JP2011068014A - Original lithographic printing plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an original lithographic printing plate which is excellent in resistance to plate wear/print smear and resistance to micro-corrosion stain and can develop an image aboard the machine. <P>SOLUTION: The original plate of lithographic printing plate has a photosensitive layer comprising a sensitizing dye (A), a polymerization initiator (B), a polymerizable compound (C) and a binder polymer (D), and a protective layer in this order on a support, wherein the substrate is made by using an aluminum alloy plate wherein the density, on the surface, of an inter-metallic compound having a circle-equivalent diameter of 0.2 μm or more is 35,000 pieces/mm<SP>2</SP>or more, and the number of aluminum carbide having the maximum length of 1 μm or more is 30,000 pieces/g or less. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a lithographic printing plate precursor. Specifically, the present invention relates to a lithographic printing plate precursor having a protective layer on a photosensitive layer.

  In general, as an offset printing plate or a lithographic printing plate, the surface of an aluminum alloy base plate is subjected to a surface treatment such as roughening treatment or anodizing treatment to form a support, and a photosensitive material is applied onto the support and dried. A so-called PS plate is used which has been subjected to plate making processing such as image exposure, development and gumming on the PS plate. In the process of the plate making process, the photosensitive layer that remains undissolved by the development process forms an image portion, while the portion where the photosensitive layer is removed and the underlying aluminum surface is hydrophilic has a hydrophilic property. Thus, a non-image part is formed.

  By the way, as such a support for offset printing or lithographic printing, generally an aluminum alloy rolled plate that is lightweight and excellent in surface treatment, workability, and corrosion resistance is used. As the aluminum alloy rolled sheet for such purpose, conventionally, an aluminum alloy rolled sheet having a thickness of about 0.1 to 0.5 mm made of JIS1050, JIS1100, JIS3003, etc. has been used. Is used for a printing plate after roughening the surface and then anodizing it.

  Specifically, as described in JP-A-48-49501 (Patent Document 1), an aluminum lithographic printing plate subjected to mechanical surface roughening treatment, chemical etching treatment, and anodized film treatment in this order, or An aluminum lithographic printing plate subjected to electrochemical treatment, post-treatment, and anodizing treatment in sequence as described in JP-A-51-146234 (Patent Document 2), Japanese Patent Publication No. 48-28123 (Patent Document 3) There are known aluminum lithographic printing plates and the like which have been subjected to the chemical etching treatment and the anodizing treatment described in the above.

  In Patent Document 4, storage is achieved by using an aluminum alloy support for a printing plate in which the number of aluminum carbides having a maximum length of 1 μm or more in a rolled plate made of a pure aluminum alloy is regulated to 30000 pieces / g or less. It is described that defects in the photosensitive layer can be suppressed.

In Patent Document 5, a lithographic printing plate precursor excellent in adhesion to a photosensitive layer and printing durability is obtained by using a support having 5000 to 35000 pieces / mm ^{2 of} an intermetallic compound having a diameter of 0.1 μm or more. It is described that it is obtained.
Patent Document 6 discloses a laser using a support obtained by roughening an aluminum plate in which the density of an intermetallic compound existing at a depth of 2 μm 2 or less from the surface is in the range of 500 to 35,000 / mm ^2. A lithographic printing plate precursor excellent in exposure suitability and printing performance is described.

In Patent Document 7, a lithographic printing plate precursor is obtained using a support having a uniform rough surface state using an aluminum alloy in which intermetallic compounds are dispersed at a density of 3000 to 30000 pieces / mm ^{2 in} the surface direction. It is described.
However, even when these supports are used, it has not been sufficient to prevent the photosensitive layer from being defective when the lithographic printing plate precursor obtained is stored.

JP 48-49501 JP 51-146234 A JP-B 48-28123 JP 2004-292862 A JP 2002-160466 A Japanese Patent No. 3788943 JP 2002-88434 A

  In a negative lithographic printing plate precursor having a photosensitive layer having a sensitizing dye, a polymerization initiator, a polymerizable compound, and a binder polymer, and a protective layer, the exposed portion is cured to become an image portion to which the ink adheres, and is not exposed. The portion is developed to become a non-image portion. When such a lithographic printing plate precursor is stored for a long period of time, there may be a problem that an exposed portion that should be an image portion is lost in a circle and becomes a non-image portion (in this application, it may be referred to as a “white spot failure”). is there). In particular, in the case of a lithographic printing plate precursor having a protective layer on the photosensitive layer, it has been observed that defects generated in the photosensitive layer due to storage tend to be large. In order to solve this problem, the present inventor has an aluminum alloy plate in which the density of intermetallic compounds on the surface is not less than a predetermined number, and the number of aluminum carbides having a predetermined size or more in the aluminum bulk is not more than the predetermined number. The present inventors have found that this problem can be solved by using a support prepared from the present invention.

  Therefore, the present invention provides a lithographic printing plate having a uniform surface roughening treatment, a lithographic printing plate using the same having excellent printing durability and stain resistance, and no defects in the photosensitive layer even when stored for a long period of time. The purpose is to provide the original edition.

That is, the present invention provides the following (1) to (7).
(1) Lithographic printing having a photosensitive layer and a protective layer in this order (A) a sensitizing dye, (B) a polymerization initiator, (C) a polymerizable compound, and (D) a binder polymer on a support. In the original edition,
The support is an aluminum alloy in which the density of an intermetallic compound having a circle-equivalent diameter of 0.2 μm or more on the surface is 35000 pieces / mm ² or more and the number of aluminum carbides having a maximum length of 1 μm or more is 30000 pieces / g or less. A lithographic printing plate precursor produced using a plate.
(2) The lithographic printing plate precursor as described in (1), wherein the support is a support obtained by subjecting the surface of the aluminum alloy plate to a roughening treatment including an electrochemical roughening treatment.
(3) The lithographic printing plate precursor as described in (1) or (2), wherein the support is further anodized after the surface roughening treatment and has an anodized film having an average thickness of 1.0 μm or more.
(4) The lithographic printing plate precursor as described in any one of (1) to (3), wherein the aluminum alloy plate is an aluminum alloy plate produced by a continuous casting method.
(5) The lithographic printing plate precursor as described in any one of (1) to (4), wherein a photosensitive layer having a mass ratio of the polymerizable compound to the binder polymer and a polymerizable compound mass / binder polymer mass of 2 to 4 is provided.
(6) The lithographic printing plate precursor as described in any one of (1) to (5), wherein the sensitizing dye is a sensitizing dye having an absorption maximum at 350 to 450 nm.
(7) The lithographic printing plate precursor as described in any one of (1) to (6), wherein the protective layer is a composition containing polyvinyl alcohol.

  According to the present invention, it is possible to obtain a lithographic printing plate precursor that does not cause defects in the photosensitive layer even when stored for a long time. Further, the lithographic printing plate precursor according to the present invention is excellent in printing durability and stain resistance.

It is a graph which shows an example of the alternating waveform current waveform figure used for an electrochemical roughening process. It is a side view which shows an example of the radial type cell in the electrochemical roughening process using alternating current. It is the schematic of the anodizing apparatus used for anodizing. It is a graph which shows an example of the sine waveform figure used for an electrochemical roughening process. It is a side view which shows the concept of the process of the brush graining used for a machine roughening process. It is the schematic of the anodizing apparatus used for anodizing.

Hereinafter, the present invention will be described in detail.
The lithographic printing plate precursor according to the invention comprises a photosensitive layer and a protective layer having (A) a sensitizing dye, (B) a polymerization initiator, (C) a polymerizable compound, and (D) a binder polymer on a support. In the lithographic printing plate precursor having
The support is an aluminum alloy in which the density of an intermetallic compound having an equivalent circle diameter of 0.2 μm or more on the surface is 35,000 pieces / mm ² or more and the number of aluminum carbides having a maximum length of 1 μm or more is 30000 pieces / g or less. It is produced using a board.

As described above, when a negative planographic printing plate precursor having a photosensitive layer and a protective layer having a sensitizing dye, a polymerization initiator, a polymerizable compound, and a binder polymer is stored for a long period of time, an exposed portion that should become an image portion May become a non-image part due to a circular defect (so-called “white defect”). The details of this cause are unknown, but during long-term storage, the aluminum carbide and / or intermetallic compound on the support surface reacts with moisture in the air, bubbles are generated, and the photosensitive layer and protective layer rise, It is presumed that a white spot failure will occur. That is, only a certain effect can be obtained by adjusting the amount of aluminum carbide, but in addition to the adjustment of aluminum carbide, by using an aluminum alloy plate having a surface intermetallic compound density higher than a predetermined number, It is considered that the size of the intermetallic compound is reduced, thereby obtaining a lithographic printing plate precursor having excellent printing durability, excellent stain resistance, and suppressed whiteout failure.
The density of the intermetallic compound having a circle-equivalent diameter of 0.2 μm or more on the surface is preferably more than 30000 / mm ^2, more preferably 35000 / mm ² or more. If the surface is an aluminum alloy plate having an intermetallic compound in this range, the size of each intermetallic compound existing on the surface of the aluminum alloy plate is reduced, and rough surface sand obtained by roughening treatment is used. Since the eye shape is uniform, the lithographic printing plate using this aluminum support has excellent printing durability and stain resistance, and if the amount of aluminum carbide in the aluminum alloy is adjusted, the above-mentioned white defect may occur. Becomes smaller.

In addition, new knowledge has been obtained that intermetallic compounds present on the surface of an aluminum alloy plate are effective starting points when electrochemically roughening the aluminum alloy plate. By using an aluminum alloy plate having an equivalent diameter of 0.2 μm or more and an intermetallic compound density of 35000 pieces / mm ² or more, the uniformity of the electrolytically roughened surface becomes better.

Furthermore, it is preferable that the number of intermetallic compounds having an equivalent circle diameter of more than 1 μm existing on the surface of the aluminum alloy plate is small. Specifically, the number of intermetallic compounds having an equivalent circle diameter of 1.0 μm or more on the surface of the aluminum alloy plate is preferably 2500 / mm ² or less, and more preferably 2000 / mm ² or less. .

Here, the number and density of intermetallic compounds on the surface of the aluminum alloy plate can be measured by the following method.
First, an aluminum alloy plate obtained by wiping off the oil on its surface with acetone is used as a measurement sample.
Next, using a scanning electron microscope (PC-SEM7401F, manufactured by JEOL Ltd.), a reflected electron image on the surface of the aluminum alloy plate is taken under the conditions of an acceleration voltage of 12.0 kV and a magnification of 2000 times.
Subsequently, five images arbitrarily selected from the obtained reflected electron images are stored in JPEG format, and converted into bmf (bitmap file) format using MS-Paint (manufactured by Microsoft).
This bmf format file is stored in the image analysis software ImageFactory Ver. 3.2 After reading into the Japanese version (Asahi Hitech Co., Ltd.) and performing image analysis, static binarization processing of the image is performed, and the portion corresponding to the white intermetallic compound is counted as a feature value. Specify the equivalent circle diameter (equivalent circle diameter) to obtain the particle size distribution.
From the result of the particle size distribution, the density of an intermetallic compound having an equivalent circle diameter of 0.2 μm or more is calculated. This calculation is performed by rounding the average value of the numbers calculated from each of the five image data (particle size distributions) to the nearest hundred.
The density of the intermetallic compound on the surface of the aluminum alloy plate or the number of intermetallic compounds is the same on the back surface of the aluminum alloy plate on which the photosensitive layer is not formed after the lithographic printing plate precursor is produced. Can be measured.

The intermetallic compound present in the aluminum alloy plate varies depending on the type of metal element contained in the aluminum alloy plate, but in the case of a preferred embodiment of the aluminum alloy plate described later, which contains Al, Si and Fe as essential components, the aluminum alloy plate Specific examples of intermetallic compounds present in the above include, for example, Al—Fe intermetallic compounds such as Al ₃ Fe, Al ₆ Fe, and Al _m Fe, and AlFeSi intermetallic metals such as α-AlFeSi and β-AlFeSi. Compounds.
The aluminum alloy plate used in the present invention has an Al content of 99% by mass or more, and from trace elements such as Si, Fe, Ni, Mn, Cu, Mg, Cr, Zn, Bi, Ti, and V It contains at least one element selected from the group consisting of:
The aluminum alloy plate used in the present invention is preferably a preferred embodiment of an aluminum alloy plate to be described later, which contains Al, Si and Fe as essential components.

In the aluminum alloy plate used in the present invention, the number of aluminum carbides having a maximum length of 1 μm or more is 30000 pieces / g or less.
An extremely minute aluminum carbide having a maximum length of less than 1 μm is usually corroded and disappeared during the surface roughening treatment, and an anodic oxide film is normally formed in that portion, so that there is no particular problem. On the other hand, aluminum carbide having a maximum length of 1 μm or more remains after the surface roughening treatment, so that an anodic oxide film is not formed on the surface, and the aluminum carbide is corroded upon contact with dampening water thereafter. If the number of carbides of a predetermined size or more is a predetermined number or more per gram of aluminum, the carbides are the starting point, the ink stain resistance is remarkably lowered, and a reaction product such as a hydrate is formed. This may cause defects in the photosensitive layer itself and the protective layer thereon. Therefore, in the present invention, the number of aluminum carbides having a maximum length of 1 μm or more in the rolled sheet is 30000 pieces / g or less, and the density of the intermetallic compound having a circle equivalent diameter of 0.2 μm or more on the surface is 35000 pieces / mm. this problem was resolved by ² or more. More preferably, the number of aluminum carbides having a maximum length of 1 μm or more is 27000 pieces / g or less. Furthermore, 19000 pieces / g or less is preferable and 10,000 pieces / g or less is more preferable.

Here, the number of carbides in aluminum is measured as follows.
First, 1 g of an aluminum sample is taken from a rolled plate, immersed in 100 ml of dehydrated methanol (special reagent grade), and then mixed with several drops of bromine (special reagent express) (cool the entire container so as not to exceed 40 ° C.). Add 5 ml and completely dissolve the aluminum at 40 ° C. for 3 hr. Thereafter, the mixture is filtered through a Teflon (registered trademark) filter having a mesh diameter of 1 μm, and 50 ml of 10% NaOH solution is poured onto the filter at room temperature for 10 minutes. Thereafter, it is washed with water and dried, and a fixed area of the filter is observed with a SEM of 2000 times, and the number of aluminum carbides confirmed by elemental analysis such as EPMA or EDX analysis is measured. Then, the number of aluminum carbides contained in 1 g of dissolved aluminum is obtained by calculation from the relationship between the number in the fixed area measured here and the total filtration area of the filter.

<Aluminum alloy plate (rolled aluminum)>
Hereinafter, the suitable aspect of the aluminum alloy plate used for this invention is described.
The preferred embodiment of the aluminum alloy plate used in the present invention is that the Al content is 99% by mass or more, 0.03 to 0.20% by mass of Si, and 0.11 to 0.45% by mass of Fe. The solid solution amount of Si is preferably 120 to 600 ppm, and the solid solution amount of Fe is preferably 100 ppm or less.
By using the preferred embodiment of the aluminum alloy plate described above, the stability of the electrolytic surface roughening treatment can be improved, and the uniformity of the electrolytic surface roughened surface can be enhanced. As a result, a support having a uniform electrolytic roughened surface can be obtained even under various electrolytic roughening treatment conditions. By using the support, lithographic printing excellent in printing durability and stain resistance is obtained. You can get the original version.
Although the alloy component in the suitable aspect of the aluminum alloy plate mentioned above is Al, Fe, and Si, you may contain copper (Cu) as an arbitrary component.

  Si is an element contained as an inevitable impurity in an Al ingot, which is a raw material, in an amount of about 0.03 to 0.1% by mass, and is often intentionally added in a small amount to prevent variation due to a difference in raw materials. Si exists as a solid solution in aluminum, or as an intermetallic compound or a single precipitate.

In the present invention, the Si content is preferably 0.03 to 0.20 mass%, more preferably 0.04 to 0.18 mass%, and 0.05 to 0.15 mass%. More preferably.
When the Si content is within this range, the necessary amount of Si solid solution is ensured, and even when anodizing is performed after electrolytic surface roughening, defects in the anodized film are unlikely to occur. Thus, the stain resistance as a lithographic printing plate is also improved.

Moreover, in this invention, it is preferable that the solid solution amount of Si is 120-600 ppm, It is more preferable that it is 150-600 ppm, It is further more preferable that it is 150-500 ppm.
When the solid solution amount of Si is within this range, the electrolytic roughened surface becomes uniform, and pits having average opening diameters of 0.01 to 0.05 μm and 0.05 to 1.5 μm are uniform over the entire surface. Formed.

  Fe is an element that hardly dissolves in aluminum and remains as an intermetallic compound.

In the present invention, the Fe content is preferably 0.11 to 0.45 mass%, more preferably 0.15 to 0.45 mass%, and 0.20 to 0.43 mass%. More preferably.
When the Fe content is within this range, Fe is dispersed as a fine intermetallic compound, and these act as starting points for the electrolytic surface roughening treatment, so that the electrolytic surface roughened surface becomes uniform.

In the present invention, from the viewpoint of securing a necessary intermetallic compound of Fe, the solid solution amount of Fe is preferably 100 ppm or less, more preferably 50 ppm or less, and further preferably 40 ppm or less. preferable.
Further, from the viewpoint of ensuring the heat resistance of the aluminum alloy plate, the solid solution amount of Fe is preferably 10 ppm or more.

Cu is an important element in controlling the electrolytic surface roughening treatment, but may be included arbitrarily.
In the present invention, from the viewpoint of maintaining the uniformity of electrolytic surface roughening, the content when Cu is contained is preferably 0.030% by mass or less.

  Since the grain refinement element does not affect the uniformity of the electrolytic surface roughening, it may be added as appropriate to prevent cracking during casting. Therefore, for example, Ti can be added in a range of 0.05% by mass or less, and B can be added in a range of 0.02% by mass or less.

The balance of the aluminum alloy plate is made of Al and inevitable impurities.
As this inevitable impurity, Mg, Mn, Zn, Cr, Zr, V, Zn, Be etc. are mentioned, for example, These may each be contained 0.05 mass% or less.
Moreover, most of inevitable impurities are contained in the Al ingot. For example, if the inevitable impurities are contained in a metal having an Al purity of 99.5%, the effects of the present invention are not impaired.
For inevitable impurities, see, for example, L.A. F. The amount of impurities described in Mondolfo's “Aluminum Alloys: Structure and properties” (1976) and the like may be contained.

The preferred embodiment of the aluminum alloy plate described above is preferably manufactured by a continuous casting method.
Rolling by continuous casting has a high solidification rate on the surface of the cast material, so that the crystallized material is fine and uniform, does not require the homogenization heat treatment of the ingot required by the DC casting method, and is not subjected to long-time processing. Therefore, it is suitable as a base plate for a lithographic printing plate support.

Specifically, the following method is preferably exemplified.
First, a molten aluminum alloy adjusted to a predetermined alloy component content can be subjected to a cleaning treatment as necessary according to a conventional method.
Examples of the cleaning treatment include degassing treatment for removing unnecessary gas such as hydrogen in the molten metal (eg flux treatment using argon gas, chlorine gas, etc.); ceramic tube filter, ceramic foam filter, etc. Examples include a filtering process using a so-called rigid media filter, a filter using alumina flakes, alumina balls or the like as a filter medium, a glass cloth filter, or the like; a process combining such a degassing process and a filtering process.

In producing a rolled plate made of an aluminum alloy, the alloy is melted at the melting stage before casting, and 1) the molten metal is held for 10 minutes or more, 2) then subjected to in-line degassing treatment, or 3) further molten metal. When one of these processes, or a combination of two or more, is performed after passing through an in-line filter, the maximum length in the rolled plate is 1 μm or more even when the aluminum alloy used contains a relatively large amount of carbide. This is preferable because the number of aluminum carbides can be easily reduced to 30000 pieces / g or less.
In addition, since the process is simple as in the continuous casting method, the number of aluminum carbide having a maximum length of 1 μm or more can be easily reduced to 30000 pieces / g or less because there is little carbon (C) contamination from the outside. Therefore, it is preferable.

  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 present applicant has also proposed a technique relating to degassing of molten metal in Japanese Patent Application Laid-Open No. 7-40017.

Next, continuous casting is performed using a molten metal that has been subjected to a cleaning treatment as necessary.
The aluminum alloy sheet of the present invention is obtained by continuous casting in which molten aluminum alloy is supplied between a pair of cooling rollers via a molten metal supply nozzle, and rolling is performed while the molten aluminum alloy is solidified by the pair of cooling rollers. Is preferred.
Rolling by continuous casting has a high solidification rate on the surface of the cast material, so that the crystallized material is fine and uniform, does not require the homogenization heat treatment of the ingot required by the DC casting method, and is not subjected to long-time processing. Therefore, it is suitable as a base plate for a lithographic printing plate support.
Continuous casting is a process in which a molten aluminum alloy is supplied between a pair of cooling rollers via a molten metal supply nozzle, and rolling is performed while the molten aluminum alloy is solidified by the pair of cooling rollers. Method), a method using a cooling roll represented by the 3C method, a double belt method (Hasley method), a method using a cooling belt or a cooling block represented by the Al-Swiss Caster II type, and the like.
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. Moreover, it solidifies in the range whose cooling rate is 100-1000 degrees C / sec.
A cooling rate within this range is preferable because the density of an intermetallic compound having an equivalent circle diameter of 0.2 μm or more on the surface of the obtained aluminum alloy plate can be easily set to 35000 pieces / mm ² or more.
Regarding the continuous casting method, the techniques proposed by the present applicant 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.

In continuous casting, 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 continuously cast, and the hot rolling step can be omitted. Benefits are gained.
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.
In the present invention, from the viewpoint of generating a large number of intermetallic compounds, a method using a cooling roll is preferable, and the plate thickness is preferably 7 mm or less.

  After the continuous casting, the obtained aluminum alloy plate is finished to a predetermined thickness, for example, a thickness of 0.1 to 0.5 mm, through a cold rolling process or the like applied as necessary.

In the present invention, intermediate annealing treatment may be performed from the viewpoint of increasing the Si solid solution amount or suppressing the Fe solid solution amount before, after, or during the cold rolling. Further, the appropriate intermediate annealing treatment has an effect of making the crystal grains fine, and the surface quality can be improved.
As a suitable condition for the intermediate annealing treatment, a batch annealing furnace is used at 280 to 550 ° C. for 2 to 20 hours, preferably 350 to 550 ° C. for 2 to 10 hours, more preferably 350 to 550 ° C. for 2 to 5 hours. Conditions for heating for a period of time; conditions for heating at 400 to 550 ° C. for 6 minutes or less, preferably 450 to 550 ° C. for 2 minutes or less using a continuous annealing furnace;

The flatness of the aluminum alloy 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 alloy 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 into a predetermined plate width.
Furthermore, in order to prevent the generation | occurrence | production of the damage | wound by friction between aluminum alloy plates, you may provide a thin oil film on the surface of an aluminum alloy plate. As the oil film, a volatile or non-volatile film is appropriately used as necessary.

<Roughening treatment>
The lithographic printing of the present invention is carried out by subjecting the surface of the aluminum alloy plate obtained through the above-described continuous casting process and various processes (for example, intermediate annealing process, cold rolling process, etc.) to be performed as desired. A support used for the plate precursor can be prepared.
As the roughening treatment, generally one or a combination of two or more of mechanical roughening treatment, chemical roughening treatment and electrochemical roughening treatment is used.
In the present invention, as the surface roughening treatment, it is preferable to perform at least electrolytic surface roughening treatment and to perform alkali etching treatment (first alkali etching treatment) before the electrolytic surface roughening treatment. It is preferable to perform an alkali etching process (second alkali etching process) later.

As the surface roughening treatment, electrochemical surface roughening treatment is preferably performed twice, and an etching treatment in an alkaline aqueous solution is preferably performed between them. 1 alkali etching treatment), desmutting treatment in acidic aqueous solution (first desmutting treatment), electrochemical roughening treatment in aqueous solution containing nitric acid or hydrochloric acid (first electrolytic roughening treatment), in alkaline aqueous solution Etching treatment (second alkali etching treatment), desmutting treatment in acidic aqueous solution (second desmutting treatment), electrochemical surface roughening treatment in aqueous solution containing hydrochloric acid (second electrolytic surface roughening treatment) Etching treatment in alkaline aqueous solution (third alkaline etching treatment), desmutting treatment in acidic aqueous solution (third desmutting treatment), and anodizing treatment in this order Be treated are preferably exemplified.
Moreover, it is preferable to perform a mechanical surface roughening process before the said alkali etching process (1st alkali etching process).
Furthermore, it is also preferable to perform sealing treatment and hydrophilization treatment after the anodizing treatment.

When manufacturing the support body used for the lithographic printing plate precursor according to the invention, various processes other than those described above may be included.
Hereinafter, each step of the surface treatment will be described in detail.

<Mechanical roughening>
In this invention, it is preferable to perform the mechanical roughening process performed in order to make the center average surface roughness of the surface of an aluminum alloy plate 0.35-1.0 micrometer.
Hereinafter, the brush grain method used suitably as a mechanical roughening process is demonstrated.

The brush grain method generally uses a roller-shaped brush in which a large number of brush hairs such as synthetic resin hair made of synthetic resin such as nylon (trade name), propylene, and vinyl chloride resin are implanted on the surface of a cylindrical body. This is performed by rubbing one or both of the surfaces of the aluminum alloy plate while spraying a slurry liquid containing an abrasive on a rotating roller brush.
Instead of the roller brush and the slurry liquid, a polishing roller which is a roller having a polishing layer on the surface can be used.

When a roller brush is used, the flexural modulus is preferably 10,000 to 40,000 kg / cm ² , more preferably 15,000 to 35,000 kg / cm ² , and the bristle strength is preferably Brush hair that is 500 g or less, more preferably 400 g or less is used. The diameter of the brush bristles is generally 0.2 to 0.9 mm. The length of the brush bristles can be appropriately determined according to the outer diameter of the roller brush and the diameter of the body, but is generally 10 to 100 mm.
In the present invention, it is preferable to use a plurality of nylon brushes, specifically, 3 or more are more preferable, and 4 or more are particularly preferable. By adjusting the number of brushes, the wavelength component of the recess formed on the aluminum alloy plate surface can be adjusted.

  Further, the load of the drive motor that rotates the brush is preferably 1 kW plus or more, more preferably 2 kW plus or more, and particularly preferably 8 kW plus or more with respect to the load before the brush roller is pressed against the aluminum alloy plate. By adjusting the load, the depth of the recess formed on the surface of the aluminum alloy plate can be adjusted. The number of rotations of the brush is preferably 100 or more, and particularly preferably 200 or more.

A well-known thing can be used for an abrasive | polishing agent. For example, abrasives such as pumice stone (pumice stone), 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. Quartz sand is harder than pumicestone and is less likely to break, so it has better surface roughening efficiency. Further, aluminum hydroxide is suitable for the case where it is not desired to locally generate deep recesses because particles are damaged when an excessive load is applied.
The median diameter of the abrasive is preferably from 2 to 100 μm, more preferably from 20 to 60 μm, from the viewpoint of excellent surface roughening efficiency and the ability to narrow the graining pitch. By adjusting the median diameter of the abrasive, the depth of the recess formed on the aluminum alloy plate surface can be adjusted.

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.

  As for details of an apparatus for performing a mechanical surface roughening process using a brush and an abrasive, those described in JP-A-2002-2111159 can be used by the present applicant.

  Examples of the mechanical surface roughening process other than the brush grain method include a process of forming irregularities on the surface by transfer at the end of the cold rolling described above. In the present invention, instead of the brush grain method, or a brush Can be applied together with the grain method.

<First alkali etching treatment>
The first alkali etching treatment is a treatment for dissolving the surface layer by bringing the aluminum alloy plate into contact with an alkali solution.

The first alkali etching treatment performed before the electrolytic surface roughening treatment (first electrolytic surface roughening treatment) is to smooth the uneven shape when the mechanical surface roughening is performed. When forming a uniform recess by the treatment (first electrolytic surface roughening treatment) and when mechanical surface roughening is not performed, the rolling oil, dirt, natural oxide film, etc. on the surface of the aluminum alloy plate are removed. It is done for the purpose of doing.
In the first alkali etching treatment, the etching amount is preferably 0.1 g / m ² or more, more preferably 0.5 g / m ² or more, and further preferably 1 g / m ² or more. Further, it is preferably 12 g / m ² or less, more preferably 10 g / m ² or less, and still more preferably 8 g / m ² or less. When the lower limit of the etching amount is within the above range, uniform pits can be generated in the electrolytic surface roughening treatment (first electrolytic surface roughening treatment), and further, the occurrence of processing unevenness can be prevented. When the upper limit of the etching amount is in the above range, the amount of the alkaline aqueous solution used is reduced, which is economically advantageous.

  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, primary sodium phosphate, primary 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.

In the first alkali etching treatment, the concentration of the alkaline solution is preferably 30 g / L or more, more preferably 300 g / L or more, and preferably 500 g / L or less, 450 g / L. The following is more preferable.
The alkaline solution preferably contains aluminum ions. The aluminum ion concentration is preferably 1 g / L or more, more preferably 50 g / L or more, and preferably 200 g / L or less, more preferably 150 g / L or less. Such an alkaline solution can be prepared using, for example, water, a 48 mass% sodium hydroxide aqueous solution, and sodium aluminate.

In the first alkali etching treatment, the temperature of the alkali solution is preferably 30 ° C. or higher, more preferably 50 ° C. or higher, and preferably 80 ° C. or lower, and 75 ° C. or lower. Is more preferable.
In the first alkaline etching treatment, the treatment time is preferably 1 second or longer, more preferably 2 seconds or longer, more preferably 30 seconds or shorter, and more preferably 15 seconds or shorter. preferable.

When the aluminum alloy plate is continuously etched, the aluminum ion concentration in the alkaline solution increases and the etching amount of the aluminum alloy plate varies. Therefore, the composition management of the etching solution is preferably performed as follows.
That is, a matrix of conductivity, specific gravity, and temperature, or a matrix of conductivity, ultrasonic propagation velocity, and temperature corresponding to the matrix of caustic soda concentration and aluminum ion concentration is prepared in advance, and the conductivity and specific gravity are prepared. The liquid composition is measured according to the temperature and temperature, or the electrical conductivity, the ultrasonic wave propagation speed, and the temperature, and caustic soda and water are added so that the control target value of the liquid composition is reached. Then, the amount of the etching solution increased by adding caustic soda and water is overflowed from the circulation tank, thereby keeping the amount of the solution constant. As caustic soda to be added, 40 to 60% by mass for industrial use can be used.
As the conductivity meter and the specific gravity meter, it is preferable to use those that are temperature-compensated. As the specific gravity meter, a differential pressure type is preferably used.

  Examples of the method of bringing the aluminum alloy plate into contact with the alkaline solution include, for example, a method of passing the aluminum alloy plate through a tank containing an alkaline solution, a method of immersing the aluminum alloy plate in a tank containing an alkaline solution, and an alkali. The method of spraying a solution on the surface of an aluminum alloy plate is mentioned.

  Among these, a method of spraying an alkaline solution onto the surface of the aluminum alloy plate is preferable. Specifically, a method of spraying an etching solution in an amount of 10 to 100 L / min per spray tube from a spray tube having φ2 to 5 mm holes at a pitch of 10 to 50 mm is preferable. It is preferable to provide a plurality of spray tubes.

After the alkali etching process is completed, it is preferable to drain the liquid with a nip roller, and further perform the water washing process for 1 to 10 seconds and then drain the liquid with a nip roller.
The water washing treatment is preferably carried out using an apparatus for washing with a free-falling curtain-like liquid film, and further using a spray tube.

The apparatus for washing with a free-fall curtain liquid film is a water storage tank for storing water, a water supply pipe for supplying water to the water storage tank, and a free-fall curtain liquid film from the water storage tank to the aluminum alloy plate. And a rectifying unit.
In this apparatus, water is supplied to the water supply tank from the water supply cylinder, and when the water overflows from the water supply tank, the water is rectified by the rectifying unit, and a free-falling curtain-like liquid film is supplied to the aluminum alloy plate. When this apparatus is used, the liquid amount is preferably 10 to 100 L / min. Moreover, it is preferable that the distance L in which water exists as a free fall curtain-like liquid film between a rectification | straightening part and aluminum is 20-50 mm. Moreover, it is preferable that the angle (alpha) of an aluminum alloy plate is 30-80 degrees with respect to a horizontal direction.

  If an apparatus for performing water washing treatment with a free-fall curtain-like liquid film is used, the aluminum alloy plate can be uniformly washed with water, so that the uniformity of the treatment performed before the water washing treatment can be improved. As a specific apparatus for washing with a free-fall curtain-like liquid film, for example, an apparatus described in JP-A-2003-96584 is preferably exemplified.

  Moreover, as a spray tube used for the water washing process, for example, a spray tube having a plurality of spray tips spreading in a fan shape in the width direction of the aluminum alloy plate can be used. The distance between spray tips is preferably 20 to 100 mm, and the amount of liquid per spray tip is preferably 0.5 to 20 L / min. It is preferable to use a plurality of spray tubes.

<First desmut treatment>
After the first alkali etching treatment, it is preferable to perform pickling (first desmutting treatment) in order to remove dirt (smut) remaining on the surface. The desmut treatment is performed by bringing the aluminum alloy plate into contact with an acidic solution.

Examples of the acid used include nitric acid, sulfuric acid, phosphoric acid, chromic acid, hydrofluoric acid, and borohydrofluoric acid.
In the first desmutting process performed after the first alkali etching process, when nitric acid electrolysis is subsequently performed as the electrolytic surface roughening process (first electrolytic surface roughening process), the electrolytic solution used for nitric acid electrolysis It is preferable to use an overflow waste liquid.

In the composition management of the desmut treatment liquid, a method of managing by conductivity and temperature, a method of managing by conductivity, specific gravity and temperature, and a conductivity and superconductivity corresponding to a matrix of acidic solution concentration and aluminum ion concentration. Either of the methods managed by the propagation speed of sound waves and temperature can be selected and used.
In the first desmutting treatment, it is preferable to use an acidic solution containing 1 to 400 g / L acid and 0.1 to 5 g / L aluminum ions.

  The temperature of the acidic solution is preferably 20 ° C. or more, more preferably 30 ° C. or more, and preferably 70 ° C. or less, more preferably 60 ° C. or less.

  In the first desmutting treatment, the treatment time is preferably 1 second or longer, more preferably 4 seconds or longer, and preferably 60 seconds or shorter, more preferably 40 seconds or shorter. .

Examples of the method of bringing an aluminum alloy plate into contact with an acidic solution include a method of passing an aluminum alloy plate through a tank containing an acidic solution, a method of immersing an aluminum alloy plate in a tank containing an acidic solution, and an acidic solution. The method of spraying a solution on the surface of an aluminum alloy plate is mentioned.
Among these, a method in which an acidic solution is sprayed on the surface of the aluminum alloy plate is preferable. Specifically, a method of spraying an etching solution in an amount of 10 to 100 L / min per spray tube from a spray tube having holes of φ2 to 5 mm at a pitch of 10 to 50 mm is preferable. It is preferable to provide a plurality of spray tubes.

After the desmutting process is completed, it is preferable to drain the liquid with a nip roller, and further perform the water washing process for 1 to 10 seconds, and then drain the liquid with a nip roller.
The water washing treatment is the same as the water washing treatment after the alkali etching treatment. However, the amount of liquid per spray tip is preferably 1 to 20 L / min.
In the first desmutting process, when using the overflow waste liquid of the electrolyte used for the subsequent nitric acid electrolysis as the desmutting process liquid, the draining and rinsing processes with the nip roller are not performed after the desmutting process. It is preferable to handle the aluminum alloy plate until the nitric acid electrolysis step while spraying a desmut treatment liquid as necessary so that the surface does not dry.

<First electrolytic surface roughening treatment>
The first electrolytic surface roughening treatment is an electrolytic surface roughening treatment in an aqueous solution containing nitric acid or hydrochloric acid.
In the present invention, the first electrolytic surface roughening treatment is preferably a treatment using a trapezoidal waveform alternating current in an electrolytic solution containing nitric acid because the latitude of the electrolytic surface roughened surface is increased. It is preferable to use a sinusoidal alternating current in the electrolyte solution containing slag for the reason that it is easy to control the surface shape of the electrolytically roughened surface.
The average roughness R _a of the aluminum alloy plate surface of the first electrolytic graining treatment is preferably 0.2 to 1.0 [mu] m.

(Electrolytic roughening treatment in aqueous solution containing nitric acid (nitric acid electrolysis))
A suitable uneven structure can be formed on the surface of the aluminum alloy plate by nitric acid electrolysis. In the present invention, when the aluminum alloy plate contains a relatively large amount of Cu, a relatively large and uniform recess is formed in nitric acid electrolysis. As a result, the lithographic printing plate using the lithographic printing plate support of the present invention has excellent printing durability.

An aqueous solution containing nitric acid can be used for an electrochemical surface roughening treatment using ordinary direct current or alternating current, and an aqueous solution of nitric acid having a concentration of 1 to 100 g / L, aluminum nitrate, sodium nitrate, ammonium nitrate, etc. At least one of the nitrate compounds having the nitrate ion can be added and used in the range from 1 g / L to saturation.
Moreover, the metal contained in aluminum alloys, such as iron, copper, manganese, nickel, titanium, magnesium, a silica, may melt | dissolve in the aqueous solution containing nitric acid. Hypochlorous acid or hydrogen peroxide may be added at 1 to 100 g / L.
Specifically, a solution prepared by dissolving aluminum nitrate in an aqueous nitric acid solution having a nitric acid concentration of 5 to 15 g / L and adjusting the aluminum ion concentration to 3 to 7 g / L is preferable.

  The temperature of the aqueous solution containing nitric acid is preferably 20 ° C. or higher, and preferably 55 ° C. or lower.

  Pits having an average opening diameter of 1 to 10 μm can be formed by nitric acid electrolysis. However, when the amount of electricity is relatively large, the electrolytic reaction is concentrated, and honeycomb pits exceeding 10 μm are also generated.

In order to obtain such a grain, the total amount of electricity furnished to anode reaction on the aluminum alloy plate up until the electrolysis reaction is completed is preferably at 150C / dm ² or more, 170C / dm ² or more more preferably is, but preferably not 600C / dm ² or less, more preferably 500C / dm ² or less.
In this case, the current density is preferably 5 A / dm ² or more, more preferably 20 to 100 A / dm ² in terms of current peak value.

(Electrolytic roughening treatment in aqueous solution containing hydrochloric acid (hydrochloric acid electrolysis))
As the aqueous solution containing hydrochloric acid, those used for electrochemical surface roughening treatment using ordinary direct current or alternating current can be used. One or more of hydrochloric acid or nitric acid compounds having nitrate ions such as sodium nitrate and ammonium nitrate, and hydrochloric acid ions such as aluminum chloride, sodium chloride and ammonium chloride can be added to 1 g / L to saturation.
Moreover, the metal contained in aluminum alloys, such as iron, copper, manganese, nickel, titanium, magnesium, a silica, may melt | dissolve in the aqueous solution containing hydrochloric acid. Hypochlorous acid or hydrogen peroxide may be added at 1 to 100 g / L. Furthermore, the above-mentioned compound which forms a complex with copper can also be added at a rate of 1 to 200 g / L. Moreover, sulfuric acid can also be added at a rate of 1 to 100 g / L.

Furthermore, the aqueous solution containing hydrochloric acid has an aluminum ion concentration of 3 to 7 g / L by adding an aluminum salt (aluminum chloride, AlCl ₃ .6H ₂ O) to an aqueous solution containing 2 to 10 g / L of hydrochloric acid, preferably Particularly preferred is an aqueous solution of 4 to 6 g / L.
When electrolytic surface roughening treatment is performed using such an aqueous hydrochloric acid solution, the surface roughened electrolytic surface becomes more uniform, and even if a low purity aluminum alloy plate is used, a high purity aluminum alloy plate is used. Even in this case, processing unevenness does not occur, and it is possible to achieve both excellent printing durability and stain resistance when using a planographic printing plate.

  The temperature of the aqueous solution containing hydrochloric acid is preferably 20 ° C or higher, more preferably 30 ° C or higher, more preferably 55 ° C or lower, and even more preferably 50 ° C or lower.

  As the additive, apparatus, power source, current density, flow rate, and temperature to the aqueous solution containing hydrochloric acid, those used for known electrochemical surface roughening can be used. AC or DC is used as the power source used for electrochemical roughening, but AC is particularly preferable.

Since hydrochloric acid itself has a strong ability to dissolve aluminum, it is possible to form fine irregularities on the surface by applying a slight current. The fine irregularities have an average opening diameter (pit diameter) of 0.01 to 1.5 μm and are uniformly generated on the entire surface of the aluminum alloy plate.
Further, when the amount of electricity is increased (the total amount of electricity (anode reaction) is 150 to 2000 C / dm ² ), the average opening diameter is 1 to 30 μm having pits with an average opening diameter of 0.01 to 0.4 μm on the surface. A pit is generated. In order to obtain such a grain, the total amount of electricity involved in the anode reaction of the aluminum alloy plate at the time when the electrolytic reaction is completed is preferably 10 C / dm ² or more, and more preferably 50 C / dm ² or more. Is more preferable, and more preferably 100 C / dm ² or more. But preferably not more 2000C / dm ² or less, more preferably 600C / dm ² or less.

In hydrochloric acid electrolysis, the current density is preferably 5 A / dm ² or more, more preferably 20 to 100 A / dm ² in terms of the peak current value.

  When the aluminum alloy plate is subjected to hydrochloric acid electrolysis with the above-mentioned large electric quantity, large waviness and fine irregularities can be formed at the same time, and by making the large waviness more uniform by the second alkali etching process described later, the stain resistance is improved. Can be improved.

  The first electrolytic surface roughening treatment can be performed according to, for example, the electrochemical grain method (electrolytic grain method) described in Japanese Patent Publication No. 48-28123 and British Patent No. 896,563. This electrolytic grain method uses a sinusoidal alternating current, but it may be performed using a special waveform as described in JP-A-52-58602. Further, the waveform described in JP-A-3-79799 can also be used. JP-A-55-158298, JP-A-56-28898, JP-A-52-58602, JP-A-52-152302, JP-A-54-85802, JP-A-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, including US Pat. No. 4,203,637, JP-A-56-123400, JP-A-57-59770, JP-A-53-12738, JP 53-32821, JP 53-32222, JP 53-32823, JP 55-122896, JP 55-13284, JP 62-127500, JP Those described in 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.
Further, 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-53-149135 And those described in JP-A No. 54-146234 and the like can also be used.

As the aluminum alloy plate is continuously subjected to electrolytic surface roughening, the aluminum ion concentration in the alkaline solution increases, and the shape of the irregularities of the aluminum alloy plate formed by the first electrolytic surface roughening treatment varies. To do. Therefore, the composition management of the nitric acid electrolytic solution or hydrochloric acid electrolytic solution is preferably performed as follows.
That is, a matrix of conductivity, specific gravity, and temperature, or a matrix of conductivity, ultrasonic propagation velocity, and temperature corresponding to a matrix of nitric acid concentration or hydrochloric acid concentration and aluminum ion concentration is prepared in advance. The liquid composition is measured by the degree, specific gravity and temperature, or the electric conductivity, the ultrasonic wave propagation speed and the temperature, and nitric acid or hydrochloric acid and water are added so as to reach the control target value of the liquid composition. Then, the electrolytic solution increased by adding nitric acid or hydrochloric acid and water is overflowed from the circulation tank, so that the amount of the electrolytic solution is kept constant. As nitric acid to be added, 30 to 70% by mass of industrial grade can be used. As hydrochloric acid to add, the industrial thing of 30-40 mass% can be used.

As the conductivity meter and the specific gravity meter, it is preferable to use those that are temperature-compensated. As the specific gravity meter, a differential pressure type is preferably used.
Samples taken from the electrolyte for use in measuring the liquid composition are used for measurement after being controlled at a constant temperature (eg, 40 ± 0.5 ° C.) using a heat exchanger different from the electrolyte. However, it is preferable in that the accuracy of measurement is increased.

The AC power supply wave used for the electrochemical surface roughening treatment is not particularly limited, and a sine wave (sin wave, sine wave), a rectangular wave, a trapezoidal wave, a triangular wave, or the like is used. Waves are preferred and trapezoidal waves are particularly preferred. In the case of the first hydrochloric acid electrolysis, a sine wave is particularly preferable in that pits having an average diameter of 1 μm or more are easily generated. The sine wave refers to that shown in FIG.
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 0.5 to 3 msec. When TP exceeds 3 msec, especially when an aqueous solution containing nitric acid is used, it becomes susceptible to the influence of trace components in the electrolytic solution typified by ammonium ions and the like that spontaneously increase by electrolytic treatment, and uniform graining. Is difficult to be performed. As a result, the stain resistance tends to decrease when a lithographic printing plate is obtained.

An AC duty ratio of 1: 2 to 2: 1 can be used. However, as described in Japanese Patent Laid-Open No. 5-195300, the duty ratio is used in an indirect power feeding method in which no conductor roll is used for aluminum. Is preferably 1: 1.
An 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.

FIG. 2 is a side view showing an example of a radial type cell used for electrochemical surface roughening using alternating current.
One or more AC power supplies can be connected to the electrolytic cell. For the purpose of controlling the current ratio between the alternating current anode and cathode applied to the aluminum alloy plate facing the main electrode, uniform graining, and dissolving the carbon of the main electrode are shown in FIG. Thus, it is preferable to install an auxiliary anode and divert part of the alternating current. In FIG. 2, 11 is an aluminum alloy 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. Yes, 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 anode acting on the aluminum alloy 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 rectifying element or a switching element It is possible to control the ratio between the current value for the reaction and the current value for the cathode reaction. On the aluminum alloy 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.

  In addition, in the electrochemical surface roughening treatment using direct current, an electrolytic solution used for the normal electrochemical surface roughening treatment using direct current can be used. Specifically, the same electrolyte solution used for the electrochemical surface roughening treatment using the alternating current can be used.

The DC power source wave used for the electrochemical surface roughening treatment is not particularly limited as long as the current does not change in polarity. Smoothed continuous direct current is preferred.
The electrochemical surface roughening treatment using direct current can be performed by any of a batch method, a semi-continuous method and a continuous method, but is preferably performed by a continuous method.

  The apparatus used for the electrochemical surface roughening treatment using direct current applies a direct current voltage between anodes and cathodes arranged alternately, and an aluminum alloy plate is spaced from the anode and cathode. If it can be passed, it will not be specifically limited.

An electrode is not specifically limited, The conventionally well-known electrode used for an electrochemical roughening process can be used.
As the anode, for example, a valve metal such as titanium, tantalum, or niobium is plated or clad with a platinum group metal; the valve metal is coated with a platinum group metal oxide or sintered. Aluminium; stainless steel. Among these, a valve metal obtained by cladding platinum is preferable. The life of the anode can be further extended by a method such as passing water through the electrode to cool it.
As the cathode, for example, a metal that does not dissolve when the electrode potential is negative can be selected and used from the Boolean Bay diagram. Among these, carbon is preferable.

  The arrangement of the electrodes can be appropriately selected according to the wave structure. In addition, by changing the length of the aluminum alloy plate in the traveling direction between the anode and the cathode, changing the passage speed of the aluminum alloy plate, changing the flow rate of the electrolyte, the liquid temperature, the liquid composition, the current density, etc. The structure can be adjusted. In addition, in the case of using an apparatus in which the anode tank and the cathode tank are separated from each other, the electrolysis conditions of each treatment tank can be changed.

After the first electrolytic surface roughening treatment is completed, it is preferable to drain the liquid with a nip roller, and further perform the water washing treatment for 1 to 10 seconds and then drain the liquid with a nip roller.
The washing treatment is preferably carried out using a spray tube. As a spray tube used for the water washing treatment, for example, a spray tube having a plurality of spray tips in the width direction of the aluminum alloy plate in which spray water spreads in a fan shape can be used. The interval between spray tips is preferably 20 to 100 mm, and the amount of liquid per spray tip is preferably 1 to 20 L / min. It is preferable to use a plurality of spray tubes.

<Second alkali etching treatment>
The second alkaline etching process performed between the first electrolytic surface roughening process and the second electrolytic surface roughening process includes dissolving the smut generated in the first electrolytic surface roughening process, and first electrolytic roughening process. This is performed for the purpose of dissolving the edge portion of the pit formed by the surface treatment.
As a result, the edge portion of the large pit formed by the first electrolytic surface roughening treatment is melted and the surface becomes smooth, so that the ink is not easily caught on the edge portion. Obtainable.
Since the second alkali etching process is basically the same as the first alkali etching process, only different points will be described below.

In the second alkali etching treatment, the etching amount is preferably at 0.05 g / m ² or more, more preferably 0.1 g / m ² or more, and it is at 4g / m ² or less Preferably, it is 3.5 g / m ² or less. When the etching amount is 0.05 g / m ² or more, in the non-image portion of the lithographic printing plate, the edge portion of the pit generated by the first electrolytic surface-roughening treatment becomes smooth and the ink is less likely to get caught. Excellent in properties. On the other hand, when the etching amount is 4 g / m ² or less, the unevenness generated by the first electrolytic surface roughening treatment becomes large, and thus the printing durability is excellent.

In the second alkali etching treatment, the concentration of the alkaline solution is preferably 30 g / L or more, more preferably 300 g / L or more, and preferably 500 g / L or less, 450 g / L. The following is more preferable.
The alkaline solution preferably contains aluminum ions. The aluminum ion concentration is preferably 1 g / L or more, more preferably 50 g / L or more, and preferably 200 g / L or less, more preferably 150 g / L or less. Such an alkaline solution can be prepared using, for example, water, a 48 mass% sodium hydroxide aqueous solution, and sodium aluminate.

<Second desmut treatment>
After the second alkali etching treatment, it is preferable to perform pickling (second desmut treatment) in order to remove dirt (smut) remaining on the surface. The second desmut process can be performed in the same manner as the first desmut process.

In the second desmut treatment, nitric acid or sulfuric acid is preferably used.
In the second desmutting treatment, it is preferable to use an acidic solution containing 1 to 400 g / L acid and 0.1 to 8 g / L aluminum ions.
When using sulfuric acid, specifically, use a solution prepared by dissolving aluminum sulfate in a sulfuric acid aqueous solution having a sulfuric acid concentration of 100 to 350 g / L so that the aluminum ion concentration becomes 0.1 to 5 g / L. Can do. Moreover, the overflow waste liquid of the electrolyte solution used for the anodizing process mentioned later can also be used.

In the second desmut treatment, the treatment time is preferably 1 second or longer, more preferably 4 seconds or longer, and preferably 60 seconds or shorter, more preferably 20 seconds or shorter. .
In the second desmut treatment, the temperature of the acid aqueous solution is preferably 20 ° C. or higher, more preferably 30 ° C. or higher, and preferably 70 ° C. or lower, and preferably 60 ° C. or lower. More preferred.

<Second electrolytic surface roughening treatment (second hydrochloric acid electrolysis)>
The second electrolytic surface roughening treatment is an electrochemical surface roughening treatment using alternating current or direct current in an aqueous solution containing hydrochloric acid.
In the present invention, only the first electrolytic surface roughening treatment described above may be used, but by combining this second electrolytic surface roughening treatment, a more complicated uneven structure can be formed on the surface of the aluminum alloy plate, As a result, the printing durability can be improved.

The second electrolytic surface roughening treatment is basically the same as the hydrochloric acid electrolysis described in the first electrolytic surface roughening treatment.
The total amount of electricity that the aluminum alloy plate takes part in the anodic reaction by electrochemical surface roughening in an aqueous solution containing hydrochloric acid in the second electrolytic surface roughening treatment is the time when the electrochemical surface roughening treatment is completed. in may be selected from the range of 10~200C / dm ^2, to first electrolytic graining increase destroying not formed was roughened by treatment is preferably ^{10~100C / dm 2, 50~80C / dm} 2 is Particularly preferred.

<First Alkaline Etching Treatment-First Electrolytic Roughening Treatment (Nitric Acid Electrolysis) -Second Alkaline Etching Treatment-Second Electrolytic Roughening Treatment (Second Hydrochloric Acid Electrolysis)>
When performing the above treatment in combination, nitric acid electrolysis in which the total amount of electricity in the anode reaction is 65 to 500 C / dm ² in an electrolytic solution containing nitric acid, and alkaline etching in which the dissolution amount is 0.1 g / m ² or more. Treatment, second hydrochloric acid electrolysis in which the total amount of electricity in the anodic reaction is 25 to 100 C / dm ² in an electrolytic solution containing hydrochloric acid, and alkaline etching treatment in which the dissolution amount is 0.03 g / m ² or more. It is preferable to apply in order.
By roughening with this combination, a lithographic printing plate precursor having better stain resistance and printing durability can be obtained.

<Third alkali etching treatment>
The third alkali etching process performed after the second electrolytic surface roughening process involves dissolving the smut generated by the second electrolytic surface roughening process, and the edge of the pit formed by the second electrolytic surface roughening process. This is done for the purpose of dissolving the part. Since the third alkali etching process is basically the same as the first alkali etching process, only different points will be described below.

In the third alkali etching treatment, the etching amount is preferably at 0.05 g / m ² or more, more preferably 0.1 g / m ² or more, is 0.3 g / m ² or less Of 0.25 g / m ² or less is more preferable. When the etching amount is 0.05 g / m ² or more, the edge portion of the pit generated by the second hydrochloric acid electrolysis becomes smooth in the non-image portion of the lithographic printing plate, and the ink is difficult to catch, so that the stain resistance is excellent. . On the other hand, when the etching amount is 0.3 g / m ² or less, the unevenness generated by the first electrolytic surface roughening treatment and the second electrolytic surface roughening treatment becomes large, and thus the printing durability is excellent.

In the third alkali etching treatment, the concentration of the alkali solution is preferably 30 g / L or more, and in order not to make the unevenness generated by the hydrochloric acid alternating current electrolysis in the previous stage too small, the concentration is 100 g / L or less. It is preferable that it is 70 g / L or less.
The alkaline solution preferably contains aluminum ions. The aluminum ion concentration is preferably 1 g / L or more, more preferably 3 g / L or more, preferably 50 g / L or less, more preferably 8 g / L or less. Such an alkaline solution can be prepared using, for example, water, a 48 mass% sodium hydroxide aqueous solution, and sodium aluminate.

In the third alkali etching treatment, the temperature of the alkaline solution is preferably 25 ° C or higher, more preferably 30 ° C or higher, and preferably 60 ° C or lower, and 50 ° C or lower. Is more preferable.
In the third alkali etching treatment, the treatment time is preferably 1 second or longer, more preferably 2 seconds or longer, more preferably 30 seconds or shorter, and more preferably 10 seconds or shorter. preferable.

<Third desmut treatment>
After the third alkali etching treatment, pickling (third desmutting treatment) is preferably performed to remove dirt (smut) remaining on the surface. Since the third desmut process is basically the same as the first desmut process, only the differences will be described below.
In the third desmutting treatment, it is preferable to use an acidic solution containing 5-400 g / L acid and 0.5-8 g / L aluminum ions. When sulfuric acid is used, specifically, a solution prepared by dissolving aluminum sulfate in a sulfuric acid aqueous solution having a sulfuric acid concentration of 100 to 350 g / L to adjust the aluminum ion concentration to 1 to 5 g / L is preferable.

In the third desmut treatment, the treatment time is preferably 1 second or longer, more preferably 4 seconds or longer, and preferably 60 seconds or shorter, more preferably 15 seconds or shorter. .
In the third desmut process, when the same type of liquid as the electrolyte used in the subsequent anodizing process is used as the desmut process liquid, the draining with a nip roller and the water washing process can be omitted after the desmut process.

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

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

The conditions for anodizing treatment vary depending on the electrolyte used, and thus cannot be determined unconditionally. ˜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), more preferably 50 to 200 g / L (5 to 20% by mass), and the aluminum ion concentration. Is preferably 1 to 25 g / L (0.1 to 2.5% by mass), more preferably 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.

  The composition management of the electrolyte is conducted using the same method as in the case of nitric acid electrolysis described above, and the conductivity, specific gravity and temperature, or conductivity and ultrasonic wave propagation corresponding to the matrix of sulfuric acid concentration and aluminum ion concentration. It is preferable to control by speed and temperature.

  The liquid temperature of the electrolytic solution is preferably 25 to 55 ° C, and more preferably 30 to 50 ° C.

When anodizing is performed in an electrolytic solution containing sulfuric acid, direct current may be applied between the aluminum alloy plate and the counter electrode, or alternating current may be applied.
When a direct current is applied to the aluminum alloy plate, the current density is preferably from 1 to 60 A / dm ^2, and more preferably 5 to 40 A / dm ^2.
In the case of continuous anodizing treatment, at the beginning of anodizing treatment, so as not to cause so-called "burn" (part where the film becomes thicker than the surroundings) due to current concentration on a part of the aluminum alloy plate. It is preferable to increase the current density to 30 to 50 A / dm ² or higher as the anodic oxidation process proceeds with a current flowing at a low current density of 5 to 10 A / m ² .
Specifically, it is preferable that the current distribution of the DC power supply is set such that the current of the downstream DC power supply is equal to or greater than the current of the upstream DC power supply. By using such current distribution, so-called burning is less likely to occur, and as a result, high-speed anodization can be performed.
In the case where the anodic oxidation treatment is continuously performed, it is preferable to carry out by a liquid power feeding method in which power is supplied to the aluminum alloy plate through the electrolytic solution.
By performing anodizing treatment under such conditions, a porous film having many pores called micropores can be obtained. Usually, the average pore diameter is about 5 to 50 nm, and the average pore density is 300. ˜800 / μm ² or so.

The amount of the anodized film is preferably 1.0 μm or more, more preferably 1.3 μm or more, and further preferably 2 μm or more. It is preferably ¹ to 5 g / m ² . If it is less than 1 g / m ² , the plate tends to be damaged, whereas 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 . Further, it is preferable that the difference in the amount of the anodized film between the center portion of the aluminum alloy plate and the vicinity of the edge portion is 1 g / m ² or less.

As electrolysis apparatuses used for anodizing treatment, those described in JP-A-48-26638, JP-A-47-18739, JP-B-58-24517, JP-A-2001-11698, etc. Can be used.
Among these, the apparatus shown in FIG. 3 is preferably used. FIG. 3 is a schematic view showing an example of an apparatus for anodizing the surface of an aluminum alloy plate.

  In the anodizing apparatus 410 shown in FIG. 3, in order to energize the aluminum alloy plate 416 via the electrolytic solution, the power supply tank 412 is provided upstream in the traveling direction of the aluminum alloy plate 416, and the anodizing treatment tank is provided downstream. 414 is installed. Aluminum alloy plate 416 is conveyed by pass rollers 422 and 428 as indicated by arrows in FIG. In the power supply tank 412 into which the aluminum alloy plate 416 is first introduced, an anode 420 connected to the positive electrode of the DC power supply 434 is installed, and the aluminum alloy plate 416 serves as a cathode. Therefore, a cathode reaction occurs in the aluminum alloy plate 416.

In the anodizing tank 414 into which the aluminum alloy plate 416 is subsequently introduced, a cathode 430 connected to the negative electrode of the DC power source 434 is installed, and the aluminum alloy plate 416 serves as an anode. Therefore, an anodic reaction occurs in the aluminum alloy plate 416, and an anodized film is formed on the surface of the aluminum alloy plate 416.
The distance between the aluminum alloy plate 416 and the cathode 430 is preferably 50 to 200 mm. Aluminum is used as the cathode 430. The cathode 430 is not an electrode having a large area but an electrode divided into a plurality of pieces in the traveling direction of the aluminum alloy plate 416 so that the hydrogen gas generated by the anode reaction can easily escape from the system. preferable.

  Between the power supply tank 412 and the anodizing tank 414, it is preferable to provide a tank called an intermediate tank 413 that does not accumulate an electrolyte as shown in FIG. By providing the intermediate tank 413, it is possible to prevent the current from bypassing the anode 420 to the cathode 430 without passing through the aluminum alloy plate 416. It is preferable to reduce the bypass current as much as possible by installing a nip roller 424 in the intermediate tank 413 to drain the liquid. The electrolyte discharged by draining is discharged out of the anodizing apparatus 410 from the drain port 442.

  The electrolyte solution 418 stored in the power supply tank 412 has a higher temperature and / or higher concentration than the electrolyte solution 426 stored in the anodizing tank 414 in order to reduce voltage loss. In addition, the composition, temperature, and the like of the electrolytic solutions 418 and 426 are determined from the formation efficiency of the anodized film, the micropore shape of the anodized film, the hardness of the anodized film, the voltage, the cost of the electrolytic solution, and the like.

  Electrolyte is ejected from the liquid supply nozzles 436 and 438 and supplied to the power supply tank 412 and the anodizing treatment tank 414. For the purpose of making the distribution of the electrolyte constant and preventing local current concentration of the aluminum alloy plate 416 in the anodizing tank 414, the liquid supply nozzles 436 and 438 are provided with slits, and the ejected liquid flow is changed in the width direction. It has a structure that makes it constant.

  In the anodizing bath 414, a shielding plate 440 is provided on the opposite side of the aluminum alloy plate 416 from the anode 430, and current flows on the opposite side of the surface of the aluminum alloy plate 416 where the anodized film is to be formed. Suppresses The distance between the aluminum alloy plate 416 and the shielding plate 440 is preferably 5 to 30 mm. It is preferable to use a plurality of DC power supplies 434 and connect the positive electrode sides in common. Thereby, the current distribution in the anodizing bath 414 can be controlled.

<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.

<Hydrophilic treatment>
A hydrophilization treatment may be performed after the anodizing treatment or the sealing treatment. Examples of the hydrophilization treatment include treatment with potassium fluorozirconate described in US Pat. No. 2,946,638 and phosphomolybdate described in US Pat. No. 3,201,247. Treatment, alkyl titanate treatment described in British Patent 1,108,559, polyacrylic acid treatment described in German Patent 1,091,433, German Patent 1,134, No. 093 and British Patent No. 1,230,447, polyvinylphosphonic acid treatment, Japanese Patent Publication No. 44-6409, phosphonic acid treatment, US Pat. No. 3,307,951 Phytic acid treatment described in the specification of JP, No. 58-16893 and JP-A No. 58-18291 Treatment with a salt of a molecular compound and a divalent metal, as described in US Pat. No. 3,860,426, hydrophilic cellulose (eg, zinc acetate) containing a water-soluble metal salt (eg, zinc acetate) Carboxymethyl cellulose) is provided with a primer layer, and a water-soluble polymer having a sulfo group described in JP-A-59-101651.

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

  In addition, hydrophilic vinyl polymers such as a method of immersion treatment or electrolytic treatment in an aqueous solution of alkali metal silicate such as sodium silicate and potassium silicate, a method of treatment with potassium zirconate fluoride, a method of treatment with polyvinylphosphonic acid, etc. Alternatively, the hydrophilic treatment is preferably performed by a method of applying a hydrophilic compound to form a hydrophilic undercoat layer. A method of immersing in an aqueous polyvinylphosphonic acid solution is preferably used.

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

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

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

<Drying>
After obtaining the support used for the lithographic printing plate precursor according to the present invention by the procedure described above, it is preferable to dry the surface of the support before providing the photosensitive layer on the support. Drying is preferably performed after the final treatment of the surface treatment, after washing with water and draining with a nip roller.
The drying temperature is preferably 70 ° C or higher, more preferably 80 ° C or higher, preferably 110 ° C or lower, more preferably 100 ° C or lower.
The drying time is preferably 1 second or more, more preferably 2 seconds or more, and preferably 20 seconds or less, more preferably 15 seconds.

<Management of liquid composition>
In the present invention, it is preferable to manage the composition of various processing solutions used for the surface treatment described above by the method described in JP-A-2001-121837. Prepare a large number of treatment liquid samples of various concentrations in advance, measure the ultrasonic wave propagation speed at each of the two liquid temperatures, create a matrix-like data table, It is preferable to measure the propagation speed of the light in real time and control the concentration based on the measurement. In particular, in the desmutting treatment, when an electrolytic solution having a sulfuric acid concentration of 250 g / L or more is used, it is preferable to control the concentration by the method described above.
In addition, it is preferable that each electrolyte solution used for an electrolytic roughening process and an anodic oxidation process is 100 ppm or less of Cu concentration. If the Cu concentration is too high, Cu is deposited on the aluminum alloy plate when the line is stopped, and Cu deposited when the line is operated again may be transferred to a pass roll, which may cause processing unevenness.

[Photosensitive layer]
A photosensitive layer is formed on the support prepared by the procedure described above. As described above, the photosensitive layer of the lithographic printing plate precursor according to the invention has (A) a sensitizing dye, (B) a polymerization initiator, (C) a polymerizable compound, and (D) a binder polymer. .

(A) Sensitizing dye The photosensitive layer of the invention contains a sensitizing dye. A sensitizing dye is particularly limited as long as it absorbs light at the time of image exposure and becomes excited, supplies energy to a polymerization initiator described later by electron transfer, energy transfer, or heat generation, and improves the polymerization initiation function. It can be used without. In particular, a sensitizing dye having a maximum absorption at 300 to 450 nm or 750 to 1400 nm is preferably used.

  Examples of the sensitizing dye having the maximum absorption in the wavelength range of 350 to 450 nm include merocyanine dyes, benzopyrans, coumarins, aromatic ketones, and anthracenes.

  Of the sensitizing dyes having an absorption maximum in a wavelength range of 360 nm to 450 nm, a dye more preferable from the viewpoint of high sensitivity is a dye represented by the following general formula (IX).

(In the general formula (IX), A represents an aromatic ring group or a heterocyclic group which may have a substituent, and X represents an oxygen atom, a sulfur atom or N- (R ₃ ). R ₁ , R ₂ and R ₃ each independently represent a monovalent nonmetallic atomic group, and A and R ₁ and R ₂ and R ₃ are bonded to each other to form an aliphatic or aromatic ring. May be good.)

General formula (IX) will be described in more detail. R ₁ , R ₂ and R ₃ are each independently a monovalent nonmetallic atomic group, preferably a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted aryl group. Represents a substituted or unsubstituted aromatic heterocyclic residue, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted alkylthio group, a hydroxyl group, or a halogen atom.

Next, A in the general formula (IX) will be described. A represents an aromatic ring group or a heterocyclic group which may have a substituent. Specific examples of the aromatic ring or heterocyclic ring which may have a substituent include R ₁ in the general formula (IX). , R ₂ and R ₃ are the same.

  As specific examples of such sensitizing dyes, compounds described in JP-A 2007-58170 [0047] to [0053] are preferably used.

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

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

  As specific examples of such a sensitizing dye, compounds described in European Patent Application Publication No. 1349006 and WO2005 / 029187 are preferably used.

  Also, there are sensitizing dyes described in JP2007-171406, JP2007-206216, JP2007-206217, JP2007-225701, JP2007-225702, JP2007-316582, and JP2007-328243. It can be preferably used.

  Subsequently, a sensitizing dye having a maximum absorption at 750 to 1400 nm that is preferably used in the present invention (hereinafter, sometimes referred to as “infrared absorber”) will be described in detail. As the infrared absorber, a dye or a pigment is preferably used.

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.
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 formula (a), X ¹ represents a hydrogen atom, a halogen _{atom, -N (Ph) 2, -X} 2 -L 1 or a group shown below. Here, Ph represents a phenyl group, 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, a hetero atom (N, S, O, halogen atom, Se ), An aromatic ring having 1 to 12 carbon atoms including a hetero atom. In the group shown below, Xa ^- has Za described later ^- is defined as for, R ^a represents a hydrogen atom, an alkyl group, an aryl group, a substituted or unsubstituted amino group, substituted or unsubstituted amino group and a halogen atom .

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

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

  In the present invention, specific examples of the cyanine dye represented by the general formula (a) that can be suitably used include those described in paragraph numbers [0017] to [0019] of JP-A No. 2001-133969. be able to.

  Further, other particularly preferable examples include specific indolenine cyanine dyes described in JP-A-2002-278057.

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

  The preferred addition amount of these sensitizing dyes is preferably 0.05 to 30% by mass, more preferably 0.1 to 20% by mass, and most preferably 0.2 to 10% by mass with respect to the total solid content of the photosensitive layer. Range.

(B) Polymerization initiator The photosensitive layer of the invention contains a polymerization initiator (hereinafter also referred to as an initiator compound). In the present invention, a radical polymerization initiator is preferably used.

  As the initiator compound in the present invention, those known among those skilled in the art can be used without limitation. Specifically, for example, trihalomethyl compounds, carbonyl compounds, organic peroxides, azo compounds, azide compounds, metallocene compounds can be used. , Hexaarylbiimidazole compounds, organic boron compounds, disulfone compounds, oxime ester compounds, onium salt compounds, and iron arene complexes. Among these, at least one selected from the group consisting of hexaarylbiimidazole compounds, onium salts, trihalomethyl compounds, and metallocene compounds is preferable, and hexaarylbiimidazole compounds are particularly preferable. Two or more of the above polymerization initiators can be used in combination as appropriate.

Examples of hexaarylbiimidazole compounds include lophine dimers described in JP-B-45-37377 and JP-B-44-86516, such as 2,2'-bis (o-chlorophenyl) -4,4 ', 5. , 5'-tetraphenylbiimidazole, 2,2'-bis (o-bromophenyl) -4,4 ', 5,5'-tetraphenylbiimidazole, 2,2'-bis (o, p-dichlorophenyl) -4,4 ', 5,5'-tetraphenylbiimidazole, 2,2'-bis (o-chlorophenyl) -4,4', 5,5'-tetra (m-methoxyphenyl) biimidazole, 2, 2'-bis (o, o'-dichlorophenyl) -4,4 ', 5,5'-tetraphenylbiimidazole, 2,2'-bis (o-nitrophenyl) -4,4', 5,5 ' -Te Raphenylbiimidazole, 2,2'-bis (o-methylphenyl) -4,4 ', 5,5'-tetraphenylbiimidazole, 2,2'-bis (o-trifluorophenyl) -4,4 ', 5,5'-tetraphenylbiimidazole and the like.
The hexaarylbiimidazole compound is particularly preferably used in combination with a sensitizing dye having a maximum absorption at 300 to 450 nm.

  As the onium salt suitably used in the present invention, a sulfonium salt, an iodonium salt, and a diazonium salt are preferably used. In particular, diaryliodonium salts and triarylsulfonium salts are preferably used. The onium salt is particularly preferably used in combination with an infrared absorber having a maximum absorption at 750 to 1400 nm.

  As other polymerization initiators, the polymerization initiators described in JP-A 2007-206217 [0071] to [0129] can be preferably used.

The polymerization initiator in the present invention is suitably used alone or in combination of two or more.
The amount of the polymerization initiator used in the photosensitive layer in the present invention is preferably 0.01 to 20% by mass, more preferably 0.1 to 15% by mass, based on the total solid content of the photosensitive layer. More preferably, it is 1.0 mass%-10 mass%.

(C) Polymerizable compound The polymerizable compound that can be used in the present invention is an addition polymerizable compound having at least one ethylenically unsaturated double bond, and preferably has at least one terminal ethylenically unsaturated bond, preferably It is preferably selected from compounds having two or more. These have chemical forms such as monomers, prepolymers, ie dimers, trimers and oligomers, or mixtures thereof.

  Examples of monomers include unsaturated carboxylic acids (for example, acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid, maleic acid, etc.), esters and amides thereof, preferably unsaturated carboxylic acids. An ester of an acid and a polyhydric alcohol compound and an amide of an unsaturated carboxylic acid and a polyvalent amine compound are used. In addition, an addition reaction product of an unsaturated carboxylic acid ester or amide having a nucleophilic substituent such as a hydroxyl group, amino group or mercapto group with a monofunctional or polyfunctional isocyanate or epoxy, and monofunctional or polyfunctional A dehydration condensation reaction product with a functional carboxylic acid is also preferably used. Further, an addition reaction product of an unsaturated carboxylic acid ester or amide having an electrophilic substituent such as an epoxy group or an epoxy group with a monofunctional or polyfunctional alcohol, amine or thiol, a halogen group or 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 the ester of a polyhydric alcohol compound and an unsaturated carboxylic acid include acrylic acid esters such as ethylene glycol diacrylate, 1,3-butanediol diacrylate, tetramethylene glycol diacrylate, propylene glycol diacrylate, Examples include trimethylolpropane triacrylate, hexanediol diacrylate, tetraethylene glycol diacrylate, pentaerythritol tetraacrylate, sorbitol triacrylate, isocyanuric acid ethylene oxide (EO) -modified triacrylate, and polyester acrylate oligomer. Methacrylic acid esters include tetramethylene glycol dimethacrylate, neopentyl glycol dimethacrylate, trimethylolpropane trimethacrylate, ethylene glycol dimethacrylate, pentaerythritol trimethacrylate, bis [p- (3-methacryloxy-2-hydroxypropoxy) phenyl ] Dimethylmethane, bis- [p- (methacryloxyethoxy) phenyl] dimethylmethane, and the like. Specific examples of amide monomers of polyvalent amine compounds and unsaturated carboxylic acids include methylene bis-acrylamide, methylene bis-methacrylamide, 1,6-hexamethylene bis-acrylamide, 1,6-hexamethylene bis-methacrylic. Examples include amide, diethylenetriamine trisacrylamide, xylylene bisacrylamide, and xylylene bismethacrylamide.

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

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

  Also, urethane acrylates such as those described in JP-A-51-37193, JP-B-2-32293, JP-B-2-16765, JP-B-58-49860, JP-B-56- Urethane compounds having an ethylene oxide skeleton described in Japanese Patent No. 17654, Japanese Patent Publication No. 62-39417, and Japanese Patent Publication No. 62-39418 are also suitable.

  Further, photo-oxidizable polymerizable compounds described in JP-T-2007-506125 are also suitable, and polymerizable compounds containing at least one urea group and / or tertiary amino group are particularly preferred. Specific examples include the following compounds.

  Details of the usage method such as the structure of these polymerizable compounds, whether they are used alone or in combination, and the amount added can be arbitrarily set in accordance with the performance design of the final lithographic printing plate precursor. The polymerizable compound is preferably used in the range of 5 to 75% by mass, more preferably 25 to 70% by mass, and particularly preferably 30 to 60% by mass with respect to the total solid content of the photosensitive layer.

(D) Binder polymer The photosensitive layer according to the invention has a binder polymer. As the binder polymer, one that can carry the photosensitive layer component on a support and can be removed by a developer is used. As the binder polymer, (meth) acrylic polymer, polyurethane resin, polyvinyl alcohol resin, polyvinyl butyral resin, polyvinyl formal resin, polyamide resin, polyester resin, epoxy resin and the like are used. In particular, (meth) acrylic polymers, polyurethane resins, and polyvinyl butyral resins are preferably used.

  In the present invention, “(meth) acrylic polymer” means (meth) acrylic acid, (meth) acrylic acid ester (alkyl ester, aryl ester, allyl ester, etc.), (meth) acrylamide, and (meth). A copolymer having a (meth) acrylic acid derivative such as an acrylamide derivative as a polymerization component. “Polyurethane resin” refers to a polymer produced by a condensation reaction of a compound having two or more isocyanate groups and a compound having two or more hydroxyl groups. “Polyvinyl butyral resin” refers to a polymer synthesized by reacting polyvinyl alcohol obtained by saponifying part or all of polyvinyl acetate and butyraldehyde under an acidic condition (acetalization reaction), Polymers having an acid group or the like introduced by a method of reacting a compound having a remaining hydroxy group and an acid group or the like are also included.

  A suitable example of the binder polymer in the present invention includes a copolymer having a repeating unit containing an acid group. Examples of the acid group include a carboxylic acid group, a sulfonic acid group, a phosphonic acid group, a phosphoric acid group, and a sulfonamide group, but a carboxylic acid group is particularly preferable, and a repeating unit derived from (meth) acrylic acid or the following general formula Those represented by (I) are preferably used.

(In General Formula (I), R ¹ represents a hydrogen atom or a methyl group, R ² represents a single bond or an n + 1 valent linking group, A represents an oxygen atom or —NR ³ —, and R ³ represents a hydrogen atom. Or, it represents a monovalent hydrocarbon group having 1 to 10 carbon atoms, and n represents an integer of 1 to 5.)

The linking group represented by R ² in the general formula (I) is composed of a hydrogen atom, an oxygen atom, a nitrogen atom, a sulfur atom and a halogen atom, and the number of atoms is preferably 1 to 80. 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. R ² is preferably a single bond, alkylene or substituted alkylene, particularly preferably a single bond, alkylene having 1 to 5 carbons or substituted alkylene having 1 to 5 carbons, single bond or carbon number 1 It is most preferable that it is -3 alkylene and a C1-C3 substituted alkylene.
Examples of the substituent include a monovalent non-metallic atomic group excluding a hydrogen atom, a halogen atom (—F, —Br, —Cl, —I), a hydroxyl group, an alkoxy group, an aryloxy group, a mercapto group, An acyl group, a carboxyl group and its conjugate base group, an alkoxycarbonyl group, an aryloxycarbonyl group, a carbamoyl group, an aryl group, an alkenyl group, an alkynyl group and the like can be mentioned.

R ³ is preferably a hydrogen atom or a hydrocarbon group having 1 to 5 carbon atoms, particularly preferably a hydrogen atom or a hydrocarbon group having 1 to 3 carbon atoms, and most preferably a hydrogen atom or a methyl group. n is preferably 1 to 3, particularly preferably 1 or 2, and most preferably 1.

From the viewpoint of developability, the proportion (mol%) of the copolymer component having a carboxylic acid group in the total copolymer components of the binder polymer is preferably 1 to 70%. Considering compatibility between developability and printing durability, 1 to 50% is more preferable, and 1 to 30% is particularly preferable.
Preferable specific examples of the carboxylic acid group-containing unit include the following examples.

  Furthermore, the acid group of the polymer containing an acid group, which is a preferred example of the binder polymer in the present invention, may be neutralized with a basic compound, and in particular, a base such as an amino group, an amidine group, or a guanidine group. It is preferably neutralized with a compound containing basic nitrogen. Furthermore, it is also preferable that the compound containing basic nitrogen has an ethylenically unsaturated group. Specific examples of the compound include compounds described in WO2007 / 057442.

  In the present invention, a copolymer of (meth) acrylic acid and (meth) acrylic acid alkyl ester is preferably used. In particular, a copolymer of (meth) acrylic acid and (meth) acrylic acid methyl ester is preferably used.

  The binder polymer used in the present invention preferably further has a crosslinkable group. Here, the crosslinkable group is a group that crosslinks the binder polymer in the process of radical polymerization reaction that occurs in the photosensitive layer when the lithographic printing plate precursor is exposed. Although it will not specifically limit if it is a group of such a function, For example, an ethylenically unsaturated bond group, an amino group, an epoxy group etc. are mentioned as a functional group which can be addition-polymerized. Moreover, the functional group which can become a radical by light irradiation may be sufficient, and as such a crosslinkable group, a thiol group, a halogen group, etc. are mentioned, for example. Of these, an ethylenically unsaturated bond group is preferable. As the ethylenically unsaturated bond group, a styryl group, a (meth) acryloyl group, and an allyl group are preferable.

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

  The content of the crosslinkable group in the binder polymer (content of unsaturated double bond capable of radical polymerization by iodometric titration) is preferably 0.01 to 10.0 mmol, more preferably 0.05, per 1 g of the binder polymer. -5.0 mmol, most preferably 0.1-2.0 mmol.

  The binder polymer used in the present invention may have a polymer unit of an alkyl (meth) acrylate or an aralkyl ester in addition to the polymer unit having an acid group and a polymer unit having a crosslinkable group. The alkyl group of the (meth) acrylic acid alkyl ester is preferably an alkyl group having 1 to 5 carbon atoms, and more preferably a methyl group. Examples of (meth) acrylic acid aralkyl esters include benzyl (meth) acrylate.

The binder polymer preferably has a mass average molecular weight of 5,000 or more, more preferably 10,000 to 300,000, and a number average molecular weight of 1,000 or more, preferably 2000 to 250,000. More preferred. The polydispersity (mass average molecular weight / number average molecular weight) is preferably 1.1 to 10.
A binder polymer may be used independently or may be used in mixture of 2 or more types. The content of the binder polymer is preferably from 5 to 75 mass%, more preferably from 10 to 70 mass%, more preferably from 10 to 70 mass%, based on the total solid content of the photosensitive layer, from the viewpoint of good image area strength and image formability. More preferably, it is 60 mass%.
The total content of the polymerizable compound and the binder polymer is preferably 80% by mass or less based on the total solid content of the photosensitive layer. If it exceeds 80% by mass, the sensitivity and developability may be lowered. More preferably, it is 35-75 mass%.

  In the present invention, by adjusting the ratio of the polymerizable compound and the binder polymer in the photosensitive layer of the lithographic printing plate precursor, the permeability of the developer into the photosensitive layer is further improved, and the developability is further improved. That is, the mass ratio of the radical polymerizable compound / binder polymer in the photosensitive layer is preferably 1.2 or more, more preferably 1.25 to 4.5, and most preferably 2 to 4.

(Other photosensitive layer components)
The photosensitive layer preferably further contains a chain transfer agent. As the chain transfer agent, for example, a compound group having SH, PH, SiH, GeH in the molecule is used. These can donate hydrogen to low-activity radical species to generate radicals, or can be oxidized and then deprotonated to generate radicals.
In the photosensitive layer of the present invention, in particular, thiol compounds (for example, 2-mercaptobenzimidazoles, 2-mercaptobenzthiazoles, 2-mercaptobenzoxazoles, 3-mercaptotriazoles, 5-mercaptotetrazoles, etc.) Can be preferably used as a chain transfer agent.
The photosensitive layer of the present invention can further contain various additives as required. Additives include surfactants for improving developability and improving the surface of the coating, microcapsules for achieving both developability and printing durability, and improving the developability and dispersion stability of microcapsules. A hydrophilic polymer, a colorant and a print-out agent for visually recognizing the image area and the non-image area, a polymerization inhibitor for preventing unnecessary thermal polymerization of the radical polymerizable compound during production or storage of the photosensitive layer, Higher fat derivatives to prevent polymerization inhibition by oxygen, inorganic fine particles to improve the cured film strength of the image area, hydrophilic low molecular weight compounds to improve developability, co-sensitizers and chain transfer to improve sensitivity An agent, a plasticizer for improving plasticity, and the like can be added. Any of these compounds can be used, for example, compounds described in JP-A 2007-206217 [0161] to [0215] can be used.

<Formation of photosensitive layer>
The photosensitive layer of the present invention is formed by preparing or applying a coating solution by dispersing or dissolving the necessary components described above in a solvent. Examples of the solvent used here include methyl ethyl ketone, ethylene glycol monomethyl ether, 1-methoxy-2-propanol, 2-methoxyethyl acetate, 1-methoxy-2-propyl acetate, and γ-butyllactone. It is not limited to this. These solvents are used alone or in combination. The solid content concentration of the coating solution is preferably 1 to 50% by mass.

The photosensitive layer coating amount (solid content) on the support obtained after coating and drying is preferably 0.3 to 3.0 g / m ² . Within this range, good film properties can be obtained. Various methods can be used as a coating method. Examples thereof include bar coater coating, spin coating, spray coating, curtain coating, dip coating, air knife coating, blade coating, and roll coating.

<Protective layer>
In the lithographic printing plate precursor according to the invention, a protective layer (oxygen blocking layer) is provided on the photosensitive layer in order to block diffusion and penetration of oxygen that hinders the polymerization reaction during exposure. As a material that can be used for the protective layer, for example, it is preferable to use a water-soluble polymer compound having relatively excellent crystallinity. Specifically, it is preferable to use polyvinyl alcohol as a main component for oxygen barrier properties and development removability. Gives the best results in terms of basic characteristics.

  The polyvinyl alcohol used for the protective layer may be partially substituted with an ester, an ether, and an acetal as long as it contains an unsubstituted vinyl alcohol unit for having necessary oxygen barrier properties and water solubility. Similarly, some of them may have other copolymer components. Polyvinyl alcohol can be obtained by hydrolyzing polyvinyl acetate, and specific examples of polyvinyl alcohol include those having a hydrolysis rate of 71 to 100 mol% and a polymerization repeating unit in the range of 300 to 2400. Specifically, Kuraray Co., Ltd. PVA-105, PVA-110, PVA-117, PVA-117H, PVA-120, PVA-124, PVA-124H, PVA-CS, PVA-CST, PVA-HC, PVA-203, PVA-204, PVA-205, PVA-210, PVA-217, PVA-220, PVA-224, PVA-217EE, PVA-217E, PVA-220E, PVA-224E, PVA-405, PVA- 420, PVA-613, L-8 and the like, and these can be used alone or in combination. In a preferred embodiment, the content of polyvinyl alcohol in the protective layer is 20 to 95% by mass, and more preferably 30 to 90% by mass.

  Moreover, well-known modified polyvinyl alcohol can also be used preferably. In particular, acid-modified polyvinyl alcohol having a carboxylic acid group or a sulfonic acid group is preferably used. As a component used by mixing with polyvinyl alcohol, polyvinyl pyrrolidone or a modified product thereof is preferable from the viewpoint of oxygen barrier properties and development removability, and the content in the protective layer is 3.5 to 80% by mass, preferably 10 to 60%. It is 15 mass%, More preferably, it is 15-30 mass%.

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

  Further, the protective layer in the lithographic printing plate precursor according to the invention is an inorganic layered material described in JP-A-2006-106700 [0018] to [0024] for the purpose of improving oxygen barrier properties and photosensitive layer surface protection. It is also preferable to contain a compound. Among inorganic layered compounds, fluorine-based swellable synthetic mica, which is a synthetic inorganic layered compound, is particularly useful.

The coating amount of the protective layer is preferably in the range of 0.05 to 10 g / m ^{2 in} terms of the coating amount after drying. When the inorganic layered compound is contained, 0.1 to 0.5 g / The range of m ² is more preferable, and when the inorganic layered compound is not contained, the range of 0.5 to 5 g / m ² is more preferable.

(Undercoat layer)
The lithographic printing plate precursor according to the invention may be provided with an undercoat layer (sometimes referred to as an intermediate layer) between the photosensitive layer and the support.

As the undercoat layer, an undercoat layer having a compound having an acid group such as phosphonic acid, phosphoric acid or sulfonic acid is preferably used. These compounds preferably further contain a polymerizable group in order to improve the adhesion to the photosensitive layer. Furthermore, compounds having a hydrophilicity-imparting group such as an ethylene oxide group can also be mentioned as suitable compounds.
These compounds may be low molecular weight or high molecular weight polymers. A silane coupling agent having an addition-polymerizable ethylenic double bond reactive group described in JP-A-10-282679, and an ethylenic double bond reactive group described in JP-A-2-304441. Preferred examples include phosphorus compounds.
As the most preferable undercoat layer, a crosslinkable group (preferably an ethylenically unsaturated bond group) described in JP-A-2005-238816, JP-A-2005-125649, JP-A-2006-239867, and JP-A-2006-215263, a support The thing containing the low molecular or high molecular compound which has the functional group and hydrophilic group which interact on the surface is mentioned.

The coating amount (solid content) of the undercoat layer is preferably from 0.1-100 mg / m ^2, and more preferably 1 to 30 mg / m ^2.

[Back coat layer]
After the surface treatment is performed on the support or after the undercoat layer is formed, a back coat can be provided on the back surface of the support, if necessary.
Examples of the back coat include hydrolysis and polycondensation of organic polymer compounds described in JP-A-5-45885, organometallic compounds or inorganic metal compounds described in JP-A-6-35174. A coating layer made of a metal oxide obtained in this manner is preferred. Among them, it is inexpensive to use a silicon alkoxy compound such as Si (OCH ₃ ) ₄ , Si (OC ₂ H ₅ ) ₄ , Si (OC ₃ H ₇ ) ₄ , Si (OC ₄ H ₉ ) _4. It is preferable in terms of easy availability.

[Plate making method]
A lithographic printing plate is prepared by subjecting the lithographic printing plate precursor according to the invention to image exposure and development. Examples of the development treatment include (1) a method of developing with a developer, and (2) a method of developing while adding dampening water and / or ink (on-press development) on a printing press. There is no particular limitation.
[Developer]
The developer used in the plate making method of the lithographic printing plate is not particularly limited. For example, the developer contains an inorganic alkali salt and a surfactant and has a pH of 11 to 13 (surfactant and / or water-soluble polymer). Those having a pH of 2 to 11 (described in JP-A-2007-079136) are preferably used.
The inorganic alkali salt can be used as appropriate. For example, sodium hydroxide, potassium, ammonium, lithium, sodium silicate, potassium, ammonium, lithium, tribasic sodium phosphate, potassium, ammonium Inorganic alkaline agents such as sodium carbonate, potassium, ammonium, sodium hydrogencarbonate, potassium, ammonium, sodium borate, potassium, and ammonium. These may be used alone or in combination of two or more.

In the case of using silicate, developability can be achieved by adjusting the mixing ratio and concentration of silicon oxide SiO ₂ which is a component of silicate and alkali oxide M ₂ O (M represents an alkali metal or ammonium group). Can be adjusted easily. Among the alkali aqueous solutions, those having a mixing ratio (SiO ₂ / M ₂ O: molar ratio) of silicon oxide SiO ₂ and alkali oxide M ₂ O of 0.5 to 3.0 are preferable, and 1.0 to 2 0.0 is preferred. When the SiO ₂ / M ₂ O is less than 0.5, it is preferably 1 to 10% by mass, more preferably 3 to 8% by mass, and most preferably 4 to 7% by mass with respect to the mass of the alkaline aqueous solution. When this concentration is 1% by mass or more, developability and processing capacity are not lowered, and when it is 10% by mass or less, it is difficult to form precipitates and crystals, and further, it is difficult to gel during neutralization in the waste liquid. Does not interfere with waste liquid treatment.

  Further, an organic alkali agent may be supplementarily used for the purpose of slightly adjusting the alkali concentration and assisting the solubility of the photosensitive layer. Examples of the organic alkali agent include monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monoisopropylamine, diisopropylamine, triisopropylamine, n-butylamine, monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, Examples thereof include diisopropanolamine, ethyleneimine, ethylenediamine, pyridine, tetramethylammonium hydroxide and the like. These alkali agents are used alone or in combination of two or more.

  The surfactant can be used as appropriate, but the anionic surfactant used in the developer of the present invention is not particularly limited, but fatty acid salts, abietic acid salts, hydroxyalkanesulfonic acid salts, alkanesulfonic acid salts. , Dialkyl sulfosuccinates, linear alkylbenzene sulfonates, branched alkylbenzene sulfonates, alkylnaphthalene sulfonates, alkyl diphenyl ether (di) sulfonates, alkylphenoxy polyoxyethylene propyl sulfonates, polyoxyethylene alkyl sulfo Phenyl ether salts, N-methyl-N-oleyl taurine sodium, N-alkylsulfosuccinic acid monoamide disodium salt, petroleum sulfonates, sulfated castor oil, sulfated beef oil, fatty acid alkyl Sulfuric acid ester salts, alkyl sulfuric acid ester salts, polyoxyethylene alkyl ether sulfuric acid ester salts, fatty acid monoglyceride sulfuric acid ester salts, polyoxyethylene alkylphenyl ether sulfuric acid ester salts, polyoxyethylene styryl phenyl ether sulfuric acid ester salts, alkyl phosphoric acid ester salts , Polyoxyethylene alkyl ether phosphate ester salts, polyoxyethylene alkyl phenyl ether phosphate ester salts, partial saponification products of styrene-maleic anhydride copolymer, partial saponification products of olefin-maleic anhydride copolymer, naphthalene sulfone And acid salt formalin condensates. Among these, alkylbenzene sulfonates, alkyl naphthalene sulfonates, and alkyl diphenyl ether (di) sulfonates are particularly preferably used.

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

  The nonionic surfactant used in the developer of the present invention is not particularly limited, but is a polyethylene glycol type higher alcohol ethylene oxide adduct, alkylphenol ethylene oxide adduct, alkyl naphthol ethylene oxide adduct, phenol ethylene oxide adduct. , Naphthol ethylene oxide adduct, fatty acid ethylene oxide adduct, polyhydric alcohol fatty acid ester ethylene oxide adduct, higher alkylamine ethylene oxide adduct, fatty acid amide ethylene oxide adduct, fat and oil ethylene oxide adduct, polypropylene glycol ethylene oxide addition Dimethylsiloxane-ethylene oxide block copolymer, dimethylsiloxane- (propylene oxide-ethylene oxide) Id) Block copolymer, fatty acid ester of polyhydric alcohol type glycerol, fatty acid ester of pentaerythritol, fatty acid ester of sorbitol and sorbitan, fatty acid ester of sucrose, alkyl ether of polyhydric alcohol, fatty acid amide of alkanolamines, etc. Is mentioned. Among these, those having an aromatic ring and an ethylene oxide chain are preferable, and an alkyl-substituted or unsubstituted phenol ethylene oxide adduct or an alkyl-substituted or unsubstituted naphthol ethylene oxide adduct is more preferable.

Examples of the zwitterionic surfactant include, but are not limited to, amine oxides such as alkyldimethylamine oxide, betaines such as alkyl betaines, and amino acids such as alkylamino fatty acid sodium.
In particular, alkyldimethylamine oxide which may have a substituent, alkylcarboxybetaine which may have a substituent, and alkylsulfobetaine which may have a substituent are preferably used. As these specific examples, those described in JP-A-2008-203359 [0255] to [0278], JP-A-2008-276166 [0028] to [0052] and the like can be used.

  Two or more surfactants may be used, and the ratio of the surfactant contained in the developer is preferably 0.01 to 20% by mass, more preferably 0.1 to 10% by mass.

  Examples of the water-soluble polymer compound used in the developer include water-soluble polymer compounds described in JP 2007-079136 A.

The pH of the developer used for the plate making of the lithographic printing plate of the present invention is not particularly limited, but is preferably 11.0 to 12.7, more preferably 11.5 to 12.5.
The conductivity of the developer is preferably 3 to 30 mS / cm. When it is 3 mS / cm or more, the photopolymerizable photosensitive layer on the surface of the aluminum support can be surely eluted, and there is no stain in printing, and when it is 30 mS / cm or less, the salt concentration does not become too high. The elution rate of the polymerizable photosensitive layer does not become extremely slow, and no residual film is formed in the unexposed area. Particularly preferred conductivity is in the range of 5-20 mS / cm.

The development of the lithographic printing plate in the present invention is carried out at a temperature of about 0 to 60 ° C., preferably about 15 to 40 ° C., for example, by immersing the exposed lithographic printing plate in a developer and rubbing with a brush according to a conventional method. Do.
Further, when developing using an automatic developing machine, the developing solution becomes fatigued according to the amount of processing, so that the processing capability may be restored by using a replenishing solution or a fresh developing solution.
The lithographic printing plate thus developed is washed with water, surfactants, etc. as described in JP-A Nos. 54-8002, 55-1115045, 59-58431, etc. And a desensitizing solution containing gum arabic, starch derivatives and the like. In the present invention, these treatments can be used in various combinations for the post-treatment of the planographic printing plate.
Moreover, the photosensitive layer of a lithographic printing plate can be made soluble in neutral water or weak alkaline water by using a highly water-soluble component, and the lithographic printing plate having such a configuration is It is also possible to develop with a developer of pH 2-11. When a developer having a pH of 2 to 10 is used, post-treatment with washing water or a desensitizing solution may not be performed.
Furthermore, when the photosensitive layer becomes soluble in neutral water or weak alkaline water, it can be developed on the machine, and used for a method of performing exposure-development on the machine after loading in the printing machine. You can also. Such a system is described in detail in Japanese Patent Laid-Open Nos. 2005-119273, 2006-256035, and 2005-14347.
In addition, as the plate-making process of the lithographic printing plate from the lithographic printing plate precursor according to the present invention, the entire surface may be heated before exposure, during exposure, and between exposure and development, if necessary. By such heating, the image forming reaction in the photosensitive layer is promoted, and advantages such as improvement in sensitivity and printing durability and stabilization of sensitivity may occur. Further, for the purpose of improving the image strength and printing durability, it is also effective to subject the developed image to full post heating or full exposure. Usually, the heating before development is preferably performed under a mild condition of 150 ° C. or less. If the temperature is too high, problems such as curing of the unexposed area occur. Very strong conditions are used for heating after development. Usually, it is the range of 100-500 degreeC. If the temperature is low, sufficient image strengthening action cannot be obtained. If the temperature is too high, problems such as deterioration of the support and thermal decomposition of the image area occur.
Prior to the above development processing, the lithographic printing plate precursor is exposed imagewise by laser exposure through a transparent original image having a line image, a halftone dot image or the like, or by laser beam scanning by digital data.
A desirable light source wavelength is preferably 300 nm to 450 nm or 750 nm to 1400 nm. In the case of 300 nm to 450 nm, a lithographic printing plate precursor having a sensitizing dye having an absorption maximum in this region in the photosensitive layer is used, and in the case of 750 nm to 1400 nm, infrared absorption which is a sensitizing dye having absorption in this region. A lithographic printing plate precursor containing an agent is used. As a light source of 300 nm to 450 nm, a semiconductor laser, particularly an AlGaInN semiconductor laser (commercially available InGaN-based semiconductor laser 5 to 30 mW) is preferable in terms of wavelength characteristics and cost. As the light source of 750 nm to 1400 nm, a solid-state laser and a semiconductor laser that emit infrared rays are suitable. The exposure mechanism may be any of an internal drum system, an external drum system, a flat bed system, and the like.
The planographic printing plate obtained by such processing is loaded on an offset printing machine and used for printing a large number of sheets.

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

[Manufacture of aluminum alloy sheets]
(Examples 1-12)
An aluminum alloy sheet was manufactured by continuous casting using the molten aluminum alloy having the composition shown in Table 1 below and intermediate annealing under the conditions shown in Table 2.
The aluminum carbide in the molten aluminum was adjusted by the number of carbon members (from no carbon member to 12) by immersing carbon members at the outlet of the melting furnace using an aluminum material with very little carbide.
Specifically, first, continuous casting was performed using a molten aluminum alloy of each composition so that the cast plate thickness was 5.5 mm by twin roll type continuous casting.
Next, the obtained continuous cast plate was cold-rolled to a thickness of 0.9 mm, then subjected to intermediate annealing heat treatment under the conditions shown in Table 2 below, and further cold-rolled again to 0.3 mm. Finished with a thickness of.
Next, flatness was corrected using a tension leveler to produce an aluminum alloy plate. In addition, the composition of the manufactured aluminum alloy plate is the same as the composition of the molten aluminum alloy used for each.

(Comparative Examples 1-4)
An aluminum alloy plate was manufactured by DC casting using a molten aluminum alloy having the composition shown in Table 1 below. Specifically, a slab having a thickness of 500 mm was cast by DC casting.
Next, both sides of the obtained slab were chamfered by 20 mm and subjected to soaking at 500 to 600 ° C.
Subsequently, it hot-rolled and rolled to thickness 3mm, it was made to recrystallize with rolling processing heat, and cold-rolled and finished to thickness 0.3mm. Intermediate annealing at 410 ° C. to 550 ° C. was performed.
Next, flatness was corrected using a tension leveler to produce an aluminum alloy plate. In addition, the composition of the manufactured aluminum alloy plate is the same as the composition of the molten aluminum alloy.

(Number of aluminum carbide per unit mass)
First, 1 g of an aluminum sample is taken from a rolled plate, immersed in 100 ml of dehydrated methanol (special reagent grade), and then mixed with several drops of bromine (special reagent express) (cool the entire container so as not to exceed 40 ° C.). 5 ml was added, and aluminum was completely dissolved at 40 ° C. for 3 hours. Thereafter, the mixture was filtered through a Teflon (registered trademark) filter having a mesh diameter of 1 μm, and 50 ml of a 10% NaOH solution was poured onto the filter at room temperature for 10 minutes. Thereafter, it was washed with water and dried, and a fixed area of the filter was observed with a 2000 times SEM, and the number of aluminum carbides confirmed by elemental analysis such as EPMA and EDX analysis was measured. Then, the number of aluminum carbides contained in 1 g of dissolved aluminum was obtained by calculation from the relationship between the number in the constant area measured here and the total filtration area of the filter. The results are shown in Table 2.

The number per unit area of the intermetallic compound of each manufactured aluminum alloy plate was measured by the method shown below. The results are shown in Table 2.
(Number of intermetallic compounds per unit area)
First, about the manufactured aluminum alloy plate, what wiped off the oil of the surface with acetone was used as a measurement sample.
Next, using a scanning electron microscope (PC-SEM7401F, manufactured by JEOL Ltd.), a reflected electron image on the surface of the aluminum alloy plate was taken under the conditions of an acceleration voltage of 12.0 kV and a magnification of 2000 times.
Next, five images arbitrarily selected from the obtained reflected electron images were stored in JPEG format, and converted into bmf (bitmap file) format using MS-Paint (manufactured by Microsoft).
This bmf format file is stored in the image analysis software ImageFactory Ver. 3.2 After reading into the Japanese version (Asahi Hitech Co., Ltd.) and performing image analysis, static binarization processing of the image is performed, and the portion corresponding to the white intermetallic compound is counted as a feature value. The particle size distribution was obtained by specifying the equivalent circle diameter (equivalent circle diameter).
From the result of the particle size distribution, the number of intermetallic compounds having an equivalent circle diameter of 0.2 μm or more was calculated. This calculation was performed by rounding the average value of the numbers calculated from each of the five image data (particle size distributions) to the nearest hundred.

[Manufacture of support]
Each manufactured aluminum alloy plate was subjected to the following roughening treatment to obtain a support used for a lithographic printing plate precursor.

  As the roughening treatment, the following treatments (a) to (k) were performed. In addition, the water washing process was performed between all the process steps.

(A) Mechanical roughening treatment (brush grain method)
Rotating while supplying an aqueous suspension (specific gravity 1.12 g / cm ³ ) of an abrasive (pumice) as a polishing slurry liquid to the surface of the aluminum alloy plate using an apparatus as schematically shown in FIG. The surface was mechanically roughened with a roller nylon brush. In FIG. 5, 1 is an aluminum alloy plate, 2 and 4 are roller brushes, 3 is a polishing slurry, and 5, 6, 7 and 8 are support rollers.
Here, 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 alloy plate. The rotation direction of the brush was the same as the movement direction of the aluminum alloy plate. The rotation speed of the brush was 200 rpm.

(B) Alkaline etching treatment Using an aqueous solution having a caustic soda concentration of 25 mass%, an aluminum ion concentration of 100 g / L, and a temperature of 60 ° C., an aluminum alloy plate was dissolved by 3 g / m ² . Then, water washing by spraying was performed.

(C) Desmut treatment The desmut treatment was performed by spraying from a spray tube for 5 seconds with an aqueous sulfuric acid solution (concentration: 300 g / L) having a temperature of 35 ° C. (containing 0.5 mass% of aluminum ions), and then washed with water by spraying.

(D) Electrolytic roughening treatment Thereafter, an electrolytic solution (liquid temperature 35 ° C.) in which aluminum chloride is dissolved in 1% by mass hydrochloric acid aqueous solution to have an aluminum ion concentration of 4.5 g / L is used, and a 60 Hz AC power source is used. Then, an electrochemical surface roughening treatment was continuously performed using a flat cell type electrolytic cell. A sine wave was used as the waveform of the AC power supply. In the electrochemical surface roughening treatment, the current density during the anode reaction of the aluminum alloy plate at the peak of alternating current was 30 A / dm ² . The ratio of the amount of electricity during the anode reaction of the aluminum alloy plate to the amount of electricity during the cathode reaction was 0.95. The amount of electricity was 480 C / dm ^{2 as the} total amount of electricity at the time of anode of the aluminum alloy plate. The electrolytic solution was stirred in the electrolytic cell by circulating the solution using a pump.
(E) Alkaline etching treatment An aqueous solution having a caustic soda concentration of 5 mass%, an aluminum ion concentration of 5 g / L, and a temperature of 35 ° C. was sprayed from a spray tube onto the aluminum alloy plate to carry out an etching treatment. The etching amount of the aluminum alloy plate subjected to the electrolytic surface roughening treatment was 0.05 g / m ² .
(F) Desmut treatment A desmut treatment was performed by spraying an aqueous solution having a sulfuric acid concentration of 300 g / L, an aluminum ion concentration of 5 g / L, and a liquid temperature of 35 ° C. from a spray tube for 5 seconds.

(J) Anodizing treatment Anodizing treatment was performed using an anodizing apparatus having a structure shown in FIG. 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. Then, water washing by spraying was performed. The final oxide film amount was adjusted to the anodic oxidation treatment time to the anodized film thickness shown in Table 3.

(K) Hydrophilization treatment (polyvinylphosphonic acid treatment)
It was immersed for 10 seconds in a 40 ° C. aqueous solution containing 4 g / L of polyvinylphosphonic acid, washed with pure water, and dried. The temperature was 38 ° C. Then, water washing by spraying was performed.

[Manufacture of lithographic printing plate precursors]
A lithographic printing plate precursor was obtained by forming a photosensitive layer on the substrates of Examples and Comparative Examples obtained by the above procedure according to the following procedure.

(1) Formation of photosensitive layer On the above support, a photopolymerizable composition P-1 having the following composition was applied so that the dry coating mass was 1.4 g / m ^2, and dried at 100 ° C. for 1 minute. A photosensitive layer was formed.

Photopolymerizable composition P-1
Polymerizable compound (1) 0.9 parts by mass Polymerizable compound (2) 4.5 parts by mass Binder polymer (2) 2.3 parts by mass Sensitizing dye (1) 0.4 parts by mass Agent (1) 0.9 parts by mass Chain transfer agent (1) 0.5 parts by mass Dispersion of ε-phthalocyanine pigment 0.9 parts by mass (pigment: 15 parts by mass, dispersant (allyl methacrylate / methacrylic acid co Polymer (copolymerization molar ratio 83/17)): 10 parts by mass, cyclohexanone: 15 parts by mass)
・ Fluorine-based nonionic surfactant (Megafac F780 0.02 parts by mass (Dainippon Ink Chemical Co., Ltd.))
-Thermal polymerization inhibitor 0.03 parts by mass
(N-nitrosophenylhydroxylamine aluminum salt)
・ Methyl ethyl ketone 58 parts by mass ・ Propylene glycol monomethyl ether acetate 53 parts by mass

Sensitizing dye (1)

Chain transfer agent (1)

(2) Formation of protective layer A protective layer coating solution having the following composition was applied onto the photosensitive layer so that the dry coating mass was 2.3 g / m ² and dried at 125 ° C. for 75 seconds. Then, lithographic printing plate precursors of Examples and Comparative Examples were obtained.

Coating liquid for protective layer Polyvinyl alcohol (saponification degree 95 mol%, polymerization degree 500) 36 parts by weight Polyvinylpyrrolidone (molecular weight 50,000) 9 parts by weight Poly (vinylpyrrolidone / vinyl acetate (1/1)) molecular weight 70,000 0.5 Part by weight Surfactant (Emalex 710, manufactured by Nippon Emulsion Co., Ltd.) 0.5 part by weight Water 950 parts by weight

[Evaluation of lithographic printing plate precursor]
The lithographic printing plate precursor obtained by the above procedure was evaluated as follows. The results are shown in Table 3.

(1) Evaluation of printing durability The exposure of the obtained lithographic printing plate precursor to Vx9600CTP (light source wavelength: 405 nm) manufactured by Fuji Photo Film Co., Ltd. is 0.05 mJ / cm ^2. The image was drawn and adjusted to. The exposure image included a solid image. Thereafter, using a PS processor IP850HD manufactured by G & J Co., which was charged with an alkaline developer having the following composition, development was performed at a preheating temperature of 115 ° C./12 seconds, a developer temperature of 25 ° C., and a development time of 28 seconds. As the finisher, a 1: 3 water dilution of FN-6 manufactured by Fuji Photo Film Co., Ltd. was used.

(Alkali developer composition)
・ Potassium hydroxide 0.15g
・ Polyoxyethylene naphthyl ether (n = 13) 5.0 g
・ Chillest 400 (chelating agent) 0.1g
・ Water 94.75g
The resulting lithographic printing plate was printed on a Lithrone printing machine manufactured by Komori Corporation, and DIC-GEOS (N) ink manufactured by Dainippon Ink & Chemicals, Ltd. as ink and Fuji Photo Film Co., Ltd. as dampening water. Printed using a mixture of etchant EU-3 / water / isopropyl alcohol = 1/89/10 (volume ratio), and the number of printed sheets at the time when it was visually confirmed that the density of the solid image started to decrease, The printability was evaluated. The results are shown in Table 3.
○… More than 70,000 sheets ○ △… More than 50,000 sheets to less than 70,000 sheets △… More than 30,000 sheets to less than 70,000 sheets △ ×… Less than 30,000 sheets

(2) Evaluation of stain resistance The stain of the blanket after printing 10,000 sheets was visually confirmed and evaluated according to the following criteria. The results are shown in Table 3.
○… Blanket is not dirty ○ △… Blanket is slightly dirty but good △… Blanket is dirty but within acceptable range △ ×… Blanket is dirty and printed matter is clearly dirty ( 3) Evaluation of white spot failure resistance A lithographic printing plate precursor on which a photosensitive layer and a protective layer are formed is stored at room temperature for 3 months in an atmosphere within a humidity range of 20 to 90%. Evaluated. These results are shown in Table 3.
◎ White failure is 120 / m ² or less ○ White failure is 121 / m ² to 250 / m ²
○ △ White spot failure 251 / m ^{2 to} 350 / m ²
△ 351 white defects / m ^{2 to} 500 / m ²
Δ × White spot failure is 501 / m ² to 600 / m ²
× 601 or more white spots / m ² or more

  From the results of Examples and Comparative Examples, when the anodic oxide film thickness is 1.3 μm or more, the whiteout failure may be reduced as compared with the number of aluminum carbides having a predetermined size or more in the aluminum bulk. I understand.

DESCRIPTION OF SYMBOLS 1 Aluminum alloy plate 2, 4 Roller-like brush 3 Polishing slurry liquid 5, 6, 7, 8 Support roller 11 Aluminum alloy plate 12 Radial drum roller 13a, 13b Main electrode 14 Electrolytic treatment liquid 15 Electrolytic solution supply port 16 Slit 17 Electrolytic solution Passage 18 Auxiliary anode 19a, 19b Thyristor 20 AC power supply 40 Main electrolytic tank 50 Auxiliary anode tank 410 Anodizing device 412 Feed tank 413 Intermediate tank 414 Anodizing tank 416 Aluminum alloy plate 418, 426 Electrolyte 420 Anode 422, 428 Pass roller 424 Nip roller 430 Cathode 434 DC power source 436, 438 Liquid supply nozzle 440 Shielding plate 442 Drain outlet 610 Anodizing device 612 Power supply tank 614 Electrolytic treatment tank 616 Aluminum alloy plate 618, 626 Electrolytic solution 620 Power supply 622,628 roller 624 nip roller 630 electrolytic electrode 632 tank wall 634 a DC power source

Claims (7)

In a lithographic printing plate precursor having a photosensitive layer and a protective layer in this order (A) a sensitizing dye, (B) a polymerization initiator, (C) a polymerizable compound, and (D) a binder polymer on a support. ,
The support is an aluminum alloy in which the density of an intermetallic compound having an equivalent circle diameter of 0.2 μm or more on the surface is 35,000 pieces / mm ² or more and the number of aluminum carbides having a maximum length of 1 μm or more is 30,000 pieces / g or less. A lithographic printing plate precursor produced using a plate.   The lithographic printing plate precursor according to claim 1, wherein the support is a support obtained by subjecting the surface of the aluminum alloy plate to a roughening treatment including an electrochemical roughening treatment.   The lithographic printing plate precursor as claimed in claim 1, wherein the support is further anodized after the surface roughening treatment and has an anodized film having an average thickness of 1.0 μm or more.   The lithographic printing plate precursor as claimed in any one of claims 1 to 3, wherein the aluminum alloy plate is an aluminum alloy plate produced by a continuous casting method.   The lithographic printing plate precursor according to any one of claims 1 to 4, wherein a photosensitive layer having a mass ratio of the polymerizable compound to the binder polymer and a polymerizable compound mass / binder polymer mass of 2 to 4 is provided.   The lithographic printing plate precursor as claimed in claim 1, wherein the sensitizing dye is a sensitizing dye having an absorption maximum at 350 to 450 nm.   The lithographic printing plate precursor according to any one of claims 1 to 6, wherein the protective layer is a composition containing polyvinyl alcohol.