalcohol-based 2-bromo-2-nitropropane-1,3diol, 1,1-dibromo-1-nitro-2-ethanol, 1,1-dibromo-1-nitro-2-propanol and the like can be preferably used.

  Examples of chelate compounds include ethylenediaminetetraacetic acid, potassium salt thereof, sodium salt thereof; diethylenetriaminepentaacetic acid, potassium salt thereof, sodium salt thereof; triethylenetetraminehexaacetic acid, potassium salt thereof, sodium salt thereof, and hydroxyethylethylenediaminetriacetic acid. Nitrilotriacetic acid, sodium salt; 1-hydroxyethane-1,1-diphosphonic acid, potassium salt, sodium salt; aminotri (methylenephosphonic acid), potassium salt, sodium salt And organic phosphonic acids and phosphonoalkanetricarboxylic acids. Organic amine salts are also effective in place of the sodium and potassium salts of the chelating agents.

  As the antifoaming agent, a general silicon-based self-emulsifying type, emulsifying type, or nonionic surfactant having a HLB of 5 or less can be used. Silicon antifoaming agents are preferred. Among them, emulsification dispersion type and solubilization can be used.

  Examples of organic acids include citric acid, acetic acid, succinic acid, malonic acid, salicylic acid, caprylic acid, tartaric acid, malic acid, lactic acid, levulinic acid, p-toluenesulfonic acid, xylenesulfonic acid, phytic acid, and organic phosphonic acid. . The organic acid can also be used in the form of its alkali metal salt or ammonium salt.

  Examples of inorganic acids and inorganic salts include phosphoric acid, metaphosphoric acid, primary ammonium phosphate, secondary ammonium phosphate, primary sodium phosphate, secondary sodium phosphate, primary potassium phosphate, secondary potassium phosphate, Examples include sodium tripolyphosphate, potassium pyrophosphate, sodium hexametaphosphate, magnesium nitrate, sodium nitrate, potassium nitrate, ammonium nitrate, sodium sulfate, potassium sulfate, ammonium sulfate, sodium sulfite, ammonium sulfite, sodium hydrogen sulfate, nickel sulfate and the like.

[Lithographic printing plate precursor]
The lithographic printing plate precursor used in the present invention has a negative image recording layer that is cured by exposure. The negative type image recording layer is not particularly limited, but a polymerizable image containing a polymerization initiator, a polymerizable compound, and a hydrophobic binder polymer from the viewpoint of easy development and good printing durability. A recording layer is preferred. Hereinafter, components and components of the lithographic printing plate precursor such as the image recording layer and the support will be described.

(Image recording layer)
<Polymerization initiator>
The polymerization initiator used in the present invention is a compound that initiates and accelerates the polymerization of a compound having a polymerizable unsaturated group by generating radicals or acids by light or thermal energy. As such a polymerization initiator, a known radical generator or acid generator, a compound having a bond having a small bond dissociation energy, or the like can be appropriately selected and used.

  Examples of the compound that generates radicals or acids include, for example, organic halides, carbonyl compounds, organic peroxides, azo polymerization initiators, azide compounds, metallocene compounds, hexaarylbiimidazole compounds, organic boron compounds, and disulfone compounds. , Oxime 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 53-133428, JP 55-3070, JP 60-239736, JP 61-169835, JP 61-169837, JP 62- 58241, JP-A 62-212401, JP-A 63-70243, JP-A 63-298339, P. Hutt "
Journal of Heterocyclic Chemistry “1 (No 3), (1970)”. Of these, oxazole compounds substituted with a trihalomethyl group and S-triazine compounds are preferred.

  More preferable examples include s-triazine derivatives in which at least one mono, di, or trihalogen-substituted methyl group is bonded to the s-triazine ring, and oxadiazole derivatives in which the oxadiazole ring 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- (3,4-epoxyphenyl) -4,6-bis (trichloromethyl) -s-triazine, 2- [1- (P-methoxyphenyl) -2,4-butadienyl] -4,6-bis (trichloromethyl) -s-triazine, 2-styryl-4,6-bis (trichloromethyl) -s-triazine, 2- ( -Methoxystyryl) -4,6-bis (trichloromethyl) -s-triazine, 2- (pi-propyloxystyryl) -4,6-bis (trichloromethyl) -s-triazine, 2- (p- Tolyl) -4,6-bis (trichloromethyl) -s-triazine, 2- (4-methoxynaphthyl) -4,6-bis (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) Etc. -s- triazine and the following compounds.

  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-butylphenyl) 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- Examples thereof include 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 ′, 4,4 ′ − Tra- (t-hexylperoxycarbonyl) benzophenone, 3,3 ′, 4,4′-tetra- (p-isopropylcumylperoxycarbonyl) benzophenone, carbonyldi (t-butylperoxydihydrogen diphthalate), carbonyl And di (t-hexylperoxydihydrogen diphthalate).

  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, iron-arene complexes described in JP-A-1-304453 and JP-A-1-152109, and the like.

  Examples of the hexaarylbiimidazole compound include the specification of JP-B-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'-tetra (m-methoxyphenyl) biidazole, 2,2'-bis (o, o'-dichlorophenyl) -4,4', 5,5 '-Tetraphenylbiimidazole, 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 boron compounds include JP-A-62-143044, JP-A-62-1050242, JP-A-9-188585, JP-A-9-188686, JP-A-9-188710, JP-A-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. 1, 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, Examples thereof 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 compounds include JCS Perkin II (1979) 1653-1660), JCS
Perkin II (1979) 156-162, Journal of Photopolymer Science and Technology (1995) 202
-232, compounds described in JP-A No. 2000-66385, compounds described in JP-A No. 2000-80068, specifically, compounds represented by the following structural formulas.

  Examples of the onium salt compound include S.I. I. Schlesinger, Photogr. Sci. Eng. 18, 387 (1974), T.W. 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, 4,069,056, phosphonium salts described in European Patent Nos. 104,143, US Pat. Nos. 339,049, 410,201, JP -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 No. 4,734,444, No. 2,833,827, German Patent No. 2,904,626, No. 3,604,580, No. 3,604,581 Or a sulfonium salt 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.

  The onium salt suitably used in the present invention is an onium salt 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 a carbon number. 1-12 alkenyl group, C1-C12 alkynyl group, C1-C12 aryl group, C1-C12 alkoxy group, C1-C12 aryloxy group, halogen atom, C1-C1 12 alkylamino groups, C1-C12 dialkylamino groups, C1-C12 alkylamide groups or arylamide groups, carbonyl groups, carboxyl groups, cyano groups, sulfonyl groups, C1-C12 thioalkyl groups And a thioaryl group having 1 to 12 carbon atoms. Z ₁₁ ^- represents a monovalent anion, specifically a halogen ion, perchlorate ion, hexafluorophosphate ion, tetrafluoroborate ion, sulfonate ion, sulfinate ion, thiosulfonate ion, a sulfate ion Can be mentioned. Of these, perchlorate ion, hexafluorophosphate ion, tetrafluoroborate ion, sulfonate ion and sulfinate ion are preferable from the viewpoint of stability.

In the 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 include 1 to 1 carbon atoms. 12 alkyl groups, 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, Halogen atom, C1-C12 alkylamino group, C1-C12 dialkylamino group, C1-C12 alkylamide group or arylamide group, carbonyl group, carboxyl group, cyano group, sulfonyl group, carbon Examples thereof include a thioalkyl group having 1 to 12 carbon atoms and a thioaryl group having 1 to 12 carbon atoms. Z ₂₁ ^- represents a monovalent anion. Specific examples include halogen ions, perchlorate ions, hexafluorophosphate ions, tetrafluoroborate ions, sulfonate ions, sulfinate ions, thiosulfonate ions, and sulfate ions. Of these, perchlorate ion, hexafluorophosphate ion, tetrafluoroborate ion, sulfonate ion, sulfinate ion, and carboxylate ion are preferable in terms of stability and reactivity.

In the formula (RI-III), R ₃₁ , R ₃₂ and R ₃₃ are each independently an aryl group, alkyl group, alkenyl group or alkynyl having 20 or less carbon atoms, which may have 1 to 6 substituents. Represents a group. Among these, an aryl group is preferable from the viewpoint of reactivity and stability. Examples of the substituent include an 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, an aryl group having 1 to 12 carbon atoms, an alkoxy group 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. Specific examples include halogen ions, perchlorate ions, hexafluorophosphate ions, tetrafluoroborate ions, sulfonate ions, sulfinate ions, thiosulfonate ions, and sulfate ions. Of these, perchlorate ion, hexafluorophosphate ion, tetrafluoroborate ion, sulfonate ion, sulfinate ion, and carboxylate ion are preferable from the viewpoints of stability and reactivity. More preferred are the carboxylate ions described in JP-A No. 2001-343742, and particularly preferred are the carboxylate ions described in JP-A No. 2002-148790.

  The polymerization initiator is not limited to the above, but a triazine-based initiator, an organic halide, an oxime ester compound, a diazonium salt, an iodonium salt, and a sulfonium salt are more preferable from the viewpoints of reactivity and stability.

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. These polymerization initiators are 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. It can be added in proportions.

<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 selected from compounds having at least one ethylenically unsaturated bond, preferably two or more. It is. Such a compound group is widely known in the industrial field, and can be used without any particular limitation in the present invention.
These have chemical forms such as monomers, prepolymers, i.e. dimers, trimers and oligomers, or mixtures thereof and copolymers thereof. Examples of such monomers and copolymers thereof include unsaturated carboxylic acids (for example, acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid, maleic acid, etc.), esters and amides thereof. Preferably, 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 hydroxyl group, an amino group or a 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 isocyanate group or an epoxy group with a monofunctional or polyfunctional alcohol, amine or thiol, a halogen group or In addition, a substitution reaction product of an unsaturated carboxylic acid ester or amide having a leaving substituent such as a tosyloxy group and a monofunctional or polyfunctional alcohol, amine or thiol is also suitable. As another example, it is also possible to use a group of compounds substituted with unsaturated phosphonic acid, styrene, 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 -, and the like [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.

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

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

  Further, urethane acrylates such as those described in JP-A-51-37193, JP-B-2-32293, JP-B-2-16765, JP-B-58-49860, JP-B-56-17654 Urethane compounds having an ethylene oxide skeleton described in JP-B-62-39417 and JP-B-62-39418 are also suitable. Furthermore, by using 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, It is possible to obtain a photopolymerizable composition excellent in the photosensitive speed.

Other examples include reacting polyester acrylates, epoxy resins and (meth) acrylic acid as described in JP-A-48-64183, JP-B-49-43191, JP-B-52-30490. And polyfunctional acrylates and methacrylates such as epoxy acrylates. Further, specific unsaturated compounds described in JP-B-46-43946, JP-B-1-40337, JP-B-1-40336, and vinylphosphonic acid compounds described in JP-A-2-25493 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.

  Examples of the compound having a vinyl ether group used in the present invention include compounds described in JP-A-2002-029162. Specific examples include tetramethylene glycol divinyl ether, trimethylolpropane trivinyl ether, tetraethylene glycol divinyl ether, pentaerythritol divinyl ether, pentaerythritol trivinyl ether, pentaerythritol tetravinyl ether, 1,4-bis {2- (vinyloxy) ethyloxy} Benzene, 1,2-bis {2- (vinyloxy) ethyloxy} benzene, 1,3-bis {2- (vinyloxy) ethyloxy} benzene, 1,3,5-tris {2- (vinyloxy) ethyloxy} benzene, 4 , 4′-bis {2- (vinyloxy) ethyloxy} biphenyl, 4,4′-bis {2- (vinyloxy) ethyloxy} diphenyl ether, 4,4′-bis {2- (vinyloxy) ester Ruoxy} diphenylmethane, 1,4-bis {2- (vinyloxy) ethyloxy} naphthalene, 2,5-bis {2- (vinyloxy) ethyloxy} furan, 2,5-bis {2- (vinyloxy) ethyloxy} thiophene, , 5-bis {2- (vinyloxy) ethyloxy} imidazole, 2,2-bis [4- {2- (vinyloxy) ethyloxy} phenyl] propane {bis (vinyloxyethyl) ether of bisphenol A}, 2,2- Examples include, but are not limited to, bis {4- (vinyloxymethyloxy) phenyl} propane, 2,2-bis {4- (vinyloxy) phenyl} propane, and the like.

About these addition polymerizable compounds, the details of usage, such as the structure, single use or combined use, and addition amount, 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.
In addition, the selection and use method of the addition polymerization compound is also an important factor for compatibility and dispersibility with other components in the image recording layer (for example, water-insoluble polymer, initiator, colorant, etc.). For example, the compatibility may be improved by using a low-purity compound or 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, based on the total solid content constituting the image recording layer. These may be used alone or in combination of two or more.

<Binder polymer having an acid value of 0.3 meq / g or less>
The binder polymer used in the image recording layer of the present invention has an acid value (the acid content per gram of polymer expressed by the number of chemical equivalents) of 0.3 meq / g or less. The binder polymer (hereinafter abbreviated as a binder as appropriate) is preferably one that does not substantially contain an acid group such as a carboxyl group, a sulfo group, or a phosphate group. The acid value of the binder is preferably 0.1 meq / g or less. When the acid value exceeds 0.3 meq / g, problems such as deterioration in developability (generation of residual film) and reduction in printing durability due to increase in hydrophilicity may occur.

Moreover, it is preferable that the binder used for this invention is substantially insoluble with respect to water and aqueous solution of pH 10 or more. The solubility of the binder in water (polymer concentration at the time of saturated dissolution) is preferably 1.0% by mass or less. The solubility measurement temperature is 25 ° C., which is a normal temperature during plate-making development.
By using such a binder, it is possible to improve the printing durability by improving the film strength, water resistance and wall-thickness of the image recording layer while maintaining good developability with respect to an aqueous developer.

As the binder, as long as the performance of the lithographic printing plate precursor according to the present invention is not impaired, a conventionally known one can be used without limitation within the above range, and a linear organic polymer having film properties is preferable.
Examples of such binders are preferably polymers selected from acrylic resins, methacrylic resins, styrene resins, polyvinyl acetal resins, polyurethane resins, polyamide resins, epoxy resins, and polyester resins. Of these, vinyl copolymers such as acrylic resins, methacrylic resins, and styrene resins, and polyurethane resins are preferable.

  Such a vinyl copolymer can be obtained by using a known vinyl monomer and adjusting the type and amount ratio of the monomer so as to have the above properties (acid value, solubility, etc.). Examples of vinyl monomers include (meth) acrylic acid esters, crotonic acid esters, vinyl esters, maleic acid diesters, fumaric acid diesters, itaconic acid diesters, (meth) acrylamides, vinyl ethers, and styrene. And (meth) acrylonitrile are preferred. Specific examples of such compounds include the following compounds.

  Examples of (meth) acrylic acid esters include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, tert-butyl (meth) acrylate, n-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, acetoxyethyl (meth) acrylate, phenyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (Meth) acrylate, 4-hydroxybutyl (meth) acrylate, 2-methoxyethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, 2- (2-methoxyethoxy) ethyl (meth) acrylate , Cyclohexyl (meth) acrylate, benzyl (meth) acrylate, diethylene glycol monomethyl ether (meth) acrylate, diethylene glycol monoethyl ether (meth) acrylate, diethylene glycol monophenyl ether (meth) acrylate, triethylene glycol monomethyl ether (meth) acrylate, tri Ethylene glycol monoethyl ether (meth) acrylate, dipropylene glycol monomethyl ether (meth) acrylate, polyethylene glycol monomethyl ether (meth) acrylate, polypropylene glycol monomethyl ether (meth) acrylate, monomethyl copolymer of ethylene glycol and propylene glycol Ether (meth) acrylate, N, N-di Chill aminoethyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylate.

Examples of the crotonic acid esters include butyl crotonic acid and hexyl crotonic acid. Examples of vinyl esters include vinyl acetate, vinyl propionate, vinyl butyrate, vinyl methoxyacetate, vinyl benzoate and the like.
Examples of maleic acid diesters include dimethyl maleate, diethyl maleate, and dibutyl maleate. Examples of the fumaric acid diesters include dimethyl fumarate, diethyl fumarate, dibutyl fumarate and the like. Examples of the itaconic acid diesters include dimethyl itaconate, diethyl itaconate, and dibutyl itaconate.

Examples of (meth) acrylamides include (meth) acrylamide, N-methyl (meth) acrylamide, N-ethyl (meth) acrylamide, N-propyl (meth) acrylamide, Nn butylacryl (meth) amide, N-tert. Butyl (meth) acrylamide, N-cyclohexyl (meth) acrylamide, N- (2-methoxyethyl) (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, N -Phenyl (meth) acrylamide, N-benzyl (meth) acrylamide, (meth) acryloylmorpholine, etc. are mentioned.
Examples of vinyl ethers include methyl vinyl ether, butyl vinyl ether, hexyl vinyl ether, and methoxyethyl vinyl ether.

Styrenes include styrene, methyl styrene, dimethyl styrene, trimethyl styrene, ethyl styrene, isopropyl styrene, butyl styrene, hydroxy styrene, methoxy styrene, butoxy styrene, acetoxy styrene, chloro styrene, dichloro styrene, bromo styrene, chloromethyl styrene, Examples include methyl vinylbenzoate and α-methylstyrene.
In addition, vinyl pyridine, vinyl pyrrolidone, vinyl carbazole, (meth) acrylonitrile and the like can also be used.
A vinyl monomer having a urethane group or a urea group can also be used. Examples of such a compound include the following compounds.

In order to form an image with a developer having a pH of 2 to 10 using a binder having an acid value of 0.3 meq / g or less, a vinyl monomer having a non-acidic hydrophilic group is used as a component of the binder. It is preferable to use some.
Examples of the hydrophilic group include hydroxyl group, carboxylate group, hydroxyethyl group, ethyleneoxy group, hydroxypropyl group, amino group, aminoethyl group, aminopropyl group, ammonium group, amide group, carboxymethyl group, and the like. Polyether groups (diethylene oxide, triethylene oxide, polyethylene oxide, dipropylene oxide, tripropylene oxide, polypropylene oxide, ditetramethylene oxide, tritetramethylene oxide, polytetramethylene oxide, combinations thereof, etc.) It is preferable to use a vinyl monomer having such a hydrophilic group.
More specifically, R of the ester residue (—COOR) of (meth) acrylic acid ester is —CH ₂ CH ₂ O— unit, —CH ₂ CH (CH ₃ ) O— unit or —CH ₂ CH _2. Copolymers containing at least one kind such as (meth) acrylic acid esters containing NH units, hydroxyl group-containing (meth) acrylic acid esters, (meth) acrylamides and the like are particularly preferred. Moreover, 5-70 mol% is preferable, as for the ratio of the vinyl monomer which has a hydrophilic group in the binder of this invention, 10-60 mol% is more preferable, and 15-50 mol% is especially preferable. If the ratio of the vinyl monomer having a hydrophilic group is less than 5 mol%, the developability may be lowered, and if it exceeds 70 mol%, the printing durability may be lowered.

Further, a polyurethane resin can be preferably used as the binder of the image recording layer of the present invention. The image recording layer of the present invention needs to have a strength that the image portion can sufficiently withstand strong rubbing. When the image portion is greatly damaged by the rubbing member, printing durability may be poor, or scratches may remain on the image portion. In the case of a polymerization-type image recording layer, the strength generally tends to be strong. Among them, polyurethane resin has a very strong image recording layer and can be preferably used.
The polyurethane resin is obtained by a polyaddition reaction between a known diisocyanate compound and a diol compound. The type and amount ratio of the diisocyanate compound and the diol compound are appropriately adjusted so as to have the above-mentioned characteristics (acid value, solubility, etc.). Can be obtained.

1) Diisocyanate compound Examples of the diisocyanate compound include the following. Preferred is a diisocyanate compound represented by the following general formula (6).

OCN-L ¹ -NCO (6)

In General Formula (6), L ¹ represents a divalent aliphatic or aromatic hydrocarbon group which may have a substituent. If necessary, L ¹ may have another functional group that does not react with an isocyanate group, such as an ester, urethane, amide, or ureido group.

Specific examples of the diisocyanate compound represented by the general formula (6) include those shown below.
That is, 2,4-tolylene diisocyanate, dimer of 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, p-xylylene diisocyanate, m-xylylene diisocyanate, 4,4′-diphenylmethane diisocyanate Aromatic diisocyanate compounds such as 1,5-naphthylene diisocyanate, 3,3′-dimethylbiphenyl-4,4′-diisocyanate;
Aliphatic diisocyanate compounds such as hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, lysine diisocyanate, dimer acid diisocyanate and the like;
Alicyclic diisocyanate compounds such as isophorone diisocyanate, 4,4′-methylenebis (cyclohexyl isocyanate), methylcyclohexane-2,4 (or 2,6) diisocyanate, 1,3- (isocyanatomethyl) cyclohexane;
And a diisocyanate compound which is a reaction product of a diol and a diisocyanate such as an adduct of 1 mol of 1,3-butylene glycol and 2 mol of tolylene diisocyanate.

2) Examples of the diol compound diol compound include a polyether diol compound, a polyester diol compound, and a polycarbonate diol compound.

  Examples of the polyether diol compound include compounds represented by the following formulas (7), (8), (9), (10) and (11), and random copolymerization of ethylene oxide and propylene oxide having a hydroxyl group at the terminal. Coalescence is mentioned.

In formulas (7) to (11), R ¹⁴ represents a hydrogen atom or a methyl group, and X ¹ represents the following group. Moreover, a, b, c, d, e, f, and g each represent an integer of 2 or more, and preferably an integer of 2 to 100.

Specific examples of the polyether diol compound represented by the above formulas (7) and (8) include the following.
That is, diethylene glycol, triethylene glycol, tetraethylene glycol, pentaethylene glycol, hexaethylene glycol, heptaethylene glycol, octaethylene glycol, di-1,2-propylene glycol, tri-1,2-propylene glycol, tetra-1, 2-propylene glycol, hexa-1,2-propylene glycol, di-1,3-propylene glycol, tri-1,3-propylene glycol, tetra-1,3-propylene glycol, di-1,3-butylene glycol, Tri-1,3-butylene glycol, hexa-1,3-butylene glycol, polyethylene glycol having a weight average molecular weight of 1000, polyethylene glycol having a weight average molecular weight of 1500, poly having a weight average molecular weight of 2,000 Tylene glycol, polyethylene glycol with a weight average molecular weight of 3000, polyethylene glycol with a weight average molecular weight of 7500, polypropylene glycol with a weight average molecular weight of 400, polypropylene glycol with a weight average molecular weight of 700, polypropylene glycol with a weight average molecular weight of 1000, polypropylene glycol with a weight average molecular weight of 2000 , Polypropylene glycol having a weight average molecular weight of 3000, polypropylene glycol having a weight average molecular weight of 4000, and the like.

Specific examples of the polyether diol compound represented by the formula (9) include those shown below.
That is, Sanyo Chemical Industries, Ltd. (trade name) PTMG650, PTMG1000, PTMG2000, PTMG3000, and the like.

Specific examples of the polyether diol compound represented by the formula (10) include those shown below.
That is, Sanyo Chemical Industries, Ltd. (trade name) New Pole PE-61, New Pole PE-62, New Pole PE-64, New Pole PE-68, New Pole PE-71, New Pole PE-74, New Pole PE-75, New Pole PE-78, New Pole PE-108, New Pole PE-128, New Pole PE-61, and the like.

Specific examples of the polyether diol compound represented by the formula (11) include those shown below.
That is, Sanyo Chemical Industries, Ltd. (trade name) New Pole BPE-20, New Pole BPE-20F, New Pole BPE-20NK, New Pole BPE-20T, New Pole BPE-20G, New Pole BPE-40, New Pole BPE-60, New Pole BPE-100, New Pole BPE-180, New Pole BPE-2P, New Pole BPE-23P, New Pole BPE-3P, New Pole BPE-5P, and the like.

Specific examples of the random copolymer of ethylene oxide and propylene oxide having a hydroxyl group at the terminal include the following.
That is, Sanyo Chemical Industries, Ltd. (trade name) New Pole 50HB-100, New Pole 50HB-260, New Pole 50HB-400, New Pole 50HB-660, New Pole 50HB-2000, New Pole 50HB-5100, etc. It is.

  Examples of the polyester diol compound include compounds represented by formulas (12) and (13).

In formulas (12) and (13), L ² , L ³ and L ⁴ may be the same or different and each represents a divalent aliphatic or aromatic hydrocarbon group, and L ⁵ represents a divalent aliphatic carbonization. Represents a hydrogen group. Preferably, L ^{2 to} L ⁴ each represent an alkylene group, an alkenylene group, an alkynylene group, or an arylene group, and L ⁵ represents an alkylene group. In addition, other functional groups that do not react with the isocyanate group, such as ether, carbonyl, ester, cyano, olefin, urethane, amide, ureido group or halogen atom may be present in L ^{2 to} L ⁵ . n1 and n2 are each an integer of 2 or more, preferably an integer of 2 to 100.
As the polycarbonate diol compound, there is a compound represented by the formula (14).

In the formula (14), L ⁶ may be the same or different and each represents a divalent aliphatic or aromatic hydrocarbon group. Preferably, L ⁶ represents an alkylene group, an alkenylene group, an alkynylene group or an arylene group. In addition, other functional groups that do not react with the isocyanate group, such as ether, carbonyl, ester, cyano, olefin, urethane, amide, ureido group or halogen atom may be present in L ⁶ . n3 is an integer of 2 or more, and preferably represents an integer of 2 to 100.

  Specific examples of the diol compound represented by the above formula (12), (13) or (14) include (Exemplary Compound No. 1) to (Exemplary Compound No. 18) shown below. N in the specific examples represents an integer of 2 or more.

  Moreover, in the synthesis | combination of specific polyurethane resin, the diol compound which has a substituent which does not react with an isocyanate group other than the said diol compound can also be used together. Examples of such diol compounds include those shown below.

^{HO-L 7 -O-CO-} L 8 -CO-O-L 7 -OH (15)
^{HO-L 8 -CO-O-} L 7 -OH (16)

In the formulas (15) and (16), L ⁷ and L ⁸ may be the same or different, and each may have a substituent (for example, an alkyl group, an aralkyl group, an aryl group, an alkoxy group, an aryloxy group, —F, — And a divalent aliphatic hydrocarbon group, an aromatic hydrocarbon group or a heterocyclic group, which may have a halogen atom such as Cl, -Br, and -I. If necessary, L ⁷ and L ⁸ may have another functional group that does not react with an isocyanate group, such as a carbonyl group, an ester group, a urethane group, an amide group, or a ureido group. Note that L ⁷ and L ⁸ may form a ring.

  Furthermore, the binder can be provided with a crosslinking property 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 or may be introduced by a polymer reaction.

  Here, the crosslinkable group is a group that crosslinks the polymer binder in the process of radical polymerization reaction that occurs in the image recording layer when the lithographic printing plate precursor is exposed. Although it will not specifically limit if it is a group of such a function, For example, an ethylenically unsaturated bond group, an amino group, an epoxy group etc. are mentioned as a functional group which can be addition-polymerized. Moreover, the functional group which can become a radical by light irradiation may be sufficient, and as such a crosslinkable group, a thiol group, a halogen group, an onium salt structure etc. are mentioned, for example. Especially, an ethylenically unsaturated bond group is preferable and the functional group represented by the following general formula (1)-(3) is especially preferable.

In the general formula (1), R ^{1 to} R ³ each independently represents a hydrogen atom or a monovalent organic group, and R ¹ is preferably a hydrogen atom or an alkyl which may have a substituent. A hydrogen atom or a methyl group is preferable because of high radical reactivity. R ² and R ³ are each independently a hydrogen atom, a halogen atom, an amino group, a carboxyl group, an alkoxycarbonyl group, a sulfo group, a nitro group, a cyano group, an optionally substituted alkyl group, a substituted group An aryl group that may have a group, an alkoxy group that may have a substituent, an aryloxy group that may have a substituent, an alkylamino group that may have a substituent, and a substituent An arylamino group which may have a substituent, an alkylsulfonyl group which may have a substituent, an arylsulfonyl group which may have a substituent, and the like. Among them, a hydrogen atom, a carboxyl group, an alkoxycarbonyl group, a substituent An alkyl group which may have a substituent and an aryl group which may have a substituent are preferable because of high radical reactivity.

X represents an oxygen atom, a sulfur atom, or —N (R ¹² ) —, wherein R ¹² represents a hydrogen atom or a monovalent organic group. Examples of the monovalent organic group include an alkyl group which may have a substituent. R ¹² is preferably a hydrogen atom, a methyl group, an ethyl group, or an isopropyl group because of high radical reactivity.

  Here, examples of the substituent that can be introduced include an alkyl group, an alkenyl group, an alkynyl group, an aryl group, an alkoxy group, an aryloxy group, a halogen atom, an amino group, an alkylamino group, an arylamino group, a carboxyl group, an alkoxycarbonyl group, A sulfo group, a nitro group, a cyano group, an amide group, an alkylsulfonyl group, an arylsulfonyl group and the like can be mentioned.

In the general formula (2), R ^{4 to} R ⁸ each independently represents a hydrogen atom or a monovalent organic group, and R ^{4 to} R ⁸ are preferably a hydrogen atom, a halogen atom, an amino group, or a dialkyl. Amino group, carboxyl group, alkoxycarbonyl group, sulfo group, nitro group, cyano group, alkyl group which may have a substituent, aryl group which may have a substituent, alkoxy which may have a substituent A group, an aryloxy group which may have a substituent, an alkylamino group which may have a substituent, an arylamino group which may have a substituent, an alkylsulfonyl group which may have a substituent, Examples include an arylsulfonyl group which may have a substituent. Among them, a hydrogen atom, a carboxyl group, an alkoxycarbonyl group, an alkyl group which may have a substituent, and an aryl which may have a substituent The ru group is preferred.

Examples of the substituent that can be introduced are the same as those in the general formula (1). Y represents an oxygen atom, a sulfur atom, or N (R ¹² ) —. R ¹² has the same meaning as R ¹² in general formula (1), and preferred examples are also the same.

In the general formula (3), R ⁹ represents a hydrogen atom or a monovalent organic group, and preferably includes a hydrogen atom or an alkyl group which may have a substituent. A methyl group is preferable because of high radical reactivity. R ¹⁰ and R ¹¹ are each independently a hydrogen atom, a halogen atom, an amino group, a dialkylamino group, a carboxyl group, an alkoxycarbonyl group, a sulfo group, a nitro group, a cyano group, or an alkyl group which may have a substituent. An aryl group which may have a substituent, an alkoxy group which may have a substituent, an aryloxy group which may have a substituent, an alkylamino group which may have a substituent, a substituent An arylamino group that may have, an alkylsulfonyl group that may have a substituent, an arylsulfonyl group that may have a substituent, and the like, among them, a hydrogen atom, a carboxyl group, an alkoxycarbonyl group, An alkyl group which may have a substituent and an aryl group which may have a substituent are preferable because of high radical reactivity.

Here, examples of the substituent that can be introduced are the same as those in the general formula (1). Further, Z is an oxygen atom, a sulfur atom, -N (R ¹³⁾ -, or a phenylene group which may have a substituent. Examples of R ¹³ include an alkyl group which may have a substituent. Among them, a methyl group, an ethyl group, and an isopropyl group are preferable because of high radical reactivity.

  Among the above, a vinyl copolymer having a crosslinkable group in the side chain and a polyurethane resin having a crosslinkable group in the side chain are more preferable.

In the binder having crosslinkability, for example, free radicals (polymerization initiating radicals or growth radicals in the polymerization process of the polymerizable compound) are added to the crosslinkable functional group, and the binder is directly or via a polymerization chain of the polymerizable compound. Then, addition polymerization is performed, and a crosslink is formed between the binder molecules to be cured. Alternatively, atoms in the binder (for example, hydrogen atoms on carbon atoms adjacent to the functional bridging group) are extracted by free radicals to form polymer radicals that are bonded to each other, thereby causing cross-linking between the binder molecules. Forms and cures.
The content of the crosslinkable group in the binder (content of unsaturated double bond capable of radical polymerization by iodometric titration) is preferably 0.1 to 10.0 mmol, more preferably 1.0 to 7 per gram of binder. 0.0 mmol, most preferably 2.0-5.5 mmol.
The glass transition temperature (Tg) of the binder according to the present invention is preferably 0 to 150 ° C, more preferably 20 to 120 ° C, and particularly preferably 30 to 100 ° C. When the glass transition temperature is less than 0 ° C., the printing durability may be deteriorated, and when the glass transition temperature exceeds 150 ° C., the developability may be deteriorated.

The binder preferably has a mass average molecular weight of 5,000 or more, more preferably 10,000 to 300,000, more preferably a number average molecular weight of 1,000 or more, and more preferably 2000 to 250,000. preferable. The polydispersity (mass average molecular weight / number average molecular weight) is preferably 1.1 to 10.
The binder may be any of random polymer, block polymer, graft polymer and the like.
A binder may be used independently or may mix and use 2 or more types.
The content of the binder is preferably from 5 to 75 mass%, more preferably from 10 to 60 mass%, more preferably from 20 to 50 mass%, based on the total solid content of the image recording layer, from the viewpoint of good image area strength and image formability. Mass% is particularly preferred.

<Infrared absorber>
For the image recording layer of the lithographic printing plate precursor that performs imagewise exposure using a light source that emits infrared rays, an infrared absorber can be used in combination with the polymerization initiator. The infrared absorber has a function of converting the absorbed infrared rays into heat, and the polymerization initiator is thermally decomposed by the heat generated at this time to generate radicals. The infrared absorber used in the present invention is 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 Is mentioned.

  Preferred dyes include, for example, cyanine dyes described in JP-A-58-125246, JP-A-59-84356, JP-A-60-78787, JP-A-58-173696, The methine dyes described in Japanese Laid-Open Patent Publication Nos. 58-181690 and 58-194595, JP-A 58-112793, JP-A 58-224793, JP-A 59-48187, Naphthoquinone dyes described in Japanese Laid-Open Patent Publication Nos. 59-73996, 60-52940 and 60-63744, and squarylium dyes described in Japanese Laid-Open Patent Publication No. 58-112792. And cyanine dyes described in British Patent 434,875.

  In addition, a near infrared absorption sensitizer described in US Pat. No. 5,156,938 is also preferably used, and a substituted arylbenzo (thio) described in US Pat. No. 3,881,924 is also suitable. ) Pyrylium salt, trimethine thiapyrylium salt described in JP-A-57-142645 (US Pat. No. 4,327,169), JP-A-58-181051, 58-220143, 59- No. 41363, 59-84248, 59-84249, 59-146063, 59-146061, pyranyl compounds described in JP-A-59-216146, cyanine dyes described in JP-A-59-216146, Patented in US Pat. No. 4,283,475, such as pentamethine thiopyrylium salt, and Japanese Patent Publication Nos. 5-13514 and 5-19702 Pyrylium compounds are also preferably used. Another example of a preferable dye is a near-infrared absorbing dye described in US Pat. No. 4,756,993 as formulas (I) and (II).

  Particularly preferred among these dyes are cyanine dyes, 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 shown below. Here, X ² represents an oxygen atom, a nitrogen atom or a sulfur atom, and L ¹ represents a hydrocarbon group having 1 to 12 carbon atoms, an aromatic ring having a hetero atom, or 1 to 1 carbon atom containing a hetero atom. 12 hydrocarbon groups are shown. In addition, a hetero atom here shows N, S, O, a halogen atom, and Se. Xa ^- the Za described later ^- is defined as for, R ^a represents a hydrogen atom, an alkyl group, an aryl group, a substituted or unsubstituted amino group, substituted or unsubstituted amino group and a halogen atom.

R ¹ and R ² each independently represents a hydrocarbon group having 1 to 12 carbon atoms. From the storage stability of the 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 or It is particularly preferable that a 6-membered ring is formed.

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

  Specific examples of the cyanine dye represented by formula (i) that can be suitably used in the present invention include those described in paragraphs [0017] to [0019] of JP-A No. 2001-133969. be able to. Further, other particularly preferable examples include specific indolenine cyanine dyes described in JP-A-2002-278057.

  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 , Quinophthalone pigments, dyed lake pigments, azine pigments, nitroso pigments, nitro pigments, natural pigments, fluorescent pigments, inorganic pigments, carbon black, and the like. 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 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 of the pigment dispersion in the image recording layer coating solution and good uniformity of the image recording layer can be obtained.

  As a method for dispersing the pigment, a known dispersion technique used for ink production or toner production 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 addition of these infrared absorbers to the image recording layer is preferably made the minimum necessary amount in order to suppress side effects that inhibit the polymerization reaction.

  These infrared absorbers are added in a proportion of 0.001 to 50% by mass, preferably 0.005 to 30% by mass, particularly preferably 0.01 to 10% by mass, based on the total solid content of the image recording layer. Can do. Within this range, high sensitivity can be obtained without adversely affecting the uniformity and film strength of the image recording layer.

<Sensitizer>
It is also possible to increase radical generation efficiency by using a sensitizer in combination with the above polymerization initiator in the image recording layer of a lithographic printing plate precursor that performs imagewise exposure using a light source that emits light of 250 to 420 nm. it can.

  Specific examples of the sensitizer include benzoin, benzoin methyl ether, benzoin ethyl ether, 9-fluorenone, 2-chloro-9-fluorenone, 2-methyl-9-fluorenone, 9-anthrone, and 2-bromo-9-anthrone. 2-ethyl-9-anthrone, 9,10-anthraquinone, 2-ethyl-9,10-anthraquinone, 2-t-butyl-9,10-anthraquinone, 2,6-dichloro-9,10-anthraquinone, xanthone 2-methylxanthone, 2-methoxyxanthone, thioxanthone, benzyl, dibenzalacetone, p- (dimethylamino) phenyl styryl ketone, p- (dimethylamino) phenyl p-methylstyryl ketone, benzophenone, p- (dimethylamino) ) Benzophenone (or Michlerketo) ), P- (diethylamino) benzophenone, and the like benzanthrone.

  Furthermore, preferred sensitizers in the present invention include compounds represented by general formula (ii) described in JP-B-51-48516.

In the formula, R ¹⁴ is an alkyl group (for example, methyl group, ethyl group, propyl group, etc.) or a substituted alkyl group (for example, 2-hydroxyethyl group, 2-methoxyethyl group, carboxymethyl group, 2-carboxyethyl group) Etc.). R ¹⁵ represents an alkyl group (eg, methyl group, ethyl group, etc.) or an aryl group (eg, phenyl group, p-hydroxyphenyl group, naphthyl group, thienyl group, etc.).

Z ² is a group of nonmetallic atoms necessary for forming a heterocyclic nucleus containing nitrogen, which is usually used in cyanine dyes, such as benzothiazoles (benzothiazole, 5-chlorobenzothiazole, 6-chlorobenzothiazole, etc.), naphtho Thiazoles (α-naphthothiazole, β-naphthothiazole, etc.), benzoselenazoles (benzoselenazole, 5-chlorobenzoselenazole, 6-methoxybenzoselenazole, etc.), naphthoselenazoles (α-naphthoselenazole) , Β-naphthselenazole, etc.), benzoxazoles (benzoxazole, 5-methylbenzoxazole, 5-phenylbenzoxazole, etc.) and naphthoxazoles (α-naphthoxazole, β-naphthoxazole, etc.).

Specific examples of the compound represented by the general formula (ii) are those having a chemical structure combining these Z ² , R ¹⁴ and R ¹⁵ , and many exist as known substances. Therefore, it can be used by appropriately selecting from these known ones. Furthermore, preferred sensitizers in the present invention include merocyanine dyes described in JP-B-5-47095 and ketocoumarin compounds represented by the following general formula (iii).

Here, R ¹⁶ represents an alkyl group such as a methyl group or an ethyl group.

  These sensitizers are preferably from 0.1 to 50 mass%, more preferably from 0.5 to 30 mass%, particularly preferably from 0.8 to 20 mass%, based on the total solid content constituting the image recording layer. Can be added.

<Microcapsule>
In the present invention, as a method for incorporating the above-mentioned image recording layer constituents and other constituents described later into the image recording layer, for example, as described in JP-A Nos. 2001-277740 and 2001-277742. At least a part of the constituent components can be encapsulated in microcapsules and added to the image recording layer. In that case, each component can be contained in any ratio in and out of the microcapsule.

  A known method can be applied as a method for microencapsulating the constituent components of the image recording layer. 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 said water-insoluble polymer.

  The average particle size of the microcapsules 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.

<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.

<Hydrophilic polymer>
The image recording layer of the present invention may contain a hydrophilic polymer for the purpose of improving developability and improving microcapsule dispersion stability.
Examples of the hydrophilic polymer include hydroxyl group, carboxyl group, carboxylate group, hydroxyethyl group, polyoxyethyl group, hydroxypropyl group, polyoxypropyl group, amino group, aminoethyl group, aminopropyl group, ammonium group, Those having a hydrophilic group such as an amide group, a carboxymethyl group, a sulfo group, and a phosphoric acid group are preferred.

  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 hydrophilic polymer preferably has a mass average molecular weight of 5000 or more, more preferably 10,000 to 300,000. The hydrophilic polymer may be any of a random polymer, a block polymer, a graft polymer, and the like. The content of the hydrophilic polymer in the image recording layer is preferably 20% by mass or less, more preferably 10% by mass or less, based on the total solid content of the image recording layer.

<Chain transfer agent>
The image recording layer of the present invention can contain a chain transfer agent for improving sensitivity and storage stability. As the compound that acts as a chain transfer agent, for example, a compound group having SH, PH, SiH, and GeH in the molecule is used. 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, a thiol compound is particularly preferably used as a chain transfer agent. Of these, the thiol compounds described in JP-A-2006-91479 are particularly preferably used. Specific examples include 1-phenyl-2-mercaptobenzothiazole, 1-methyl-2-mercaptobenzothiazole, 1-n-heptyl-2-mercaptobenzothiazole, 1-cyclohexyl-2-mercaptobenzothiazole, 1- Methyl-2-mercapto-5-phenyl-1,3,4-triazole, 1-n-butyl-2-mercapto-5-phenyl-1,3,4-triazole, 1- (2-phenylethyl) -2 Examples include, but are not limited to, mercapto-5-phenyl-1,3,4-triazole, 1-benzyl-2-mercapto-5-phenyl-1,3,4-triazole and the like.

  The amount of these chain transfer agents (thiol compounds) 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%.

<Surfactant>
In the present invention, it is preferable to use a surfactant in the image recording layer in order to promote developability and improve the coated surface state. Examples of the surfactant include nonionic surfactants, anionic surfactants, cationic surfactants, amphoteric surfactants, and fluorosurfactants. Surfactant may be used independently and may be used in combination of 2 or more type.

  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 anionic surfactant used in the present invention is not particularly limited, and conventionally known anionic 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.
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 acid 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 anionic 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. Also preferred are the fluorosurfactants described in JP-A-62-170950, JP-A-62-226143 and JP-A-60-168144.

  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 7% by mass with respect to the total solid content of the image recording layer.

<Colorant>
In 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 dyes described in Japanese Patent No. 293247. Also, pigments such as phthalocyanine pigments, azo pigments, carbon black, titanium oxide, etc. can be suitably used.

  These colorants are preferably added since it is easy to distinguish an image area from a non-image area after image formation. The addition amount is 0.01 to 10% by mass with respect to the total solid content of the image recording material.

<Bakeout agent>
In the image recording layer of the present invention, a compound that changes color by an acid or a radical can be added to produce a printout 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, Malachide Green, Parafuchsin, Victoria Pure Blue BOH [manufactured by Hodogaya Chemical Co., Ltd.], Oil Blue # 603 [Orient Chemical Kogyo Co., Ltd.], Oil Pink # 312 [Orient Chemical Co., Ltd.], Oil Red 5B [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 acid or radical is 0.01 to 15% by mass relative to the solid content of the image recording layer.

<Polymerization inhibitor>
In the image recording layer of the present invention, it is preferable to add a small amount of a thermal polymerization inhibitor in order to prevent unnecessary thermal polymerization of the radical polymerizable compound during the production or storage of the image recording layer.
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.

<Higher fatty acid derivatives, etc.>
In order to prevent polymerization inhibition by oxygen, a higher fatty acid derivative such as behenic acid or behenic acid amide is added to the image recording layer of the present invention, and the surface of the image recording layer is dried during the coating process. It may be unevenly distributed. 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.

<Plasticizer>
The image recording layer of the present invention may contain a plasticizer. 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.

<Inorganic fine particles>
The image recording layer of the present invention may contain inorganic fine particles in order to improve the strength of the cured film in the image area. As the inorganic fine particles, for example, silica, alumina, magnesium oxide, titanium oxide, magnesium carbonate, calcium alginate, or a mixture thereof is preferably exemplified. Even if they are not photothermally convertible, they can be used for strengthening the film, enhancing 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 to 3 μm. Within the above range, it is possible to form a non-image portion excellent in hydrophilicity that 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 20% by mass or less, and more preferably 10% by mass or less, based on the total solid content of the image recording layer.

<Low molecular hydrophilic compound>
The image recording layer of the present invention can contain a hydrophilic low molecular weight compound in order to improve developability. Examples of hydrophilic low molecular weight compounds include water-soluble organic compounds such as glycols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, and tripropylene glycol, and ether or ester derivatives thereof, glycerin, Polyhydroxys such as pentaerythritol, organic amines such as triethanolamine and diethanolamine monoethanolamine and salts thereof, organic sulfonic acids such as toluenesulfonic acid and benzenesulfonic acid and salts thereof, organic phosphonic acids such as phenylphosphonic acid and the like Examples thereof include organic carboxylic acids such as salts thereof, tartaric acid, oxalic acid, citric acid, malic acid, lactic acid, gluconic acid and amino acids, and salts thereof.

<Formation of image recording layer>
The image recording layer of the present invention is formed by preparing or applying a coating solution by dispersing or dissolving the necessary components described above 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 also 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 repeatedly applying and drying a plurality of times.

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.

(Support)
The support used for the lithographic printing plate precursor according to the invention is not particularly limited as long as it is a dimensionally stable plate-like hydrophilic support. For example, paper, paper laminated with plastic (eg, polyethylene, polypropylene, polystyrene, etc.), metal plate (eg, aluminum, zinc, copper, etc.), plastic film (eg, cellulose diacetate, cellulose triacetate, cellulose propionate) Cellulose butyrate, cellulose acetate butyrate, cellulose nitrate, polyethylene terephthalate, polyethylene, polystyrene, polypropylene, polycarbonate, polyvinyl acetal, etc.), and paper or plastic films on which the above-mentioned metals are laminated or deposited. Preferable supports include a polyester film and an aluminum plate. Among these, an aluminum plate that has good dimensional stability and is relatively inexpensive is preferable.

  The aluminum plate is a pure aluminum plate, an alloy plate containing aluminum as a main component and containing a trace amount of different elements, or a plastic laminated on a thin film of aluminum or an aluminum alloy. Examples of foreign elements contained in the aluminum alloy include silicon, iron, manganese, copper, magnesium, chromium, zinc, bismuth, nickel, and titanium. The content of foreign elements in the alloy is preferably 10% by mass or less. In the present invention, a pure aluminum plate is preferable, but completely pure aluminum is difficult to manufacture in terms of refining technology, and therefore may contain a slightly different element. The composition of the aluminum plate is not specified, and a publicly known material can be used as appropriate.

  The thickness of the support is preferably 0.1 to 0.6 mm, more preferably 0.15 to 0.4 mm, and still more preferably 0.2 to 0.3 mm.

  Prior to using the aluminum plate, it is preferable to perform a surface treatment such as roughening treatment or anodizing treatment. By the surface treatment, it is easy to improve hydrophilicity and secure adhesion between the image recording layer and the support. Prior to roughening the aluminum plate, a degreasing treatment with a surfactant, an organic solvent, an alkaline aqueous solution or the like for removing rolling oil on the surface is performed as desired.

  The surface roughening treatment of the aluminum plate is performed by various methods. For example, mechanical surface roughening treatment, electrochemical surface roughening treatment (surface roughening treatment for dissolving the surface electrochemically), chemical treatment, etc. Surface roughening treatment (roughening treatment that chemically selectively dissolves the surface). As a method for the mechanical surface roughening treatment, a known method such as a ball polishing method, a brush polishing method, a blast polishing method, or a buff polishing method can be used. Examples of the electrochemical surface roughening treatment include a method in which an alternating current or a direct current is used in an electrolytic solution containing an acid such as hydrochloric acid or nitric acid. Another example is a method using a mixed acid as described in JP-A-54-63902.

  The surface-roughened aluminum plate is subjected to an alkali etching treatment using an aqueous solution of potassium hydroxide, sodium hydroxide or the like, if necessary, further neutralized, and if desired, wear resistant. In order to increase the anodic oxidation treatment.

As the electrolyte used for the anodizing treatment of the aluminum plate, various electrolytes that form a porous oxide film can be used. In general, sulfuric acid, hydrochloric acid, oxalic acid, chromic acid or a mixed acid thereof is used. The concentration of these electrolytes is appropriately determined depending on the type of electrolyte. The conditions for anodizing treatment vary depending on the electrolyte used and cannot be specified in general. In general, however, the electrolyte concentration is 1 to 80% by mass solution, the liquid temperature is 5 to 70 ° C., and the current density is 5 to 60 A / day. d m ² , voltage 1 to 100 V, and electrolysis time 10 seconds to 5 minutes are preferable. The amount of the anodized film formed is preferably from 1.0 to 5.0 g / m ^2, and more preferably 1.5 to 4.0 g / m ^2. Within this range, good printing durability and good scratch resistance of the non-image area of the lithographic printing plate can be obtained.

  As the support used in the present invention, the substrate having the above-mentioned surface treatment and having an anodized film may be used as it is, but for further improvement in adhesion to the upper layer, hydrophilicity, resistance to contamination, heat insulation and the like. If necessary, it contains a micropore enlargement treatment, a micropore sealing treatment, and a hydrophilic compound described in Japanese Patent Application Laid-Open Nos. 2001-253181 and 2001-322365. A surface hydrophilization treatment immersed in an aqueous solution can be selected as appropriate. Of course, these enlargement processing and sealing processing are not limited to those described above, and any conventionally known method can be performed.

  Sealing treatment includes vapor sealing, single treatment with zirconic fluoride, treatment with an aqueous solution containing an inorganic fluorine compound such as treatment with sodium fluoride, vapor sealing with addition of lithium chloride, sealing with hot water. Hole processing is also possible. Of these, sealing treatment with an aqueous solution containing an inorganic fluorine compound, sealing treatment with water vapor, and sealing treatment with hot water are preferable.

  The hydrophilization treatment is described in the specifications of US Pat. Nos. 2,714,066, 3,181,461, 3,280,734, and 3,902,734. There are such alkali metal silicate methods. In this method, the support is immersed in an aqueous solution such as sodium silicate or electrolytically treated. In addition, the treatment with potassium zirconate fluoride described in JP-B 36-22063, U.S. Pat. Nos. 3,276,868, 4,153,461 and 4,689, And a method of treating with polyvinylphosphonic acid as described in the specification of No. 272.

  When using a support with insufficient surface hydrophilicity such as a polyester film as the support of the present invention, it is desirable to apply a hydrophilic layer to make the surface hydrophilic. As the hydrophilic layer, at least one element selected from beryllium, magnesium, aluminum, silicon, titanium, boron, germanium, tin, zirconium, iron, vanadium, antimony, and a transition metal described in JP-A-2001-199175 A hydrophilic layer formed by coating a coating solution containing a colloid of oxide or hydroxide, or organic hydrophilicity obtained by crosslinking or pseudo-crosslinking an organic hydrophilic polymer described in JP-A-2002-79772 A hydrophilic layer having a hydrophilic matrix, a hydrophilic layer having an inorganic hydrophilic matrix obtained by sol-gel conversion comprising hydrolysis, condensation reaction of polyalkoxysilane, titanate, zirconate or aluminate, or a metal oxide A hydrophilic layer made of an inorganic thin film having a surface is preferred. Arbitrariness. Among these, a hydrophilic layer formed by applying a coating solution containing a silicon oxide or a hydroxide colloid is preferable.

  Moreover, when using a polyester film etc. as a support body of this invention, it is preferable to provide an antistatic layer in the hydrophilic layer side of a support body, the opposite side, or both sides. In the case where the antistatic layer is provided between the support and the hydrophilic layer, it also contributes to improving the adhesion with the hydrophilic layer. As the antistatic layer, a polymer layer in which metal oxide fine particles or a matting agent are dispersed as described in JP-A-2002-79772 can be used.

The support preferably has a center line average roughness of 0.10 to 1.2 μm. Within this range, good adhesion with the image recording layer, good printing durability and good stain resistance can be obtained.
The color density of the support is preferably 0.15 to 0.65 as the reflection density value. Within this range, good image formability by preventing halation during image exposure and good plate inspection after development can be obtained.

(Undercoat layer)
In the lithographic printing plate precursor according to the invention, it is preferable to provide an undercoat layer of a compound containing a polymerizable group on a support. When an undercoat layer is used, the image recording layer is provided on the undercoat layer. The undercoat layer enhances the adhesion between the support and the image recording layer in the exposed area, and in the unexposed area, the image recording layer is easily peeled off from the support, so that the developability is improved. .
As the undercoat layer, specifically, a silane coupling agent having an addition-polymerizable ethylenic double bond reactive group described in JP-A-10-282679, JP-A-2-304441. The phosphorus compound etc. which have the ethylenic double bond reactive group of description are mentioned suitably. Particularly preferred compounds include compounds having a polymerizable group such as a methacryl group and an allyl group and a support-adsorbing group such as a sulfo group, a phosphate group, and a phosphate ester. A compound having a hydrophilicity-imparting group such as an ethylene oxide group in addition to the polymerizable group and the support-adsorbing group can also be exemplified as a suitable compound. 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.

(Protective layer)
In the lithographic printing plate precursor according to the present invention, a water-soluble protective layer may be provided on the image recording layer in order to prevent the occurrence of scratches in the image recording layer, to block oxygen, and to prevent ablation during high-illuminance laser exposure. it can.
In the present invention, exposure is usually carried out in the atmosphere, but the protective layer is an image of low molecular weight compounds such as oxygen and basic substances present in the atmosphere that inhibit radical polymerization reactions caused by exposure in the image recording layer. This prevents the recording layer from being mixed, and prevents the image formation reaction from being hindered by exposure in the air. Therefore, the properties desired for the protective layer are low permeability of low-molecular compounds such as oxygen, furthermore, good transparency of light used for exposure, excellent adhesion to the image recording layer, and It is preferable that it can be easily removed with an aqueous solution of simple development after exposure. Various studies have been made on the protective layer having such characteristics, and are described in detail, for example, in US Pat. No. 3,458,311 and JP-B-55-49729.

Examples of the material used for the protective layer include water-soluble polymer compounds that are relatively excellent in crystallinity. Specific examples include water-soluble polymers such as polyvinyl alcohol, polyvinyl pyrrolidone, acidic celluloses, gelatin, gum arabic, and polyacrylic acid. Among these, when polyvinyl alcohol (PVA) is used as a main component, the best results are obtained for basic characteristics such as oxygen barrier properties and development removability. The polyvinyl alcohol may be partially substituted with an ester, ether or acetal as long as it contains an unsubstituted vinyl alcohol unit for providing the oxygen barrier property and water solubility necessary for the protective layer, and a part of the other You may have a copolymerization component.
Specific examples of the polyvinyl alcohol include those having a hydrolysis degree of 71 to 100% and a degree of polymerization of 300 to 2400. Specifically, for example, PVA-105, PVA-110, PVA-117, PVA-117H, PVA-120, PVA-124, PVA-124H, PVA-CS, PVA-CST, PVA manufactured by Kuraray Co., Ltd. -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, and L-8.

Furthermore, inorganic layered compounds such as silica gel and mica can be added to these to adjust the surface properties.
The inorganic layered compound used in the present invention is a particle having a thin tabular shape, for example, a general formula A (B, C) _2-5 D ₄ O ₁₀ (OH, F, O) ₂ [wherein A is any of K, Na, and Ca, B and C are any of Fe (II), Fe (III), Mn, Al, Mg, and 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.

In the mica group, natural mica includes muscovite, soda mica, phlogopite, biotite, and sericite. Synthetic mica includes non-swellable 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 2} /5 Li Examples thereof include swelling mica such as _1/8 (Si ₄ O ₁₀ ) F ₂ . Synthetic smectites are also useful.

  As for the particle diameter of the inorganic stratiform compound used in the present invention, the average major axis is 0.3 to 20 μm, preferably 0.5 to 10 μm, particularly preferably 1 to 5 μm. The average thickness of the particles is 0.1 μm or less, preferably 0.05 μm or less, particularly preferably 0.01 μm or less. For example, among 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.

The components of the protective layer (selection of PVA, use of additives, etc.), coating amount, etc. are appropriately selected in consideration of fogging properties, adhesion, scratch resistance, etc. in addition to oxygen barrier properties and development removability. Generally, the higher the hydrolysis rate of PVA (that is, the higher the content of the unsubstituted vinyl alcohol unit in the protective layer), and the thicker the film thickness, the higher the oxygen barrier property, which is preferable in terms of sensitivity. . On the other hand, in order to prevent unnecessary polymerization reaction during production and storage, unnecessary fogging during image exposure, thickening of image lines, and the like, it is preferable that the oxygen barrier property is not too high. Accordingly, the oxygen permeability A at 25 ° C. and 1 atm is preferably 0.2 ≦ A ≦ 20 (ml / m ² · day).

  As another composition of the protective layer, glycerin, dipropylene glycol and the like can be added in an amount corresponding to several mass% with respect to the (co) polymer to provide flexibility. Anionic surfactants such as sodium acid salts; amphoteric surfactants such as alkylaminocarboxylates and alkylaminodicarboxylates; nonionic surfactants such as polyoxyethylene alkylphenyl ethers to the water-soluble polymer compound Several mass% can be added.

  In addition, adhesion to the image area, scratch resistance, and the like are extremely important in handling the lithographic printing plate precursor. That is, when a protective layer that is hydrophilic because it contains a water-soluble polymer compound is laminated on an image recording layer that is oleophilic, the protective layer is easily peeled off due to insufficient adhesion, and polymerization is inhibited by oxygen at the peeled portion. This may cause defects such as poor film hardening due to.

  On the other hand, various proposals have been made to improve the adhesion between the image recording layer and the protective layer. For example, JP-A-49-70702 and British Patent Application No. 1303578 disclose an acrylic emulsion, a water-insoluble vinylpyrrolidone-vinyl acetate copolymer, etc. in a hydrophilic polymer mainly composed of polyvinyl alcohol. It is described that sufficient adhesiveness can be obtained by mixing 20 to 60% by mass and laminating 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 thickness of the protective layer is suitably from 0.1 to 5 μm, particularly preferably from 0.2 to 2 μm. The method for applying the protective layer is described in detail, for example, in US Pat. No. 3,458,311 and JP-B-55-49729.

(Back coat layer)
After the surface treatment is performed on the support or after the undercoat layer is formed, a back coat can be provided on the back surface of the support, if necessary.
Examples of the back coat include hydrolysis and polycondensation of an organic polymer compound described in JP-A-5-45885, an organometallic compound or an inorganic metal compound described in JP-A-6-35174. A coating layer made of a metal oxide obtained in this way is preferred. 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, etc. is inexpensive. It is preferable in that it is easily available.

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

<Production of support>
In order to remove rolling oil on the surface of an aluminum plate (material 1050) having a thickness of 0.3 mm, a degreasing treatment was performed at 50 ° C. for 30 seconds using a 10 mass% sodium aluminate aqueous solution, and then the hair diameter was 0.3 mm. The aluminum surface was grained using three bundle-planted nylon brushes and a pumice-water suspension (specific gravity 1.1 g / cm ³ ) having a median diameter of 25 μm 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. The etching amount of the grained surface at this time 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 nitric acid aqueous solution (containing 0.5% by mass of aluminum ions) and a liquid temperature of 50 ° C. The AC power supply waveform is electrochemical roughening treatment using a trapezoidal rectangular wave AC with a time 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 AC. 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 the nitric acid electrolysis was 175 C / dm ² when the aluminum plate was the anode. Then, water washing by spraying was performed.

Next, a 0.5% by mass hydrochloric acid aqueous solution (containing 0.5% by mass of aluminum ions) and an electrolytic solution having a liquid temperature of 50 ° C. and nitric acid electrolysis under the condition of an electric quantity of 50 C / dm ² when the aluminum plate is an anode In the same manner as above, an electrochemical surface roughening treatment was performed, followed by washing with water by spraying. The plate was provided with a DC anodized film of 2.5 g / m ² at a current density of 15 A / dm ² using 15% by mass sulfuric acid (containing 0.5% by mass of aluminum ions) as an electrolytic solution, then washed with water and dried. The centerline average roughness (Ra) of this substrate was measured using a needle having a diameter of 2 μm and found to be 0.51 μm.

Next, the following undercoat liquid (1) was applied so that the dry coating amount was 10 mg / m ² to prepare a support used in the following experiments.

Undercoat liquid (1)
・ Undercoat compound (1) below 0.017g
・ Methanol 9.00 g
・ Water 1.00g

<Preparation of lithographic printing plate precursor A>
The image recording layer coating solution (1) is bar-coated on the support provided with the undercoat layer, and then oven-dried at 100 ° C. for 75 seconds to form an image recording layer having a dry coating amount of 1.0 g / m ^2. Then, a protective layer coating solution (1) having the following composition was further applied thereon using a bar so that the coating amount at the time of drying was 1.0 g / m ^2, and then the condition was 100 ° C. for 90 seconds. And dried in an oven to obtain a lithographic printing plate precursor A.
The image recording layer coating solution (1) was obtained by mixing and stirring the following photosensitive solution (1) and microcapsule solution (1) immediately before coating.

Photosensitive solution (1)
-Binder polymer (1) 0.162g
・ The following polymerization initiator (1) 0.100 g
・ The following infrared absorber (1) 0.020 g
・ Polymerizable compound, Aronix M-315 (manufactured by Toa Gosei Co., Ltd.) 0.385 g
・ The following water-soluble fluorosurfactant (1) 0.044 g
・ Methyl ethyl ketone 1.091g
・ 1-methoxy-2-propanol 8.609g

Microcapsule liquid (1)
・ Microcapsule synthesized as follows (1) 2.640 g
・ Water 2.425g

Synthesis of Microcapsule (1) As oil phase components, trimethylolpropane and xylene diisocyanate adduct (Mitsui Takeda Chemical Co., Ltd., Takenate D-110N, 75% ethyl acetate solution) 10 g, Aronix M-215 (Toho) Synthetic Co., Ltd. (6.00 g) and Pionein 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 12000 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 microcapsule solution thus obtained was diluted with distilled water so that the solid content concentration was 15% by mass. The average particle size was 0.2 μm.

Protective layer coating solution (1)
・ 88g of water
・ Polyvinyl alcohol PVA105 (Kuraray Co., Ltd.) 10g
・ Polyethylene glycol (molecular weight 2000) 2g
・ 1g of the following surfactant

<Preparation of lithographic printing plate precursor B>
An image recording layer coating solution (2) having the following composition was bar-coated on the support provided with the undercoat layer, followed by oven drying at 100 ° C. for 60 seconds, and an image having a dry coating amount of 1.4 g / m ² . A recording layer is formed, and a protective layer coating solution (1) having the above composition is coated thereon so that the dry coating mass is 0.5 g / m ^2, and dried at 120 ° C. for 1 minute to be a lithographic printing plate An original version B was obtained.

Image recording layer coating solution (2)
・ 2.0 g of the above binder polymer (1)
・ Polymerizable compound 1.5g
Isocyanuric acid EO-modified triacrylate (manufactured by Toa Gosei Co., Ltd., Aronix M-315)
-Compound represented by the following (1) 0.15 g
-Compound represented by (2) below 0.20 g
・ 0.4 g of the compound represented by the following (3)
・ Ethyl violet 0.1g
・ Thermal polymerization inhibitor 0.1g
N-nitrosophenylhydroxylamine aluminum salt 0.02 g of the above water-soluble fluorosurfactant (1)
・ Tetraethylammonium chloride 0.06g
・ 17.5 g of 1-methoxy-2-propanol
・ Methyl ethyl ketone 19.0g

<Preparation of lithographic printing plate precursor C>
An image recording layer coating solution (3) having the following composition was bar-coated on the support provided with the undercoat layer, followed by oven drying at 70 ° C. for 60 seconds, and an image having a dry coating amount of 1.1 g / m ² . A recording layer is formed, and a protective layer coating solution (2) having the following composition is coated thereon using a bar so that the dry coating amount is 0.2 g / m ^2, and then dried at 125 ° C. for 70 seconds. Thus, a lithographic printing plate precursor C was obtained.

Image recording layer coating solution (3)
-Binder polymer (1) with the above structure (average molecular weight 80,000) 0.54 g
・ Polymerizable compound 0.40g
Isocyanuric acid EO-modified triacrylate (manufactured by Toa Gosei Co., Ltd., Aronix M-315)
・ Polymerizable compound Ethoxylated trimethylolpropane triacrylate 0.08 g
(Nippon Kayaku Co., Ltd., SR9035, EO addition mole number 15, molecular weight 1000)
・ The following sensitizing dye (1) 0.06 g
・ The following polymerization initiator (2) 0.18 g
・ The following chain transfer agent (1) 0.07 g
・ 0.40 g of ε-phthalocyanine pigment dispersion
(Pigment: 15 parts by mass, dispersant Binder polymer (1): 10 parts by mass, solvent cyclohexanone / methoxypropyl acetate / 1-methoxy-2-propanol = 15 parts by mass / 20 parts by mass / 40 parts by mass)
・ Thermal polymerization inhibitor 0.01g
N-nitrosophenylhydroxylamine aluminum salt-The above water-soluble fluorosurfactant (1) 0.001 g
・ Polyoxyethylene-polyoxypropylene condensate 0.04g
(Asahi Denka Kogyo Co., Ltd., Pluronic L44)
・ Tetraethylammonium chloride 0.01g
・ 3.5 g of 1-methoxy-2-propanol
・ Methyl ethyl ketone 8.0g

Protective layer coating solution (2)
・ The following mica dispersion (1) 13.0 g
Polyvinyl alcohol (saponification degree 98 mol%, polymerization degree 500) 1.3 g
-Sodium 2-ethylhexyl sulfosuccinate 0.2g
・ Poly (vinyl pyrrolidone / vinyl acetate (1/1)) molecular weight 70,000 g
・ Surfactant (Emalex 710, manufactured by Nippon Emulsion Co., Ltd.) 0.05g
・ 133g of water

Preparation of Mica Dispersion (1) 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) was added, and the average particle size (laser scattering method) was obtained using a homogenizer. ) Disperse to 0.5 μm to obtain a mica dispersion (1).
Furthermore, when the oxygen transmission rate of the protective layer was measured under the following conditions, the oxygen transmission rate of the protective layer was 2.0 ml / (m ² · day · atom).

Measurement of oxygen permeability A protective layer is applied to the surface of a photographic paper having a thickness of about 200 μm and coated on both sides with polyethylene having a thickness of about 20 μm, and dried, and a measurement sample. Was made. The oxygen permeability of the photographic paper measured in advance was about 700 ml / (m ² · day · atom) under the following measurement conditions, and was a value that could be sufficiently ignored when measuring the permeability in the oxygen barrier layer.
Using the sample thus obtained, according to the gas permeability test method described in JIS K7126B and ASTM D3985, oxygen permeation was performed at 25 ° C. and 60% RH using OX-TRAN 2/20 manufactured by Mocon. The rate [ml / (m ² · day · atom)] was measured.

<Preparation of lithographic printing plate precursor F>
The polymerizable compound Aronix M-315 in the image recording layer coating solution (3) was replaced with PLEX6661-O (Rohm GmbH & KG, 7,7,9-trimethyl-4,13-dioxo-3,14-dioxa-5,12-dia. A lithographic printing plate precursor F was obtained in the same manner as the lithographic printing plate precursor C except that the binder polymer was changed to the following polyurethane (1) instead of the hexadecane-1,16-diyldimethacrylate).

<Preparation of lithographic printing plate precursor G>
The polymerizable compound Aronix M-315 in the image recording layer coating solution (3) was replaced with PLEX6661-O (Rohm GmbH & KG, 7,7,9-trimethyl-4,13-dioxo-3,14-dioxa-5,12-dia. A lithographic printing plate precursor G was obtained in the same manner as the lithographic printing plate precursor C except that the binder polymer was changed to the following polyurethane (2) instead of the hexadecane-1,16-diyldimethacrylate).

Polyurethane (1) (average molecular weight 100,000)

Polyurethane (2) (average molecular weight 100,000)

<Preparation of developer>
Developers 1 and 2 having compositions shown in Tables 1 and 2 below were prepared. Developer 1 contains a gum component and is for “development + finisher simultaneous processing”. The developer 2 is a surfactant aqueous solution type, and a finisher is used in a post-bath after development.
Here, the pH of the developer was adjusted to 7 using phosphoric acid and sodium hydroxide.

<Preparation of lithographic printing plate>
[Examples 1 to 13 and Comparative Examples 1 to 4]
The lithographic printing plate precursor obtained as described above was exposed and processed under the conditions shown in Table 4, and then naturally dried to prepare a lithographic printing plate.
Exposure was performed as follows according to the lithographic printing plate precursor used.
(Lithographic printing plate precursor A)
The exposure was performed with a Trend setter 3244VX (equipped with a water-cooled 40 W infrared semiconductor laser) manufactured by Creo under the conditions of an output of 9 W, an outer drum rotating speed of 210 rpm, and a resolution of 2400 dpi.
(Lithographic printing plate precursors B, C, F and G)
FUJIFILM Electronic Imaging Ltd. Violet semiconductor laser plate setter Vx9600 (InGaN-based semiconductor laser 405 nm ± 10 nm emission / output 30 mW mounted) was exposed under the condition of 2438 dpi resolution.
The plate exposure amount was set as follows.
(1) When there is no preheating: Examples 4 to 7, 12, 13 and Comparative Examples 3 and 4 are 150 μJ / cm ² , and Example 11 is 200 μJ / cm ^2.
(2) When there is preheating: Examples 1 to 3 and 9 to 10, Comparative Examples 1 and 2 are 50 μJ / cm ²

In the case of no preheating / pre-water washing, the treatment was carried out using the self-supporting machine shown in FIG. In the case of preheating / pre-water washing, a preheating and pre-water washing apparatus was attached in front of the self-machine shown in FIG. In Example 12, two brushes of rubbing members were used. In Example 13, a horizontal conveyance type self-machine as shown in FIG. 3 was used.
In either case, the developing solution temperature was 30 ° C., the developing bath residence time was 20 seconds, and the brush rotation speed was 120 rpm. As shown in Table 3, the brush rubbing force was set by adjusting the brush material and the pressing amount.
In the case where there was a post-bath after development, finishing gum FP-2W (dilution ratio 1: 1) manufactured by Fuji Film Co., Ltd. was used for the post-bath.

<Evaluation>
Using the lithographic printing plate thus prepared, developability, scratches on the printing plate, and printability were evaluated.

(1) Non-image area optical density (OD) measurement In order to evaluate developability, the optical density (OD) of a lithographic printing plate non-image area was measured as reflection density in cyan mode using Gretag Macbeth D19C. . The reflection density of the aluminum support was 0.65.

(2) Scratching of printing plate The image portion of the obtained lithographic printing plate was visually observed with a 25-fold magnifier to evaluate the presence or absence of scratches.

(3) Printability evaluation The obtained lithographic printing plate was attached to a cylinder of a printing machine SOR-M manufactured by Heidelberg, and dampening water (EU-3 (Fuji Film Co., Ltd. etchant) / water / isopropyl alcohol = 1). / 89/10 (volume ratio)) and TRANS-G (N) black ink (manufactured by Dainippon Ink & Chemicals, Inc.), after supplying dampening water and ink at a printing speed of 6000 sheets per hour 500 sheets were printed, and print stains were evaluated according to the following criteria.
○ Good without dirt
△ Slightly stained immediately after printing, but basically good, acceptable level × ground stain, NG
Furthermore, printing was continued and printing durability was evaluated. These results are shown in Table 4. Table 4 also shows evaluation judgments that combine the above evaluation results.

[Examples 14 to 15 and Comparative Example 5]
Development was performed in the same manner as in Example 4 under the conditions shown in Table 5 for the purpose of evaluating the influence of the degree of immersion of the brush in the developer and the rubbing force on foaming of the developing bath. The results are shown in Table 5.

Configuration diagram of rubbing force measurement Schematic configuration diagram of automatic processor Schematic configuration diagram of horizontal transport type automatic development processor

Explanation of symbols

1. Rotating brush roll Force gauge 3. Pressing jig 4. Roller rotation motor Brush rotation motor Belt 104. Planographic printing plate precursor 106. Developing tank 107. Developer 108. Transport roller pair 110. Drive roller 112. Rubbing member 126. Developer spray pipe 127. Transport guide plate 128. Equipment base

Claims (6)

The lithographic printing plate precursor having the image recording layer on the support is cured by imagewise exposure after the image recording layer in the exposed portion is cured, and then the image recording layer is rubbed with a rubbing member in the presence of a developer having a pH of 2 to 10. In the method for producing a lithographic printing plate in which an unexposed portion is removed, the rubbing force F of the rubbing member is in the following range.
5 (g / mm) ≦ F ≦ 100 (g / mm)   2. The method for producing a lithographic printing plate according to claim 1, wherein when the unexposed portion of the image recording layer is removed, the pressing amount of the rubbing member against the lithographic printing plate precursor is 0.2 to 6 mm.   The method for preparing a lithographic printing plate according to claim 1 or 2, wherein a developing processor having two or more rubbing members is used.   The lithographic printing according to any one of claims 1 to 3, wherein the image recording layer contains a polymerization initiator, a polymerizable compound, and a binder polymer having an acid value of 0.3 meq / g or less. Plate making method.   The method for preparing a lithographic printing plate according to claim 4, wherein the binder polymer having an acid value of 0.3 meq / g or less is a polyurethane resin. 6. The developer according to claim 1, wherein the developer contains at least one compound selected from the group consisting of compounds represented by the following formula <1>, <2> or <3>. A method for producing a lithographic printing plate as described in the paragraph.

In the formula <1>, R1 represents a hydrogen atom or an alkyl group, and A is a group containing a hydrogen atom, an ethylene oxide group, a carboxylic acid group, or a carboxylate. B is a group containing an ethylene oxide group, a carboxylic acid group, or a carboxylate. In formula <2>, R2 and R3 represent H or an alkyl group, C is an alkyl group or an ethylene oxide group, and D is a group containing a carboxylate anion. In formula <3>, R 4, R 5, R 6 and R 7 each independently represent H or an alkyl group, and Z ⁻ represents a counter anion. The alkyl group of R1 to R7 may have a substituent.

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