JP2006251656A - Planographic printing original plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a planographic printing original plate having a negative image recording layer by use of a laser, without causing production of aluminum chips during development, having no contamination on an edge even when a slip sheet is not used, and having favorable plate wear. <P>SOLUTION: The planographic printing original plate comprises an image recording layer containing a polymerization initiator, a polymerizable compound and a binder polymer and a protective layer containing an inorganic layered compound, layered in this order on a supporting body for a planographic printing plate made of an aluminum plate having 1.0 to 8 mg/m<SP>2</SP>Si content on the surface,. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a lithographic printing plate precursor.

The development of lasers in recent years has been remarkable, and in particular, solid-state lasers, semiconductor lasers, gas lasers, and the like that emit ultraviolet light, visible light, or infrared light having a wavelength of 300 to 1200 nm can be easily obtained with small outputs. It has become. These lasers are extremely useful as recording light sources when directly making a plate from digital data such as a computer in lithographic printing.
Conventionally, various studies have been made on recording materials that can use these various lasers. For example, a positive recording material (for example, see Patent Document 1) compatible with an infrared laser having a photosensitive wavelength of 760 nm or more and an acid catalyst cross-linking negative recording material (for example, see Patent Document 2) are known. Further, radical polymerization type negative recording materials (for example, see Patent Documents 3 and 4) compatible with ultraviolet light or visible light laser having a wavelength of 300 to 700 nm are also known.

  Usually, an image recording layer comprising such a negative image recording material is composed of a compound that generates radicals by light or heat (hereinafter also referred to as “radical initiator”) and a compound having an ethylenically unsaturated bond (hereinafter referred to as “radical initiator”). The polymerization reaction of the polymerizable compound occurs using a radical generated by light or heat as an initiator, and the exposed portion of the image recording layer is cured to form an image portion. .

U.S. Pat. No. 4,708,925 JP-A-8-276558 U.S. Pat. No. 2,850,445 Japanese Patent Publication No. 44-20189

  However, as a result of intensive studies on the negative type image recording layer using these lasers by the present inventors, it has been found that there is a problem that aluminum is eluted from the support during development, and aluminum residue is generated in the developer. It was. This aluminum residue adheres to the non-image area of the planographic printing plate and causes stains.

Also, usually, an interleaf is inserted between the original and the original in order to prevent adhesion between the originals, but it is necessary to remove the interleaf in the exposure process, so that the time efficiency is poor. However, there are problems such as high costs, troubles at the time of removal, and the removal of the interleaving paper as industrial waste.
On the other hand, as a result of the inventors' research, by providing a specific protective layer on the outermost surface of the lithographic printing plate precursor on the image recording layer side, adhesion between the original plates can be achieved without using interleaf paper. It was found that it can be prevented.
However, even when such a protective layer is provided, there is a problem that a portion corresponding to an edge of a lithographic printing plate of a printed matter is stained at the time of printing unless a slip sheet is used. Hereinafter, in this specification, the dirt corresponding to the edge is simply referred to as “edge dirt”.

  On the other hand, in Japanese Patent Application Laid-Open No. 2004-219806, “in a photosensitive lithographic printing plate having a photopolymerizable photosensitive layer, the contact angle to water on the surface of the support before coating the photopolymerizable photosensitive layer is 30 °. The photosensitive lithographic printing plate (Claim 1) characterized in that the temperature is not less than 70 ° and the support is treated with a sodium silicate solution having a temperature of 20 ° C. or more and 50 ° C. or less after the anodizing treatment. The photosensitive lithographic printing plate according to claim 1 (claim 3) is described. However, the present inventor examined the photosensitive lithographic printing plate described in this publication, and the lithographic printing plate (aspect of claim 3) was subjected to a so-called silicate treatment with a sodium silicate solution. Further, there was a problem that the generation of aluminum residue and edge contamination could not be sufficiently suppressed and the printing durability was inferior.

  Therefore, the present invention is a negative type image recording using a laser that does not generate aluminum residue during development, does not cause edge smearing even if no interleaf is used, and has good printing durability. An object is to provide a lithographic printing plate precursor having a layer.

  As a result of diligent research to achieve the above object, the present inventor can prevent the generation of aluminum residue and edge contamination during development by setting the amount of Si on the support surface to a specific amount, and It has been found that by containing a specific inorganic compound in the protective layer, it is possible to prevent a decrease in printing durability due to Si on the surface of the support, and the present invention has been completed.

That is, the present invention provides the following (1) to (4).
(1) An image recording layer containing a polymerization initiator, a polymerizable compound, and a binder polymer on a lithographic printing plate support comprising an aluminum plate having a surface Si amount of 1.0 to 8 mg / m ² ; A lithographic printing plate precursor comprising a protective layer containing an inorganic layered compound in this order.
(2) The lithographic printing plate support has a grain-like 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. The lithographic printing plate precursor as described in (1) above.
(3) The lithographic printing plate precursor as described in (2) above, wherein the grain shape is a structure in which a large wave structure formed by mechanical roughening treatment, the medium wave structure, and the small wave structure are superimposed. .
(4) The lithographic printing plate precursor as described in (3) above, wherein the average wavelength of the large wave structure is 5 to 100 μm.

  As shown below, according to the present invention, a lithographic printing plate precursor having a negative type image recording layer using a laser is free from the generation of aluminum residue during development and does not use interleaving paper. However, it is possible to provide a lithographic printing plate precursor that does not cause edge stains and has good printing durability.

Hereinafter, the present invention will be described in detail.
[Support for lithographic printing plate]
<Surface treatment>
The lithographic printing plate support used in the lithographic printing plate precursor according to the invention is a lithographic printing plate support comprising an aluminum plate having a surface Si content of 1.0 to 8 mg / m ² .
The manufacturing process of this support is not particularly limited, and may include various processes.

Specifically, for example, an aluminum plate is subjected to an alkali etching treatment, a desmut treatment in an acidic aqueous solution, an electrochemical surface roughening treatment with an electrolytic solution containing nitric acid (hereinafter also referred to as “nitric acid electrolysis”), and alkali etching. Treatment, desmutting treatment in acidic aqueous solution, electrochemical surface roughening treatment with electrolyte containing hydrochloric acid (hereinafter also referred to as “hydrochloric acid electrolysis”), alkali etching treatment, desmutting treatment in acidic aqueous solution, anodizing treatment And a method of performing the alkali metal silicate treatment in this order is preferable.
Further, a method of performing a sealing treatment after the anodizing treatment and before the alkali metal silicate treatment is also preferable.
Further, a mechanical surface roughening treatment can be performed before the first alkali etching treatment. Thereby, the quantity of electricity used for nitric acid electrolysis can be reduced.
Hereinafter, each step of the surface treatment will be described in detail.

<Mechanical roughening>
Since the mechanical surface roughening treatment can form a surface with irregularities (large wave structure) having an average wavelength of 5 to 100 μm at a lower cost than the electrochemical surface roughening treatment, it is preferably roughened. It is effective as a processing means.
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, transfer is performed several times. The method described in JP-A-6-24168 and JP-A-6-24168 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, etc. may be used. it can. 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-like brush in which a large number of brushes such as synthetic resin bristles made of synthetic resin such as nylon, propylene, and vinyl chloride resin are planted 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 the 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 using a roller-like brush, the flexural modulus is preferably 10,000 to 40,000 kgf / cm ² , more preferably 15,000 to 35,000 kgf / cm ² , and the bristle strength is preferably Brush hair of 500 gf or less, more preferably 400 gf 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 treatment>
The electrochemical graining treatment (hereinafter also referred to as “electrolytic graining treatment”) is, for example, an electrochemical grain described in Japanese Patent Publication No. 48-28123 and British Patent No. 896,563. Method (electrolytic grain method). 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-60-190392, JP-A-58-120531, JP-A-63-176187, JP-A-1-5889, JP-A-1-280590, JP-A-1-118489, JP-A-1-148592, and JP-A-1-17896. JP-A-1-188315, JP-A-1-1549797, JP-A-2-235794, JP-A-3-260100, JP-A-3-253600, JP-A-4-72079, JP-A-4-72098, The methods described in JP-A-3-267400 and JP-A-1-141094 can also 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. U.S. Pat. No. 4,023,637, JP-A-56-123400, JP-A-57-59770, JP-A-53-12738, JP-A-53. -32821, JP-A 53-32822, JP-A 53-32823, JP-A 55-122896, JP-A 55-13284, JP-A 62-127500, JP-A-1-52100 JP-A-1-52098, JP-A-60-67700, JP-A-1-230800, JP-A-3-257199 and the like can be used.
Also, JP-A-52-58602, JP-A-52-152302, JP-A-53-12738, JP-A-53-12739, JP-A-53-32821, JP-A-53-32822, JP 53-32833, JP 53-32824, JP 53-32825, JP 54-85802, JP 55-122896, JP 55-13284, JP 48-28123, JP-B-51-7081, JP-A-52-13338, JP-A-52-133840, JP-A-52-133844, JP-A-52-133845, JP-A-53- Nos. 149135 and 54-146234 can be used.

  As an acidic solution which is an electrolytic solution, in addition to nitric acid and hydrochloric acid, 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, 4,416,972, 4,374,710, The electrolyte solution described in each specification of 4,336,113 and 4,184,932 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.

  As an electrolytic solution containing nitric acid and an electrolytic solution containing hydrochloric acid, a nitric acid compound or aluminum chloride having nitrate ions such as aluminum nitrate, sodium nitrate, ammonium nitrate in an aqueous solution of nitric acid or hydrochloric acid having a concentration of 1 to 100 g / L, At least one hydrochloric acid compound having a chloride ion such as sodium chloride or ammonium chloride 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 electrolyte solution. It is preferable to use a solution obtained by adding aluminum nitrate or aluminum chloride to an aqueous solution of nitric acid or hydrochloric acid having a concentration of 0.5 to 2% by mass so that aluminum ions are 3 to 50 g / L.

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), etc. 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 0.3 to 3 msec. If it is 0.3 msec or more, processing irregularities such as chatter marks that occur perpendicular to the traveling direction of the aluminum plate are less likely to occur. When the TP is 3 msec or less, even in nitric acid electrolysis, it is difficult to be affected by trace components in the electrolyte represented by ammonium ions and the like that spontaneously increase by electrolytic treatment, and uniform graining is easily performed. Become. As a result, the stain resistance tends to be improved when a lithographic printing plate is obtained.

A trapezoidal wave alternating current duty ratio 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 ratio of 1: 1 is preferable.
A trapezoidal AC frequency of 0.1 to 120 Hz can be used, but 50 to 70 Hz is preferable in terms of equipment. If it is lower than 50 Hz, the carbon electrode of the main electrode is likely to be dissolved, and if it is higher than 70 Hz, it is likely to be affected by the 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. 3, the current ratio between the AC anode and cathode 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. 3, 11 is an aluminum plate, 12 is a radial drum roller, 13a and 13b are main poles, 14 is an electrolytic treatment liquid, 15 is an electrolytic solution 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, 40 is a main electrolytic cell, and 50 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 containing nitric acid. However, when the amount of electricity is relatively large, the electrolytic reaction is concentrated, and honeycomb pits exceeding 5 μm can be generated.
In order to obtain such a grain, the total amount of electricity involved in the anode reaction of the aluminum plate at the time when the electrolytic reaction is completed is preferably 1 to 1,000 C / dm ² , and preferably 50 to 300 C / more preferably in the range of dm ^2. The current density at this time is preferably ²⁰ to 100 A / dm ² .

(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. These 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 the present invention, as the first electrolytic surface roughening treatment, the electrolytic surface roughening treatment (nitric acid electrolysis) using the above-described electrolytic solution containing nitric acid is performed, and the second electrolytic surface roughening treatment is described above. Electrolytic surface roughening treatment (hydrochloric acid electrolysis) using an electrolytic solution containing hydrochloric acid is preferably performed.

It is one of the preferred embodiments that the cathode electrolytic treatment is performed on the aluminum plate during the first and second electrolytic surface roughening treatments performed in the 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 . 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 that is performed before electrolytic surface roughening removes rolling oil, dirt, natural oxide film, etc. on the surface of the aluminum plate (rolled aluminum) when mechanical surface roughening 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. When the etching amount is 0.1 g / m ² or more, the rolling oil, dirt, natural oxide film, etc. on the surface do not remain, and uniform pits can be generated in the subsequent electrolytic surface-roughening treatment, and unevenness does not occur. . If the etching amount is too large, it will be economically disadvantageous.

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. When the etching amount is 3 g / m ² or more, uneven unevenness formed by mechanical surface roughening or the like can be smoothed, and uniform pits can be formed in the subsequent electrolytic surface roughening treatment. Can do. Also, the stain resistance is excellent. When the etching amount is 20 g / m ² or less, the concavo-convex structure formed by the mechanical surface roughening treatment does not disappear.

  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. .

It is preferable that the etching amount of the alkali etching process performed after nitric acid electrolysis is 0.1 to 5 g / m ² .

Etching amount of the alkali etching treatment performed after the hydrochloric acid electrolysis is preferably less than 0.1 g / m ^2, and more preferably 0.03~0.08g / m ^2. Within the above range, the shape of the small wave structure formed by hydrochloric acid electrolysis can be effectively utilized.

  The alkali etching treatment performed after the hydrochloric acid electrolysis dissolves the edge portions of the pits of the small wave structure formed by the hydrochloric acid electrolysis, thereby preventing the ink from being caught during printing and improving the stain resistance.

  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 the alkali metal salt include alkali metal silicates such as sodium metasilicate, 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 in which the aluminum plate is passed through a tank containing the alkaline solution, a method in which the aluminum plate is immersed in a tank containing the alkaline solution, The method of spraying on the surface of a board is mentioned.

<Desmut treatment>
After the electrolytic surface roughening treatment or the alkali etching treatment, pickling (desmut treatment) is preferably performed in order 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 contains an electrolytic solution containing nitric acid or an electrolytic solution containing hydrochloric acid discharged in the electrolytic surface-roughening treatment described above, or sulfuric acid discharged in an anodic oxidation treatment described later. It is possible to use an aqueous solution waste 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 preferably further subjected to an 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 aluminum plate can be energized as an anode to form an anodized film. 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; Cations such as ammonium ions; anions such as nitrate ions, carbonate ions, chloride ions, phosphate ions, fluoride ions, sulfite ions, titanate ions, silicate ions, borate ions, etc. May be contained at a concentration of about 1,000 ppm.

The conditions for anodizing treatment vary depending on the electrolyte used, and thus cannot be determined unconditionally. In general, however, 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.

  Further, 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-60-200366, JP-A-62-136696, JP-A-63-176494, JP-A-4-17697, JP-A-4-280997, JP-A-6-280997 The methods described in JP-A-207299, JP-A-5-24377, JP-A-5-32083, JP-A-5-125597, JP-A-5-195291 and the like 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 where continuous anodizing treatment is performed, 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 anodic oxidation treatment proceeds with the current flowing at the density.
When the anodizing process is continuously performed, it is preferable to perform the liquid feeding method in which the aluminum plate is fed with an electrolyte.
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 less than 1 g / m ² , the plate is likely to be scratched. On the other hand, if it exceeds 5 g / m ² , a large amount of electric power is required for production, which is economically disadvantageous. 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, and the like can be used.
Among these, the apparatus shown in FIG. 4 is preferably used. FIG. 4 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 transported as indicated by 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 transported upward by the roller 422 in the power supply tank 412, and the direction is changed downward by the nip roller 424, and then transported 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. 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.

  A feature of the anodizing apparatus 410 in FIG. 4 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, even if the sealing treatment is carried out by the apparatus and method described in JP-B-56-12518, JP-A-4-4194, JP-A-5-20296, JP-A-5-179482, etc. Good.

<Alkali metal silicate treatment>
After the anodizing treatment, an alkali metal silicate treatment is preferably performed. By performing the alkali metal silicate treatment, a silicate having a predetermined amount of Si can be easily present on the surface of the lithographic printing plate support.
The alkali metal silicate treatment is performed by bringing an aqueous solution of alkali metal silicate into contact with the surface of the aluminum plate. Specifically, a method of immersing an aluminum plate in an aqueous solution of an alkali metal silicate such as sodium silicate or potassium silicate is preferable.

The alkali metal silicate treatment can be performed according to the methods and procedures described in US Pat. No. 2,714,066 and US Pat. No. 3,181,461.
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.

In the present invention, Si content of the surface of the lithographic printing plate support is a 1.0~8mg / m ^2, preferably from 1.5 to 5 mg / m ^2.
When the Si amount is 1.0 mg / m ² or more, there is no generation of aluminum residue during development, and contamination due to residue is suppressed. This is because silicate is present on the surface of the support, so that there are few exposed portions on the surface of the anodized film made of aluminum oxide, and dissolution of aluminum oxide by the alkaline developer is suppressed, while silicate This is because the alkali solubility is lower than that of aluminum oxide, and is less affected by residue generated from the silicate.
Further, when the Si amount is 1.0 mg / m ² or more, edge smear does not occur even if no slip sheet is used. As a result of studying the cause of the occurrence of edge contamination, the present inventor found that when the planographic printing plate precursor was cut without using the slip sheet, the edge of the end face became extremely sharp compared to when the slip sheet was used, and the vicinity of the edge It was found that ink easily adheres to the surface. Further, the present inventor has found that when the Si amount is 1.0 mg / m ² or more, the hydrophilicity is increased, so that even if the vicinity of the edge is a non-image portion, the ink is easily removed. The present inventor has completed the present invention based on these findings.
When the Si amount is 8 mg / m ² or less, the printing durability is excellent due to a synergistic effect with a protective layer containing a specific inorganic compound described later.

<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.

<Surface grain shape>
The support for a lithographic printing plate used in the lithographic printing plate precursor according to the present invention has 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. It is preferable to have a grain shape on the surface.
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 recording layer mainly by an anchor (throwing) effect and imparting printing durability. When the average opening diameter of the pits having the medium wave structure is 0.5 μm or more, the adhesiveness with the image recording layer provided on the upper layer is excellent, and the printing durability of the lithographic printing plate is excellent. Further, when the average opening diameter of the pits having the medium wave structure is 5 μm or less, the number of pit boundary portions serving as anchors is sufficiently increased, so that the printing durability is excellent.

  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 can be obtained in forming a water film. Further, when the average opening diameter of the pits having the small wave structure is 0.2 μm or less, the medium wave structure is not broken, and the effect of improving the printing durability by the above-described medium wave structure can be obtained. Preferably it is 0.18 micrometer or less, More preferably, it is 0.16 micrometer or less.

  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 overlapped may be a structure in which the large wave structure is further overlapped. The large wave structure preferably has an average wavelength of 5 to 100 μm.
This large wave structure has the effect of increasing the amount of water retained on the surface of the non-image part of the lithographic printing plate. The more water is retained 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. When the average wavelength of the large wave structure is 5 μm or more, a difference from the medium wave structure is likely to occur. When the average wavelength of the large wave structure is 100 μm or less, the exposed non-image area does not appear to flicker after exposure and development, and the plate inspection is more excellent. The average wavelength of the large wave structure is preferably 10 to 80 μm.

  In the present invention, the average aperture diameter of the medium wave structure on the surface, the average aperture diameter of the small wave structure, the average of the depth with respect to the aperture diameter, and the measurement method of the average wavelength of the large wave are 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 circular 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) at the average wavelength stylus roughness meter large wave structure performs a two-dimensional roughness measurement, the average peak distance S _m as defined in ISO4287 were measured 5 times, and the average value as the average wavelength.

<Aluminum plate (rolled aluminum)>
In order to obtain the lithographic printing plate precursor according to the present invention, a known aluminum plate can be used. The aluminum plate used in the present invention is a metal mainly composed of 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 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 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 aluminum plates such as A1050, JIS A1100, 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% by 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. 59-153861, 61-51395, 62-146694, 60-215725, and 60-215725. JP 60-215726, JP 60-215727, JP 60-216728, JP 61-272367, JP 58-11759, JP 58-42493, JP 58- 221254, 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. It is described in each publication of -140894. In addition, techniques described in Japanese Patent Publication No. 1-35910 and Japanese Patent Publication No. 55-28874 are also known.

  Regarding the JIS1070 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, JP-A-8-108659 and It is described in JP-A-8-92679.

  Regarding Al-Mg alloys, the techniques proposed by the applicant of the present application are disclosed in Japanese Patent Publication Nos. Sho 62-5080, Sho 63-60823, Shoko 3-61753, JP Sho 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-A-63-47349. JP-A 64-1293, JP-A 63-135294, JP-A 63-87288, JP-B 4-73392, JP-B 7-100844, JP-A 62-149856, JP-B JP-A-4-73394, JP-A-62-181191, JP-B-5-76530, JP-A-63-30294, and JP-B-6-37116. Also described in JP-A-2-215599, JP-A-61-201747, and the like.

  With regard to Al—Mn alloys, 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. In addition, JP-B-54-42284, JP-B-4-19290, JP-B-4-19291, JP-B-4-19292, JP-A-61-35995, JP-A-64-51992, JP-A-4-19592, No. 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. JP-B 63-60824, JP-A 60-63346, JP-A 60-63347, JP-A-1-293350, European Patent No. 223,737, US Pat. No. 4,818, No. 300, British Patent No. 1,222,777, etc.

  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 using 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-5-311261, JP-A-5-311261 6-136466 and the like. Further, the degassing of the molten metal is described in JP-A-5-51659, Japanese Utility Model Laid-Open No. 5-49148, and the like. The applicant of the present application has also proposed a technique relating to degassing of molten metal in Japanese Patent Application Laid-Open No. 7-40017.

Next, casting is performed using the molten metal that has been subjected to the cleaning treatment as described above. Regarding 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 0.5 ° C., a large number of 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 the soaking process, heat treatment is performed at 450 to 620 ° C. for 1 to 48 hours so that the intermetallic compound does not become coarse. If the heat treatment is shorter than 1 hour, the effect of soaking may be insufficient.

  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 using a batch annealing furnace, preferably 350 to 500 ° C. for 2 to 10 hours, or using a continuous annealing furnace at 400 to 600 ° C. 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 productivity, it is preferably performed in a continuous coil state. Further, a slitter line may be used for processing to 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 1,000 ° 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, and JP-A-6-122949. JP-A-6-210406 and JP-A-6-26308.

  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 when 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, It is described in JP-A-8-92709.

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. Further, 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 may cause poor surface quality when the surface of the aluminum plate is subjected to chemical or electrochemical surface roughening. It is preferably not too coarse. The crystal structure on the surface of the aluminum plate preferably has a width of 200 μm or less, more preferably 100 μm or less, 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 7-132689.

  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.

The aluminum plate used in the present invention is 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 hardly damaged during transportation.
In the case of an aluminum web, for example, the packaging 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 iron is used to squeeze it, and the display is performed on the outer periphery. Moreover, a polyethylene film can be used as the packaging material, and needle felt and 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 used in the present invention is about 0.1 to 0.6 mm, preferably 0.15 to 0.4 mm, and more preferably 0.2 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.

[Lithographic printing plate precursor]
The lithographic printing plate precursor according to the invention comprises an image recording layer described later and a protective layer described later in this order on the lithographic printing plate support described above.

<Image recording layer>
The image recording layer used in the present invention contains a polymerization initiator, a polymerizable compound, and a binder polymer.

<Polymerization initiator>
The polymerization initiator used in the present invention has a function of initiating and advancing the curing reaction of the polymerizable compound described later.
The polymerization initiator is not particularly limited as long as it generates radicals by applying energy. When making the image recording layer heat-sensitive, for example, a thermal decomposition type radical generator (for example, an onium salt) that decomposes by heat to generate radicals and accepts excited electrons from an infrared absorber to generate radicals. Electron transfer type radical generators (for example, active halogen compounds) and electron transfer type radical generators (for example, borate compounds) that generate radicals by electron transfer to an excited infrared absorber.
Moreover, when making an image recording layer photosensitive, the photoinitiator which generate | occur | produces a radical by light is mentioned, for example.

When making the image recording layer heat-sensitive, specific examples of the polymerization initiator include onium salts, active halogen compounds, oxime ester compounds, and borate compounds. These may be used alone or in combination of two or more.
Of these, onium salts are preferable, and sulfonium salts are more preferable.

  Examples of the sulfonium salt suitably used in the present invention include onium salts represented by the following general formula (1).

In the general formula (1), R ¹¹ , R ¹² and R ¹³ may be the same or different and each represents a hydrocarbon group having 20 or less carbon atoms which may have a substituent. Preferable substituents include a halogen atom, a nitro group, an alkyl group having 12 or less carbon atoms, an alkoxy group having 12 or less carbon atoms, or an aryloxy group having 12 or less carbon atoms. (Z ¹¹ ) ⁻ represents a counter ion selected from the group consisting of halogen ion, perchlorate ion, tetrafluoroborate ion, hexafluorophosphate ion, carboxylate ion, and sulfonate ion, preferably perchloric acid Ions, hexafluorophosphate ions, carboxylate ions, and aryl sulfonate ions.

  Specific examples ([OS-1] to [OS-12]) of the onium salt represented by the general formula (1) are shown below, but are not limited thereto.

  In addition to the above, specific aromatic sulfonium salts described in JP-A Nos. 2002-148790, 2002-148790, 2002-350207, and 2002-6482 are also preferably used.

  In the present invention, in addition to the sulfonium salt polymerization initiator, other polymerization initiators (other radical generators) can be used. Other radical generators include onium salts other than sulfonium salts, triazine compounds having a trihalomethyl group, peroxides, azo polymerization initiators, azide compounds, quinonediazides, active halogen compounds, oxime ester compounds, triaryls. Examples thereof include monoalkyl borate compounds. Among them, onium salts are preferable because of their high sensitivity. Moreover, these polymerization initiators (radical generators) can be used in combination with the sulfonium salt polymerization initiator as an essential component.

Other onium salts that can be suitably used in the present invention include iodonium salts and diazonium salts. In the present invention, these onium salts function not as acid generators but as radical polymerization initiators.
Other onium salts in the present invention include onium salts represented by the following general formulas (2) and (3).

In the general formula (2), Ar ²¹ and Ar ²² each independently represent an aryl group having 20 or less carbon atoms which may have a substituent. Preferred substituents when this aryl group has a substituent include a halogen atom, a nitro group, an alkyl group having 12 or less carbon atoms, an alkoxy group having 12 or less carbon atoms, or a group having 12 or less carbon atoms. An aryloxy group is mentioned. (Z ²¹ ) ⁻ represents a counter ion having the same meaning as (Z ¹¹ ) ⁻ .

In the general formula (3), Ar ³¹ represents an aryl group having 20 or less carbon atoms which may have a substituent. Preferred examples of the substituent include a halogen atom, a nitro group, an alkyl group having 12 or less carbon atoms, an alkoxy group having 12 or less carbon atoms, an aryloxy group having 12 or less carbon atoms, and 12 or less carbon atoms. Examples thereof include an alkylamino group, a dialkylamino group having 12 or less carbon atoms, an arylamino group having 12 or less carbon atoms, or a diarylamino group having 12 or less carbon atoms. (Z ³¹ ) ⁻ represents a counter ion having the same meaning as (Z ¹¹ ) ⁻ .

  In the present invention, an onium salt represented by the general formula (2) ([OI-1] to [OI-10]) and an onium salt represented by the general formula (3) ([ Specific examples of ON-1] to [ON-5] are given below, but are not limited thereto.

  Specific examples of onium salts that can be suitably used as a polymerization initiator (radical generator) in the present invention include those described in JP-A No. 2001-133696.

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

  The total content of the polymerization initiator in the present invention is 0.1 to 50% by mass, preferably 0, based on the total solid content constituting the image recording layer, from the viewpoint of sensitivity and generation of stains in the non-image area during printing. 0.5 to 30% by mass, particularly preferably 1 to 20% by mass.

As a polymerization initiator in this invention, only 1 type may be used and 2 or more types may be used together. When two or more polymerization initiators are used in combination, for example, a plurality of suitably used sulfonium salt polymerization initiators may be used, or a sulfonium salt polymerization initiator and another polymerization initiator may be used in combination. Also good.
When the sulfonium salt polymerization initiator and another polymerization initiator are used in combination, the content ratio (mass ratio) is preferably 100/1 to 100/50, more preferably 100/5 to 100/25.
Moreover, a polymerization initiator may be added to the same layer as other components, or another layer may be provided and added thereto.

  When a highly sensitive sulfonium salt polymerization initiator, which is preferable as a polymerization initiator, is used for the image recording layer in the present invention, the radical polymerization reaction proceeds effectively, and the strength of the formed image area becomes very high. . Therefore, combined with the high oxygen blocking function of the protective layer described later, a lithographic printing plate having high image area strength can be produced, and as a result, printing durability is further improved. In addition, since the sulfonium salt polymerization initiator itself is excellent in stability over time, even when the produced lithographic printing plate precursor is stored, the occurrence of an undesirable polymerization reaction is effectively suppressed. Will also have.

  When the image recording layer is photosensitive, the polymerization initiator may be various photopolymerization initiators known in patents, literatures, etc., or a combination system of two or more photopolymerization initiators, depending on the wavelength of the light source used. (Photoinitiation system) can be appropriately selected and used.

Specifically, various photoinitiating systems have been proposed when using visible light having a wavelength of 400 nm or more, Ar laser, second harmonic of a semiconductor laser, or SHG-YAG laser as a light source. , 850, 445, certain photoreductive dyes, rose bengal, eosin and erythrodin; systems based on combinations of dyes and initiators such as complex initiator systems of dyes and amines (Japanese Patent Publication No. 44-20189) ), A combination system of hexaarylbiimidazole, radical generator and dye (Japanese Patent Publication No. 45-37377), a system of hexaarylbiimidazole and p-dialkylaminobenzylidene ketone (Japanese Patent Publication No. 47-2528 and JP-A-54-155292), a system of a cyclic cis-α-dicarbonyl compound and a dye (JP-A-48- No. 4183), cyclic triazine and merocyanine dye systems (JP 54-151024), 3-ketocoumarin and activator systems (JP 52-11281 and JP 58-15503). ), Biimidazole, styrene derivatives, thiol systems (Japanese Patent Laid-Open No. 59-140203), organic peroxides and dye systems (Japanese Patent Laid-Open Nos. 59-1504, 59-140203, Japanese Patent Laid-Open No. 59-189340, JP-A 62-174203 and JP-B 62-1641, US Pat. No. 4,766,055), a system of a dye and an active halogen compound (JP-A 63-258903, JP 2-63054, etc.), dye and borate compound systems (JP-A-62-143044, JP-A-62-1050242, JP-A-64-131). No. 40, JP-A No. 64-13141, JP-A No. 64-13142, JP-A No. 64-13143, JP-A No. 64-13144, JP-A No. 64-17048, JP-A No. 1-222903, JP-A-1-298348, JP-A-1-138204, etc.), a dye and radical generator having a rhodanine ring (JP-A-2-179634 and JP-A-2-244050), titanocene, 3-ketocoumarin dye system (Japanese Patent Laid-Open No. 63-221110), titanocene and xanthene dye, and a system comprising an addition-polymerizable ethylenically unsaturated bond-containing compound containing an amino group or a urethane group (Japanese Patent Laid-Open No. Hei 4-221958) And JP-A-4-219756), titanocene and a specific merocyanine dye system (JP-A-6-295061) Broadcast), a dye system with titanocene and benzopyran ring (JP-A-8-334897 JP), and the like.
In particular, a system using a titanocene compound or hexaarylbiimidazole is preferable.

  Further, a laser having a wavelength of 400 to 410 nm (violet laser) has been developed, and a photoinitiating system exhibiting high sensitivity at a wavelength of 450 nm or less, which is sensitive to the laser, has been developed. And photoinitiating systems such as a merocyanine dye / titanocene system (JP 2000-147663 A) and a carbazole type dye / titanocene system (JP 2001-42524 A). In particular, a system using a titanocene compound is preferable because of its excellent sensitivity.

  As the titanocene compound, various compounds can be used. For example, various titanocene compounds described in JP-A-59-152396 and JP-A-61-151197 can be appropriately selected and used. . More specifically, di-cyclopentadienyl-Ti-di-chloride, di-cyclopentadienyl-Ti-bis-phenyl, di-cyclopentadienyl-Ti-bis-2,3,4,5 , 6-pentafluorophen-1-yl, di-cyclopentadienyl-Ti-bis-2,3,5,6-tetrafluorophen-1-yl, di-cyclopentadienyl-Ti-bis-2 , 4,6-trifluorophen-1-yl, di-cyclopentadienyl-Ti-bis-2,6-di-fluorophen-1-yl, di-cyclopentadienyl-Ti-bis-2, 4-fluorophen-1-yl, dimethylcyclopentadienyl-Ti-bis-2,3,4,5,6-tetrafluorophen-1-yl, di-methylcyclopentadienyl-Ti-bis-2 , 6-Diff Orofeni-1-yl, di - cyclopentadienyl -Ti- bis-2,6'-difluoro-3 can be mentioned (pill-1-yl) 1-yl and the like.

Furthermore, as required for the above photopolymerization initiator, thiol compounds such as 2-mercaptobenzthiazole, 2-mercaptobenzimidazole, 2-mercaptobenzoxazole, N-phenylglycine, N, N-dialkylamino aromatic alkyl ester, etc. It is known that the photoinitiating ability can be further enhanced by adding a hydrogen-donating compound such as an amine compound.
The addition amount of these photopolymerization initiators (systems) is usually 0.05 to 100 parts by mass, preferably 0.1 to 70 parts by mass, and more preferably 0 to 100 parts by mass of the ethylenically unsaturated bond-containing compound. Used in the range of 2 to 50 parts by mass.

<Polymerizable compound>
The polymerizable compound used in the present invention is an addition polymerizable compound having at least one ethylenically unsaturated double bond, and is selected from compounds having at least one ethylenically unsaturated bond, preferably two or more. . Such compound groups are widely known in the industrial field, and in the present invention, these compounds can be used without any particular limitation. These have chemical forms such as monomers, prepolymers, that is, 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.), esters and amides thereof. In this case, an ester of an unsaturated carboxylic acid and an aliphatic polyhydric alcohol compound, or an amide of an unsaturated carboxylic acid and an aliphatic polyvalent amine compound is used. In addition, an addition reaction product of an unsaturated carboxylic acid ester or amide having a nucleophilic substituent such as a hydroxy group, an amino group or a mercapto group with a monofunctional or polyfunctional isocyanate or epoxy, and a monofunctional or polyfunctional A dehydration-condensation reaction product with 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 In addition, a substitution reaction product of an unsaturated carboxylic acid ester or amide having a leaving substituent such as a tosyloxy group and a monofunctional or polyfunctional alcohol, amine or thiol is also suitable. As another example, it is also possible to use a group of compounds substituted with unsaturated phosphonic acid, styrene, vinyl ether or the like instead of the unsaturated carboxylic acid.

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

  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 monomers include those having a cyclohexylene structure described in JP-B No. 54-21726.

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

CH ₂ = C (R ^a ) COOCH ₂ CH (R ^b ) OH

(However, R ^a and R ^b represent H or CH _3. )

  Also, urethane acrylates such as those described in JP-A-51-37193, JP-B-2-32293, and JP-B-2-16765, JP-B-58-49860, JP-B-56-17654 And urethane compounds having an ethylene oxide skeleton described in JP-B-62-39417 and JP-B-62-39418. Furthermore, 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. Thus, an image recording layer having an extremely excellent photosensitive speed can be obtained.

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

  About these polymerizable compounds, the details of the usage, such as the structure, single use or combination, addition amount, etc. can be arbitrarily set according to the final performance design. For example, it is selected from the following viewpoints. From the viewpoint of the speed of photosensitivity, 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 ester, methacrylic ester, styrenic compound, A method of adjusting both photosensitivity and strength by using a vinyl ether compound) is also effective. A compound having a large molecular weight or a compound having high hydrophobicity is excellent in the speed of photosensitivity and film strength, but is not preferable in terms of development speed and precipitation in a developer. In addition, the selection and use method of the polymerizable compound is an important factor for the compatibility and dispersibility with other components in the image recording layer (for example, specific binder polymer, initiator, colorant, etc.). For example, the compatibility may be improved by using a low-purity compound or using two or more kinds in combination.

Regarding the content of the polymerizable compound in the image recording layer, the solid content in the image recording layer is considered from the viewpoint of sensitivity, occurrence of phase separation, adhesion of the image recording layer, and precipitation from the developer. The amount is preferably 5 to 80% by mass, more preferably 40 to 75% by mass.
These may be used alone or in combination of two or more. In addition, as for the method of using the polymerizable compound, an appropriate structure, blending, and addition amount can be arbitrarily selected from the viewpoint of polymerization inhibition with respect to oxygen, resolution, fogging property, refractive index change, surface tackiness, and the like. Furthermore, in the lithographic printing plate precursor according to the invention, a layer constitution / coating method such as undercoating or overcoating can be carried out.

<Binder polymer>
The binder polymer used in the present invention is contained from the viewpoint of improving the film property, and any conventionally known binder polymer can be used as long as it has a function of improving the film property. it can. Specifically, an acrylic main chain binder, a urethane binder, or the like often used in the industry can be used.

In the present invention, the use of a binder polymer having a repeating unit represented by the following general formula (i) (hereinafter also referred to as “specific binder polymer”) is a lithographic printing plate comprising a lithographic printing plate precursor obtained. This is preferable because the printing durability is good.
Hereinafter, the specific binder polymer will be described in detail.

In general formula (i), R ¹ represents a hydrogen atom or a methyl group. Of these, a methyl group is preferable.

In general formula (i), R ² has 2 to 82 atoms composed of two or more atoms selected from the group consisting of carbon atom, hydrogen atom, oxygen atom, nitrogen atom and sulfur atom. , Preferably 2 to 50, more preferably 2 to 30. Here, when the linking group has a substituent, the “number of atoms” refers to the number of atoms including the substituent. More specifically, the number of atoms constituting the main skeleton of the linking group represented by R ² is preferably 1-30, more preferably 3-25, and 4-20. More preferably, it is 5-10. The “main skeleton of the linking group” in the present invention refers to an atom or an atomic group used only for linking A and the terminal COOH in the general formula (i), and particularly when there are a plurality of linking paths. Refers to an atom or atomic group that constitutes a path with the least number of atoms used. Therefore, when a linking group has a ring structure, the number of atoms to be included differs depending on the linking site (for example, o-, m-, p-, etc.).

More specific examples include alkylene, substituted alkylene, arylene, substituted arylene, and the like, and a structure in which a plurality of these divalent groups are linked by an amide bond or an ester bond may be used.
Examples of the linking group having a chain structure include ethylene and propylene. A structure in which these alkylenes are linked via an ester bond can also be exemplified as a preferable example.

Among these, the linking group represented by R ² is preferably an (n + 1) -valent hydrocarbon group having an aliphatic cyclic structure having 3 to 30 carbon atoms. More specifically, a compound having an aliphatic cyclic structure such as cyclopropane, cyclopentane, cyclohexane, cycloheptane, cyclooctane, cyclodecane, dicyclohexyl, tercyclohexyl, norbornane and the like, which may be substituted by one or more arbitrary substituents And (n + 1) valent hydrocarbon groups by removing (n + 1) hydrogen atoms on an arbitrary carbon atom constituting. R ² preferably has 3 to 30 carbon atoms including a substituent.

  One or more arbitrary carbon atoms of the compound constituting the aliphatic cyclic structure may be replaced with a hetero atom selected from a nitrogen atom, an oxygen atom, or a sulfur atom. In terms of printing durability, R2 represents condensed polycyclic aliphatic hydrocarbons, bridged cyclic aliphatic hydrocarbons, spiro aliphatic hydrocarbons, and aliphatic hydrocarbon ring assemblies (in which multiple rings are connected by a bond or a linking group) And the like, (n + 1) -valent hydrocarbon group having an aliphatic cyclic structure which may have a substituent of 5 to 30 carbon atoms containing two or more rings. Also in this case, the carbon number includes the carbon atom of the substituent.

As the linking group represented by R ² , those having 5 to 10 atoms constituting the main skeleton of the linking group are particularly preferred, and are structurally a chain structure, and an ester bond in the structure. And those having a cyclic structure as described above are preferred.

Examples of the substituent that can be introduced into the linking group represented by R ² include monovalent nonmetallic atomic groups other than hydrogen, such as halogen atoms (—F, —Br, —Cl, —I), hydroxyl groups. Group, alkoxy group, aryloxy group, mercapto group, alkylthio group, arylthio group, alkyldithio group, aryldithio group, amino group, N-alkylamino group, N, N-dialkylamino group, N-arylamino group, N, N-diarylamino group, N-alkyl-N-arylamino group, acyloxy group, carbamoyloxy group, N-alkylcarbamoyloxy group, N-arylcarbamoyloxy group, N, N-dialkylcarbamoyloxy group, N, N- Diarylcarbamoyloxy group, N-alkyl-N-arylcarbamoyloxy group, alkylsulfoxy , Arylsulfoxy group, acylthio group, acylamino group, N-alkylacylamino group, N-arylacylamino group, ureido group, N′-alkylureido group, N ′, N′-dialkylureido group, N′-aryl Ureido group, N ′, N′-diarylureido group, N′-alkyl-N′-arylureido group, N-alkylureido group, N-arylureido group, N′-alkyl-N-alkylureido group, N ′ -Alkyl-N-arylureido group, N ', N'-dialkyl-N-alkylureido group, N', N'-dialkyl-N-arylureido group, N'-aryl-N-alkylureido group, N ' -Aryl-N-arylureido group, N ', N'-diaryl-N-alkylureido group, N', N'-diaryl-N-a Lilleureido group, N'-alkyl-N'-aryl-N-alkylureido group, N'-alkyl-N'-aryl-N-arylureido group, alkoxycarbonylamino group, aryloxycarbonylamino group, N-alkyl -N-alkoxycarbonylamino group, N-alkyl-N-aryloxycarbonylamino group, N-aryl-N-alkoxycarbonylamino group, N-aryl-N-aryloxycarbonylamino group, formyl group, acyl group, carboxyl Group and its conjugate base group, alkoxycarbonyl group, aryloxycarbonyl group, carbamoyl group, N-alkylcarbamoyl group, N, N-dialkylcarbamoyl group, N-arylcarbamoyl group, N, N-diarylcarbamoyl group, N-alkyl -N-arylcal Moil group, alkylsulfinyl group, arylsulfinyl group, an alkylsulfonyl group, an arylsulfonyl group, a sulfo group (-SO ₃ H) and its conjugated base group, alkoxy sulfonyl group, aryloxy sulfonyl group, sulfinamoyl group, N- alkylsulfamoyl Fina Moyl group, N, N-dialkylsulfinamoyl group, N-arylsulfinamoyl group, N, N-diarylsulfinamoyl group, N-alkyl-N-arylsulfinamoyl group, sulfamoyl group, N-alkylsulfato group Famoyl group, N, N-dialkylsulfamoyl group, N-arylsulfamoyl group, N, N-diarylsulfamoyl group, N-alkyl-N-arylsulfamoyl group, N-acylsulfamoyl group Group and its conjugate base group, N-alkylsulfonate A sulfamoyl group _{(-SO 2 NHSO 2 (alkyl)} ) and its conjugated base group, N- aryl sulfonylsulfamoyl group _{(-SO 2 NHSO 2 (aryl)} ) and its conjugated base group, N- alkylsulfonylcarbamoyl group (- CONHSO ₂ (alkyl)) and its conjugate base group, N-arylsulfonylcarbamoyl group (—CONHSO ₂ (aryl)) and its conjugate base group, alkoxysilyl group (—Si (Oalkyl) ₃ ), aryloxysilyl group (— Si (Oaryl) 3), hydroxysilyl group (—Si (OH) 3) and its conjugate base group, phosphono group (—PO ₃ H ₂ ) and its conjugate base group, dialkylphosphono group (—PO ₃ (alkyl)) 2), diaryl phosphono group (-PO ₃ (aryl) 2), alkylaryl ho Honomoto _{(-PO 3 (alkyl) (aryl} )), monoalkyl phosphono group (-PO ₃ H (alkyl)) and its conjugated base group, monoaryl phosphono group (-PO ₃ H (aryl)) and its Conjugated base group, phosphonooxy group (—OPO ₃ H ₂ ) and its conjugated base group, dialkylphosphonooxy group (—OPO ₃ (alkyl) ₂ ), diarylphosphonooxy group (—OPO ₃ (aryl) ₂ ), alkyl An arylphosphonooxy group (—OPO ₃ (alkyl) (aryl)), a monoalkylphosphonooxy group (—OPO ₃ H (alkyl)) and its conjugate base group, a monoarylphosphonooxy group (—OPO ₃ H ( aryl)) and its conjugate base group, cyano group, nitro group, dialkylboryl group (-B (alkyl) ₂ ), diarylbo Lyl group (-B (aryl) ₂ ), alkylarylboryl group (-B (alkyl) (aryl)), dihydroxyboryl group (-B (OH) ₂ ) and its conjugate base group, alkylhydroxyboryl group (-B (Alkyl) (OH)) and its conjugate base group, arylhydroxyboryl group (-B (aryl) (OH)) and its conjugate base group, aryl group, alkenyl group and alkynyl group.

In the lithographic printing plate precursor of the present invention, depending on the design of the image recording layer comprises or substituent having a hydrogen atom capable of hydrogen bonding, in particular, acidic acid dissociation constant (pK _a) is smaller than the carboxylic acid-substituted The group is not preferable because it tends to lower the printing durability. On the other hand, hydrophobic substituents such as halogen atoms, hydrocarbon groups (alkyl groups, aryl groups, alkenyl groups, alkynyl groups), alkoxy groups, aryloxy groups and the like are more preferable because they tend to improve printing durability. When the cyclic structure is a monocyclic aliphatic hydrocarbon having 6 or less members such as cyclopentane or cyclohexane, it preferably has such a hydrophobic substituent. If possible, these substituents may be bonded to each other or with a substituted hydrocarbon group to form a ring, and the substituent may be further substituted.

In general formula (i), A represents an oxygen atom or —NR ³ —, and R ³ represents a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms.
Examples of the monovalent hydrocarbon group having 1 to 10 carbon atoms represented by R ³ include an alkyl group, an aryl group, an alkenyl group, and an alkynyl group.
Specific examples of the alkyl group include methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, isopropyl group, isobutyl group, sec-butyl group, 1 carbon number such as tert-butyl group, isopentyl group, neopentyl group, 1-methylbutyl group, isohexyl group, 2-ethylhexyl group, 2-methylhexyl group, cyclopentyl group, cyclohexyl group, 1-adamantyl group, 2-norbornyl group Up to 10 linear, branched or cyclic alkyl groups.
Specific examples of the aryl group include carbon having one heteroatom selected from the group consisting of an aryl group having 1 to 10 carbon atoms such as a phenyl group, a naphthyl group, and an indenyl group, a nitrogen atom, an oxygen atom, and a sulfur atom. Examples include heteroaryl groups of 1 to 10, such as a furyl group, a thienyl group, a pyrrolyl group, a pyridyl group, and a quinolyl group.
Specific examples of the alkenyl group include those having 1 to 10 carbon atoms such as vinyl group, 1-propenyl group, 1-butenyl group, 1-methyl-1-propenyl group, 1-cyclopentenyl group, 1-cyclohexenyl group and the like. A linear, branched, or cyclic alkenyl group is mentioned.
Specific examples of the alkynyl group include alkynyl groups having 1 to 10 carbon atoms such as ethynyl group, 1-propynyl group, 1-butynyl group, and 1-octynyl group.
The substituent that R ³ may have is the same as those exemplified as the substituent that R ² can introduce. However, the carbon atoms of R ³ is 1 to 10, including the number of carbon atoms of the substituent.

  A is preferably an oxygen atom or NH— from the viewpoint of easy synthesis.

  In general formula (i), n represents an integer of 1 to 5, and is preferably 1 in terms of printing durability.

  Although the preferable specific example of the repeating unit represented by general formula (i) below is shown, this invention is not limited to these.

  The repeating unit represented by the general formula (i) may be only one kind in the specific binder polymer, or may be contained in two or more kinds. The specific binder polymer in the present invention may be a polymer composed only of the repeating unit represented by the general formula (i), but is usually used as a copolymer in combination with other copolymerization components. The total content of the repeating unit represented by the general formula (i) in the copolymer is appropriately determined depending on the structure, the design of the image recording layer, etc., but is preferably 1 to 99 mol with respect to the total molar amount of the polymer component. %, More preferably 5 to 40 mol%, still more preferably 5 to 20 mol%.

  As a copolymerization component in the case of using as a copolymer, a conventionally well-known thing can be used without a restriction | limiting if it is a monomer which can be radically polymerized. Specific examples include monomers described in “Polymer Data Handbook—Basic Edition” (Edition of Polymer Society, Bafukan, 1986). One type of such copolymerization component may be used, or two or more types may be used in combination.

  The molecular weight of the specific binder polymer in the present invention is appropriately determined from the viewpoint of image formability and printing durability. The molecular weight is preferably 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.

The binder polymer other than the specific binder polymer used in the present invention (hereinafter, also referred to as “other binder polymer”) includes, as described above, an acrylic main chain binder, a urethane binder, and the like. A binder polymer having a radical polymerizable group is preferably exemplified.
The radical polymerizable group is not particularly limited as long as it can be polymerized by radicals, but α-substituted methylacrylic group [—OC (═O) —C (—CH ₂ Z) ═CH ₂ , Z = A hydrocarbon group starting from a hetero atom], an acryl group, a methacryl group, an allyl group, and a styryl group. Among these, an acryl group and a methacryl group are preferable.
The content of the radical polymerizable group in the binder polymer (content of unsaturated double bond capable of radical polymerization by iodine titration) is preferably 0.1 to 1 g of the binder polymer from the viewpoint of sensitivity and storage stability. It is 10.0 mmol, More preferably, it is 1.0-7.0 mmol, More preferably, it is 2.0-5.5 mmol.

  In the present invention, the other binder polymer preferably further has an alkali-soluble group. The content of the alkali-soluble group in the binder polymer (acid value by neutralization titration) is preferably from 0.1 to 3.0 mmol, more preferably from 1 g of the binder polymer, from the viewpoints of depositability of developing residue and printing durability. Is 0.2 to 2.0 mmol, more preferably 0.45 to 1.0 mmol.

  Specific examples of such other binder polymers include polymer compounds represented by the following formulas (4) to (6).

  The binder polymer used in the present invention may be used alone or in combination of two or more. For example, the above-mentioned specific binder polymer and other binder polymers may be used alone or in combination as a mixture.

The content of such a binder polymer in the image recording layer can be determined as appropriate, but is usually 10 to 90% by mass, preferably 20%, based on the total mass of nonvolatile components in the image recording layer. It is -80 mass%, More preferably, it is the range of 30-70 mass%.
Moreover, as an acid value (meg / g) of such a binder polymer, it is preferable that it is the range of 2.00-3.60.

  Further, the weight average molecular weight of such a binder polymer is preferably 2,000 to 1,000,000, more preferably 10,000, from the viewpoint of film property (printing durability) and solubility in a coating solvent. It is in the range of ˜300,000, more preferably 20,000 to 200,000.

Furthermore, the glass transition point (T _g ) of such a binder polymer is preferably 70 to 300 ° C., more preferably 80 to 250 ° C., and still more preferably 90 from the viewpoints of storage stability, printing durability, and sensitivity. It is the range of -200 degreeC.
As a means for increasing the glass transition point of the binder polymer, the molecule preferably contains an amide group or an imide group, and particularly preferably contains a methacrylamide or a methacrylamide derivative.

<Infrared absorber>
When making an image recording layer heat sensitive, an image recording layer contains an infrared absorber further. The infrared absorber exhibits a transfer function (electron transfer), a photothermal conversion function, and the like by heat, and generates radicals in the above-described polymerization initiator.
The infrared absorber is in an electronically excited state with high sensitivity to the irradiation (exposure) of the infrared laser, and the electron transfer, energy transfer, heat generation (photothermal conversion function), etc. related to the electron excited state act on the above-described polymerization initiator. Thus, it is useful for generating a radical by causing a chemical change in the polymerization initiator with high sensitivity.
The infrared absorbent used in the present invention is preferably a dye or pigment having an absorption maximum in the wavelength range of 750 to 1400 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.
Preferred dyes include, for example, cyanine dyes described in JP-A-58-125246, JP-A-59-84356, JP-A-60-78787, JP-A-58-173696, 58-181690, JP-A-58-194595, etc., methine dyes, JP-A-58-112793, JP-A-58-224793, JP-A-59-48187, JP-A-59- No. 73996, JP-A-60-52940 and JP-A-60-63744, naphthoquinone dyes, squarylium dyes described in JP-A-58-112792, etc., British Patent 434 , 875 specification, the cyanine dye etc. can be mentioned.

In addition, a near infrared absorption sensitizer described in US Pat. No. 5,156,938 is also preferably used, and a substituted arylbenzo (thio) described in US Pat. No. 3,881,924 is also suitable. ) Pyrylium salt, trimethine thiapyrylium salt described in JP-A-57-142645 (US Pat. No. 4,327,169), JP-A-58-181051, 58-220143, 59- No. 41363, 59-84248, 59-84249, 59-146063, and 59-146061, and pyrine compounds described in JP-A-59-216146. And pentamethine thiopyrylium salts described in US Pat. No. 4,283,475, and Japanese Patent Publication No. 5-13514 and 5-19702. And pyrylium compounds disclosed in Japanese is also preferably used. Moreover, as another example preferable as a dye, the near-infrared absorptive dye described as the formula (I) and (II) in US Patent 4,756,993 can be mentioned.
Other preferable examples of the infrared absorbing dye in the present invention include specific indolenine cyanine dyes described in JP-A-2002-278057 as exemplified below.

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

In the general formula (a), X ¹ represents a hydrogen atom, a halogen atom, -NPh ₂ , X ² -L ¹ or a group shown below. Here, X ² represents an oxygen atom, a nitrogen atom or a sulfur atom, and L ¹ represents a hydrocarbon group having 1 to 12 carbon atoms, an aromatic ring having a hetero atom, or 1 to 1 carbon atom containing a hetero atom. 12 hydrocarbon groups are shown. In addition, a hetero atom here shows N, S, O, a halogen atom, and Se. X a ^_- is Z _a which will be described below ^_- has the same definition as, R _a represents a hydrogen atom, an alkyl group, an aryl group, a substituted or unsubstituted amino group, substituted or unsubstituted amino group and a halogen atom.

In the general formula (a), R ¹ and R ² each independently represents a hydrocarbon group having 1 to 12 carbon atoms. From the storage stability of the image recording layer coating solution, R ¹ and R ² are preferably hydrocarbon groups having 2 or more carbon atoms, and R ¹ and R ² are bonded to each other to form a 5-membered ring. It is particularly preferable that a 6-membered ring is formed.

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

Specific examples of the cyanine dye represented by formula (a) that can be suitably used in the present invention include those described in paragraph numbers [0017] to [0019] of JP-A No. 2001-133969. Can do.
Further, other particularly preferable examples include specific indolenine cyanine dyes described in JP-A-2002-278057 described above.
However, a counter ion that does not contain a halogen ion is particularly preferable.

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

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

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

  The particle size of the pigment is preferably in the range of 0.01 to 10 μm, more preferably in the range of 0.05 to 1 μm, and still more preferably in the range of 0.1 to 1 μm. Within this preferred particle size range, excellent dispersion stability of the pigment in the image recording layer can be obtained, and a uniform image recording layer can be obtained.

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

  These infrared absorbers may be added to the same layer as other components, or another layer may be provided and added thereto.

  From the viewpoint of uniformity in the image recording layer and durability of the image recording layer, these infrared absorbers are 0.01 to 50% by mass, preferably 0.1 to 10% by mass based on the total solid content constituting the image recording layer. In the case of 10% by mass and dye, more preferably 0.5 to 10% by mass, and in the case of a pigment, more preferably 0.1 to 10% by mass.

  When the image recording layer contains an infrared absorber, it is sensitive to infrared light, and can be exposed to an infrared laser useful for CTP (for example, an infrared laser beam having a wavelength of 750 to 1400 nm).

<Co-sensitizer>
When the image recording layer is photosensitive, the sensitivity of the image recording layer can be further improved by using 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 photoreaction initiated by light absorption of the photopolymerization initiation system described above and various intermediate active species (radicals, peroxides, oxidizing agents, reducing agents, etc.) generated in the course of the subsequent addition polymerization reaction, It is presumed that the sensitizer reacts to generate new active radicals.
The co-sensitizers are roughly classified into the following (a) to (c), but there are many cases where there is no general knowledge as to which of the individual compounds belongs.
(A) a compound that can be reduced to produce an active radical (b) a compound that can be oxidized to produce an active radical (c) reacts with a less active radical to convert to a more active radical, or a chain transfer agent Compounds that act as

(A) Compound that is reduced to produce an active radical Compound having a carbon-halogen bond: It is considered that an active radical is generated by reductive cleavage of the carbon-halogen bond. Specifically, for example, trihalomethyl-s-triazines and trihalomethyloxadiazoles can be preferably used.
Compound having nitrogen-nitrogen bond: It is considered that the nitrogen-nitrogen bond is reductively cleaved to generate an active radical. Specifically, hexaarylbiimidazoles and the like are preferably used.
Compound having oxygen-oxygen bond: It is considered that the oxygen-oxygen bond is reductively cleaved to generate an active radical. Specifically, for example, organic peroxides are preferably used.
Onium compounds: It is considered that carbon-hetero bonds and oxygen-nitrogen bonds are reductively cleaved to generate active radicals. Specifically, for example, diaryliodonium salts, triarylsulfonium salts, N-alkoxypyridinium (azinium) salts and the like are preferably used.
Ferrocene and iron arene complexes: An active radical can be reductively generated.

(B) Compound which is oxidized to generate an active radical Alkylate complex: It is considered that a carbon-hetero bond is oxidatively cleaved to generate an active radical. Specifically, for example, triarylalkyl borates are preferably used.
Alkylamine compound: It is considered that the C—X bond on carbon adjacent to nitrogen is cleaved by oxidation to generate an active radical. X is preferably a hydrogen atom, a carboxyl group, a trimethylsilyl group, a benzyl group or the like. Specific examples include ethanolamines, N-phenylglycines, N-trimethylsilylmethylanilines, and the like.
Sulfur-containing and tin-containing compounds: Compounds in which the nitrogen atoms of the above-described amines are replaced with sulfur atoms and tin atoms can generate active radicals by the same action. Further, a compound having an SS bond is also known to be sensitized by SS cleavage.
α-Substituted methylcarbonyl compound: An active radical can be generated by oxidative cleavage of the carbonyl-α carbon bond. Moreover, what converted carbonyl into the oxime ether also shows the same effect | action. Specifically, 2-alkyl-1- [4- (alkylthio) phenyl] -2-morpholinopronone-1 and these and a hydroxylamine are reacted, and then N—OH is etherified. Oxime ethers.
Sulfinic acid salts: An active radical can be reductively generated. Specific examples include sodium arylsulfinate.

(C) A compound that reacts with a radical to be converted into a highly active radical or acts as a chain transfer agent. For example, a compound group having SH, PH, SiH, and GeH in the molecule is used. These are either hydrogen donated to low activity radical species to generate radicals, or, after being oxidized, deprotonated to generate radicals. Specifically, 2-mercaptobenzimidazoles etc. are mentioned, for example.
More specific examples of co-sensitizers are described, for example, in JP-A-9-236913 as additives for the purpose of improving sensitivity. Some examples are shown below, but the present invention is not limited thereto.

With respect to the co-sensitizer, various chemical modifications for improving the characteristics of the image recording layer can also be performed.
A co-sensitizer can be used individually or in combination of 2 or more types.
The addition amount of the co-sensitizer is usually 0.05 to 100 parts by mass, preferably 1 to 80 parts by mass, and more preferably 3 to 50 parts by mass with respect to 100 parts by mass of the polymerizable compound described above.

<Other ingredients>
In addition to the basic components described above, other components suitable for the intended use, production method, and the like can be appropriately added to the image recording layer. Hereinafter, preferred additives will be exemplified.

<Colorant>
A dye or a pigment may be added to the image recording layer for the purpose of coloring. As a result, it is possible to improve the so-called plate inspection properties such as the visibility of the image after plate making as a printing plate and the suitability of an image density measuring machine. Specific examples of the colorant 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. Among them, a cationic dye is preferable.
The addition amount of the dye and the pigment as the colorant is preferably about 0.5 to about 5% by mass with respect to the non-volatile components in the entire image recording layer.

<Polymerization inhibitor>
In the image recording layer, it is preferable to add a small amount of a thermal polymerization inhibitor in order to prevent unnecessary thermal polymerization of a polymerizable compound, that is, a compound having a polymerizable ethylenically unsaturated double bond. 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-t-butylphenol), N-nitrosophenylhydroxyamine primary cerium salt and the like. The addition amount of the thermal polymerization inhibitor is preferably about 0.01 to about 5% by mass relative to the mass of the nonvolatile component in the image recording layer. If necessary, a higher fatty acid derivative such as behenic acid or behenic acid amide or the like may be added to prevent polymerization inhibition by oxygen and may be unevenly distributed on the surface of the layer in the course of drying after coating. The addition amount of the higher fatty acid derivative is preferably about 0.5 to about 10% by mass with respect to the nonvolatile component in the image recording layer.

<Other additives>
Furthermore, the image recording layer contains known additives such as inorganic fillers for improving the physical properties of the cured film, other plasticizers, and oil-sensitizing agents that can improve the ink inking property on the surface of the image recording layer. May be added. Examples of the plasticizer include dioctyl phthalate, didodecyl phthalate, triethylene glycol dicaprylate, dimethyl glycol phthalate, tricresyl phosphate, dioctyl adipate, dibutyl sebacate, triacetyl glycerin, and the like. Binder polymer and polymerizable compound In general, it can be added in a range of 10% by mass or less with respect to the total mass.
Further, in order to enhance the effect of heating / exposure after development for the purpose of improving the film strength (printing durability), a UV initiator, a thermal crosslinking agent, or the like can be added.

<Protective layer>
The lithographic printing plate precursor according to the invention has a protective layer containing an inorganic layered compound.
In general, when the image recording layer is a polymerizable negative image recording layer, since exposure is performed in the atmosphere, low molecules such as oxygen, moisture, and basic substances present in the atmosphere that inhibit the image formation reaction. A protective layer is provided for the purpose of preventing the compound from entering the image recording layer.

In the present invention, an inorganic layered compound is contained in the protective layer provided for such purposes. Thereby, the matting property is imparted to the protective layer, and the film strength can be improved. As a result, it becomes possible to prevent deterioration of the protective layer due to deformation or the like in addition to the above-described barrier property of oxygen and the like, and further, since the protective layer is provided with matting properties, the lithographic printing plate precursor according to the invention is used. When laminated, adhesion between the image recording layer side surface (protective layer surface) of the lithographic printing plate precursor and the support side surface of the adjacent lithographic printing plate precursor can be suppressed.
Further, the negative type image recording layer usually has a reduced printing durability when the support is subjected to a silicate treatment. However, in the present invention, the protective layer contains an inorganic layered compound described later. Even if the amount of Si on the surface is 1.0 to 8 mg / m ² , the printing durability is excellent. As a cause of a decrease in printing durability when the silicate treatment is performed, the present inventor has found that the moisture in the coating solution at the time of coating the coating solution for the protective layer and the moisture in the atmosphere in the storage state before the development processing. Adhering to the image recording layer by penetrating into the image recording layer or penetrating to the interface between the silicate formed on the substrate and the image recording layer through a pinhole of the image recording layer that occurs extremely rarely It was found that the sexuality was lowered. Based on this finding, the present inventor has found that by forming a protective layer containing an inorganic layered compound, it is possible to suppress the penetration of moisture into the image recording layer and the penetration of pinholes in the image recording layer. The lithographic printing plate precursor of the present invention, which can provide a lithographic printing plate excellent in printing durability even when the Si amount on the surface of the support is 1.0 to 8 mg / m ² , has been completed. In the present invention, since the inorganic inorganic layered compound in the protective layer has the property of being easily adsorbed to the image recording layer, the inorganic layered compound is laminated on the image recording layer. In addition, it is considered that the arrival of moisture in the atmosphere in the storage state before development processing can be significantly suppressed.
Hereinafter, the inorganic layered compound will be described.

<Inorganic layered compound>
The inorganic layered compound used in the present invention is an inorganic layered compound and is a particle having a thin flat plate shape. Specific examples thereof include a general formula A (B, C) ₂ -5D ₄ O ₁₀ ( OH, F, O) ₂ [wherein A is any of K, Na and Ca, B and C are any of Fe (II), Fe (III), Mn, Al, Mg and V, D is Si or Al. And mica groups such as natural mica and synthetic mica represented by the following formula: talc, teniolite, montmorillonite, saponite, hectorite, and zirconium phosphate represented by the general formula 3MgO.4SiO.H ₂ O.

Specific examples of the natural mica include muscovite, soda mica, phlogopite, biotite, sericite, and the like. Specific examples of the synthetic mica include non-swellable mica such as fluorine phlogopite KMg ₃ (AlSi ₃ O ₁₀ ) F ₂ and potassium tetrasilicon mica KMg _2.5 (Si ₄ O ₁₀ ) F ₂ ; 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 Swellable mica such as _{/ 8} Mg _2/5 Li _1/8 (Si ₄ O ₁₀ ) F ₂ . Furthermore, synthetic smectite is also useful as another mica group.

In the present invention, among the inorganic layered compounds described above, fluorine-based swellable synthetic mica that is a synthetic inorganic layered compound; swellable viscosity minerals such as montmorillonite, saponite, hectorite, and bentonite; are particularly useful. This is because the swellable synthetic mica, swellable viscosity minerals, and the like have 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 more than other viscosity minerals. This is because, 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 in order to compensate for it. The cations present between these layers are called exchangeable cations and exchange with various cations. In particular, when the cation between the layers is Li ⁺ or Na ⁺ , since the ionic radius is small, the bond between the layered crystal lattices is weak, 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. Bentonite and swellable synthetic mica have this tendency and are useful in the present invention, and swellable synthetic mica is particularly preferably used.

  As the shape of the inorganic layered compound used in the present invention, from the viewpoint of diffusion control, the smaller the thickness, the better. The plane size is large as long as the smoothness of the coated surface and the transmittance of actinic rays are not hindered. Moderate. 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.

  Moreover, as for the particle diameter of the inorganic stratiform compound used in this invention, the average major axis is 0.3-20 micrometers, Preferably it is 0.5-10 micrometers, Most preferably, it is 1-5 micrometers. 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 size of the swellable synthetic mica that is a representative compound among the inorganic layered compounds is about 1 to 50 nm in thickness and about 1 to 20 μm in surface size (major axis).

In this invention, it is preferable that the quantity of the inorganic stratiform compound contained in a protective layer is the range of 5-55 mass% with respect to the total solid content of a protective layer. More preferably, it is the range of 10-40 mass%. When it is 5% by mass or more, excellent adhesion resistance is obtained, and when it is 55% by mass or less, coating film formation is sufficient and the sensitivity is good.
Even when a plurality of types of inorganic layered compounds are used in combination, the total amount of these inorganic layered compounds is preferably the above-described mass ratio.

<Binder>
As in the present invention, a basic characteristic desired for a protective layer provided on a polymerizable negative image recording layer is low permeability of a low-molecular compound such as oxygen, and the light used for exposure is also low. Permeation does not substantially hinder, is excellent in adhesion to the image recording layer, and can be easily removed in the development step after exposure.
Such a device relating to the protective layer has been conventionally devised and is described in detail in US Pat. No. 3,458,311 and Japanese Patent Publication No. 55-49729. As a material that can be used for the protective layer, for example, a water-soluble polymer compound having relatively excellent crystallinity is preferably used. Specific examples include water-soluble polymers such as polyvinyl alcohol (PVA), polyvinyl pyrrolidone, acidic celluloses, gelatin, gum arabic, and polyacrylic acid. Of these, the use of polyvinyl alcohol as a main component gives the best results in terms of basic characteristics such as oxygen barrier properties and development removability.
The protective layer formed in the present invention can obtain various properties desired for the protective layer by using these water-soluble polymer compounds as a binder in addition to the inorganic layered compound described above.

The polyvinyl alcohol suitable as a binder 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 for having necessary oxygen barrier properties and water solubility. Similarly, some of them may have other copolymer components. Examples of polyvinyl alcohol include those having a hydrolysis rate of 71 to 100% and a molecular weight in the range of 300 to 2400.
Specifically, Kuraray PVA-105, PVA-110, PVA-117, PVA-117H, PVA-120, PVA-124, PVA-124H, PVA-CS, PVA-CST, PVA-HC, PVA -203, PVA-204, PVA-205, PVA-210, PVA-217, PVA-220, PVA-224, PVA-217EE, PVA-217E, PVA-220E, PVA-224E, PVA-405, PVA-420 , PVA-613, L-8, KL-318, KL-506 and the like.

The components of the protective layer (PVA, selection of inorganic layered compound, 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. In general, the higher the hydrolysis rate of the PVA used (the higher the content of the unsubstituted vinyl alcohol unit in the protective layer) and the thicker the film thickness, the higher the oxygen barrier property, which is advantageous in terms of sensitivity. However, when the oxygen barrier property is extremely increased, there arises a problem that unnecessary polymerization reaction occurs during production and raw storage, and unnecessary fogging and image line thickening occur during image exposure. In addition, adhesion to the image portion of the image recording layer and scratch resistance are extremely important in handling the plate. That is, when a hydrophilic layer made of a water-soluble polymer is laminated on an oleophilic image recording 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, U.S. Patent Application No. 292,501 and U.S. Patent Application No. 44,563 disclose an acrylic emulsion or a water-insoluble vinylpyrrolidone-vinyl acetate copolymer in a hydrophilic polymer mainly composed of polyvinyl alcohol. It is described that sufficient adhesiveness can be obtained by mixing 20 to 60% by mass and the like and laminating on the image recording layer.
Any of these known techniques can be applied to the protective layer formed in the present invention as long as the effect of containing the above-mentioned inorganic layered compound is not impaired.

  In addition, the protective layer formed in the present invention may use polyvinyl alcohol and polyvinyl pyrrolidone as a binder from the viewpoint of adhesive strength with the image recording layer, sensitivity, and generation of unnecessary fog. The addition ratio (mass ratio) is preferably 3/1 or less of polyvinyl alcohol / polyvinylpyrrolidone.

<Formation of Protective Layer Containing Inorganic Layered Compound>
The protective layer containing the inorganic stratiform compound in the present invention is prepared by preparing a dispersion in which the inorganic stratiform compound is dispersed, and blending the dispersion and the above-described binder component or an aqueous solution in which the binder component is dissolved. It is formed by applying a coating liquid for coating on the image recording layer.

First, an example of a general dispersion method of the inorganic layered compound used for the protective layer will be described. First, 5 to 10 parts by mass of the swellable layered compound mentioned above as a preferred inorganic layered 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. A dispersion of 2 to 15% by mass of the inorganic stratiform compound dispersed by the above method is highly viscous or gelled, and has very good storage stability.
When preparing a coating solution for a protective layer using this dispersion, it is preferably prepared by diluting with water and stirring sufficiently, and then blending with a binder component (or an aqueous solution in which the binder component is dissolved).

  In the present invention, known additives such as a surfactant for improving the coating property and a water-soluble plasticizer for improving the physical properties of the coating film can be added to the coating solution for the protective layer. 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 adhesion to the image recording layer and stability with time of the coating solution may be added to the coating solution.

  In the present invention, the method for applying the protective layer coating solution is not particularly limited, and the method described in US Pat. No. 3,458,311 or JP-A-55-49729 is used. Can be applied.

Further, in the present invention, the coating amount of the protective layer coating solution is ^{0.5g / m 2 ~2.0g / m 2} . Preferably from ^{0.75g / m 2 ~1.5g / m 2} . When it is 0.5 g / m ² or more, the film strength of the protective layer can be maintained and scratch resistance can be maintained, and when it is 2.0 g / m ² or less, scattering of light incident on the protective layer by exposure Can be suppressed.

<Preparation of lithographic printing plate precursor>
The lithographic printing plate precursor according to the invention can be obtained by dissolving the above-described components in a suitable organic solvent on the above-described lithographic printing plate support, and applying and drying the solution.
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 coating amount of the image recording layer mainly affects the sensitivity, developability, exposure film strength and printing durability of the image recording layer, and is preferably selected as appropriate according to the application. 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. For example, in the case of a lithographic printing plate precursor, the coverage of the image recording layer is suitably in the range of about 0.1 to about 10 g / m ² in terms of the mass after drying. More preferably from 0.5 to 5 g / m ^2.

  The lithographic printing plate precursor according to the invention may have a layer other than the image recording layer and the protective layer. For example, an intermediate layer, a backcoat layer, and the like can be provided depending on the purpose.

  The planographic printing plate precursor of the present invention can record an image through at least an exposure and development process.

As a light source for exposing the lithographic printing plate precursor according to the invention, a known light source can be used without limitation. The wavelength of a preferable light source is 300 to 1200 nm. Specifically, it is preferable to use various lasers as the light source, and among them, an infrared laser having a wavelength of 780 to 1200 nm is preferably used.
The exposure mechanism may be any of an internal drum system, an external drum system, a flat bed system, and the like.

  In addition, as other exposure light rays for the lithographic printing plate precursor of the present invention, ultra high pressure, high pressure, medium pressure, low pressure mercury lamps, chemical lamps, carbon arc lamps, xenon lamps, metal halide lamps, various visible and ultraviolet laser lamps Fluorescent lamps, tungsten lamps, sunlight, etc. can also be used.

  The lithographic printing plate precursor according to the invention is developed after being exposed. As the developer used for such development processing, an alkaline aqueous solution having a pH of 14 or less is particularly preferred, and an alkaline aqueous solution having a pH of 8 to 12 containing an anionic surfactant is more preferably used. For example, tribasic sodium phosphate, potassium, ammonium, dibasic sodium phosphate, potassium, ammonium, sodium carbonate, potassium, ammonium, sodium bicarbonate, potassium, ammonium, sodium borate, Inorganic alkaline agents such as potassium, ammonium, sodium hydroxide, ammonium, potassium, and lithium can be used. Moreover, monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monoisopropylamine, diisopropylamine, triisopropylamine, n-butylamine, monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, diisopropanolamine, Organic alkali agents such as ethyleneimine, ethylenediamine, and pyridine are also used. These alkali agents are used alone or in combination of two or more.

In the development processing of the lithographic printing plate precursor according to the invention, 1 to 20% by mass of an anionic surfactant is added to the developer, and more preferably 3 to 10% by mass. If the amount is too small, the developability deteriorates. If the amount is too large, the strength such as wear resistance of the image deteriorates. Anionic surfactants include, for example, sodium salt of lauryl alcohol sulfate, ammonium salt of lauryl alcohol sulfate, sodium salt of octyl alcohol sulfate, such as sodium salt of isopropyl naphthalene sulfonic acid, sodium salt of isobutyl naphthalene sulfonic acid, polyoxy 8-20 carbon atoms such as sodium salt of ethylene glycol mononaphthyl ether sulfate ester, sodium salt of dodecylbenzenesulfonic acid, alkylarylsulfonate such as sodium salt of metanitrobenzenesulfonic acid, secondary sodium alkyl sulfate, etc. Fatty alcohol phosphate salts such as higher alcohol sulfates, sodium salt of cetyl alcohol phosphate, etc., for example, C _{17 H 33 CON (CH 3)} CH 2 CH 2 SO 3 sulfonates of alkylamides such as Na or the like, for example, sodium dioctylsulfosuccinate, sodium sulfo sulfonate dibasic aliphatic esters such as succinic acid dihexyl ester Salts etc. are included.

  If necessary, an organic solvent such as benzyl alcohol mixed with water may be added to the developer. As the organic solvent, those having a solubility in water of about 10% by mass or less are suitable, and preferably selected from those having 5% by mass or less. For example, 1-phenylethanol, 2-phenylethanol, 3-phenylpropanol, 1,4-phenylbutanol, 2,2-phenylbutanol, 1,2-phenoxyethanol, 2-benzyloxyethanol, o-methoxybenzyl alcohol, m Examples include -methoxybenzyl alcohol, p-methoxybenzyl alcohol, benzyl alcohol, cyclohexanol, 2-methylcyclohexanol, 4-methylcyclohexanol, and 3-methylcyclohexanol. The content of the organic solvent is preferably 1 to 5% by mass with respect to the total mass of the developer at the time of use. The amount used is closely related to the amount of surfactant used, and it is preferable to increase the amount of anionic surfactant as the amount of organic solvent increases. This is because when the amount of the organic solvent is large and the amount of the anionic surfactant is small, the organic solvent is not dissolved, so that it is impossible to expect good developability.

Further, additives such as an antifoaming agent and a water softening agent can be further contained as required. Examples of the hard water softener 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 (sodium polymetaphosphate) Such as polyphosphates, aminopolycarboxylic acids (for example, ethylenediaminetetraacetic acid, its potassium salt, its sodium salt; diethylenetriaminepentaacetic acid, its potassium salt, its sodium salt; triethylenetetraminehexaacetic acid, its potassium salt, its sodium salt 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, its potassium salt, Sodium salt), other polycarboxylic acids (for example, 2-phosphonobutanetricarboxylic acid-1,2,4, its potassium salt, its sodium salt; 2 monophosphonobutanone tricarboxylic acid-2,3,4, its potassium Salts, sodium salts thereof, etc.), organic phosphonic acids (for example, 1-phosphonoethanetricarboxylic acid-1,2,2, potassium salt thereof, sodium salt thereof; 1-hydroxyethane-1,1-diphosphonic acid, potassium thereof Salts thereof, sodium salts thereof; aminotri (methylenephosphonic acid), potassium salts thereof, sodium salts thereof and the like. The optimum amount of such a hard water softener varies depending on the hardness of the hard water used and the amount used, but is generally 0.01 to 5% by weight in the developer at the time of use, more preferably It is made to contain in 0.01-0.5 mass%.

  Furthermore, when developing the lithographic printing plate precursor using an automatic developing machine, the developing solution becomes fatigued depending on the amount of processing, so that replenishing solution or fresh developing solution is used to restore processing capacity. May be. In this case, 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.

  The lithographic printing plate precursor thus developed is subjected to washing water, surface activity as described in JP-A Nos. 54-8002, 55-11545, 59-58431, and the like. It may be post-treated with a rinsing liquid containing an agent, a desensitizing liquid containing 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.

As the plate-making process of the lithographic printing plate precursor according to the invention, the entire surface may be heated before exposure, during exposure, and between exposure and development, if necessary. Such heating promotes an image forming reaction in the image recording layer, and may have advantages such as improvement in sensitivity and printing durability and stabilization of sensitivity. Further, for the purpose of improving the image strength and printing durability, it is also effective to perform whole surface post-heating or whole surface exposure on the developed image.
Usually, heating before development is preferably performed under mild conditions of 150 ° C. or less. If the temperature is too high, problems such as causing an undesired curing reaction in the non-image area are caused. Extremely 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 mounted on an offset printing machine and used for printing a large number of sheets.
As a plate cleaner used for removing stains on the plate during printing, a conventionally known plate cleaner for PS plate is used. For example, CL-1, CL-2, CP, CN-4, CN, CG-1 PC-1, SR, IC (manufactured by Fuji Photo Film Co., Ltd.) and the like.

The present invention will be specifically described below with reference to examples. However, the present invention is not limited to these.
1. Preparation of planographic printing plate precursor (Example 1)
<Aluminum plate>
Si: 0.06 mass%, Fe: 0.30 mass%, Cu: 0.005 mass%, Mn: 0.001 mass%, Mg: 0.001 mass%, Zn: 0.001 mass%, Ti: Containing 0.03% by mass, the balance is prepared using Al and an inevitable impurity aluminum alloy, and after performing the molten metal treatment and filtration, an ingot having a thickness of 500 mm and a width of 1200 mm is obtained by a DC casting method. Created. After the surface was shaved with a chamfering machine with an average thickness of 10 mm, the temperature was kept constant at 550 ° C. for about 5 hours, and when the temperature dropped to 400 ° C., rolling with a thickness of 2.7 mm using a hot rolling mill A board was used. Furthermore, after performing heat processing using a continuous annealing machine at 500 degreeC, it finished by cold rolling to 0.24 mm in thickness, and obtained the aluminum plate of JIS1050 material. After making this aluminum plate into width 1030mm, it used for the surface treatment shown below.

<Surface treatment>
The surface treatment was performed by continuously performing the following various treatments (b) to (g). After each treatment and washing with water, the liquid was removed with a nip roller.

(B) Alkali etching treatment The aluminum plate obtained above was subjected to an etching treatment by spraying using an aqueous solution having a caustic soda concentration of 26% by mass, an aluminum ion concentration of 6.5% by mass, and a temperature of 70 ° C. ² dissolved. Then, water washing by spraying was performed.

(C) Desmutting treatment Desmutting treatment was performed by spraying with a 1% by weight aqueous solution of nitric acid at a temperature of 30 ° C. (containing 0.5% by weight of aluminum ions), and then washed with water by spraying. The nitric acid aqueous solution used for the desmut treatment was a waste liquid from a step of performing an electrochemical surface roughening treatment using alternating current in a nitric acid aqueous solution.

(D) Electrochemical roughening treatment An electrochemical roughening treatment was carried out continuously using an alternating voltage of 60 Hz. The electrolytic solution at this time was a nitric acid 10.0 g / L aqueous solution (containing 5 g / L of aluminum ions and 0.007% by mass of ammonium ions), and the liquid temperature was 36 ° C. The AC power supply waveform is the waveform shown in FIG. 2, the time TP until the current value reaches the peak from zero is 0.8 msec, the duty ratio is 1: 1, the trapezoidal rectangular wave AC is used, with the carbon electrode as the counter electrode An electrochemical roughening treatment was performed. Ferrite was used for the auxiliary anode. The electrolytic cell used was the one shown in FIG. The current density was 30 A / dm ² at the peak current value, and the amount of electricity was 268 C / dm 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.
Then, water washing by spraying was performed.

(E) Alkali etching treatment An aluminum plate was subjected to an etching treatment at 32 ° C. using an aqueous solution having a caustic soda concentration of 26 mass% and an aluminum ion concentration of 6.5 mass%, and the aluminum plate was dissolved at 0.20 g / m ² . Removes the smut component mainly composed of aluminum hydroxide that was generated when electrochemical roughening treatment was performed using the alternating current of the previous stage, and also melted the edge part of the generated pit to smooth the edge part. did. Then, water washing by spraying was performed.

(F) Anodizing treatment Anodizing treatment was performed using an anodizing apparatus having a structure shown in FIG. 4 to obtain a support for a lithographic printing plate. Sulfuric acid was used as the electrolytic solution supplied to the first and second electrolysis units. All electrolytes had a sulfuric acid concentration of 170 g / L (containing 0.5 mass% of aluminum ions) and a temperature of 38 ° C. The current density was 27 A / dm ² for all. The anodizing treatment was performed by adjusting the electrolysis time so that the final oxide film amount was 2.7 g / m ² . Then, water washing by spraying was performed.

(G) Silicate treatment The aluminum plate was immersed in a 1.0 mass% aqueous solution of sodium silicate (temperature 20 ° C.) for 10 seconds. The amount of Si on the surface of the aluminum plate measured with a fluorescent X-ray analyzer was 3.5 mg / m ² .
Thereafter, the liquid was drained with a nip roller, further washed with water, and drained with a nip roller. Furthermore, 90 degreeC wind was sprayed for 10 seconds, it was made to dry, and the support body for lithographic printing plates was obtained.

<Formation of image recording layer>
Each lithographic printing plate support obtained above was provided with a thermal negative type image recording layer as follows to obtain a lithographic printing plate precursor. Before providing the image recording layer, an undercoat layer was provided as described later.

On the lithographic printing plate support, an undercoat layer coating solution having the following composition was applied with a wire bar and dried at 90 ° C. for 30 seconds to form an undercoat layer coating film. The coating amount of the coating film after drying was 10 mg / m ² .

<Coating solution composition for undercoat layer>
・ High molecular compound 0.2g
・ Methanol 100g
・ Water 1g

Furthermore, an image recording layer coating solution having the following composition was prepared, and the coating amount for the image recording layer (image recording layer coating amount) after drying the image recording layer coating solution on a lithographic printing plate support provided with an undercoat layer was A lithographic printing plate precursor is obtained by applying with a wire bar to 1.3 g / m ² and drying with a hot air dryer at 34 ° C. for 34 seconds to form a heat-sensitive layer (thermal negative type image recording layer). It was.

<Coating liquid for image recording layer>
-Infrared absorber (IR-1) represented by the following formula 0.074 g
-Polymerization initiator (OS-12) represented by the above formula 0.280 g
・ 0.151 g of additive (PM-1) represented by the following formula
-1.00 g of polymerizable compound (AM-1) represented by the following formula
-Specific binder polymer (BT-1) represented by the following formula: 1.00 g
-Ethyl violet (C-1) represented by the following formula 0.04 g
-Fluorosurfactant (Megafac F-780-F, manufactured by Dainippon Ink & Chemicals, Inc., 30% by weight methyl isobutyl ketone solution) 0.015 g
・ Methyl ethyl ketone 10.4g
・ Methanol 4.83g
・ 10.4 g of 1-methoxy-2-propanol

<Formation of protective layer>
After the image recording layer was formed on the lithographic printing plate support as described above, the protective layer coating solution shown below was applied on the image recording layer to form a protective layer, whereby a lithographic printing plate precursor was obtained. .

(1) Preparation of dispersion of inorganic layered compound (mica) 6.4 g of synthetic mica (“Somasif ME-100”: manufactured by Co-op Chemical Co., aspect ratio: 1000 or more) was added to 193.6 g of water, and a homogenizer was used. The average particle size was dispersed until the diameter corresponding to a circle was 3 μm (laser scattering method) to obtain a mica dispersion.

(2) Application of coating solution for protective layer On the surface of the image recording layer, the obtained mica dispersion, polyvinyl alcohol (manufactured by Kuraray Co., Ltd., PVA-105: saponification degree 98 mol%, polymerization degree 500), polyvinyl A mixed aqueous solution (for protective layer) of a copolymer of pyrrolidone and vinyl acetate (ICP, LUVITEC VA64W: polyvinylpyrrolidone / vinyl acetate = 6/4) and a surfactant (Emulex 710, manufactured by Nippon Emulsion) Application liquid) was applied with a wire bar, and dried at 125 ° C. for 75 seconds with a hot air dryer.
The content ratio of mica solid content / polyvinyl alcohol / copolymer of polyvinylpyrrolidone and vinyl acetate / surfactant in this mixed aqueous solution (protective layer coating solution) was 16/80/2/2 (mass%). The total coating amount (the coating amount after drying) was 1.15 g / m ² .

<Cutting of lithographic printing plate precursor>
The obtained lithographic printing plate precursor was wound up in a roll shape without sandwiching a slip sheet. Thereafter, the roll-shaped planographic printing plate precursor was cut with a slitter in a state without interleaf.

(Example 2)
As a surface treatment of the aluminum plate to be used, the lithographic printing plate precursor was obtained in the same manner as in Example 1 except that the following (h) to (k) were performed in this order between (e) and (f). Got.

(H) Desmut treatment Desmut treatment by spraying was performed with a 15% by weight aqueous solution of sulfuric acid having a temperature of 30 ° C. (containing 4.5% by weight of aluminum ions), and then washed with water by spraying. The nitric acid aqueous solution used for the desmut treatment was a waste liquid from a step of performing an electrochemical surface roughening treatment using alternating current in a nitric acid aqueous solution.

(I) Electrochemical roughening treatment An electrochemical roughening treatment was continuously performed using an alternating voltage of 60 Hz. The electrolytic solution at this time was a hydrochloric acid 5.0 g / L aqueous solution (containing 5 g / L of aluminum ions) at a temperature of 35 ° C. The AC power supply waveform is the waveform shown in FIG. 2. The time TP until the current value reaches a peak from zero is 0.8 msec, the duty ratio is 1: 1, a trapezoidal rectangular wave AC is used, with the carbon electrode as the counter electrode An electrochemical roughening treatment was performed. Ferrite was used for the auxiliary anode. The electrolytic cell used was the one shown in FIG. The current density was 17.5 A / dm ² at the peak current value, and the amount of electricity was 50 C / dm ² in terms of the total amount of electricity when the aluminum plate was the anode.
Then, water washing by spraying was performed.

(J) Alkali etching treatment An aluminum plate was spray-etched at 32 ° C. using an aqueous solution having a caustic soda concentration of 26 mass% and an aluminum ion concentration of 6.5 mass% to dissolve the aluminum plate by 0.05 g / m ² . Removes the smut component mainly composed of aluminum hydroxide generated when electrochemical surface roughening treatment was performed using alternating current in the previous stage, and also melted the edge part of the generated pit to smooth the edge part. did. Then, water washing by spraying was performed.

(K) Desmutting treatment A desmutting treatment by spraying was performed with a 25% by weight aqueous solution of sulfuric acid at a temperature of 60 ° C. (containing 0.5% by weight of aluminum ions), followed by washing with water by spraying.

(Comparative Example 1)
A lithographic printing plate precursor was obtained in the same manner as in Example 2 except that (g) was not performed.

(Comparative Example 2)
In the formation of the protective layer, a lithographic printing plate precursor was obtained in the same manner as in Example 2 except that the inorganic layered compound (mica) dispersion was not used.

(Examples 3 and 4 and Comparative Example 3)
In the above (g), the concentration and temperature of the aqueous sodium silicate solution are as shown in Table 1, and the amount of Si on the surface of the support is as shown in Table 1. A lithographic printing plate precursor was obtained.

(Example 5)
A lithographic printing plate precursor was obtained in the same manner as in Example 2 except that the thermal negative type image recording layer shown below was provided. Before providing the image recording layer, an undercoat layer was provided as described later.

On the lithographic printing plate support, an undercoat layer coating solution having the following composition was applied with a wire bar and dried at 80 ° C. for 30 seconds to form an undercoat layer coating film. The coating amount of the coating film after drying was 2 mg / m ² .

<Coating solution composition for undercoat layer>
・ High molecular compound 0.2g
・ Methanol 100g
・ Water 1g

Furthermore, an image recording layer coating solution having the following composition was prepared, and the coating amount for the image recording layer (image recording layer coating amount) after drying the image recording layer coating solution on a lithographic printing plate support provided with an undercoat layer was It is applied with a wire bar so as to be 1.1 g / m ^2, and is dried at 115 ° C. for 34 seconds with a hot air dryer to form a heat-sensitive layer (thermal negative type image recording layer) to obtain a lithographic printing plate precursor It was.

<Coating liquid for image recording layer>
-0.46 part by mass of an ethylenically unsaturated bond-containing compound (A-1) represented by the following formula-0.51 part by mass of a binder polymer (B-3) represented by the following formula-represented by the following formula Sensitizing dye (D-39) 0.03 parts by mass Bisimidazole (manufactured by Kurokin Kasei) 0.12 parts by mass Epsilon-phthalocyanine (F-1) dispersion represented by the following formula 0.47 parts by mass -0.09 part by mass of a mercapto compound represented by the following formula (S-2)-Fluorosurfactant (Megafac F-780-F, manufactured by Dainippon Ink & Chemicals, Inc., 30% by weight methyl isobutyl ketone solution) 0.009 parts by mass-Cuperon (manufactured by Wako Pure Chemical Industries) 0.003 parts by mass-Methyl ethyl ketone 7.4 parts by mass-Propylene glycol monomethyl ether 7.4 parts by mass

(Comparative Example 4)
A lithographic printing plate precursor was obtained in the same manner as in Example 5 except that in the formation of the protective layer, a dispersion of an inorganic stratiform compound (mica) was not used.

(Example 6)
A lithographic printing plate support was obtained in the same manner as in Example 2 except that the following (a) was performed before (b).

(A) Mechanical roughening treatment Using an apparatus as shown in FIG. 1, a suspension of slurry (pumice) and water (specific gravity 1.12) is supplied to the surface of the aluminum plate as a polishing slurry. However, a mechanical surface roughening treatment was performed with a rotating roller-like nylon brush. In FIG. 1, 1 is an aluminum plate, 2 and 4 are roller brushes, 3 is a polishing slurry, and 5, 6, 7 and 8 are support rollers. The average particle size of the abrasive was 40 μm, and the maximum particle size was 100 μm. The material of the nylon brush was 6 · 10 nylon, the hair length was 50 mm, and the hair diameter was 0.3 mm. The nylon brush was planted so as to be dense by making a hole in a stainless steel tube having a diameter of 300 mm. Three rotating brushes were used. The distance between the two support rollers (φ200 mm) at the bottom of the brush was 300 mm. The brush roller was pressed until the load of the drive motor for rotating the brush became 7 kW plus with respect to the load before the brush roller was pressed against the aluminum plate. The rotating direction of the brush was the same as the moving direction of the aluminum plate. The rotation speed of the brush was 200 rpm.

2. Measurement of surface shape of lithographic printing plate support The following measurements (1) to (3) were performed on the concave portions of the surface of the lithographic printing plate support used in the lithographic printing plate precursor obtained above.
The results are shown in Table 1. In Table 1, “-” 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.

(3) Average wavelength of large-wave structure Two-dimensional roughness measurement is performed with a stylus type roughness meter (SUFCOM 575, manufactured by Tokyo Seimitsu Co., Ltd.), and the average peak interval S _m defined in ISO 4287 is measured five times. The value was taken as the average wavelength. Two-dimensional roughness measurement was performed under the following conditions.

<2D roughness measurement conditions>
cut off 0.8, tilt correction FLAT-ML, measurement length 3 mm, vertical magnification 10,000 times, scanning speed 0.3 mm / sec, stylus tip diameter 2 μm

3. Measurement of aluminum elution amount of lithographic printing plate support A test piece having a size of 6 dm ² was cut out from the lithographic printing plate support used in the lithographic printing plate precursor obtained above, and a developer at 30 ° C. (Fuji A sample solution was prepared by immersing in a developer solution DN-6 (1: 4 water diluted solution) manufactured by Photo Film Co., Ltd. for 12 seconds.
The obtained sample solution was diluted with a 0.1N KOH aqueous solution, and an aluminum concentration was semi-quantified using an ICP-AES apparatus (ICPS-1000IV, manufactured by Shimadzu Corporation) to obtain an aluminum elution amount.
The results are shown in Table 1. The measured aluminum elution amount indicates the solubility of aluminum in the developer and serves as an index representing the degree of generation of aluminum residue during development.

4). Exposure and development of lithographic printing plate precursor Using a Trendsetter 3244 manufactured by Creo on a lithographic printing plate precursor after cutting, an 80% flat screen image with a resolution of 2400 dpi, output 7 W, external drum rotation speed 150 rpm, plate surface energy 110 mJ / cm Exposure was performed under the conditions of ² .
After the exposure, neither heat treatment nor water washing treatment is performed, and a conveyance speed (line speed) of 2 m / min (development time 12 seconds) and a development temperature 30 using an automatic developing machine LP-1310HII manufactured by Fuji Photo Film Co., Ltd. Development was performed at a temperature of ° C to obtain a lithographic printing plate. The developer used was a 1: 4 water diluted solution of DH-N manufactured by Fuji Photo Film Co., Ltd., and the 1: 1 water diluted solution of GN-2K manufactured by Fuji Photo Film Co., Ltd. was used as the finisher. .

5. Evaluation of lithographic printing plate precursor The edge stain resistance and printing durability of the lithographic printing plate obtained above were evaluated by the following methods.
(1) Resistance to edge stains Whether or not linear stains are seen on the portion of the printed material that corresponds to the edges of the lithographic printing plate slitter printed using a printing press Lislon manufactured by Komori Corporation. Were visually observed to evaluate edge stain resistance.
The results are shown in Table 1. In the table, the case where no linear stain was seen was indicated by “◯”, and the case where it was seen was indicated by “x”.

(2) Printing durability Printing durability was evaluated based on the number of printed sheets printed at the time when it was visually recognized that the density of the solid image of the printed matter started to become thin, using a printing press Lislon manufactured by Komori Corporation.
The results are shown in Table 1.

As is clear from Table 1, the planographic printing plate precursors (Examples 1 to 6) of the present invention have no generation of aluminum residue during development, and no edge smearing occurs even without using slip sheets. Excellent in printing durability.
On the other hand, when the Si amount on the support surface is 0 (Comparative Example 1), there is generation of aluminum residue during development, and edge smearing occurs when no interleaf is used. Further, when the inorganic layered compound is not used for the protective layer (Comparative Examples 2 and 4), or when the amount of Si on the support surface is too large (Comparative Example 3), the printing durability is inferior.

It is a side view which shows the concept of the process of the brush graining used for the mechanical roughening process in preparation of the support body for lithographic printing plates used for the lithographic printing plate precursor of this invention. 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 used for the lithographic printing plate precursor of 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 used for the lithographic printing plate precursor of 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 used for the lithographic printing plate precursor of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Aluminum plate 2, 4 Roller-shaped brush 3 Polishing slurry liquid 5, 6, 7, 8 Support roller 11 Aluminum plate 12 Radial drum roller 13a, 13b Main electrode 14 Electrolytic process liquid 15 Electrolyte supply port 16 Slit 17 Electrolyte path 18 Auxiliary anodes 19a, 19b Thyristors 20 AC power supply 40 Main electrolytic tank 50 Auxiliary anode tank 410 Anodizing device 412 Power supply tank 414 Electrolytic treatment tank 416 Aluminum plate 418, 426 Electrolytic solution 420 Power supply electrode 422, 428 Roller 424 Nip roller 430 Electrolytic electrode 432 Tank wall 434 DC power supply

Claims (4)

An image recording layer containing a polymerization initiator, a polymerizable compound, and a binder polymer on a lithographic printing plate support comprising an aluminum plate having a surface Si amount of 1.0 to 8 mg / m ² , and an inorganic layered compound A lithographic printing plate precursor comprising a protective layer containing   The lithographic printing plate support has on its surface a grain shape having 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. Item 2. The lithographic printing plate precursor as described in Item 1.   The planographic printing plate precursor according to claim 2, wherein the grain shape is a structure in which a large wave structure, a medium wave structure, and the small wave structure formed by a mechanical roughening treatment are superimposed.   The lithographic printing plate precursor as claimed in claim 3, wherein an average wavelength of the large wave structure is 5 to 100 μm.

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