JP2009163003A - Planographic printing original plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a planographic printing original plate excelling in antifouling property of a non-image part and its durability, and also in printing durability caused by adhesion of an image part and a support body. <P>SOLUTION: The planographic printing original plate is formed by laminating an intermediate layer containing a polymeric compound having a carboxyl group and a carboxylate group in a side chain, and an image forming layer containing a polymerization initiator, a polymerizable compound and a binder polymer, sequentially on a support body having, on its surface, grain shape where a medium wave structure with an average aperture diameter of 0.5-5 μm overlaps a small wave structure with the average aperture diameter of 0.01-0.2 μm. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a lithographic printing plate precursor.

  Conventionally, as a lithographic printing plate precursor, a PS plate having a configuration in which a lipophilic photosensitive resin layer is provided on a hydrophilic support is widely used. As the plate making method, mask exposure (typically through a lithographic film) After the surface exposure), the desired printing plate was obtained by dissolving and removing the non-image area. In recent years, digitization techniques that electronically process, store, and output image information using a computer have become widespread. Various new image output methods corresponding to such digitization techniques have come into practical use. As a result, computer-to-plate (CTP) technology that scans highly directional light such as laser light according to digitized image information and directly produces a printing plate without going through a lithographic film is eagerly desired. Obtaining a lithographic printing plate precursor adapted to this is an important technical issue.

As such a lithographic printing plate precursor capable of scanning exposure, an oleophilic photosensitive resin layer containing a photosensitive compound capable of generating active species such as radicals and Bronsted acids by laser exposure on a hydrophilic support (hereinafter referred to as “lithographic printing plate precursor”) , Which is also referred to as an image forming layer) has been proposed and is already on the market. This lithographic printing plate precursor is laser-scanned based on digital information to generate active species, which causes physical or chemical changes in the image forming layer to insolubilize it, followed by development processing, thereby developing negative lithographic printing You can get a version.
In particular, on a hydrophilic support, a photopolymerization type image forming layer containing a photopolymerization initiator excellent in photosensitive speed, an addition-polymerizable ethylenically unsaturated compound, and a binder polymer soluble in an alkali developer, and A lithographic printing plate precursor (for example, see Patent Document 1) provided with an oxygen-blocking protective layer as required has advantages such as excellent productivity, simple development processing, and good resolution and thickness. Therefore, it has desirable printing performance.

Further, in order to improve productivity, that is, to improve plate making speed, photopolymerizability comprising a cyanine dye having a specific structure, an iodonium salt and an addition-polymerizable compound having an ethylenically unsaturated double bond. A recording material that uses the composition for an image forming layer and does not require heat treatment after imagewise exposure has been proposed (see, for example, Patent Document 2). However, this recording material has a problem in that the sensitivity may be lowered and the strength of the formed image area may be lowered due to polymerization inhibition by oxygen in the air during the polymerization reaction.
For this problem, a method of providing a protective layer containing a water-soluble polymer on the image forming layer or a method of providing a protective layer containing an inorganic layered compound and a water-soluble polymer (for example, see Patent Document 3). Are known. The presence of these protective layers prevents polymerization inhibition, promotes the curing reaction of the image forming layer, and improves the strength of the image area.

  As a recent market trend, there is a strong demand for shortening the exposure time to improve productivity and to use as low power as possible to extend the life of the laser. There is a strong demand for lithographic printing plate precursors that do not lose their properties. In order to obtain such a lithographic printing plate support having good printing durability, various shapes have been proposed for graining the surface of an aluminum plate (for example, see Patent Document 4). However, in the prior art, high printing durability is realized by strengthening the adhesion between the support and the photosensitive layer (image forming layer), so thermal radicals are generated during long-term storage and dark polymerization occurs. In such a case, there is a problem that the non-image portion is not sufficiently developed and removed and becomes dirty.

In order to improve the development and removability of the unexposed areas of the image forming layer, it is common to provide an intermediate layer (sometimes referred to as an undercoat layer or an adhesion improving layer) between the support and the image forming layer. (For example, refer to Patent Document 5).
However, when the conventional intermediate layer is used, the development removability decreases for a long time, particularly when stored for a long time under high temperature and high humidity conditions, or an image forming layer is applied to the upper layer of the intermediate layer. In some cases, the intermediate layer may be dissolved or swollen by the solvent of the image forming layer, which may adversely affect the printing durability and stain resistance, which is sufficient for the recent improvement in the required level of high printing durability and low stain resistance. It was hard to say that it was compatible.

In the intermediate layer, an example using a polymer compound having an acid group, for example, a polymer compound having a sulfonic acid or a carboxylic acid as an acid group is disclosed (for example, see Patent Document 6). In the case of having sulfonic acid in the side chain as an acid group, examples of forming an alkali metal salt, an ammonium salt, and a water-soluble amine salt are disclosed. The compounds described in this patent document give good printing durability and stain resistance in specific lithographic printing materials. For example, in order to improve printing durability, high durability with increased surface roughness (Ra). When used for lithographic printing plate precursors, it may be difficult to achieve both sufficient stain resistance.
Japanese Patent Laid-Open No. 10-228109 Japanese Examined Patent Publication No. 7-103171 JP 11-38633 A JP-A-2003-112484 JP 2001-272787 A JP 2005-99113 A

  In view of the above circumstances, the present invention provides a lithographic printing plate precursor that is excellent in both anti-staining properties and durability of non-image areas, and printing durability resulting from adhesion between image areas and a support. For the purpose.

As a result of diligent research, the present inventor has formed an intermediate layer having a specific polymer compound and an image forming layer in this order on a support having a specific surface shape (preferably an aluminum support). The inventors have found that the above object can be achieved and completed the present invention.
That is, the present invention has the following configuration.

<1> On a support having a grained shape with a structure in which a medium wave structure with an average opening diameter of 0.5 to 5 μm and a small wave structure with an average opening diameter of 0.01 to 0.2 μm are superimposed on the surface, A lithographic plate comprising an intermediate layer containing a polymer compound having a carboxyl group and a carboxylic acid ester group, and an image forming layer containing a polymerization initiator, a polymerizable compound, and a binder polymer in this order. It is a printing plate master.

<2> The lithographic printing plate as described in <1> above, wherein part or all of the carboxyl groups of the polymer compound having a carboxyl group and a carboxylic ester group in the side chain are neutralized The original version.

<3> The first electrochemical surface roughening treatment in which the support is roughened using an alternating current in an aqueous solution containing nitric acid and an alternating current in an aqueous solution containing hydrochloric acid. The lithographic printing plate precursor as described in <1> above, wherein the lithographic printing plate precursor is obtained by performing a second electrochemical roughening treatment in which the surface of the support is roughened.

  According to the present invention, it is possible to provide a lithographic printing plate precursor that is excellent in both anti-staining properties of non-image areas and their durability, and printing durability resulting from the adhesion between the image areas and the support. .

[Support]
<Surface grain shape>
The support used in the lithographic printing plate precursor according to the present invention has a structure in which the surface overlaps a medium wave structure with an average opening diameter of 0.5 to 5 μm and a small wave structure with an average opening diameter of 0.01 to 0.2 μm. It is characterized by having a grain shape.
In the present invention, the medium wave structure having an average opening diameter of 0.5 to 5 μm has a function of holding the image forming layer mainly by an anchor (throwing) effect and imparting printing durability. When the average opening diameter of the pits having a medium wave structure is 0.5 μm or more, the adhesiveness with the image forming layer provided on the upper surface of the support is good, and the printing durability of the planographic printing plate is excellent. Further, if the average opening diameter of the pits having the medium wave structure is 5 μm or less, the decrease in the number of pit boundary portions serving as anchors can be suppressed, which is also useful for improving the printing durability.

  The small wave structure having an average opening diameter of 0.01 to 0.2 μm superimposed on the medium wave structure mainly plays a role of improving stain resistance. By combining the medium wave structure with the small wave structure, when dampening water is supplied to the lithographic printing plate during printing, a water film is uniformly formed on the surface of the lithographic printing plate, thereby suppressing the occurrence of stains on the non-image area. it can. When the average opening diameter of the pits having the small wave structure is 0.01 μm or more, a great effect is obtained in the formation of a water film, and when the average opening diameter of the pits having the small wave structure is 0.2 μm or less, the above-described medium wave The effect of improving printing durability by the structure is not impaired.

  With this small wave structure, not only the opening diameter of the pit but also the depth of the pit can be controlled to obtain even better stain resistance. That is, it is preferable that the average of the ratio of the depth to the opening diameter of the small wave structure is 0.2 or more. As a result, the uniformly formed water film is reliably held on the surface, and the stain resistance of the surface of the non-image part is maintained for a long time.

The structure in which the medium wave structure and the small wave structure are superimposed may be a structure in which the large wave structure having an average wavelength of 5 to 100 μm is further superimposed. This large wave structure has the effect of increasing the amount of water retained on the surface of the non-image area of the lithographic printing plate. The more water held on the surface, the less the surface of the non-image area is affected by contamination in the atmosphere, and a non-image area that is less likely to get dirty even when the plate is left in the middle of printing can be obtained. Further, when the large wave structure is superimposed, it becomes easy to visually confirm the amount of dampening water given to the printing plate during printing. That is, the plate inspection property of the planographic printing plate is excellent.
If the average wavelength of the large wave structure is in the above range, an effective wave shape due to the difference from the medium wave structure can be achieved.Further, after exposure and development, glare of exposed non-image areas due to the large wave structure, A decrease in plate inspection can be suppressed. The average wavelength of the large wave structure is more preferably 10 to 80 μm.

  In the support used in the lithographic printing plate precursor according to the present invention, the average opening diameter of the medium wave structure, the average opening diameter of the small wave structure, the average depth of the small wave structure with respect to the opening diameter, and the average wavelength of the large wave are measured. The method is as follows.

(1) Average aperture diameter of medium wave structure The surface of the support was photographed at a magnification of 2,000 times from directly above using an electron microscope. At least 50 pits (medium wave pits) having a structure are extracted, and the diameter is read to obtain the opening diameter, and the average opening diameter is calculated. The same method is used for a structure with a large wave structure superimposed. In addition, in order to suppress variation in measurement, it is possible to perform equivalent circle diameter measurement using commercially available image analysis software. In this case, the electron micrograph is captured by a scanner, digitized, and binarized by software, and then an equivalent circle diameter is obtained. As a result of measurement by the present inventor, the result of visual measurement and the result of digital processing showed almost the same value. The same applies to the structure in which the large wave structure is superimposed.

(2) Average aperture diameter of small wave structure The surface of the support was photographed at a magnification of 50,000 times from directly above using a high-resolution scanning electron microscope (SEM). At least 50 pits) are extracted, and the diameter is read to obtain the opening diameter, and the average opening diameter is calculated.

(3) Average of the ratio of the depth to the aperture diameter of the wavelet structure The average of the ratio of the depth to the aperture diameter of the wavelet structure was obtained by photographing the fracture surface of the support at a magnification of 50,000 times using a high resolution SEM. In the obtained SEM photograph, at least 20 wavelet pits are extracted, the aperture diameter and depth are read, the ratio is obtained, and the average value is calculated.

(4) Average Wavelength of Large Wave Structure Two-dimensional roughness measurement is performed with a stylus type roughness meter, and the average peak spacing Sm defined in ISO 4287 is measured five times, and the average value is taken as the average wavelength.

<Surface treatment>
The support used in the lithographic printing plate precursor according to the invention is preferably one in which the above-mentioned surface grain shape is formed on the surface of the aluminum plate by subjecting the aluminum plate described later to surface treatment. The support used in the lithographic printing plate precursor according to the present invention can be obtained, for example, by subjecting an aluminum plate to a surface roughening treatment and an anodizing treatment. Various steps other than the surface treatment and the anodizing treatment may be included.
As shown below, as a typical method for forming the above-described grain shape of the surface, mechanical roughening treatment, alkali etching treatment, desmutting treatment with acid, and electrochemical using an electrolytic solution are applied to an aluminum plate. A method of sequentially performing a surface roughening treatment, a method of mechanically roughening an aluminum plate, an alkali etching treatment, a desmutting treatment with an acid, and an electrochemical surface roughening treatment using different electrolytes multiple times, an aluminum plate Alkaline etching treatment, acid desmutting treatment and electrochemical surface roughening treatment using electrolytic solution in sequence, aluminum plate alkali etching treatment, acid desmutting treatment and electrochemical surface roughening using different electrolytic solution A method of performing the treatment a plurality of times is mentioned. The present invention is not limited to these.
In these methods, after the electrochemical surface roughening treatment, an alkali etching treatment and an acid desmutting treatment may be further performed. The support used in the lithographic printing plate precursor according to the present invention obtained by these methods has a structure in which the unevenness of two or more kinds of different periods as described above is superimposed on the surface, and is a lithographic printing plate. It is excellent in both stain resistance and printing durability. Hereinafter, each step of the surface treatment will be described in detail.

-Mechanical surface roughening-
The mechanical roughening treatment is effective as a roughening treatment means because it can form an uneven surface with an average wavelength of 5 to 100 μm at a lower cost than the electrochemical roughening treatment. is there. Examples of the mechanical surface roughening treatment include, for example, a wire brush grain method in which the aluminum surface is scratched with a metal wire, a ball grain method in which the aluminum surface is grained with a polishing ball and an abrasive, JP-A-6-135175, and Japanese Patent Publication A brush grain method in which the surface is grained with a nylon brush and an abrasive described in Japanese Patent No. 50-40047 can be used. A transfer method in which the uneven surface is pressed against the aluminum plate can also be used. That is, in addition to the methods described in JP-A-55-74898, JP-A-60-36195, and JP-A-60-20396, the transfer is performed several times. The method described in Japanese Patent Application Laid-Open No. 6-55871 and Japanese Patent Application No. 4-204235 (Japanese Patent Application Laid-Open No. 6-024168) characterized in that the surface is elastic is also applicable.

  In addition, by using electric discharge machining, shot blasting, laser, plasma etching, etc., a method of repeatedly transferring using a transfer roll etched with fine irregularities, and an uneven surface coated with fine particles on an aluminum plate It is also possible to use a method in which an uneven pattern corresponding to the average diameter of the fine particles is repeatedly transferred to the aluminum plate a plurality of times by contacting the surface and applying a pressure a plurality of times from above. As a method for imparting fine irregularities to the transfer roll, known methods described in JP-A-3-8635, JP-A-3-66404, JP-A-63-65017 and the like are used. Can be used. Further, a fine groove may be cut in two directions using a die, a cutting tool, a laser, or the like on the roll surface, and a square unevenness may be formed on the surface. The roll surface may be subjected to a known etching process or the like so that the formed square irregularities are rounded. Further, in order to increase the surface hardness, quenching, hard chrome plating, or the like may be performed. In addition, as the mechanical surface roughening treatment, methods described in JP-A Nos. 61-162351 and 63-104889 can be used. In the present invention, the above-described methods can be used in combination in consideration of productivity and the like. These mechanical surface roughening treatments are preferably performed before the electrochemical surface roughening treatment.

Hereinafter, the brush grain method used suitably as a mechanical roughening process is demonstrated. The brush grain method generally uses a roller-shaped brush in which a large number of brush hairs such as synthetic resin hair made of synthetic resin such as nylon (registered trademark), propylene, and vinyl chloride resin are implanted on the surface of a cylindrical body. This is carried out by rubbing one or both of the surfaces of the aluminum plate while spraying a slurry liquid containing an abrasive on a rotating roller brush. Instead of the roller brush and the slurry liquid, a polishing roller which is a roller having a polishing layer on the surface can be used. When a roller brush is used, the flexural modulus is preferably 10,000 to 40,000 kg / cm ² , more preferably 15,000 to 35,000 kg / cm ² , and the bristle strength is preferably Brush hair that is 500 g or less, more preferably 400 g or less is used. The diameter of the brush bristles is generally 0.2 to 0.9 mm. The length of the brush bristles can be appropriately determined according to the outer diameter of the roller brush and the diameter of the body, but is generally 10 to 100 mm.

  A well-known thing can be used for an abrasive | polishing agent. For example, abrasives such as pumicestone, silica sand, aluminum hydroxide, alumina powder, silicon carbide, silicon nitride, volcanic ash, carborundum, and gold sand; a mixture thereof can be used. Of these, pumiston and silica sand are preferable. In particular, silica sand is preferable in terms of excellent surface roughening efficiency because it is harder and less likely to break than Pamiston. The average particle diameter of the abrasive is preferably 3 to 50 μm, and more preferably 6 to 45 μm in terms of excellent surface roughening efficiency and a narrow graining pitch. For example, the abrasive is suspended in water and used as a slurry. In addition to the abrasive, the slurry liquid may contain a thickener, a dispersant (for example, a surfactant), a preservative, and the like. The specific gravity of the slurry liquid is preferably 0.5-2.

  As an apparatus suitable for the mechanical surface roughening treatment, for example, an apparatus described in Japanese Patent Publication No. 50-40047 can be given.

-Electrochemical roughening-
For the electrochemical surface roughening treatment (hereinafter also referred to as “electrolytic surface roughening treatment”), an electrolytic solution used for the electrochemical surface roughening treatment using ordinary alternating current can be used. Among them, the concavo-convex structure characteristic of the present invention can be formed on the surface by using an electrolytic solution mainly composed of hydrochloric acid or nitric acid.
As the electrolytic surface roughening treatment in the present invention, the first electrochemical surface roughening treatment and the second electrochemical surface roughening treatment are performed before and after the cathodic electrolysis treatment using an alternating waveform current in an acidic solution. Is preferred. By cathodic electrolysis, hydrogen gas is generated on the surface of the aluminum plate and smut is generated to make the surface state uniform, and it is possible to obtain a uniform electrolytic surface during the subsequent electrolysis with an alternating waveform current. . This electrolytic surface roughening treatment can be performed according to, for example, an electrochemical grain method (electrolytic grain method) described in Japanese Patent Publication No. 48-28123 and British Patent No. 896,563. This electrolytic grain method uses a sinusoidal alternating current, but it may be performed using a special waveform as described in JP-A-52-58602. Further, the waveform described in JP-A-3-79799 can also be used. JP-A-55-158298, JP-A-56-28898, JP-A-52-58602, JP-A-52-152302, JP-A-54-85802, JP-A JP-A-60-190392, JP-A-58-120531, JP-A-63-176187, JP-A-1-5889, JP-A-1-280590, JP-A-1-118489, JP-A-1 No. 1-148592, JP-A-1-17896, JP-A-1-188315, JP-A-1-15497, JP-A-2-235794, JP-A-3-260100, JP-A-3-260100. No. 253600, JP-A-4-72079, JP-A-4-72098, JP-A-3-267400, JP-A-1-141094 Methods described in distribution can be applied. In addition to the above, it is also possible to perform electrolysis using an alternating current having a special frequency that has been proposed as a method of manufacturing an electrolytic capacitor. For example, it is described in US Pat. Nos. 4,276,129 and 4,676,879.

  Various electrolyzers and power sources have been proposed. US Pat. No. 4,023,637, Japanese Patent Laid-Open No. 56-123400, Japanese Patent Laid-Open No. 57-59770, Japanese Patent Laid-Open No. 53-12738, Japanese Unexamined Patent Publication No. 53-32821, Japanese Unexamined Patent Publication No. 53-32822, Japanese Unexamined Patent Publication No. 53-32823, Japanese Unexamined Patent Publication No. 55-122896, Japanese Unexamined Patent Publication No. 55-132848, Japanese Unexamined Patent Publication No. 62-127500. In Japanese Patent Application Laid-Open No. 1-52100, Japanese Patent Application Laid-Open No. 1-52098, Japanese Patent Application Laid-Open No. 60-67700, Japanese Patent Application Laid-Open No. 1-230800, Japanese Patent Application Laid-Open No. 3-257199, etc. Can be used. JP-A-52-58602, JP-A-52-152302, JP-A-53-12738, JP-A-53-12739, JP-A-53-32821, JP-A-53-32821 No. 53-32822, JP-A No. 53-32833, JP-A No. 53-32824, JP-A No. 53-32825, JP-A No. 54-85802, JP-A No. 55-122896 JP-A-55-13284, JP-B-48-28123, JP-B-51-7081, JP-A-52-133638, JP-A-52-133840, JP-A-52-133844. In addition, those described in Japanese Patent Laid-Open Nos. 52-133845, 53-149135, 54-146234, etc. may be used. Kill.

  In addition to nitric acid and hydrochloric acid, the acidic solution that is an electrolytic solution includes U.S. Pat. Nos. 4,671,859, 4,661,219, 4,618,405, 4,600,482, 4,566,960, 4,566,958, 4,566,959, 4,416, No. 972, No. 4,374,710, No. 4,336,113, No. 4,184,932, etc. It can also be used.

  The concentration of the acidic solution is preferably 0.5 to 2.5% by mass, but it is particularly preferably 0.7 to 2.0% by mass in consideration of use in the smut removal treatment. Moreover, it is preferable that liquid temperature is 20-80 degreeC, and it is more preferable that it is 30-60 degreeC.

  An aqueous solution mainly composed of hydrochloric acid or nitric acid is an aqueous solution of hydrochloric acid or nitric acid having a concentration of 1 to 100 g / L, such as nitric acid compounds having nitrate ions such as aluminum nitrate, sodium nitrate, ammonium nitrate, or aluminum chloride, sodium chloride, ammonium chloride, etc. At least one of the hydrochloric acid compounds having hydrochloric acid ions can be used by adding in a range from 1 g / L to saturation. Moreover, the metal contained in aluminum alloys, such as iron, copper, manganese, nickel, titanium, magnesium, a silica, may melt | dissolve in the aqueous solution which has hydrochloric acid or nitric acid as a main component. Preferably, a solution obtained by adding aluminum chloride, aluminum nitrate or the like to an aqueous solution of hydrochloric acid or nitric acid having a concentration of 0.5 to 2% by mass so that aluminum ions are 3 to 50 g / L is preferably used.

  Further, by adding and using a compound capable of forming a complex with Cu, uniform graining is possible even for an aluminum plate containing a large amount of Cu. Examples of the compound capable of forming a complex with Cu include ammonia; hydrogen atom of ammonia such as methylamine, ethylamine, dimethylamine, diethylamine, trimethylamine, cyclohexylamine, triethanolamine, triisopropanolamine, EDTA (ethylenediaminetetraacetic acid). And amines obtained by substituting with a hydrocarbon group (aliphatic, aromatic, etc.); metal carbonates such as sodium carbonate, potassium carbonate, potassium hydrogen carbonate and the like. In addition, ammonium salts such as ammonium nitrate, ammonium chloride, ammonium sulfate, ammonium phosphate, and ammonium carbonate are also included. The temperature is preferably 10-60 ° C, more preferably 20-50 ° C.

  The AC power supply wave used for the electrochemical surface roughening treatment is not particularly limited, and a sine wave, a rectangular wave, a trapezoidal wave, a triangular wave or the like is used, but a rectangular wave or a trapezoidal wave is preferable, and a trapezoidal wave is particularly preferable. A trapezoidal wave means what was shown in FIG. In this trapezoidal wave, the time (TP) until the current reaches a peak from zero is preferably 1 to 3 msec. If it is less than 1 msec, processing irregularities such as chatter marks that occur perpendicular to the traveling direction of the aluminum plate are likely to occur. When TP exceeds 3 msec, especially when a nitric acid electrolyte is used, it is easily affected by trace components in the electrolyte typified by ammonium ions and the like that spontaneously increase by electrolytic treatment, and uniform graining is performed. It becomes hard to be broken. As a result, the stain resistance tends to decrease when a lithographic printing plate is obtained.

  A duty ratio of trapezoidal wave alternating current of 1: 2 to 2: 1 can be used. However, as described in Japanese Patent Laid-Open No. 5-195300, in an indirect power feeding method in which no conductor roll is used for aluminum, a duty is used. A ratio of 1: 1 is preferred. A trapezoidal AC frequency of 0.1 to 120 Hz can be used, but 50 to 70 Hz is preferable in terms of equipment. When the frequency is lower than 50 Hz, the carbon electrode of the main electrode is easily dissolved, and when the frequency is higher than 70 Hz, it is easily affected by an inductance component on the power supply circuit, and the power supply cost is increased.

One or more AC power supplies can be connected to the electrolytic cell. As shown in FIG. 2, the current ratio between the anode and cathode of the alternating current applied to the aluminum plate facing the main electrode is controlled to achieve uniform graining and to dissolve the carbon of the main electrode. In addition, it is preferable to install an auxiliary anode and divert part of the alternating current. In FIG. 2, 11 is an aluminum plate, 12 is a radial drum roller, 13a and 13b are main poles, 14 is an electrolytic treatment solution, 15 is an electrolyte supply port, and 16 is a slit. , 17 is an electrolyte passage, 18 is an auxiliary anode, 19a and 19b are thyristors, 20 is an AC power source, 21 is a main electrolytic cell, and 22 is an auxiliary anode cell. An anodic reaction that acts on the aluminum plate facing the main electrode by diverting a part of the current value as a direct current to an auxiliary anode provided in a tank separate from the two main electrodes via a rectifier or switching element It is possible to control the ratio between the current value for the current and the current value for the cathode reaction. On the aluminum plate facing the main electrode, the ratio of the amount of electricity involved in the anodic reaction and the cathodic reaction (the amount of electricity at the time of cathode / the amount of electricity at the time of anode) is preferably 0.3 to 0.95.
As the electrolytic cell, electrolytic cells used for known surface treatments such as a vertical type, a flat type, and a radial type can be used, but a radial type electrolytic cell as described in JP-A-5-195300 is particularly preferable. . The electrolytic solution passing through the electrolytic cell may be parallel to the traveling direction of the aluminum web or may be a counter.

(Nitric acid electrolysis)
Pits having an average opening diameter of 0.5 to 5 μm can be formed by electrochemical surface roughening using an electrolytic solution mainly composed of nitric acid. However, when the amount of electricity is relatively large, the electrolytic reaction is concentrated, and honeycomb pits exceeding 5 μm are also generated. To obtain such a grain, the total amount of electricity furnished to anode reaction on the aluminum plate up until the electrolysis reaction is completed is preferably from ^{1~1000C / dm 2, 50~300C / dm} 2 It is more preferable that The current density at this time is preferably ²⁰ to 100 A / dm ² . Further, when a high concentration or high temperature nitric acid electrolytic solution is used, a small wave structure having an average opening diameter of 0.2 μm or less can be formed.

(Hydrochloric acid electrolysis)
Since hydrochloric acid itself has a strong ability to dissolve aluminum, it is possible to form fine irregularities on the surface with only slight electrolysis. The fine irregularities have an average opening diameter of 0.01 to 0.2 μm and are uniformly generated on the entire surface of the aluminum plate. Such grained total amount of electricity furnished to anode reaction on the aluminum plate up until the electrolysis reaction is completed in order to obtain the, is preferably from 1~100C / dm ^2, in 20~70C / dm ² More preferably. The current density at this time is preferably ²⁰ to 50 A / dm ² .

In such an electrochemical surface roughening treatment with an electrolyte mainly composed of hydrochloric acid, a large crater-like swell is simultaneously formed by increasing the total amount of electricity involved in the anode reaction to 400 to 1000 C / dm ^2. In this case, fine irregularities having an average opening diameter of 0.01 to 0.4 μm are formed on the entire surface by being superimposed on a crater-like wave having an average opening diameter of 10 to 30 μm. Therefore, in this case, since the medium wave structure with an average opening diameter of 0.5 to 5 μm cannot be superimposed, the grain shape of the surface that is a feature of the present invention cannot be made.

In manufacturing the aluminum support according to the present invention, as the first electrolytic surface roughening treatment, the electrolytic surface roughening treatment (nitric acid electrolysis) using the above-described electrolytic solution mainly composed of nitric acid is performed, and the second electrolytic surface roughening treatment is performed. As the electrolytic surface roughening treatment, it is preferable to perform the electrolytic surface roughening treatment (hydrochloric acid electrolysis) using the above-described electrolytic solution mainly composed of hydrochloric acid. That is, the aluminum support according to the present invention having a specific surface shape is preferably produced by sequentially performing nitric acid electrolysis and hydrochloric acid electrolysis as a roughening treatment, and further anodizing.
In particular, when nitric acid electrolysis is performed as the first electrolytic surface roughening treatment and hydrochloric acid electrolysis is performed as the second electrolytic surface roughening treatment, if at least one of (a) to (e) is satisfied, a small wave Since it becomes easy to make the standard deviation of the opening diameter of the structure 0.2 or less, it is preferable.
(A) In hydrochloric acid electrolysis, the hydrochloric acid concentration of the electrolytic solution is 1 to 8 g / L.
(B) In hydrochloric acid electrolysis, the amount of electricity is set to 10 to 100 C / dm ^{2 in} terms of the total amount of electricity involved in the anode reaction.
(C) In hydrochloric acid electrolysis, the AC frequency is set to 100 to 300 Hz.
(D) In hydrochloric acid electrolysis, the TP of the AC waveform is set to 2 msec or less.
(E) The alkali etching process mentioned later is performed after hydrochloric acid electrolysis, and the etching amount is set to 0.1 to 0.5 g / m ² in the alkali etching process.

The aluminum plate is preferably subjected to cathodic electrolysis during the first and second electrolytic surface-roughening treatments performed in the above-described electrolytic solution such as nitric acid and hydrochloric acid. By this cathodic electrolysis treatment, smut is generated on the surface of the aluminum plate, and hydrogen gas is generated to enable more uniform electrolytic surface roughening treatment. This cathodic electrolysis treatment is carried out in an acidic solution at a cathode electric quantity of preferably 3 to 80 C / dm ² , more preferably 5 to 30 C / dm ² . If the amount of cathodic electricity is in the above range, the amount of smut adhesion is preferable without excess or deficiency. Further, the electrolytic solution may be the same as or different from the solution used in the first and second electrolytic surface roughening processes.

-Alkaline etching treatment-
The alkali etching treatment is a treatment for dissolving the surface layer by bringing the aluminum plate into contact with an alkali solution.

  Alkaline etching performed before the electrolytic surface roughening treatment removes rolling oil, dirt, natural oxide film, etc. on the surface of the aluminum plate (rolled aluminum) if mechanical surface roughening treatment is not performed. If the surface of the unevenness generated by the mechanical surface roughening treatment is dissolved, the surface with sharp undulations is smoothed. It is done for the purpose of changing.

If you do not mechanical surface-roughening treatment before the alkali etching treatment, the etching amount is preferably from 0.1 to 10 g / ^{m 2,} and more preferably 1 to 5 g / ^{m 2.} If the etching amount is 0.1 g / m ² or more, the surface rolling oil, dirt, natural oxide film, etc. are sufficiently removed, so that uniform pits can be generated in the subsequent electrolytic surface roughening treatment. Occurrence can be suppressed. On the other hand, if the etching amount is within 10 g / m ² , it is economically preferable.

When performing mechanical surface-roughening treatment before the alkali etching treatment, the etching amount is preferably from 3 to 20 g / ^{m 2,} and more preferably 5 to 15 g / ^{m 2.} If the etching amount is 3 g / m ² or more, the unevenness formed by mechanical surface roughening or the like can be smoothed, and uniform pits can be formed in the subsequent electrolytic treatment. Further, it is possible to prevent smearing during printing. On the other hand, if the etching amount is 20 g / m ² or less, the concavo-convex structure can be prevented from disappearing.

The alkali etching treatment performed immediately after the electrolytic surface roughening treatment is performed for the purpose of dissolving the smut generated in the acidic electrolytic solution and dissolving the edge portion of the pit formed by the electrolytic surface roughening treatment. . Since the pits formed by the electrolytic surface roughening treatment are different depending on the type of the electrolytic solution, the optimum etching amount is also different. ² is preferred. When a nitric acid electrolyte is used, the etching amount needs to be set larger than when a hydrochloric acid electrolyte is used. When the electrolytic surface roughening treatment is performed a plurality of times, an alkali etching treatment can be performed as necessary after each treatment.

  Examples of the alkali used in the alkaline solution include caustic alkali and alkali metal salts. Specifically, examples of caustic alkali include caustic soda and caustic potash. Examples of alkali metal salts include alkali metal silicates such as sodium silicate, sodium silicate, potassium metasilicate, and potassium silicate; alkali metal carbonates such as sodium carbonate and potassium carbonate; sodium aluminate and alumina. Alkali metal aluminates such as potassium acid; alkali metal aldones such as sodium gluconate and potassium gluconate; dibasic sodium phosphate, dibasic potassium phosphate, tribasic sodium phosphate, tertiary potassium phosphate, etc. An alkali metal hydrogen phosphate is mentioned. Among these, a caustic alkali solution and a solution containing both a caustic alkali and an alkali metal aluminate are preferable from the viewpoint of high etching rate and low cost. In particular, an aqueous solution of caustic soda is preferable.

  Although the density | concentration of an alkaline solution can be determined according to the etching amount, it is preferable that it is 1-50 mass%, and it is more preferable that it is 10-35 mass%. When aluminum ions are dissolved in the alkaline solution, the concentration of aluminum ions is preferably 0.01 to 10% by mass, and more preferably 3 to 8% by mass. The temperature of the alkaline solution is preferably 20 to 90 ° C. The treatment time is preferably 1 to 120 seconds.

  Examples of the method of bringing the aluminum plate into contact with the alkaline solution include, for example, a method of passing the aluminum plate through a bath containing the alkaline solution, a method of immersing the aluminum plate in a bath containing the alkaline solution, and an alkaline solution. Can be sprayed onto the surface of the aluminum plate.

-Desmut treatment-
After the electrolytic surface roughening treatment or the alkali etching treatment, pickling (desmut treatment) is performed to remove dirt (smut) remaining on the surface. Examples of the acid used include nitric acid, sulfuric acid, phosphoric acid, chromic acid, hydrofluoric acid, and borohydrofluoric acid. The desmutting treatment is performed, for example, by bringing the aluminum plate into contact with an acidic solution having a concentration of 0.5 to 30% by mass (containing 0.01 to 5% by mass of aluminum ions) such as hydrochloric acid, nitric acid, and sulfuric acid. . Examples of the method of bringing the aluminum plate into contact with the acidic solution include a method in which the aluminum plate is passed through a tank containing the acidic solution, a method in which the aluminum plate is immersed in a tank containing the acidic solution, and the acidic solution being aluminum. The method of spraying on the surface of a board is mentioned. In the desmutting treatment, the acidic solution is mainly composed of an aqueous solution mainly composed of nitric acid or an aqueous solution mainly composed of hydrochloric acid discharged in the above-described electrolytic surface-roughening treatment, or sulfuric acid discharged in an anodic oxidation process described later. It is possible to use a waste solution of an aqueous solution. It is preferable that the liquid temperature of a desmut process is 25-90 degreeC. Moreover, it is preferable that processing time is 1-180 second. Aluminum and aluminum alloy components may be dissolved in the acidic solution used for the desmut treatment.

-Anodizing treatment-
The aluminum plate treated as described above is further subjected to anodizing treatment. The anodizing treatment can be performed by a method conventionally used in this field. In this case, for example, in a solution having a sulfuric acid concentration of 50 to 300 g / L and an aluminum concentration of 5% by mass or less, an anodized film can be formed by energizing an aluminum plate as an anode. As a solution used for the anodizing treatment, sulfuric acid, phosphoric acid, chromic acid, oxalic acid, sulfamic acid, benzenesulfonic acid, amidosulfonic acid and the like can be used alone or in combination of two or more.

  Under the present circumstances, the component normally contained at least in an aluminum plate, an electrode, tap water, groundwater, etc. may be contained in electrolyte solution. Furthermore, the 2nd, 3rd component may be added. Examples of the second and third components herein include metal ions such as Na, K, Mg, Li, Ca, Ti, Al, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn; Cation such as ammonium ion; anion such as nitrate ion, carbonate ion, chloride ion, phosphate ion, fluoride ion, sulfite ion, titanate ion, silicate ion, borate ion, etc., 0 to 10,000 ppm It may be contained at a concentration of about.

The conditions for anodizing treatment vary depending on the electrolyte used, and thus cannot be determined in general. In general, the electrolyte concentration is 1 to 80% by mass, the solution temperature is 5 to 70 ° C., and the current density is 0.5. ˜60 A / dm ² , voltage 1 to 100 V, and electrolysis time 15 seconds to 50 minutes are appropriate and adjusted so as to obtain a desired anodic oxide film amount.

  JP-A-54-81133, JP-A-57-47894, JP-A-57-51289, JP-A-57-51290, JP-A-57-54300, JP-A 57-136596, JP-A-58-107498, JP-A-60-200226, JP-A-62-136596, JP-A-63-176494, JP-A-4-17697, JP-A-4-280997, JP-A-6-207299, JP-A-5-24377, JP-A-5-32083, JP-A-5-125597, and JP-A-5-195291 The method described in the above can also be used.

  Of these, as described in JP-A-54-12853 and JP-A-48-45303, it is preferable to use a sulfuric acid solution as the electrolytic solution. The sulfuric acid concentration in the electrolytic solution is preferably 10 to 300 g / L (1 to 30% by mass), and the aluminum ion concentration is 1 to 25 g / L (0.1 to 2.5% by mass). It is preferable that it is 2 to 10 g / L (0.2 to 1% by mass). Such an electrolytic solution can be prepared, for example, by adding aluminum sulfate or the like to dilute sulfuric acid having a sulfuric acid concentration of 50 to 200 g / L.

When anodizing is performed in an electrolytic solution containing sulfuric acid, direct current may be applied between the aluminum plate and the counter electrode, or alternating current may be applied. When a direct current is applied to the aluminum plate, the current density is preferably from 1 to 60 A / dm ^2, and more preferably 5 to 40 A / dm ^2. In the case of continuous anodizing treatment, a low current of 5 to 10 A / m ² is initially introduced so that current is concentrated on a part of the aluminum plate and so-called “burning” does not occur. It is preferable to increase the current density to 30 to 50 A / dm ² or more as the current is passed at the density and the anodization process proceeds. When the anodizing treatment is continuously performed, it is preferable that the anodizing process is performed by a liquid power feeding method in which power is supplied to the aluminum plate through an electrolytic solution. By performing anodizing treatment under such conditions, a porous film having many pores called micropores can be obtained. Usually, the average pore diameter is about 5 to 50 nm, and the average pore density is 300. ˜800 / μm ² or so.

The amount of the anodized film is preferably 1 to 5 g / m ² . If it is 1 g / m ² or more plate to hardly enter scratches, whereas, if it is 5 g / m ² or less can be produced with reduced power, it is economically preferable. The amount of the anodized film is more preferably 1.5 to 4 g / m ² . Moreover, it is preferable to carry out so that the difference in the amount of the anodized film between the center portion of the aluminum plate and the vicinity of the edge portion is 1 g / m ² or less.

  As the electrolysis apparatus used for the anodizing treatment, those described in JP-A-48-26638, JP-A-47-18739, JP-B-58-24517, etc. may be used. it can. Among these, the apparatus shown in FIG. 3 is preferably used. FIG. 3 is a schematic view showing an example of an apparatus for anodizing the surface of an aluminum plate. In the anodizing apparatus 410, the aluminum plate 416 is conveyed as shown by the arrows in FIG. In the power supply tank 412 in which the electrolytic solution 418 is stored, the aluminum plate 416 is charged to (+) by the power supply electrode 420. The aluminum plate 416 is conveyed upward by the roller 422 in the power supply tank 412, changed in direction downward by the nip roller 424, and then conveyed toward the electrolytic treatment tank 414 in which the electrolytic solution 426 is stored. The direction is changed horizontally. Next, the aluminum plate 416 is charged to (−) by the electrolytic electrode 430 to form an anodized film on the surface thereof, and the aluminum plate 416 exiting the electrolytic treatment tank 414 is conveyed to a subsequent process. In the anodizing apparatus 410, the roller 422, the nip roller 424, and the roller 428 constitute a direction changing means, and the aluminum plate 416 is disposed between the power supply tank 412 and the electrolytic treatment tank 414 in the inter-tank section. By 428, it is conveyed into a mountain shape and an inverted U shape. The feeding electrode 420 and the electrolytic electrode 430 are connected to a DC power source 434.

  The feature of the anodizing apparatus 410 in FIG. 3 is that the feeding tank 412 and the electrolytic treatment tank 414 are partitioned by a single tank wall 432, and the aluminum plate 416 is conveyed in a mountain shape and an inverted U shape between the tanks. It is in. As a result, the length of the aluminum plate 416 in the inter-tank portion can be minimized. Therefore, the overall length of the anodizing apparatus 410 can be shortened, so that the equipment cost can be reduced. In addition, by conveying the aluminum plate 416 in a mountain shape and an inverted U shape, it is not necessary to form an opening for allowing the aluminum plate 416 to pass through the tank walls of the tanks 412 and 414. Therefore, since the liquid feeding amount required to maintain the liquid level height in each tank 412 and 414 at a required level can be suppressed, the operating cost can be reduced.

-Sealing treatment-
In this invention, you may perform the sealing process which seals the micropore which exists in an anodic oxide film as needed. The sealing treatment can be performed according to a known method such as boiling water treatment, hot water treatment, steam treatment, sodium silicate treatment, nitrite treatment, ammonium acetate treatment and the like. For example, Japanese Patent Publication No. 56-12518, Japanese Patent Application Laid-Open No. 4-4194, Japanese Patent Application No. 4-33952 (Japanese Patent Application Laid-Open No. 5-202496), Japanese Patent Application No. 4-33951 (Japanese Patent Application Laid-Open No. -179482) etc. may be used for sealing treatment.

-Hydrophilization treatment-
A hydrophilization treatment may be performed after the anodizing treatment or the sealing treatment. Examples of the hydrophilization treatment include treatment with potassium fluorinated zirconate described in US Pat. No. 2,946,638 and phosphomolybdate described in US Pat. No. 3,201,247. Treatment, alkyl titanate treatment described in British Patent 1,108,559, polyacrylic acid treatment described in German Patent 1,091,433, German Patent 1, No. 134,093 and British Patent No. 1,230,447, polyvinylphosphonic acid treatment, Japanese Patent Publication No. 44-6409, phosphonic acid treatment, US Pat. No. 3,307 , 951, 951, 951, 1981, 1981, and oleic acid described in Japanese Patent Laid-Open Nos. 58-16893 and 58-18291. Treatment with a salt of an organic polymer compound and a divalent metal, as described in US Pat. No. 3,860,426, hydrophilic cellulose (for example, zinc acetate) containing a water-soluble metal salt ( Examples thereof include a treatment for forming an undercoat layer of carboxymethyl cellulose) and a treatment for undercoating a water-soluble polymer having a sulfo group described in JP-A-59-101651.

  Further, phosphates described in JP-A No. 62-019494, water-soluble epoxy compounds described in JP-A No. 62-033692, and JP-A No. 62-097892 Phosphate-modified starch, diamine compounds described in JP-A-63-056498, amino acid inorganic or organic acids described in JP-A-63-130391, JP-A-63-145092 Organic phosphonic acids containing carboxy group or hydroxy group, compounds having amino group and phosphonic acid group described in JP-A-63-165183, and JP-A-2-316290 Specific carboxylic acid derivatives, phosphate esters described in JP-A-3-215095, JP-A-3-261592 Compounds having one amino group and one oxygen acid group of phosphorus described in the publication, phosphoric esters described in JP-A-3-215095, and JP-A-5-246171 Aliphatic or aromatic phosphonic acids such as phenylphosphonic acid, compounds containing S atoms such as thiosalicylic acid described in JP-A-1-307745, and phosphorus described in JP-A-4-282737 Examples of the treatment include undercoating using a compound having a group of oxygen acids. Further, coloring with an acid dye described in JP-A-60-64352 can also be performed.

  Hydrophilicity can also be achieved by soaking in an aqueous solution of an alkali metal silicate such as sodium silicate or potassium silicate, or by applying a hydrophilic vinyl polymer or hydrophilic compound to form a hydrophilic primer layer. It is preferable to carry out the treatment.

  Hydrophilization treatment with an aqueous solution of an alkali metal silicate such as sodium silicate and potassium silicate is described in US Pat. No. 2,714,066 and US Pat. No. 3,181,461. It can be performed according to methods and procedures. Examples of the alkali metal silicate include sodium silicate, potassium silicate, and lithium silicate. The aqueous solution of alkali metal silicate may contain an appropriate amount of sodium hydroxide, potassium hydroxide, lithium hydroxide or the like. The aqueous solution of alkali metal silicate may contain an alkaline earth metal salt or a Group 4 (Group IVA) metal salt. Examples of the alkaline earth metal salt include nitrates such as calcium nitrate, strontium nitrate, magnesium nitrate, and barium nitrate; sulfates; hydrochlorides; phosphates; acetates; oxalates; Examples of the Group 4 (Group IVA) metal salt include titanium tetrachloride, titanium trichloride, potassium fluoride titanium, potassium oxalate, titanium sulfate, titanium tetraiodide, zirconium chloride, zirconium dioxide, zirconium oxychloride. And zirconium tetrachloride. These alkaline earth metal salts and Group 4 (Group IVA) metal salts are used alone or in combination of two or more.

The amount of Si adsorbed by the alkali metal silicate treatment can be measured with a fluorescent X-ray analyzer, and the amount of adsorption is preferably about 1.0 to 15.0 mg / m ² . By this alkali metal silicate treatment, the effect of improving the dissolution resistance to the alkaline developer on the surface of the lithographic printing plate support is obtained, the dissolution of the aluminum component into the developer is suppressed, and the developer fatigue It is possible to reduce the occurrence of development residue due to the above.

The hydrophilic treatment by forming a hydrophilic undercoat layer can also be performed according to the conditions and procedures described in JP-A Nos. 59-101651 and 60-149491. Examples of the hydrophilic vinyl polymer used in this method include polyvinyl sulfonic acid, a sulfo group-containing vinyl polymerizable compound such as p-styrene sulfonic acid having a sulfo group, and ordinary vinyl polymerization such as (meth) acrylic acid alkyl ester. And a copolymer with a functional compound. Examples of hydrophilic compounds that may be used in this method include, -NH ₂ group, compounds having at least one selected from the group consisting of -COOH group and sulfo group.

-Washing treatment-
It is preferable to perform water washing after the completion of the above-described processes. For washing, pure water, well water, tap water, or the like can be used. A nip device may be used to prevent the processing liquid from being brought into the next process.

<Aluminum plate (rolled aluminum)>
In order to obtain a support used in the lithographic printing plate precursor according to the invention, a known aluminum plate can be used. The aluminum plate used in the present invention is a metal whose main component is dimensionally stable aluminum, and is made of aluminum or an aluminum alloy. In addition to a pure aluminum plate, an alloy plate containing aluminum as a main component and containing a trace amount of foreign elements can also be used.

  In the present specification, various substrates made of the above-described aluminum or aluminum alloy are generically used as an aluminum plate. The foreign elements that may be contained in the aluminum alloy include silicon, iron, manganese, copper, magnesium, chromium, zinc, bismuth, nickel, titanium, and the content of the foreign elements in the alloy is 10% by mass or less. It is.

  Thus, the composition of the aluminum plate used in the present invention is not specified. For example, a conventionally known material described in the fourth edition of the Aluminum Handbook (1990, published by the Light Metal Association), for example, JIS Al-Mn based aluminum plates such as A1050, JISA1100, JIS A1070, JIS A3004 containing Mn, and internationally registered alloy 3103A can be appropriately used. For the purpose of increasing the tensile strength, an Al—Mg alloy or an Al—Mn—Mg alloy (JIS A3005) in which 0.1 mass% or more of magnesium is added to these aluminum alloys can also be used. Furthermore, an Al—Zr alloy or an Al—Si alloy containing Zr or Si can also be used. Furthermore, an Al—Mg—Si based alloy can also be used.

  Regarding the JIS 1050 material, the techniques proposed by the applicant of the present application are disclosed in Japanese Patent Application Laid-Open Nos. 59-153661, 61-51395, 62-146694, and 60-215725. JP-A-60-215726, JP-A-60-215727, JP-A-60-216728, JP-A-61-272367, JP-A-58-11759, JP-A-58. -42493, JP-A-58-212254, JP-A-62-148295, JP-A-4-254545, JP-A-4-165541, JP-B-3-68939, JP-A-3 -234594, JP-B-1-47545 and JP-A-62-2140894. In addition, techniques described in Japanese Patent Publication No. 1-35910 and Japanese Patent Publication No. 55-28874 are also known.

  Regarding the JIS 1070 material, the techniques proposed by the applicant of the present application are disclosed in JP-A-7-81264, JP-A-7-305133, JP-A-8-49034, JP-A-8-73974, and JP-A-8. -108659 and JP-A-8-92679.

  Regarding the Al-Mg alloy, the techniques proposed by the applicant of the present application are disclosed in Japanese Patent Publication No. 62-5080, Japanese Patent Publication No. 63-60823, Japanese Patent Publication No. 3-61753, Japanese Patent Publication No. 60-20396. JP-A-60-203497, JP-B-3-11635, JP-A-61-274993, JP-A-62-23794, JP-A-63-47347, JP-A-63- 47348, JP 63-47349, JP 64-1293, JP 63-135294, JP 63-87288, JP 4-73392, JP 7-100844, JP-A 62-149856, JP-B-4-73394, JP-A-62-118191, JP-B-5-76530, JP It is described in JP 63-30294 and JP fair 6-37116 JP. Also described in JP-A-2-215599, JP-A-61-201747, and the like.

  Regarding the Al—Mn alloy, the techniques proposed by the applicant of the present application are described in Japanese Patent Application Laid-Open Nos. 60-230951, 1-306288, and 2-293189. . JP-B-54-42284, JP-B-4-19290, JP-B-4-19291, JP-B-4-19292, JP-A-61-35995, JP-A-64-51992 It is also described in JP-A-4-226394, US Pat. No. 5,009,722, US Pat. No. 5,028,276, and the like.

  With regard to the Al—Mn—Mg alloy, techniques proposed by the applicant of the present application are described in Japanese Patent Application Laid-Open Nos. 62-86143 and 3-2222796. Also, Japanese Patent Publication Nos. 63-60824, 60-63346, 60-63347, 1-293350, European Patent No. 223,737, US It is also described in each specification of Japanese Patent No. 4,818,300 and British Patent No. 1,222,777.

  Regarding the Al—Zr alloy, the technique proposed by the applicant of the present application is described in Japanese Patent Publication No. 63-15978 and Japanese Patent Application Laid-Open No. 61-51395. Also described in JP-A-63-143234 and JP-A-63-143235.

  The Al—Mg—Si alloy is described in British Patent 1,421,710.

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

  These cleaning treatments are preferably performed in order to prevent defects caused by foreign matters such as non-metallic inclusions and oxides in the molten metal and defects caused by gas dissolved in the molten metal. Regarding filtering of the molten metal, JP-A-6-57432, JP-A-3-162530, JP-A-5-140659, JP-A-4-231425, JP-A-4-276031, JP-A-5-26031. No. 311261 and JP-A-6-136466. Further, the degassing of the molten metal is described in JP-A-5-51659, Japanese Utility Model Laid-Open No. 5-49148, and the like. The applicant of the present application has also proposed a technique relating to degassing of molten metal in Japanese Patent Application Laid-Open No. 7-40017.

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

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

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

  On the other hand, as the continuous casting method, a twin roll method (hunter method), a method using a cooling roll typified by the 3C method, a double belt method (Hazley method), a cooling belt or a cooling block typified by Al-Swiss Caster II type The method using is industrially performed. When the continuous casting method is used, it solidifies at a cooling rate of 100 to 1000 ° C./second. Since the continuous casting method generally has a higher cooling rate than the DC casting method, it has a feature that the solid solubility of the alloy component in the aluminum matrix can be increased. Regarding the continuous casting method, the techniques proposed by the applicant of the present application are disclosed in JP-A-3-79798, JP-A-5-201166, JP-A-5-156414, JP-A-6-262203, JP-A-6-262203. No. 6-122949, JP-A-6-210406, JP-A-6-26308, and the like.

  When continuous casting is performed, for example, if a method using a cooling roll such as a Hunter method is used, a cast plate having a thickness of 1 to 10 mm can be directly cast continuously, and the hot rolling step is omitted. The advantage of being able to In addition, when a method using a cooling belt such as the Husley method is used, a cast plate having a thickness of 10 to 50 mm can be cast. Generally, a hot rolling roll is arranged immediately after casting and continuously rolled. Thus, a continuous cast and rolled plate having a thickness of 1 to 10 mm is obtained.

  These continuous cast and rolled plates are subjected to processes such as cold rolling, intermediate annealing, improvement of flatness, slits, and the like in the same manner as described for DC casting. Finished to a thickness of 5 mm. Regarding the intermediate annealing condition and the cold rolling condition in the case of using the continuous casting method, the techniques proposed by the applicant of the present application are disclosed in JP-A-6-220593, JP-A-6-210308, JP-A-7-54111. No. 5, JP-A-8-92709, etc.

  Various characteristics described below are desired for the aluminum plate thus manufactured. As for the strength of the aluminum plate, it is preferable that the 0.2% proof stress is 140 MPa or more in order to obtain the stiffness required for a lithographic printing plate support. Moreover, in order to obtain a certain level of waist strength even when performing a burning treatment, the 0.2% yield strength after heat treatment at 270 ° C. for 3 to 10 minutes is preferably 80 MPa or more, and 100 MPa or more. It is more preferable that In particular, when the waist strength is required for an aluminum plate, an aluminum material added with Mg or Mn can be used, but if the waist is strengthened, the ease of fitting to the plate cylinder of a printing press becomes inferior. Depending on the application, the material and the amount of trace components added are appropriately selected. With regard to these, techniques proposed by the applicant of the present application are described in Japanese Patent Application Laid-Open Nos. 7-126820 and 62-140894.

  The crystal structure of the aluminum plate is too rough on the surface to prevent the occurrence of poor surface quality due to the crystal structure of the surface of the aluminum plate when chemical surface roughening treatment or electrochemical surface roughening treatment is performed. Preferably not. The crystal structure on the surface of the aluminum plate preferably has a width of 200 μm or less, more preferably 100 μm or less, even more preferably 50 μm or less, and the length of the crystal structure is 5,000 μm or less. Preferably, it is 1,000 μm or less, more preferably 500 μm or less. With regard to these, techniques proposed by the applicant of the present application are described in Japanese Patent Laid-Open Nos. 6-218495, 7-39906, and 7-124609.

  The alloy component distribution of the aluminum plate, when chemical surface roughening treatment or electrochemical surface roughening treatment is performed, poor surface quality occurs due to non-uniform distribution of the alloy component on the surface of the aluminum plate. Therefore, it is preferable that the surface is not very uneven. With regard to these, the techniques proposed by the applicant of the present application are described in Japanese Patent Laid-Open Nos. 6-48058, 5-301478, and 7-132589.

  In the intermetallic compound of the aluminum plate, the size and density of the intermetallic compound may affect the chemical roughening treatment or the electrochemical roughening treatment. With regard to these, techniques proposed by the applicant of the present application are described in Japanese Patent Laid-Open Nos. 7-138687 and 4-254545.

  In the present invention, an aluminum plate as shown above can be used with unevenness by lamination rolling, transfer or the like in the final rolling step.

  In the present invention, the aluminum plate is preferably a continuous belt-like sheet material or plate material. That is, it may be an aluminum web or a sheet-like sheet cut to a size corresponding to a planographic printing plate precursor shipped as a product. Since scratches on the surface of the aluminum plate may become defects when processed into a lithographic printing plate support, it is possible to generate scratches at the stage prior to the surface treatment process for making a lithographic printing plate support It is necessary to suppress as much as possible. For that purpose, it is preferable that the package has a stable form and is not easily damaged during transportation. In the case of an aluminum web, for example, the packing form of aluminum is, for example, laying a hardboard and felt on an iron pallet, applying cardboard donut plates to both ends of the product, wrapping the whole with a polytube, and inserting a wooden donut into the inner diameter of the coil Then, a felt is applied to the outer periphery of the coil, the band is squeezed with a band, and the display is performed on the outer periphery. Moreover, a polyethylene film can be used as the packaging material, and a needle felt or a hard board can be used as the cushioning material. There are various other forms, but the present invention is not limited to this method as long as it is stable and can be transported without being damaged.

  The thickness of the aluminum plate is preferably about 0.1 mm to 0.6 mm, more preferably 0.15 mm to 0.4 mm, and still more preferably 0.2 mm to 0.3 mm. This thickness can be appropriately changed according to the size of the printing press, the size of the printing plate, the user's desires, and the like.

[Middle layer]
The intermediate layer of the present invention will be described in detail.
The intermediate layer of the present invention contains a polymer compound having a carboxyl group and a carboxylic acid ester group in the side chain (hereinafter also referred to as “specific polymer compound”).
The specific polymer compound is not particularly limited as long as it has a carboxyl group and a carboxylic acid ester group simultaneously in the side chain. For example, even if it has a carboxyl group and a carboxylate group in one side chain, a carboxyl group and a carboxylate group may be provided in another side chain.
In the present invention, by containing a specific polymer compound, the development removability of an unexposed area at the time of image formation is enhanced.

  The specific polymer compound is a copolymer having at least a structural unit (i) represented by the following general formula (1) and a structural unit (ii) represented by the following general formula (2). preferable.

In General Formula (1), R ¹ represents a hydrogen atom, a substituent having 1 to 30 carbon atoms, or a halogen atom. L ¹ represents a single bond or a linking group. n represents an integer of 1 to 10.

In the general formula (2), ^{R 2} represents a hydrogen atom, a substituent having 1 to 30 carbon atoms or a halogen atom. Y represents a group having 2 to 30 carbon atoms including a carboxylic acid ester group.

First, general formula (1) will be described.
R ¹ in the general formula (1) is a hydrogen atom, a substituent having 1 to 30 carbon atoms (for example, alkyl having 1 to 30 carbon atoms; methyl, ethyl, propyl, butyl, pentyl, hexyl, cyclohexyl, carbon atoms having 1 to 30 carbon atoms; 30 alkoxy; methoxy, ethoxy, butoxy, acetoxy, propionyloxy, alkoxycarbonyl having 1 to 30 carbon atoms; methoxycarbonyl, ethoxycarbonyl, cyano, etc.) or halogen atom (for example, fluorine atom, chlorine atom, bromine atom, Represents an iodine atom). A hydrogen atom, a methyl group, an ethyl group, a fluorine atom, or a chlorine atom is more preferable, and a hydrogen atom or a methyl group is particularly preferable.

L ¹ in the general formula (1) represents a single bond or a linking group. Here, the linking group refers to a divalent or higher valent group composed of at least one non-metallic atom, preferably a carbon atom having 0 to 60 atoms, a nitrogen atom having 0 to 10 atoms, and 0 to 0 atoms. It is composed of 50 oxygen atoms and 0 to 20 sulfur atoms. More _preferably, -CR 2 -, - O - , - C = O -, - S -, - S = O -, - S (= O) 2 -, - NR-, vinylene, phenylene, cycloalkylene, naphthylene , Biphenylene, (wherein R represents a hydrogen atom or a substituent), and a combination of these structural units. More preferably, L ¹ is a single bond, —O (CH ₂ ) _p —, —NH (CH ₂ ) _q —, —COO—, —CONH—, wherein p and q are each independently an integer of 0 to 20 Or a phenylene group. L ¹ is particularly preferably a single bond, —COO—, —CONH—, or a phenylene group.
In addition, as the substituent represented by R when L ¹ in General Formula (1) is represented by —CR ₂ — or —NR—, the same group as the substituent described for R ¹ in General Formula (1) Preferably, it is a methyl group.

In general formula (1), n represents an integer of 1 to 10. Here, n being 2 or more indicates that a plurality of —CO ₂ H is bonded to the linking group.

Next, general formula (2) will be described.
In General Formula (2), Y represents a C2-C30 group having a carboxylic acid ester group, and the carbon number is preferably 2-20, and more preferably 2-10. Here, Y may be a total of 2 to 30 carbon atoms in combination with an alkyl group, aryl group, and the like that form a carboxylic acid ester and a carboxylic acid ester group, and is represented by the following structural formula (2-1). Can be represented.

L ² in the structural formula (2-1) is a single bond or a divalent linking group such as an alkylene group, and R ³ is a monovalent group such as an alkyl group or an aryl group forming a carboxylic acid ester. is there. R ³ may further have a halogen atom or a hydroxy group as a substituent.
L ² and R ³ can be selected within a range where the sum of the carbon number of L ^{2 and} the carbon number of R ³ is 2 to 30.

  Preferred examples of Y include carboxylic acid alkyl ester groups (for example, methoxycarbonyl, ethoxycarbonyl, propyloxycarbonyl, isopropyloxycarbonyl, butyloxycarbonyl, hexyloxycarbonyl, octyloxycarbonyl, cyclohexyloxycarbonyl, 2-ethylhexyloxy Carbonyl, benzyloxycarbonyl, 2-hydroxyethoxycarbonyl, 2-methoxyethoxycarbonyl, etc.), carboxylic acid aryl ester groups (for example, phenoxycarbonyl group, 4-methoxyphenoxycarbonyl group, naphthaleneoxycarbonyl group) and the like. .

  More preferable examples of Y include carboxylic acid alkyl ester groups (methoxycarbonyl, ethoxycarbonyl, propyloxycarbonyl, isopropyloxycarbonyl, butyloxycarbonyl, hexyloxycarbonyl, octyloxycarbonyl, cyclohexyloxycarbonyl, 2-ethylhexyloxycarbonyl. Benzyloxycarbonyl, 2-hydroxyethoxycarbonyl, 2-methoxyethoxycarbonyl, etc.).

  Particularly preferred examples of Y include methoxycarbonyl, ethoxycarbonyl, propyloxycarbonyl, isopropyloxycarbonyl, butyloxycarbonyl, hexyloxycarbonyl, 2-hydroxyethoxycarbonyl, 2-methoxyethoxycarbonyl and the like.

R ² in the general formula (2) has the same meaning as R ¹ , and the preferred range is also the same.

  In the polymer compound used in the present invention, the molar ratio between the content of the structural unit (i) represented by the general formula (1) and the content of the structural unit (ii) represented by the general formula (2) Is preferably 0.9: 0.1 to 0.1: 0.9, more preferably 0.9: 0.1 to 0.3: 0.7, and particularly preferably 0.8: 0.2-0.3: 0.7.

Furthermore, in the specific polymer compound, part or all of the carboxyl groups contained in the specific polymer compound are preferably neutralized with a base. When the specific polymer compound is a copolymer having at least the structural unit (i) represented by the general formula (1) and the structural unit (ii) represented by the general formula (2), The copolymer is preferably a polymer compound in which part or all of the carboxyl groups are neutralized with a base.
As the base, any known base can be used. Preferred examples include alkali metals (lithium, sodium, potassium, etc.), group 2 metals (magnesium, calcium, strontium, barium, etc.), Other metal ions (aluminum, titanium, iron, zinc, etc.) hydroxide, oxide, carbonate, bicarbonate, alkoxide, etc., ammonia (gas or aqueous solution), amines (methylamine, ethylamine, diethylamine) Dimethylamine, trimethylamine, triethylamine, tetraethylammonium hydroxide, tetramethylammonium hydroxide, tetrabutylammonium hydroxide, pyridine, morpholine, guanidine, and the like. More preferably, an alkali metal hydroxide, an alkali metal alkoxide, an aqueous ammonia solution, and amines can be used. Particularly preferred are sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium methoxide, potassium methoxide, aqueous ammonia, triethylamine, pyridine and the like.

  In the polymer compound of the present invention, the degree of neutralization of the carboxyl group in the copolymer is preferably 10 to 100 mol%, more preferably 20 to 80 mol%, and particularly preferably 30 to 70 mol%.

  The constituent component (i) represented by the general formula (1) and the constituent component (ii) represented by the general formula (2) may each be one kind or a combination of two or more kinds. In the range which does not deviate from the gist of the present invention, the structural component (i) represented by the general formula (1) and the structural component other than the structural component (ii) represented by the general formula (2) are further included. Also good. A component derived from an initiator, a chain transfer agent, or the like may be contained at the end of the polymer or at the side chain.

  The copolymer of the present invention can be produced by a conventional method. Specifically, any synthetic method selected from known methods such as anionic polymerization, radical polymerization, cationic polymerization, and polymer reaction method may be employed alone or in combination. Of these, radical polymerization and polymer reaction are preferred.

The method for producing the copolymer of the present invention includes a monomer corresponding to the constituent component (i) represented by the general formula (1) and a constituent component (ii) represented by the general formula (2). A production method in which neutralization is performed after copolymerizing a raw material containing at least a corresponding monomer, a part or all of the monomer corresponding to the structural unit (i) represented by the general formula (1) Any one of the production methods in which a previously neutralized monomer is prepared in advance and copolymerized with a raw material containing at least a monomer corresponding to the structural unit (ii) represented by the general formula (2) is preferable. Selected.
Particularly preferably, the copolymer containing at least the structural unit (i) represented by the general formula (1) and the structural unit (iii) represented by the general formula (3) substantially contains water. Not in a solvent (eg methanol, ethanol, propanol, isopropyl alcohol, propylene glycol monomethyl ether, dimethyl sulfoxide, tetrahydrofuran, N-methyl-2-pyrrolidone, dimethylacetamide, dimethylformamide, acetonitrile, acetone, ethyl methyl ketone, methyl isobutyl ketone Etc.), and a method of neutralizing by adding water and base simultaneously (including the case where an aqueous solution of a base is added) or sequentially is selected.

The average molecular weight of the copolymer of the specific polymer compound used in the present invention may be arbitrary, but when measured using a gel permeation chromatography (GPC) method, the weight average molecular weight (Mw) is 1,000- It is preferably 500,000, more preferably in the range of 2,000 to 200,000, and particularly preferably in the range of 5,000 to 100,000.
The amount of unreacted monomer contained in the specific polymer compound is arbitrary, but is preferably 20% by mass or less, more preferably 10% by mass or less, and particularly preferably 5% by mass or less. .

  Preferred examples (a-1 to a-24) of the specific polymer compound used in the present invention are shown below by the structural units constituting the polymer and the polymerization molar ratio thereof. The weight average molecular weight (Mw) of these specific polymer compounds is also shown. The present invention is not limited to these.

  Next, synthesis examples of the specific polymer compound will be shown. Other polymer compounds used in the present invention are synthesized in the same manner. The synthesis method of the specific polymer compound used in the present invention is not limited to these.

In addition, the average molecular weight of the specific polymer compound obtained in the following synthesis example was measured under the following analysis conditions using PEG (manufactured by Tosoh Corporation) as a standard sample.
-Analytical conditions for measurement of average molecular weight by gel permeation chromatography (GPC) method-
Column: Shodex OHpak SB-806M HQ 8x300mm
Shodex OHpak SB-806M HQ 8 × 300mm
Shodex OHpak SB-802.5 HQ 8x300mm
Moving layer: 50 mM disodium hydrogen phosphate solution (acetonitrile / water = 1/9)
Flow rate: 0.8 ml / min.
Detector: RI
Injection volume: 100 μl
Sample concentration: 0.1% by mass

(Synthesis Example 1)
-Synthesis of the exemplified compound (a-1)-
107.1 parts by mass of propylene glycol monomethyl ether was placed in a reaction vessel, heated to 80 ° C. and stirred for 30 minutes under a nitrogen stream. Separately, 75.1 parts by mass of methyl methacrylate, 64.6 parts by mass of methacrylic acid, 7.6 parts by mass of 2,2′-azobis (2-methylpropionic acid) dimethyl, 428.4 parts by mass of propylene glycol monomethyl ether A solution was prepared and dropped into the reaction solution over 2 hours. After reacting at 80 ° C. for 4 hours and 30 minutes, 3.8 parts by mass of 2,2′-azobis (2-methylpropionic acid) dimethyl was added, the temperature was raised to 90 ° C., and the mixture was further stirred for 2 hours. After cooling the reaction solution to 20 ° C. or lower, 202.5 parts by mass of a 2 mol / L aqueous sodium hydroxide solution was added and stirred to obtain a solution of the exemplary compound (a-1) (solid content concentration 17.9%). . The weight average molecular weight by GPC method was 32,000.

(Synthesis Example 2)
-Synthesis of the exemplified compound (a-2)-
99.7 parts by mass of propylene glycol monomethyl ether was placed in a reaction vessel, heated to 80 ° C. and stirred for 30 minutes under a nitrogen stream. Separately, 75.1 parts by mass of methyl methacrylate, 54.1 parts by mass of acrylic acid, 7.6 parts by mass of 2,2′-azobis (2-methylpropionic acid) dimethyl, and 398.6 parts by mass of propylene glycol monomethyl ether A solution was prepared and dropped into the reaction solution over 2 hours. After reacting at 80 ° C. for 4 hours and 30 minutes, 3.8 parts by mass of 2,2′-azobis (2-methylpropionic acid) dimethyl was added, the temperature was raised to 90 ° C., and the mixture was further stirred for 2 hours. After cooling the reaction solution to 20 ° C. or lower, 202.5 parts by mass of a 2 mol / L aqueous sodium hydroxide solution was added and stirred to obtain a solution of the exemplary compound (a-2) (solid content concentration 17.7%). . The weight average molecular weight by GPC method was 28,000.

<Formation of intermediate layer>
The intermediate layer of the present invention is provided by coating on a support by various methods. The intermediate layer can be provided, for example, by the following method. An organic solvent such as methanol, ethanol, methyl ethyl ketone, acetonitrile, N-methyl-2-pyrrolidone, dimethyl sulfoxide, propylene glycol monomethyl ether, a mixed solvent thereof, or a mixed solvent of these organic solvents and water is used in the present invention. The present invention is applied to a method in which a solution in which a copolymer is dissolved is applied on a support and dried, and to an organic solvent such as methanol, ethanol, methyl ethyl ketone, a mixed solvent of these organic solvents and water, or a mixed solvent thereof. In this method, the support is immersed in a solution in which the polymer compound is dissolved to adsorb the polymer compound, and then washed with water or the like if necessary and dried to provide an organic intermediate layer. In the former method, a solution having a concentration of preferably 0.005 to 20% by weight, more preferably 0.01 to 10% by weight, and particularly preferably 0.05 to 5% by weight of the above polymer compound is obtained by various methods. Can be applied. For example, any method such as bar coater coating, spin coating, spray coating, or curtain coating may be used. In the latter method, the concentration of the solution is 0.01 to 20% by weight, preferably 0.05 to 5% by weight, the immersion temperature is 20 to 90 ° C., preferably 25 to 50 ° C., and the immersion time. Is 0.1 second to 20 minutes, preferably 2 seconds to 1 minute. The above solutions include basic substances such as ammonia, triethylamine, sodium hydroxide and potassium hydroxide, inorganic acids such as hydrochloric acid, phosphoric acid, sulfuric acid and nitric acid, organic sulfonic acids such as nitrobenzenesulfonic acid and naphthalenesulfonic acid, phenyl The pH is adjusted with various organic acidic substances such as organic phosphonic acids such as sulfonic acid, benzoic acid, fumaric acid, malic acid and the like, and the pH is in the range of 0 to 12, more preferably 3 to 10. May be used. The coating amount after drying of the copolymer polymer compound of the present invention is preferably ² to 100 mg / m ² , more preferably 3 to 50 mg / m ² , and particularly preferably 4 to 30 mg / m ² . If the coating amount is less than 2 mg / m ² , the effects of the present invention may not be sufficiently obtained. Moreover, even if it exceeds 100 mg / m < ² >, it is the same.

  In the lithographic printing plate precursor according to the invention, in addition to the copolymer as the specific polymer compound, other known compounds may be used in combination. Specific examples of the known intermediate layer include JP-B-50-7481, JP-A-54-72104, JP-A-59-101651, JP-A-60-149491, JP-A-60-. No. 232998, JP-A-3-56177, JP-A-4-282737, JP-A-5-16558, JP-A-5-246171, JP-A-7-159983, JP-A-7-314937. JP, 8-82025, JP-A-8-320551, JP-A-9-34104, JP-A-9-236911, JP-A-9-269593, JP-A-10-69092, JP-A-10-115931, JP-A-10-161317, JP-A-10-260536, JP-A-10-282682, Japanese Laid-Open Patent Publication Nos. 11-84684, 10-69092, 10-115931, 11-38635, 11-38629, 10-282645, 10 No. -301262, JP-A-11-24277, JP-A-11-109641, JP-A-10-319600, JP-A-11-84684, JP-A-11-327152, JP-A-2000-10292. And JP-A-2000-235254, JP-A-2000-352854, JP-A-2001-209170, and Japanese Patent Application No. 11-284091.

-Infrared absorber-
When forming an image of the lithographic printing plate precursor according to the present invention using a light source that emits a laser beam having a wavelength of 760 to 1200 nm, an infrared absorber is preferably used. The infrared absorber has a function of converting the absorbed infrared ray into heat and a function of being excited by the infrared ray and transferring electrons / energy to a polymerization initiator (radical generator) described later. The infrared absorber is preferably a dye or pigment having an absorption maximum at a wavelength of 760 to 1200 nm.

  As the dye, commercially available dyes and known dyes described in documents such as “Dye Handbook” (edited by the Society for Synthetic Organic Chemistry, published in 1970) can be used. Specifically, dyes such as azo dyes, metal complex azo dyes, pyrazolone azo dyes, naphthoquinone dyes, anthraquinone dyes, phthalocyanine dyes, carbonium dyes, quinoneimine dyes, methine dyes, cyanine dyes, squarylium dyes, pyrylium salts, metal thiolate complexes, etc. Is mentioned. Examples of preferable dyes include cyanine dyes, and particularly, cyanine dyes described in JP-A-2004-252284 [0029] to [0034] are preferably used.

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

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

These infrared absorbers may be added to the same layer as the other components, or may be added to another layer, but when the lithographic printing plate precursor is prepared, the image forming layer It is preferable to add so that the absorbance at the maximum absorption wavelength in the wavelength range of 760 nm to 1200 nm is in the range of 0.3 to 1.2 by the reflection measurement method. More preferably, it is the range of 0.4-1.1. By setting it in this range, a uniform polymerization reaction in the depth direction of the image forming layer proceeds, and good film strength of the image area and adhesion to the support can be obtained.
The absorbance of the image forming layer can be adjusted by the amount of the infrared absorber added to the image forming layer and the thickness of the image forming layer. Absorbance can be measured by a conventional method. As a measuring method, for example, on a reflective support such as aluminum, an image forming layer having a thickness appropriately determined in a range in which the coating amount after drying is necessary as a lithographic printing plate is formed, and the reflection density is set to the optical density And a method of measuring with a spectrophotometer by a reflection method using an integrating sphere.

<Polymerization initiator>
The lithographic printing plate precursor according to the invention contains a polymerization initiator in the image forming layer.
Examples of the polymerization initiator used in the present invention include compounds that generate radicals by light, heat, or both energies to initiate and accelerate the polymerization of a compound having a polymerizable unsaturated group.
As the radical generator that can be used in the present invention, a known thermal polymerization initiator, a compound having a bond with a small bond dissociation energy, a photopolymerization initiator, or the like can be used, and a radical suitably used in the present invention is generated. The compound to be used refers to a compound that initiates and accelerates the polymerization of a compound having a polymerizable unsaturated group by generating a radical by thermal energy. As the thermal radical generator, a known polymerization initiator, a compound having a bond having a small bond dissociation energy, or the like can be appropriately selected and used. Moreover, the compound which generate | occur | produces a radical can be used individually or in combination of 2 or more types.

  Examples of compounds that generate radicals include organic halogenated compounds, carbonyl compounds, organic peroxide compounds, azo polymerization initiators, azide compounds, metallocene compounds, hexaarylbiimidazole compounds, organic boric acid compounds, disulfonic acid compounds, Examples include oxime ester compounds, onium salt compounds, and borate compounds. Particularly preferred radical generating compounds include borate compounds and onium compounds.

As the onium salt compound, sulfonium salts, iodonium salts, and diazonium salts are preferably used. For example, sulfonium salts described in JP-A-2004-252284 [0043] to [0048] and iodonium salts described in [0050] to [0058] can be mentioned.
In particular, from the viewpoint of reactivity and stability, the above oxime ester compounds, diazonium salts, iodonium salts, and sulfonium salts are exemplified. In the present invention, these onium salts function not as acid generators but as ionic radical polymerization initiators.
In the present invention, a particularly preferred polymerization initiator is an iodonium salt having an electron donating group or a sulfonium salt having an electron withdrawing group from the balance of reactivity and stability. Most preferred is an iodonium salt having 2 or more, more preferably an iodonium salt having 3 or more alkoxy groups.

  These polymerization initiators are added in a proportion of 0.1 to 50% by mass, preferably 0.5 to 30% by mass, particularly preferably 1 to 20% by mass, based on the total solid content constituting the image forming layer. Can do. Within this range, good sensitivity and good stain resistance of the non-image area during printing can be obtained. These polymerization initiators may be used alone or in combination of two or more. Moreover, these polymerization initiators may be added to the same layer as other components, or another layer may be provided and added thereto.

<Polymerizable compound>
The image forming layer provided on the lithographic printing plate precursor according to the invention contains a polymerizable compound.
The polymerizable compound is not particularly limited as long as it is a compound having a monofunctional group or a bifunctional or higher polyfunctional group in the molecule, but is preferably a compound having an ethylenically unsaturated bond capable of addition polymerization. .
The compound having an ethylenically unsaturated bond capable of addition polymerization is an addition polymerizable compound having at least one ethylenically unsaturated double bond, and has at least one terminal ethylenically unsaturated bond, preferably 2 or more. It is chosen from the compound which has. Such compound groups are widely known in the industrial field, and these can be used without any particular limitation in the present invention. These have chemical forms such as monomers, prepolymers, i.e. dimers, trimers and oligomers, or mixtures thereof and copolymers thereof.

  Examples of monomers and copolymers thereof include unsaturated carboxylic acids (for example, acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid, maleic acid, etc.), and esters and amides thereof. In this case, an ester of an unsaturated carboxylic acid and an aliphatic polyhydric alcohol compound, or an amide of an unsaturated carboxylic acid and an aliphatic polyvalent amine compound is used. In addition, an addition reaction product of an unsaturated carboxylic acid ester or amide having a nucleophilic substituent such as a hydroxyl group, amino group or mercapto group with a monofunctional or polyfunctional isocyanate or epoxy, and monofunctional or polyfunctional A dehydration condensation reaction product with a functional carboxylic acid is also preferably used. Further, an addition reaction product of an unsaturated carboxylic acid ester or amide having an electrophilic substituent such as an epoxy group or an epoxy group with a monofunctional or polyfunctional alcohol, amine or thiol, a halogen group or Also suitable are substitution reaction products of unsaturated carboxylic acid esters or amides having a leaving substituent such as a tosyloxy group with monofunctional or polyfunctional alcohols, amines or thiols. As another example, it is also possible to use a group of compounds substituted with unsaturated phosphonic acid, styrene, vinyl ether or the like instead of the unsaturated carboxylic acid.

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

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

  Itaconic acid esters include ethylene glycol diitaconate, propylene glycol diitaconate, 1,3-butanediol diitaconate, 1,4-butanediol diitaconate, tetramethylene glycol diitaconate, pentaerythritol diitaconate And sorbitol tetritaconate.

  Examples of crotonic acid esters include ethylene glycol dicrotonate, tetramethylene glycol dicrotonate, pentaerythritol dicrotonate, and sorbitol tetradicrotonate.

  Examples of isocrotonic acid esters include ethylene glycol diisocrotonate, pentaerythritol diisocrotonate, and sorbitol tetraisocrotonate.

  Examples of maleic acid esters include ethylene glycol dimaleate, triethylene glycol dimaleate, pentaerythritol dimaleate, and sorbitol tetramaleate.

  Examples of other esters include aliphatic alcohol esters described in JP-B-46-27926, JP-B-51-47334, JP-A-57-196231, and JP-A-59-5240. Those having an aromatic skeleton described in JP-A-59-5241, JP-A-2-226149, and those containing an amino group described in JP-A-1-165613 are also preferably used. 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-based monomers include those having a cyclohexylene structure described in JP-B No. 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 (α) to a polyisocyanate compound having two or more isocyanate groups. Compounds and the like.

In the general formula (α), R ⁵¹ and R ⁵² each independently represent H or CH ₃ .

  Also, 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- Urethane compounds having an ethylene oxide skeleton described in Japanese Patent No. 17654, Japanese Patent Publication No. 62-39417, and Japanese Patent Publication No. 62-39418 are also suitable.

  Furthermore, addition polymerizable compounds having an amino structure or a sulfide structure in the molecule described in JP-A-63-277653, JP-A-63-260909, and JP-A-1-105238 are used. Depending on the case, it is possible to obtain a photopolymerizable composition excellent in the photosensitive speed.

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

  About these polymeric compounds, the details of usage methods, such as the structure, single use, combined use, and addition amount, can be arbitrarily set according to the performance design of final polymerizable composition. For example, when the polymerizable compound in the present invention is used as an image forming layer of a negative lithographic printing plate precursor, it is selected from the following viewpoints. From the viewpoint of photosensitive speed, a structure having a high unsaturated group content per molecule is preferable, and in many cases, a bifunctional or higher functionality is preferable. Further, in order to increase the strength of the image portion, that is, the cured film, those having three or more functionalities are preferable, and furthermore, different functional numbers and different polymerizable groups (for example, acrylic acid ester, methacrylic acid ester, styrene compound, vinyl ether type). A method of adjusting both photosensitivity and intensity by using a compound) is also effective. A compound having a large molecular weight or a compound having high hydrophobicity is excellent in photosensitive speed and film strength, but is not preferable in terms of development speed and precipitation in a developer. In addition, the selection and use of an addition polymerization compound is also required for compatibility and dispersibility with other components in the image forming layer (for example, a binder polymer described later, the above-described light or thermal polymerization initiator, colorant, etc.) The method is an important factor. For example, the compatibility may be improved by using a low-purity compound or using two or more kinds in combination.

In addition, when the polymerizable compound in the present invention is applied as an image forming layer of a lithographic printing plate precursor, a specific structure is selected for the purpose of improving the adhesion of the support of the lithographic printing plate precursor or a protective layer described later. It is possible to do. With regard to the compounding ratio of the polymerizable compound in the image forming layer, a larger amount is advantageous in terms of sensitivity, but if it is too large, undesired phase separation occurs and a problem in the manufacturing process due to the adhesiveness of the image forming layer. For example, problems such as transfer of image forming layer components and manufacturing defects due to adhesion, and precipitation from the developer may occur.
From these viewpoints, the polymerizable compound is preferably used in the range of 5 to 80% by mass, and more preferably 25 to 75% by mass with respect to the nonvolatile component in the image forming layer. These may be used alone or in combination of two or more.
In addition, the polymerizable compound can be arbitrarily selected depending on the appropriate structure, blending, and addition amount from the viewpoints of polymerization inhibition with respect to oxygen, resolution, fogging, refractive index change, surface adhesiveness, etc. It can also be used for the layer configuration and coating method of the intermediate layer and the like described above.

<Binder polymer>
The image forming layer provided on the lithographic printing plate precursor according to the invention contains a binder polymer.
The binder polymer is a polymer that functions as a film forming agent for the image forming layer, and preferably contains a linear organic polymer. Any such “linear organic polymer” may be used.
As an example of such a binder polymer, a polymer selected from acrylic resins, polyvinyl acetal resins, polyurethane resins, polyamide resins, epoxy resins, methacrylic resins, styrene resins, and polyester resins is preferable. Of these, acrylic resins and polyurethane resins are preferable.

Further, the binder polymer can be cross-linked 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 course of a radical polymerization reaction that occurs in the image forming 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 (11)-general formula (13) is especially preferable.

In the general formula (11), R ^{1 to} R ³ each independently represents a monovalent organic group, and R ¹ is preferably a hydrogen atom or an alkyl group which may have a substituent. Among them, a hydrogen atom and a methyl group are 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 alkyl group which may have a substituent, or a substituted group. An aryl group which may have a group, an alkoxy group which may have a substituent, an aryloxy group which may have a substituent, an alkylamino group which 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 ) —, and R ¹² represents a hydrogen atom or a monovalent organic group. Here, examples of R ¹² include an alkyl group which may have a substituent. Among them, a hydrogen atom, a methyl group, an ethyl group, and an isopropyl group are preferable 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 (12), R ^{4 to} R ⁸ each independently represents a monovalent organic group, and R ^{4 to} R ⁸ are preferably a hydrogen atom, a halogen atom, an amino group, a dialkylamino 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 group which may have a substituent, substituted An aryloxy group which may have a group, an alkylamino group which may have a substituent, an arylamino group which may have a substituent, an alkylsulfonyl group which may have a substituent, a substituent An arylsulfonyl group that may have, and the like. Among them, a hydrogen atom, a carboxyl group, an alkoxycarbonyl group, an alkyl group that may have a substituent, and an aryl group that may have a substituent Masui.

Examples of the substituent that can be introduced are the same as those in the general formula (11). Y represents an oxygen atom, a sulfur atom, or N (R ¹² ) —. R < ¹² > is synonymous with the case of R < ¹² > of General formula (11), and its preferable example is also the same.

In the general formula (13), R ⁹ preferably includes a hydrogen atom or an alkyl group which may have a substituent. Among them, a hydrogen atom or a methyl group has high radical reactivity. To preferred. 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 that 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 (11). Z represents an oxygen atom, a sulfur atom, -N (R ¹³ )-, or an optionally substituted phenylene group. 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 these, (meth) acrylic acid copolymers having a crosslinkable group in the side chain and polyurethane are more preferable.

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

  The content of the crosslinkable group in the binder polymer (content of unsaturated double bond capable of radical polymerization by iodine titration) is preferably 0.1 to 10.0 mmol, more preferably 1.0, per 1 g of the binder polymer. -7.0 mmol, most preferably 2.0-5.5 mmol.

-Alkali-soluble binder polymer-
In an embodiment in which the development treatment is performed using an alkali developer, the binder polymer needs to be dissolved in the alkali developer, and therefore an organic high molecular polymer that is soluble or swellable in alkaline water is preferably used. In particular, when an alkali developer having a pH of 10 or more is used, an alkali-soluble binder is preferably used.
In order to be soluble in alkaline water, it preferably has an alkali-soluble group. The alkali solubility is preferably an acid group, and examples thereof include a carboxyl group, a sulfonic acid group, a phosphoric acid group, and a hydroxyl group. Among these, a binder polymer having a carboxyl group is particularly preferable from the viewpoint of achieving both film properties, counter-printing properties, and developability.
Furthermore, the alkali-soluble binder polymer can be cross-linked as described above 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.

  The mass average molecular weight of the alkali-soluble binder polymer is appropriately determined from the viewpoint of image formability and printing durability. A preferred mass average molecular weight is in the range of 2,000 to 1,000,000, more preferably 5,000 to 500,000, and still more preferably 10,000 to 200,000. Moreover, it is preferable that a number average molecular weight is 1,000 or more, and it is more preferable that it is 2,000-250,000. The polydispersity (mass average molecular weight / number average molecular weight) is preferably 1.1 to 10.

The alkali-soluble binder polymer may be any of a random polymer, a block polymer, a graft polymer, and the like, but is preferably a random polymer.
The alkali-soluble binder polymer may be used alone or in combination of two or more. The content of the alkali-soluble binder polymer is usually 5 to 90% by mass with respect to the total solid content of the image forming layer, It is preferably 10 to 70% by mass, and more preferably 10 to 60% by mass. Within this range, good image area strength and image formability can be obtained.

<Other ingredients>
In the image forming layer of the lithographic printing plate precursor according to the invention, other components suitable for its use, production method and the like can be appropriately added. Hereinafter, preferable additives will be described.

-Co-sensitizer-
The sensitivity can be further improved by using certain additives in the polymerizable composition containing the polymerizable compound, the polymerization initiator, and the binder polymer. Such a compound is hereinafter referred to as a co-sensitizer. These mechanisms of action are not clear, but many are thought to be based on the following chemical processes. That is, the photosensitivity initiated by the thermal polymerization initiator and the subsequent intermediate polymerization species (radicals and cations) generated in the course of the addition polymerization reaction react with the co-sensitizer to generate new active radicals. It is estimated that These are broadly (i) those that can be reduced to produce active radicals, specifically, for example, trihalomethyl-s-triazines, trihalomethyloxadiazoles, hexaarylbiimidazoles, etc. Iron arene complexes, (ii) those that can be oxidized to produce active radicals, specifically, for example, triarylalkyl borates, ethanolamines, N-phenylglycines, N-phenyliminodiacetic acid and its Derivatives, N-trimethylsilylmethylanilines, etc. (iii) those that react with a less active radical and convert to a more active radical or act as a chain transfer agent, specifically, for example, 2-mercaptobenz Although it can be classified into compound groups having SH, PH, SiH, GeH in the molecule such as imidazoles, With respect to the compounds of the people is belongs to any of these, in many cases there is no commonly accepted theory.
These co-sensitizers can be used alone or in combination of two or more. The amount used is 0.05 to 100 parts by weight, preferably 1 to 80 parts by weight, and more preferably 3 to 50 parts by weight with respect to 100 parts by weight of the polymerizable compound.

-Polymerization inhibitor-
Further, in the present invention, a small amount of a thermal polymerization inhibitor is added in order to prevent unnecessary thermal polymerization of the polymerizable compound during the production or storage of the polymerizable composition used for forming the image forming layer. It is desirable. Suitable thermal polymerization inhibitors include hydroquinone, p-methoxyphenol, di-t-butyl-p-cresol, pyrogallol, t-butylcatechol, benzoquinone, 4,4'-thiobis (3-methyl-6-t-butylphenol ), 2,2′-methylenebis (4-methyl-6-tert-butylphenol), N-nitrosophenylhydroxyamine primary cerium salt and the like. The addition amount of the thermal polymerization inhibitor is preferably about 0.01% by mass to about 5% by mass with respect to the mass of the entire composition. In addition, if necessary, a higher fatty acid derivative such as behenic acid or behenic acid amide is added to prevent polymerization inhibition due to oxygen, and a lithographic printing plate precursor is dried after coating on a support or the like. In this process, it may be unevenly distributed on the surface of the image forming layer. The addition amount of the higher fatty acid derivative is preferably about 0.5% by mass to about 10% by mass of the total composition.

-Colorants, etc.-
Further, in the lithographic printing plate precursor according to the invention, a dye or a pigment may be added for the purpose of coloring the image forming layer. Thereby, so-called plate inspection properties such as visibility after plate making and suitability for an image density measuring machine as a printing plate can be improved. As a colorant, many dyes cause a decrease in sensitivity of the photopolymerization type image forming layer. Therefore, as the colorant, it is particularly preferable to use a pigment. Specific examples include pigments such as phthalocyanine pigments, azo pigments, carbon black and titanium oxide, and dyes such as ethyl violet, crystal violet, azo dyes, anthraquinone dyes, and cyanine dyes. The addition amount of the dye and the pigment is preferably about 0.5% by mass to about 5% by mass of the total composition.

-Other additives-
Furthermore, in the lithographic printing plate precursor according to the present invention, an inorganic filler for improving the physical properties of the cured film, a plasticizer, a fat sensitizer that can improve the ink inking property on the surface of the image forming layer, etc. Known additives may be added.

  Examples of the plasticizer include dioctyl phthalate, didodecyl phthalate, triethylene glycol dicaprylate, dimethyl glycol phthalate, tricresyl phosphate, dioctyl adipate, dibutyl sebacate, and triacetyl glycerin, and a binder was used. In this case, 10% by mass or less can be added with respect to the total mass of the compound having an ethylenically unsaturated double bond and the binder.

Further, for the purpose of improving the film strength (printing durability) described later, a UV initiator, a thermal crosslinking agent, or the like can be added to enhance the effect of heating / exposure after development.
In addition, it is possible to provide an additive and an intermediate layer (undercoat layer) for improving the adhesion between the image forming layer and the support and improving the development removability of the unexposed area. For example, by adding or undercoating a compound having a relatively strong interaction with the substrate, such as a compound having a diazonium structure or a phosphone compound, adhesion can be improved and printing durability can be increased. By adding or undercoating a hydrophilic polymer such as acid or polysulfonic acid, the developability of the non-image area is improved, and the stain resistance can be improved.

A lithographic printing plate precursor can be produced by dissolving an image forming layer coating solution or a coating layer component of a desired layer such as a protective layer in a solvent and coating the solution on a suitable support. it can.
Solvents used here include acetone, methyl ethyl ketone, cyclohexane, ethyl acetate, ethylene dichloride, tetrahydrofuran, toluene, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol dimethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, Acetylacetone, cyclohexanone, diacetone alcohol, ethylene glycol monomethyl ether acetate, ethylene glycol ethyl ether acetate, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether acetate, 3-methoxypropanol, methoxymethoxyethanol, diethylene glycol monomethyl ether, Ethylene glycol monoethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, 3-methoxypropyl acetate, N, N-dimethylformamide, dimethyl sulfoxide, γ-butyrolactone, methyl lactate, lactic acid There are ethyl and the like. These solvents can be used alone or in combination. The solid content in the coating solution is suitably 2 to 50% by mass.

The amount of application of the image forming layer to the support is desirably selected as appropriate according to the intended use in consideration of the sensitivity of the image forming layer, the developability, the strength of the exposed film and the printing durability. When the coating amount is too small, the printing durability is not sufficient. On the other hand, if the amount is too large, the sensitivity is lowered, it takes time for exposure, and a longer time is required for development processing, which is not preferable. The coating amount of the lithographic printing plate precursor according to the present invention is generally about 0. 0 by weight after drying. A range of 1 to about 10 g / m ² is suitable. More preferably from 0.5 to 5 g / ^{m 2.}

[Protective layer]
In the lithographic printing plate precursor according to the invention, a protective layer is preferably provided on the image forming layer.
It is desirable that the protective layer does not substantially inhibit transmission of light used for exposure, has excellent adhesion to the image forming layer, and can be easily removed in a development process after exposure. Various devices relating to such a protective layer have been conventionally used, and are described in detail, for example, in US Pat. No. 3,458,311 and JP-A-55-49729. Such a protective layer can also be applied to the lithographic printing plate precursor according to the invention.
In addition, since the lithographic printing plate precursor according to the invention has a polymerization type image forming layer, it is desirable to have an oxygen blocking ability that blocks oxygen in the atmosphere and exhibits a polymerization inhibiting action during exposure. On the other hand, it is also desirable to have an oxygen permeation ability that exhibits an effect of preventing dark polymerization from the viewpoint of stability during storage or suitability for safelight. Is desirable.

-Water-soluble polymer compounds-
As a material used as a main component for the protective layer, it is preferable to use a water-soluble polymer compound having relatively excellent crystallinity. Specifically, polyvinyl alcohol, polyvinyl pyrrolidone, acidic celluloses, gelatin, gum arabic Water-soluble polymers such as polyacrylic acid are well known in the art. Of these, the use of polyvinyl alcohol as the main component gives the best results for basic properties such as oxygen barrier properties and development removability. The polyvinyl alcohol used for the protective layer may be partially substituted with an ester, an ether, and an acetal as long as it contains an unsubstituted vinyl alcohol unit to have the required oxygen barrier properties and water solubility. . Similarly, it may be a copolymer partially having other repeating units.
Specifically, PVA-105, PVA-110, PVA-117, PVA-117H, PVA-120, PVA-124, PVA-124H, PVA-CS, PVA-CST, PVA-HC manufactured by Kuraray Co., Ltd. , PVA-203, PVA-204, PVA-205, PVA-210, PVA-217, PVA-220, PVA-224, PVA-217EE, PVA-217E, PVA-220E, PVA-224E, PVA-405, PVA -420, PVA-613, L-8 and the like. Examples of the copolymer include 88-100% hydrolyzed polyvinyl acetate chloroacetate or propionate, polyvinyl formal, polyvinyl acetal, and copolymers thereof. Other useful water-soluble polymer compounds include polyvinyl pyrrolidone, gelatin and gum arabic, and these may be used alone or in combination.

Examples of the polyvinyl alcohol suitably used in the present embodiment include those having a saponification degree of 71 to 100% and a molecular weight of 200 to 2,400. It is more preferable to use polyvinyl alcohol having a saponification degree of 91 mol% or more from the viewpoint of good oxygen barrier properties, excellent film forming properties and a low adhesion surface.
Specific examples of commercially available polyvinyl alcohol that can be used for the image forming layer include PVA-102, PVA-103, PVA-104, PVA-105, PVA-110, PVA-117, and PVA- manufactured by Kuraray Co., Ltd. 120, PVA-124, PVA-117H, PVA-135H, PVA-HC, PVA-617, PVA-624, PVA-706, PVA-613, PVA-CS, PVA-CST, manufactured by Nippon Synthetic Chemical Industry Co., Ltd. , Gohsenol NL-05, NM-11, NM-14, AL-06, P-610, C-500, A-300, AH-17, JF-04, JF- 05, JF-10, JF-17, JF-17L, JM-05, JM-10, JM-17, JM-17L, JT-05, JT-13, T-15, and the like.

Furthermore, what acid-modified polyvinyl alcohol is also used suitably. Specifically, itaconic acid and maleic acid-modified carboxy-modified polyvinyl alcohol and sulfonic acid-modified polyvinyl alcohol are preferable. These acid-modified polyvinyl alcohols having a saponification degree of 91 mol% or more can be more preferably used.
Specific examples of the acid-modified polyvinyl alcohol include KL-118, KM-618, KM-118, SK-5102, MP-102, R-2105, manufactured by Kuraray Co., Ltd., and Nippon Synthetic Chemical Industry Co., Ltd. , GOHSENAL CKS-50, T-HS-1, T-215, T-350, T-330, T-330H, AF-17, AT-17, etc. manufactured by Nihon Vinegar Poval Co., Ltd., and the like.

The above water-soluble polymer compound is 45 to 95% by mass with respect to the total solid content in the protective layer, considering the sensitivity of the obtained lithographic printing plate precursor and the adhesion between the lithographic printing plate plates when laminated. It is preferable to contain in the range of 50-90 mass%, and it is more preferable to contain.
As the water-soluble polymer compound, at least one kind may be used, and plural kinds may be used in combination. Even when a plurality of types of water-soluble polymer compounds are used in combination, the total amount is preferably in the above-described mass range.

  On the other hand, in the protective layer, the adhesion of the image forming layer to the image portion and the uniformity of the film are also extremely important in handling the plate. That is, when a hydrophilic layer made of a water-soluble polymer is laminated on an oleophilic image forming layer, film peeling due to insufficient adhesion tends to occur, and the peeled part causes defects such as poor film hardening due to inhibition of oxygen polymerization. On the other hand, various proposals have been made to improve the adhesion between these two layers. For example, US Patent Application No. 292,501 and US Patent Application No. 44,563 describe an acrylic emulsion or a water-insoluble vinylpyrrolidone-vinyl 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 of an acetate copolymer and laminating on an image forming layer. Of course, any of these known techniques can be applied.

  Polyvinyl alcohol and polyvinyl pyrrolidone may be used in combination in the protective layer from the viewpoint of adhesive strength with the image forming layer, sensitivity, and the occurrence of unnecessary fog. In this case, the addition ratio (mass ratio) of polyvinyl alcohol / polyvinylpyrrolidone having a saponification degree of 91 mol% or more is preferably 3/1 or less. In addition to polyvinyl pyrrolidone, acidic celluloses, gelatin, gum arabic, polyacrylic acid, and copolymers thereof having relatively excellent crystallinity can be used in combination with polyvinyl alcohol.

-Filler-
In addition to the polymer compound, the protective layer according to the present invention preferably contains a filler. By containing the filler, the scratch resistance of the surface of the image forming layer can be improved. It is suppressed, and the releasability between the lithographic printing plate precursors can be made excellent, so that the handling property is also improved. As such a filler, any of an organic filler, an inorganic filler, an inorganic-organic composite filler, and the like may be used, and two or more of these may be mixed and used. Preferably, an inorganic filler and an organic filler are used in combination.
The shape of the filler is appropriately selected depending on the purpose, but for example, fibrous, needle-like, plate-like, spherical, granular (herein, “granular” refers to “indefinitely shaped particles”, hereinafter, In the present specification, they are used in the same meaning.), Tetrapot shape, balloon shape and the like. Among these, preferred are plate-like, spherical and granular.

  Examples of the organic filler include synthetic resin particles and natural polymer particles, and preferably acrylic resin, polyethylene, polypropylene, polyethylene oxide, polypropylene oxide, polyethyleneimine, polystyrene, polyurethane, polyurea, polyester, polyamide, polyimide, carboxy. Resin particles such as methylcellulose, gelatin, starch, chitin, and chitosan are preferable, and resin particles such as acrylic resin, polyethylene, polypropylene, and polystyrene are more preferable.

  Specific examples of commercially available fillers suitable for the organic filler added to the protective layer include Chemipearl W100, W200, W300, W308, W310, W400, W401, W4005, W410, W500, WF640, manufactured by Mitsui Chemicals, Inc. W700, W800, W900, W950, WP100, manufactured by Soken Chemicals, MX-150, MX-180, MX-300, MX-500, MX-1000, MX-1500H, MX-2000, MR-2HG, MR- 7HG, MR-10HG, MR-3GSN, MR-5GSN, MR-2G, MR-7G, MR-10G, MR-20G, MR-5C, MR-7GC, SX-130H, SX-350H, SX-500H, SGP-50C, SGP-70C, manufactured by Sekisui Plastics Co., Ltd., MBX-5, MBX-8, BX-12, MBX-15, MBX-20, MB20X-5, MB30X-5, MB30X-8, MB30X-20, SBX-6, SBX-8, SBX-12, SBX-17, and the like.

The particle size distribution may be monodisperse or polydisperse, but monodispersion is preferred. The filler preferably has an average particle size of 1 to 20 μm, more preferably an average particle size of 2 to 15 μm, and still more preferably an average particle size of 3 to 10 μm. By making it within these ranges, the effect of the present invention is more effectively expressed.
The content of the organic filler is preferably 0.1 to 20% by mass, more preferably 1 to 15% by mass, and still more preferably 2 to 10% by mass with respect to the total solid content of the protective layer.

  Examples of the inorganic filler include metals and metal compounds such as oxides, composite oxides, hydroxides, carbonates, sulfates, silicates, phosphates, nitrides, carbides, sulfides, and at least two of these. Specific examples include the above composites. Specifically, mica compounds, glass, zinc oxide, alumina, zircon oxide, tin oxide, potassium titanate, strontium titanate, aluminum borate, magnesium oxide, magnesium borate, aluminum hydroxide , Magnesium hydroxide, calcium hydroxide, titanium hydroxide, basic magnesium sulfate, calcium carbonate, magnesium carbonate, calcium sulfate, magnesium sulfate, calcium silicate, magnesium silicate, calcium phosphate, silicon nitride, titanium nitride, aluminum nitride, carbonized Silicon, titanium carbide, zinc sulfide and at least of these It includes species or more composite products, such as.

Preferably, mica compound, glass, alumina, potassium titanate, strontium titanate, aluminum borate, magnesium oxide, calcium carbonate, magnesium carbonate, calcium silicate, magnesium silicate, calcium phosphate, calcium sulfate and the like can be mentioned.
Of these, mica compounds are particularly suitable for the protective layer. The inorganic layered compound represented by this mica will be described in detail below.

-Inorganic layered compounds-
The protective layer preferably contains an inorganic layered compound. By using an inorganic stratiform compound in combination, the oxygen barrier property is further enhanced, and the film strength of the protective layer is further improved to improve scratch resistance, and matte properties can be imparted to the protective layer.
As a result, the protective layer can suppress deterioration due to deformation and generation of scratches in addition to the above-described barrier property against oxygen and the like. Further, by providing matte properties to the protective layer, when the planographic printing plate precursor is laminated, it is possible to suppress adhesion between the protective layer surface of the planographic printing plate precursor and the back surface of the adjacent lithographic printing plate precursor support. It becomes possible.

Examples of the inorganic layered compound include, for example, a general formula: A (B, C) ₂ -5D ₄ O ₁₀ (OH, F, O) ₂ [where A is any of K, Na, Ca, B and C Is one of Fe (II), Fe (III), Mn, Al, Mg, and V, and D is Si or Al. And mica compounds such as natural mica and synthetic mica.

In the mica compound, natural mica includes muscovite, soda mica, phlogopite, biotite and sericite. In addition, examples of the synthetic mica include non-swelling mica such as fluorine phlogopite mica KMg ₃ (AlSi ₃ O ₁₀ ) F ₂ and potash tetrasilicon mica KMg _2.5 (Si ₄ O ₁₀ ) F ₂ , and Na tetrasilic 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 Na or Li Hectorite (Na, Li) _1/8 Examples thereof include swellable mica such as Mg _2/5 Li _1/8 (Si ₄ O ₁₀ ) F ₂ . In addition, synthetic smectites are also useful.

Of the mica compounds, fluorine-based swellable mica is particularly useful. That is, this swellable synthetic mica has a laminated structure composed of unit crystal lattice layers with a thickness of about 10 to 15 mm, and the substitution of metal atoms in the lattice is significantly larger than other viscosity minerals. As a result, the lattice layer is deficient in positive charge, and cations such as Na ⁺ , Ca ²⁺ and Mg ²⁺ are adsorbed between the layers to compensate for this. The cations present between these layers are called exchangeable cations and exchange with various cations. In particular, when the cation between layers is Li ⁺ or Na ⁺ , the bond between the layered crystal lattices is weak because the ionic radius is small, and the layer swells greatly with water. If shear is applied in this state, it will easily cleave and form a stable sol in water. Swellable synthetic mica has a strong tendency and is useful in the present embodiment. In particular, swellable synthetic mica is preferably used.

  The shape of the mica compound is preferably as small as possible from the viewpoint of diffusion control, and the plane size is preferably as long as the smoothness of the coated surface and the transmittance of actinic rays are not impaired. Accordingly, the aspect ratio is 20 or more, preferably 100 or more, particularly preferably 200 or more. The aspect ratio is the ratio of the thickness to the major axis of the particle, and can be measured from, for example, a projected view of the particle by a micrograph. The larger the aspect ratio, the greater the effect that can be obtained.

  The average major axis of the mica compound is 0.3 to 20 μm, preferably 0.5 to 10 μm, and 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. Specifically, for example, the swellable synthetic mica that is a representative compound has a thickness of 1 to 50 nm and a surface size (major axis) of about 1 to 20 μm.

The amount contained in the protective layer of the inorganic stratiform compound is from the viewpoint of suppression of adhesion between lithographic printing plate precursors when they are laminated, suppression of scratches, sensitivity reduction due to blocking during laser exposure, low oxygen permeability, etc. The total solid content of the protective layer is preferably in the range of 5 to 50 mass%, particularly preferably in the range of 10 to 40 mass%. Even when a plurality of kinds of inorganic layered compounds are used in combination, the total amount of these inorganic layered compounds is preferably the above-described mass.
Similarly, the amount contained in the protective layer of the inorganic filler other than the inorganic stratiform compound is preferably in the range of 5 to 50% by mass, and in the range of 10 to 40% by mass with respect to the total solid content of the protective layer. Particularly preferred.

In the protective layer, an organic filler and an inorganic filler can be mixed and used, and the mixing ratio is preferably in a range of 1: 1 to 1: 5 by weight. As content to the protective layer in this case, it is preferable that it is the range of 5-50 mass% by the total amount of an inorganic filler organic filler with respect to the total solid content of a protective layer, and the range of 10-40 mass% is preferable. More preferred.
An inorganic-organic composite filler can also be used. Examples of the inorganic-organic composite filler include composites of the above organic filler and inorganic filler. Examples of the inorganic filler used for the composite include metal powders, metal compounds (for example, oxides, nitrides, sulfides). , Carbides and composites thereof), preferably oxides and sulfides, more preferably glass, SiO ₂ , ZnO, Fe ₂ O ₃ , ZrO ₂ , SnO ₂ , ZnS, CuS. And the like. As content to the protective layer of an inorganic-organic composite filler, it is preferable that it is the range of 5-50 mass% with respect to the total solid content of a protective layer, and the range of 10-40 mass% is more preferable.

Components of the protective layer (selection of polyvinyl alcohol and inorganic layered compounds, use of additives), coating amount, etc. are selected in consideration of fogging, adhesion, and scratch resistance in addition to oxygen barrier properties and development removability The
In the present invention, the protective layer is not limited to a single layer, and a plurality of protective layers having different compositions can be provided in a multilayer structure. As a preferred embodiment of the protective layer having a multilayer structure, a protective layer containing an inorganic stratiform compound is provided as a lower protective layer in the vicinity of the image forming layer, and a protective layer containing a filler on the surface thereof is used as an upper protective layer. The aspect which laminates | stacks sequentially is mentioned.
By providing a protective layer having such a laminated structure, the uppermost protective layer has the excellent oxygen barrier properties and compatibility with the lower protective layer while fully utilizing the advantages of scratch resistance and adhesion resistance due to the filler. Thus, it is possible to effectively prevent image defects due to both the generation of scratches and undesired oxygen permeation.
The protective layer in the present invention preferably has an oxygen permeability at 25 ° C.-1 atm of 0.5 ml / m ² · day to 100 ml / m ² · day, so as to achieve such oxygen permeability. Further, it is preferable to adjust the coating amount.

  The protective layer is added with a colorant (water-soluble dye) that is excellent in the transparency of light used when exposing the image forming layer and that can efficiently absorb light having a wavelength that is not related to exposure. Also good. Thereby, safelight aptitude can be improved, without reducing a sensitivity.

(Formation of protective layer)
The method for applying the protective layer is not particularly limited, and is carried out by applying an aqueous protective layer coating liquid containing the above-described components onto the image forming layer. For example, the method described in US Pat. No. 3,458,311 or JP-A-55-49729 can also be applied.

Hereinafter, a method for applying a protective layer containing an inorganic layered compound such as a mica compound and a water-soluble polymer compound such as polyvinyl alcohol will be described in detail. A dispersion in which an inorganic layered compound such as a mica compound is dispersed is prepared, and the dispersion is mixed with a water-soluble polymer compound such as polyvinyl alcohol (or an aqueous solution in which a water-soluble polymer compound is dissolved). The protective layer is formed by applying the coating liquid for protective layer formed on the image forming layer.
An example of a method for dispersing an inorganic layered compound such as a mica compound used in the protective layer will be described. First, 5 to 10 parts by mass of the swellable mica compound mentioned above as a preferable mica compound is added to 100 parts by mass of water, and the mixture is thoroughly swelled and swollen, and then dispersed by a disperser. Examples of the disperser used here include various mills that disperse mechanically by applying a direct force, a high-speed stirring disperser having a large shearing force, and a disperser that provides high-intensity ultrasonic energy. Specifically, ball mill, sand grinder mill, visco mill, colloid mill, homogenizer, tisol bar, polytron, homomixer, homo blender, ketdy mill, jet agitator, capillary emulsifier, liquid siren, electrostrictive ultrasonic generator, An emulsifying device having a Paulman whistle can be used. In general, a dispersion of 2 to 15% by mass of the mica compound dispersed by the above method is highly viscous or gelled and has very good storage stability. When preparing a coating solution for a protective layer using this dispersion, after diluting with water and stirring sufficiently, a water-soluble polymer compound such as polyvinyl alcohol (or a water-soluble polymer compound such as polyvinyl alcohol) is added. It is preferable to prepare by blending with a dissolved aqueous solution.

  Known additives such as a surfactant for improving the coating property and a water-soluble plasticizer for improving the physical properties of the resulting film can be added to the protective layer coating solution. Examples of the water-soluble plasticizer include propionamide, cyclohexanediol, glycerin, sorbitol and the like. A water-soluble (meth) acrylic polymer can also be added. Furthermore, a known additive for improving the adhesion to the image forming layer and the temporal stability of the coating solution may be added to the coating solution.

The coating amount of the protective layer is 0.1 g / m ² to 4 in terms of maintaining the film strength and scratch resistance of the protective layer to be obtained, maintaining the image quality, and maintaining appropriate oxygen permeability for imparting safelight suitability. 0.0 g / m ² is preferable, and 0.3 g / m ^{2 to} 3.0 g / m ² is more preferable.
There is no particular limitation on the coating method in the case of providing a protective layer having a multilayer structure, and either a method of simultaneous multilayer coating or a method of sequential coating and multilayering can be applied.
When performing multi-layer coating, the coating amount of the upper protective layer containing a lower protective layer and the filler containing an inorganic stratiform compound, the lower protective layer is 0.1g ^/ m ² ~1.5g / m 2 preferably , more preferably ^{0.2g / m 2 ~1.0g / m 2} , the upper protective layer is preferably ^{0.1g / m 2 ~4.0g / m 2} , 0.2g / m 2 ~3.0g / m ² is more preferable. The balance between the two is preferably 1: 1 to 1: 5.

[Plate making method]
Examples of the plate making method using the lithographic printing plate precursor according to the invention include a method in which the lithographic printing plate precursor according to the invention is exposed and then subjected to a development treatment step using an alkaline aqueous solution. Furthermore, in addition to these exposure processing steps and development processing steps, a processing step with a processing solution having a specific pH and any other steps described later may be included.

-Exposure-
The light source used for the exposure process is preferably one that can be exposed at a wavelength of 750 nm to 1400 nm, and an infrared laser is preferable. In particular, in the present invention, image exposure is preferably performed with a solid-state laser and a semiconductor laser that emit infrared rays having a wavelength of 750 nm to 1400 nm. The laser output is preferably 100 mW or more, and a multi-beam laser device is preferably used to shorten the exposure time. The exposure time per pixel is preferably within 20 μsec. The energy applied to the planographic printing plate precursor is preferably 10 to 300 mJ / cm ² . By setting the energy of exposure within the above range, it is possible to prevent the image forming layer from being sufficiently cured, and the image forming layer from being laser ablated to damage the image.

  In the exposure processing in the present invention, exposure can be performed by overlapping light beams of light sources. Overlap means that the sub-scanning pitch width is smaller than the beam diameter. The overlap can be expressed quantitatively by FWHM / sub-scanning pitch width (overlap coefficient), for example, when the beam diameter is expressed by the half width (FWHM) of the beam intensity. In the present invention, the overlap coefficient is preferably 0.1 or more.

  The scanning method of the light source of the exposure apparatus used in the present invention is not particularly limited, and a cylindrical outer surface scanning method, a cylindrical inner surface scanning method, a planar scanning method, or the like can be used. The channel of the light source may be a single channel or a multi-channel, but in the case of a cylindrical outer surface system, a multi-channel is preferably used.

  The exposed lithographic printing plate precursor may be subjected to development processing without performing special heat treatment and water washing treatment. By not performing this heat treatment, image non-uniformity due to the heat treatment can be suppressed. Further, by performing neither heat treatment nor water washing treatment, stable high-speed processing is possible in the development processing.

-Development-
In the development processing, a non-image portion of the image forming layer is removed using a developer.
In the present invention, as described above, the processing speed in the development process, that is, the transport speed (line speed) of the lithographic printing plate precursor in the development process is preferably 1.25 m / min or more, and more preferably. Is 1.35 m / min or more. Moreover, there is no restriction | limiting in particular in the upper limit of a conveyance speed, However, From a viewpoint of the stability of conveyance, it is preferable that it is 3 m / min or less.
The protective layer that may be provided on the surface of the image forming layer opposite to the side adjacent to the intermediate layer preferably contains organic resin fine particles and mica particles as described above. Since the protective layer has good dispersibility of the organic resin fine particles, the protective layer is also excellent in dispersibility of the organic resin fine particles in the developer after the development treatment. Therefore, the developer used in the present invention has good temporal stability.
Hereinafter, the developer used in the present invention will be described.

(Developer)
The developer used in the present invention is preferably an alkaline aqueous solution having a pH of 14 or less, and preferably contains an aromatic anionic surfactant.

[Aromatic anionic surfactant]
The aromatic anionic surfactant used in the developer in the present invention has a development accelerating effect and a dispersion stabilizing effect in the developer of the polymerizable negative type image forming layer component and the protective layer component. Is preferable.
These aromatic anionic surfactants may be used alone or in appropriate combination of two or more. The amount of the aromatic anionic surfactant added is preferably such that the concentration of the aromatic anionic surfactant in the developer is in the range of 1.0 to 10% by mass, more preferably in the range of 2 to 10% by mass. It is effective to do. Here, when the content is 1.0% by mass or more, it is possible to prevent a decrease in developability and a decrease in the solubility of the components of the image forming layer, and when the content is 10% by mass or less, the resistance of the printing plate. A decrease in printability can be suppressed.

In addition to the aromatic anionic surfactant, other surfactants may be used in combination with the developer. Examples of other surfactants include polyoxyethylene naphthyl ether, polyoxyethylene alkylphenyl ether, polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, polyoxyethylene alkyl ethers such as polyoxyethylene stearyl ether, Polyoxyethylene alkyl esters such as oxyethylene stearate, sorbitan monolaurate, sorbitan monostearate, sorbitan distearate, sorbitan monooleate, sorbitan sesquioleate, sorbitan trioleate, sorbitan alkyl esters, glycerol mono Nonionic surfactants such as monoglyceride alkyl esters such as stearate and glycerol monooleate.
The content of these other surfactants in the developer is preferably from 0.1 to 10% by mass in terms of active ingredients.

[Chelating agent for divalent metals]
For example, the developer preferably contains a chelating agent for a divalent metal in order to suppress the influence of calcium ions contained in hard water. Examples of the chelating agent for the divalent metal include Na ₂ P ₂ O ₇ , Na ₅ P ₃ O ₃ , Na ₃ P ₃ O ₉ , Na ₂ O ₄ P (NaO ₃ P) PO ₃ Na ₂ , Calgon (polymetalin). Polyphosphates such as ethylenediaminetetraacetic acid, its potassium salt, its sodium salt, its amine salt; diethylenetriaminepentaacetic acid, its potassium salt, sodium salt; triethylenetetraminehexaacetic acid, its potassium salt, its sodium salt Hydroxyethylethylenediaminetriacetic acid, its potassium salt, its sodium salt; nitrilotriacetic acid, its potassium salt, its sodium salt; 1,2-diaminocyclohexanetetraacetic acid, its potassium salt, its sodium salt; 1,3-diamino-2 -Propanol tetraacetic acid 2-phosphonobutane tricarboxylic acid-1,2,4, potassium salt thereof, sodium salt thereof; 2-phosphonobutanone tricarboxylic acid-2, in addition to aminopolycarboxylic acids such as potassium salt, sodium salt thereof, etc. 3,4, its potassium salt, its sodium salt; 1-phosphonoethanetricarboxylic acid-1,2,2, its potassium salt, its sodium salt; 1-hydroxyethane-1,1-diphosphonic acid, its potassium salt, Examples thereof include organic phosphonic acids such as aminotri (methylenephosphonic acid), potassium salt, sodium salt, etc. Among them, ethylenediaminetetraacetic acid, potassium salt, sodium salt, amine salt; ethylenediamine; Tetra (methylenephosphonic acid), its ammonium salt, its potash Salt; hexamethylenediamine tetra (methylene phosphonic acid), an ammonium salt, its potassium salt is preferred.
The optimum amount of such a chelating agent varies depending on the hardness of the hard water used and the amount used, but is generally 0.01 to 5% by mass, more preferably 0% in the developing solution at the time of use. It is made to contain in 0.01-0.5 mass%.

  In addition, an alkali metal salt of an organic acid or an alkali metal salt of an inorganic acid may be added to the developer as a development regulator. For example, sodium carbonate, potassium, ammonium, sodium citrate, potassium, ammonium and the like may be used alone or in combination of two or more.

[Alkaline agent]
Examples of the alkali agent used in the developer include inorganic substances such as trisodium phosphate, potassium, ammonium, sodium borate, potassium, ammonium, sodium hydroxide, potassium, ammonium, and lithium. Alkaline agents and monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monoisopropylamine, diisopropylamine, triisopropylamine, n-butylamine, monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, diisopropyl Examples include organic alkali agents such as panolamine, ethyleneimine, ethylenediamine, pyridine, and tetramethylammonium hydroxide. In the present invention, these may be used alone or in combination of two or more.

  Moreover, alkali silicate can be mentioned as alkali agents other than the above. Alkali silicates may be used in combination with a base. The alkali silicate to be used exhibits alkalinity when dissolved in water, and examples thereof include sodium silicate, potassium silicate, lithium silicate, and ammonium silicate. These alkali silicates may be used alone or in combination of two or more.

The developer used in the present invention is composed of silicon oxide SiO ₂ which is a silicate component as a hydrophilizing component of a support and alkali oxide M ₂ O as an alkali component (M represents an alkali metal or ammonium group). By adjusting the mixing ratio and concentration, it can be easily adjusted to the optimum range. The mixing ratio (SiO ₂ / M ₂ O molar ratio) of silicon oxide SiO ₂ and alkali oxide M ₂ O is the amount of unstained dirt caused by excessive dissolution (etching) of the anodized film of the support. From the viewpoint of suppressing the generation of insoluble gas due to complex formation between dissolved aluminum and silicate, the range is preferably 0.75 to 4.0, more preferably 0.75 to 3.5. Used in.

In addition, the alkali silicate concentration in the developer includes the effect of inhibiting dissolution (etching) of the anodic oxide film on the support, the developability, the effect of inhibiting precipitation and crystal formation, and the gelation during neutralization during waste From the viewpoint of the prevention effect and the like, the amount of SiO _{2 with} respect to the mass of the developer is 0.01
˜1 mol / L is preferable, and more preferably 0.05 to 0.8 mol / L.

  In addition to the above components, the following components can be used in combination in the developer used in the present invention, if necessary. For example, benzoic acid, phthalic acid, p-ethylbenzoic acid, pn-propylbenzoic acid, p-isopropylbenzoic acid, pn-butylbenzoic acid, pt-butylbenzoic acid, pt-butylbenzoic acid Acids, p-2-hydroxyethylbenzoic acid, decanoic acid, salicylic acid, organic carboxylic acids such as 3-hydroxy-2-naphthoic acid; organic solvents such as propylene glycol; other reducing agents, dyes, pigments, water softeners And preservatives.

  The developer used in the present invention preferably has a pH in the range of 10 to 12.5 at 25 ° C, and more preferably in the range of pH 11 to 12.5. Since the developer in the present invention contains the surfactant, even if such a low pH developer is used, excellent developability is exhibited in the non-image area. Thus, by setting the pH of the developing solution to a relatively low value, damage to the image area during development is reduced and the handling property of the developing solution is excellent.

The conductivity x of the developer is preferably 2 <x <30 mS / cm, more preferably 5 to 25 mS / cm.
Here, it is preferable to add an alkali metal salt of an organic acid, an alkali metal salt of an inorganic acid, or the like as a conductivity adjusting agent for adjusting the conductivity.

  The developer can be used as a developer and a development replenisher for the exposed lithographic printing plate precursor, and is preferably applied to an automatic processor. When developing using an automatic developing machine, the developing solution becomes fatigued according to the amount of processing. Therefore, the processing capability may be restored using a replenishing solution or a fresh developing solution. This replenishment method is also preferably applied to the plate making method of the present invention.

    Further, in order to restore the processing capacity of the developer using an automatic developing machine, it is preferable to replenish by the method described in US Pat. No. 4,882,246. Developers described in JP-A-50-26601, 58-54341, JP-B-56-39464, 56-42860, and 57-7427 are also preferable.

  A more preferred development replenisher used in the present invention contains an oxycarboxylic acid chelating agent having an ability to form a water-soluble chelate compound with aluminum ions, an alkali metal hydroxide, and a surfactant. It is a development replenisher characterized by being an aqueous solution having no pH and a pH of 11 to 13.5. By using such a development replenisher, it has excellent developability and characteristics that do not impair the strength of the image area of the plate material, and is formed by elution of the aluminum support by the alkali of the developer. Precipitation of aluminum is effectively suppressed, adhesion of stains mainly composed of aluminum hydroxide to the surface of the developing bath roller of the automatic processor, and subsequent accumulation of aluminum hydroxide precipitates in the washing bath are reduced. It can be processed stably for a long time.

  The lithographic printing plate precursor thus developed is washed with water as described in JP-A-54-8002, JP-A-55-115045, JP-A-59-58431, and the like. And post-treatment with a desensitizing solution containing a rinsing solution containing a surfactant and the like, gum arabic, starch derivatives and the like. These treatments can be used in various combinations for the post-treatment of the lithographic printing plate precursor according to the invention. The planographic printing plate obtained by such processing is loaded on an offset printing machine and used for printing a large number of sheets.

In the plate-making method using the lithographic printing plate precursor according to the invention, the entire developed image can be post-heated or exposed entirely for the purpose of improving image strength and printing durability.
Very strong conditions can be used for heating after development. Usually, the heating temperature is 200 to 500 ° C. If the heating temperature after development is low, sufficient image strengthening action cannot be obtained, and if it is too high, problems such as deterioration of the support and thermal decomposition of the image area may occur.

The planographic printing plate obtained by the above processing is loaded on an offset printing machine and used for printing a large number of sheets.
As plate cleaners used for removing stains on the plate during printing, conventionally known plate cleaners for PS plates are used, for example, multi cleaner, CL-1, CL-2, CP, CN-4. , CN, CG-1, PC-1, SR, IC (manufactured by FUJIFILM Corporation) and the like.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples unless it exceeds the gist thereof. Unless otherwise specified, “part” is based on mass.

Example 1
<Creation of support A>
In the surface treatment, the following various treatments (a) to (e) were continuously performed. In addition, after each process and water washing, the liquid was drained with the nip roller.

Process (a)
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. Using three bundle-planted nylon brushes and a pumice-water suspension (specific gravity 1.1 g / cm ³ ) having a median diameter of 30 μm, the aluminum surface was grained at a brush rotation speed of 250 rpm, and washed thoroughly with water.

Process (b)
This plate was etched by being immersed in a 25% aqueous sodium hydroxide solution at 45 ° C. for 9 seconds, washed with water, further immersed in 20% nitric acid at 60 ° C. for 20 seconds, and washed with water. At this time, the etching amount of the grained surface was about 3 g / m ² .

Process (c)
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 source waveform is electrochemical roughening treatment using a trapezoidal rectangular wave alternating current with a time ratio TP of 0.8 msec until the current value reaches a peak from zero, a duty ratio of 1: 1, and a trapezoidal rectangular wave alternating current. Went. Ferrite was used for the auxiliary anode. The current density was 30 A / dm ² at the peak current value, and 5% of the current flowing from the power source was shunted to the auxiliary anode. The amount of electricity in nitric acid electrolysis was 175 C / dm ² when the aluminum plate was the anode. Then, water washing by spraying was performed.

Process (d)
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.

Processing (e)
The plate was provided with a direct current anodic oxide coating of 2.5 g / m ² at a current density of 15 A / dm ² using 15% sulfuric acid (containing 0.5 mass% of aluminum ions) as an electrolyte, and then washed with water, dried and supported. Body A. 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.
The support A was prepared as described above.

<Intermediate layer>
Next, the following intermediate layer coating solution was applied to the surface of the aluminum support A with a wire bar and dried at 100 ° C. for 10 seconds to form an intermediate layer. The coating amount was 10 mg / m ² .
-Coating solution for intermediate layer-
Specific polymer compound (P-1 shown in Table 1 below) 0.05 g
・ Methanol 27g
・ Ion exchange water 3g

<Image forming layer>
On the obtained intermediate layer, a coating solution for an image forming layer having the following composition is prepared and applied using a wire bar so that the coating amount after drying is 0.9 g / m ^2. An image forming layer was formed by drying at 115 ° C. for 34 seconds using an apparatus.

-Coating liquid for image forming layer-
・ Infrared absorber (IR-1 below) 0.038g
・ Polymerization initiator A (S-1 below) 0.061g
・ Polymerization initiator B (I-1 below) 0.094g
・ Mercapto compound (SH-1 below) 0.015 g
-Sensitization aid (T-1 below) 0.081g
Addition polymerizable compound (M-1 below) 0.428g
-Binder polymer A (B-1 below) 0.311g
・ Binder polymer B (B-2 below) 0.250g
-Binder polymer C (B-3 below) 0.062g
・ Polymerization inhibitor (Q-1 below) 0.0012g
-Copper phthalocyanine pigment dispersion 0.159g
・ Fluorine surfactant 0.0081g
(Megafac F-780-F Dainippon Ink Chemical Co., Ltd.,
Methyl isobutyl ketone (MIBK) 30% by mass solution)
・ Methyl ethyl ketone 5.886g
・ Methanol 2.733g
・ 1-methoxy-2-propanol 5.886 g

<Protective layer>
(Formation of lower protective layer)
On the surface of the image forming layer obtained as described above, synthetic mica (Somasif MEB-3L, 3.2% aqueous dispersion, manufactured by Coop Chemical Co., Ltd.), polyvinyl alcohol (Goselan CKS-50: degree of saponification 99) Mol%, degree of polymerization 300, sulfonic acid-modified polyvinyl alcohol Nippon Synthetic Chemical Industry Co., Ltd.) Surfactant A (Nihon Emulsion Co., Emalex 710) and Surfactant B (Adeka Pluronic P-84: Asahi Denka Kogyo Co., Ltd.) A mixed aqueous solution (manufactured by the company) was applied with a wire bar and dried at 125 ° C. for 30 seconds using a hot air dryer.
The content ratio of synthetic mica (solid content) / polyvinyl alcohol / surfactant A / surfactant B in the mixed aqueous solution (coating liquid for protective layer) was 7.5 / 89/2 / 1.5 (mass). The coating amount (the coating amount after drying) was 0.5 g / m ² .

(Formation of upper protective layer)
On the surface of the lower protective layer, an organic filler (Art Pearl J-7P, manufactured by Negami Industrial Co., Ltd.), synthetic mica (Somasif MEB-3L, 3.2% aqueous dispersion, manufactured by Coop Chemical Co., Ltd.), polyvinyl alcohol ( L-3266: Saponification degree 87 mol%, polymerization degree 300, sulfonic acid-modified polyvinyl alcohol, manufactured by Nippon Synthetic Chemical Industry Co., Ltd., thickener (Serogen FS-B, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), polymer A mixed aqueous solution (coating solution for protective layer) of Compound A (structure shown below) and a surfactant (manufactured by Nippon Emulsion Co., Ltd., Emalex 710) is applied with a wire bar, and heated at 125 ° C. for 30 seconds with a hot air dryer. Dried.
The content ratio of the organic filler / synthetic mica (solid content) / polyvinyl alcohol / thickener / polymer compound A / surfactant in the mixed aqueous solution (protective layer coating solution) is 4.7 / 2.8. /67.4/18.6/2.3/4.2 (mass%), and the coating amount (the coating amount after drying) was 1.8 g / m ² .
Thus, the planographic printing plate precursor of Example 1 was produced.

(Examples 2 to 4)
During the production process of the lithographic printing plate precursor of Example 1, the polymer compound (P-1) in the coating solution component for the intermediate layer was changed to the polymer compounds shown in Table 2 below (respectively P-2 to P-4). The lithographic printing plate precursors of Examples 2 to 4 were obtained in the same manner as Example 1. The details of the polymer compounds P-2 to P-4 are as shown in Table 1 below.

(Example 5)
The lithographic printing of Example 5 was carried out in the same manner as in Example 1 except that the brush rotation speed was changed to 190 rpm in the process (a) for producing the support A during the production process of the lithographic printing plate precursor of Example 1. I got the original version. The support thus obtained is referred to as support B. When the center line average roughness (Ra) of this substrate was measured using a needle having a diameter of 2 μm, it was 0.40 μm.

(Example 6)
The lithographic printing of Example 6 was carried out in the same manner as in Example 1 except that the brush rotation speed was changed to 310 rpm in the process (a) for producing the support A during the production process of the lithographic printing plate precursor of Example 1. I got the original version. The support thus obtained is referred to as support C. The centerline average roughness (Ra) of this substrate was measured using a needle having a diameter of 2 μm and found to be 0.60 μm.

(Example 7)
In the production process of the lithographic printing plate precursor of Example 1, the lithographic plate of Example 7 is the same as Example 1 except that the frequency of the alternating voltage is changed to 30 Hz in the process (d) for producing the support A. A printing plate master was obtained. The support thus obtained is referred to as support D.

(Example 8)
During the production process of the lithographic printing plate precursor according to Example 1, the current density was changed to 15 A / dm ² at the peak current value in the process (c) for producing the support A. A lithographic printing plate precursor of Example 8 was obtained. The support thus obtained is referred to as support E.

Example 9
Except that the polymer compound (P-1) in the coating solution component for the intermediate layer was changed to the polymer compound (P-5) shown in Table 2 below during the production process of the planographic printing plate precursor of Example 1, this was carried out. In the same manner as in Example 1, a lithographic printing plate precursor of Example 9 was obtained. Details of the polymer compound P-5 are as shown in Table 1 below.

(Comparative Examples 1-2)
Example 1 except that the specific polymer compound used in the intermediate layer of Example 1 was changed to the following comparative polymer compound P-6 (molecular weight 20,000) and P-7 described in Table 1 below. Similarly, lithographic printing plate precursors of Comparative Example 1 and Comparative Example 2 were obtained.

(Comparative Example 3)
The lithographic plate of Comparative Example 3 was prepared in the same manner as in Example 1 except that the frequency of the alternating voltage was changed to 10 Hz in the process (d) for producing the support A during the production process of the lithographic printing plate precursor of Example 1. A printing plate master was obtained. The support thus obtained is referred to as support F.

(Comparative Example 4)
The lithographic plate of Comparative Example 4 was prepared in the same manner as in Example 1 except that the frequency of the alternating voltage was changed to 15 Hz in the process (c) for producing the support A during the production process of the lithographic printing plate precursor of Example 1. A printing plate master was obtained. The support thus obtained is referred to as support G.

(Comparative Example 5)
During the manufacturing process of the planographic printing plate precursor of Example 1, the same procedure as in Example 1 was performed except that the temperature of the electrolytic solution was set to 80 ° C. and TP was set to 0 msec in the process (c) for preparing the support A. Thus, a planographic printing plate precursor of Comparative Example 5 was obtained. The support thus obtained is referred to as support H.

(Comparative Example 6)
A lithographic printing plate precursor of Comparative Example 6 was obtained in the same manner as in Example 1 except that the processing (d) for producing the support A was not performed during the production process of the lithographic printing plate precursor of Example 1. The support thus obtained is referred to as support I.

(Comparative Example 7)
A lithographic printing plate precursor of Comparative Example 3 was obtained in the same manner as in Example 1 except that the support A in Example 1 was changed to the following support J.

<Creation of support J>
In the surface treatment, the following treatments (f) to (k) were continuously performed. In addition, after each process and water washing, the liquid was drained with the nip roller.

Process (f)
The aluminum plate was etched at a caustic soda concentration of 26 mass%, an aluminum ion concentration of 6.5 mass%, and a temperature of 70 ° C. to dissolve the aluminum plate at 5 g / m ² . Thereafter, it was washed with water.

Processing (g)
A desmut treatment was performed by spraying with a 1% by mass aqueous solution of nitric acid at a temperature of 30 ° C. (including 0.5% by mass of aluminum ions), and then washed with water.

Processing (h)
An electrochemical surface roughening treatment was continuously performed using an alternating voltage of 60 Hz. The electrolytic solution at this time was a 1% by mass aqueous nitric acid solution (including 0.5% by mass aluminum ions and 0.007% by mass ammonium ions) at a temperature of 30 ° C. The AC power source was subjected to electrochemical surface roughening using a carbon electrode as a counter electrode, using a trapezoidal rectangular wave alternating current with a time TP of 2 msec until the current value reaches a peak from zero, a duty ratio of 1: 1. Ferrite was used for the auxiliary anode. The current density was 25 A / dm ² at the current peak value, and the amount of electricity was 250 C / cm ² in terms of the total amount of electricity when the aluminum plate was the anode. 5% of the current flowing from the power source was shunted to the auxiliary anode. Thereafter, it was washed with water.

Process (i)
The aluminum plate was sprayed at 35 ° C. with a caustic soda concentration of 26% by mass and an aluminum ion concentration of 6.5% by mass, the aluminum plate was dissolved at 0.2 g / m ² , and was electrochemically converted using the previous alternating current. The removal of the smut component mainly composed of aluminum hydroxide generated when roughening was performed, and the edge portion of the generated pit was dissolved to smooth the edge portion. Thereafter, it was washed with water.

Processing (j)
The desmutting treatment was performed by spraying with a 25% by weight aqueous solution of sulfuric acid having a temperature of 60 ° C. (containing 0.5% by weight of aluminum ions), followed by washing with water by spraying.

Processing (k)
Anodization was performed for 50 seconds at a sulfuric acid concentration of 170 g / liter (containing 0.5 mass% of aluminum ions), a temperature of 33 ° C., and a current density of 5 A / dm ² . Thereafter, it was washed with water. At this time, the weight of the anodized film was 2.7 g / m ² .
The centerline average roughness (Ra) of this substrate was measured using a needle having a diameter of 2 μm and found to be 0.27 μm.

-Measurement of surface shape of lithographic printing plate support-
The following measurements were performed on the concave portions on the surface of the lithographic printing plate support obtained above. The results are shown in Table 2. In Table 2, “-” indicates that there was no concave portion of the corresponding wavelength.

(1) Average opening diameter of medium wave structure The surface of the support was photographed at a magnification of 2,000 times from directly above using an SEM. 50 pits (medium wave pits) were extracted, and the diameter was read to obtain the opening diameter, and the average opening diameter was calculated.

(2) Average aperture diameter of the small wave structure The surface of the support was photographed at a magnification of 50,000 times from directly above using a high resolution SEM, and 50 small wave structure pits (small wave pits) were extracted from the obtained SEM photograph. Then, the diameter was read to obtain the opening diameter, and the average opening diameter was calculated.

-Evaluation of planographic printing plates-
(1) Raw storage stability evaluation (time stability evaluation)
The unexposed lithographic printing plate precursor is packed in aluminum craft at 25 ° C. and 50% RH, and the package is stored at 60 ° C. for 2 days, then exposed and developed by the following method, and the non-image area density is reflected by Macbeth reflection. Densitometer RD-918 was used for measurement. The lithographic printing plate precursor immediately after production was also exposed and developed in the same manner, and the non-image area density was measured. In this example, the difference Δ between the non-image area densities was obtained and used as an index of raw preservation. The smaller the value of Δ, the better the raw preservation, and 0.02 or less is a level that causes no practical problem. The results are shown in Table 2.

(2) Printing durability evaluation and dirt evaluation An 80% flat screen image with a resolution of 175 lpi was output to the produced lithographic printing plate precursor using a water-cooled 40 W infrared semiconductor laser and a resolution of 175 lpi 80% flat screen image. The exposure was performed at a rotation speed of 206 rpm and a plate surface energy of 100 mJ / cm ² . After the exposure, the protective layer was removed by rinsing with tap water, and then developed by the same method as in (1) Sensitivity evaluation development step. The resulting lithographic printing plate is printed using a printing press Lislon manufactured by Komori Corporation, and the printed matter in the solid image portion is observed. It was used as an index. The printing smearing property was evaluated on a five-point scale by visually checking the ink smear of the non-image area after printing 1,000 sheets and printing again after 1 hour. Larger numbers indicate better soil resistance. An evaluation of 4 or more is a practical level, and an evaluation of 3 is an allowable lower limit. The results are shown in Table 2.

The printed matter in the solid image area was observed, and the printing durability of the image area was examined based on the number of images where the image started to fade. Larger numbers indicate better printing durability.

As is apparent from Table 2, the support for the planographic printing plate and the specific polymer compound of the present invention having a grained shape with a structure in which a medium wave structure of a specific wavelength and a small wave structure of a specific wavelength are superimposed are used. The lithographic printing plate precursors (Examples 1 to 9) of the present invention are excellent in both stain resistance and printing durability when used as lithographic printing plates.
In addition, it can be seen that the polymer compound used in the intermediate layer has better resistance to printing stains after aging when it contains a neutralized acid group.
On the other hand, when the polymer compound used for the intermediate layer does not contain a carboxyl group in the side chain (Comparative Example 1) or when the side chain does not contain a carboxylic ester group (Comparative Example 2), Example 1 It is inferior in raw storability, dirtiness and printing durability than the lithographic printing plate precursors No. Moreover, when the average opening diameter of a small wave is too large (comparative example 3), it is inferior to raw storability and dirtiness compared with the lithographic printing plate precursor of Examples 1-9, and the average opening diameter of a medium wave is too large or small. When it is too much (Comparative Examples 4 and 5), it is inferior to the lithographic printing plate precursors of Examples 1 to 9 in terms of raw storage, soiling and printing durability, and has no wavelet pits (Comparative Examples 6 and 7). ) Is inferior in printing durability to the planographic printing plate precursors of Examples 1 to 9.

It is a graph which shows an example of the alternating waveform current waveform figure used for the electrochemical roughening process in preparation of the support body for lithographic printing plates which concerns on this invention. It is a side view which shows an example of the radial type cell in the electrochemical roughening process using alternating current in preparation of the support body for lithographic printing plates which concerns on this invention. It is the schematic of the anodizing apparatus used for the anodizing process in preparation of the support body for lithographic printing plates which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Aluminum plate 12 Radial drum roller 13a, 13b Main electrode 14 Electrolytic process liquid 15 Electrolyte supply port 16 Slit 17 Electrolyte passage 18 Auxiliary anode 19a, 19b Thyristor 20 AC power supply 21 Main electrolytic cell 22 Auxiliary anode tank 410 Anodizing apparatus 412 Feed tank 414 Electrolytic treatment tank 416 Aluminum plate 418, 426 Electrolyte 420 Feed electrode 422, 428 Roller 424 Nip roller 430 Electrode electrode 432 Tank wall 434 DC power supply

Claims (3)

  On a support having a grain-like shape with a structure in which a medium wave structure having an average opening diameter of 0.5 to 5 μm and a small wave structure having an average opening diameter of 0.01 to 0.2 μm are superimposed on the surface, carboxyl groups and A lithographic printing plate precursor comprising: an intermediate layer containing a polymer compound having a carboxylic acid ester group; and an image forming layer containing a polymerization initiator, a polymerizable compound, and a binder polymer, which are sequentially laminated. .   2. The lithographic printing plate precursor according to claim 1, wherein a part or all of the carboxyl groups of the polymer compound having a carboxyl group and a carboxylic ester group in the side chain are neutralized.   The support is supported using an alternating current in an aqueous solution containing nitric acid, and a first electrochemical surface roughening treatment for roughening the surface of the support using an alternating current in an aqueous solution containing nitric acid, and an aqueous solution containing hydrochloric acid. 2. The lithographic printing plate precursor as claimed in claim 1, wherein the lithographic printing plate precursor is obtained by performing a second electrochemical roughening treatment for roughening the surface of the body in this order.

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