WO2019044702A1 - Lithographic printng plate precursor - Google Patents

Abstract

To provide a lithographic printing plate precursor which has an aluminum support having an anodized film and a positive image recording layer. The anodized film has a thickness ranging from 200 nm to 2,000 nm. The anodized film has micropores each extending in the depth direction from the positive image recording layer side surface. Each micropore has a large diameter pore part (i) extending from the anodized film surface to a location exceeding 60 nm in depth and a small diameter pore part (ii) communicating with the bottom of the large diameter pore part and extending further in the depth direction from the communication position. The average diameter of the small diameter pore part (ii) at the communication position is smaller than the average diameter of the large diameter pore part (i) on the anodized film surface.

Description

Lithographic printing plate precursor

The present invention relates to a lithographic printing plate precursor having a positive-working image recording layer.

Conventionally, with regard to an aluminum support having an anodized film used for a lithographic printing plate precursor, after forming the anodized film, micropores are formed on the surface of the anodized film, and then treated with an acid or alkaline solution to form a surface layer. By enlarging the pore diameter of the micropores of the part and further performing anodizing treatment, a micropore consisting of a large diameter pore part of the surface layer part and a small diameter pore part communicating with it and further extending in the depth direction is formed Patents 1 to 3 have been described. Further, Patent Documents 1 and 2 show that a lithographic printing plate prepared using a lithographic printing plate precursor having an aluminum support having such an anodic oxide film exhibits excellent printing durability and storage stain resistance. Have been described. Patent Document 3 describes that a negative photopolymerizable lithographic printing plate precursor having an aluminum support having such an anodic oxide film provides a lithographic printing plate having high sensitivity and excellent printing durability. There is.

Japanese Patent Application Laid-Open No. 2012-179738 Japanese Patent Application Laid-Open No. 2011-245844 Japanese Patent Application Laid-Open No. 11-291657

As market trends in recent years, positive-working lithographic printing plate precursors providing lithographic printing plates with superior productivity and excellent printing characteristics are required, and printing durability, leaving-to-stand, developability, and ink removal are desired. Demand levels for characteristics such as gender are further increasing. In particular, in recent years, from the viewpoint of energy saving and efficiency improvement of plate making work, further improvement of printing durability without the burning process is required.
The present inventors have described the above-mentioned various lithographic printing plate precursors and lithographic printing plates using the lithographic printing plate support obtained by subjecting the two-step anodizing treatment specifically described in Patent Documents 1 and 2 to the lithographic printing plate support. The characteristics were evaluated and examined, and it was found that the above-mentioned characteristics do not necessarily satisfy the required level recently. That is, coexistence of printing durability and stain resistance was not always sufficient.

An object of the present invention is to provide a positive-working lithographic printing plate precursor which can provide a lithographic printing plate which is excellent in printing resistance, leaving-off property and stain resistance.

As a result of intensive studies to achieve the above object, the present inventors used an aluminum support having an anodic oxide film containing micropores having large diameter pores having a depth not shown in Patent Documents 1 and 2. It has been found that the above object can be achieved by a lithographic printing plate precursor having a positive-working image recording layer, and the present invention has been completed.
The means for achieving the above purpose are described below.

(1) A lithographic printing plate precursor having an aluminum support having an anodized film and a positive type image recording layer, wherein the thickness of the anodized film is 200 nm to 2,000 nm, and the anodized film And a large-diameter hole (i) having micropores extending in the depth direction from the surface on the positive-type image recording layer side, the micropores extending from the surface of the anodized film to a position exceeding 60 nm in depth A small diameter hole (ii) in communication with the bottom of the large diameter hole and further extending in the depth direction from the communication position, and the average diameter of the small diameter hole (ii) in the communication position is the anode A lithographic printing plate precursor which is smaller than the average diameter of the large diameter holes (i) on the surface of the oxide film.
(2) The lithographic printing plate precursor as described in (1), wherein the depth of the small diameter hole (ii) from the communication position is 100 nm to less than 1940 nm.
(3) The lithographic printing plate precursor as described in (1) or (2), wherein the average diameter of the large diameter pores (i) on the surface of the anodic oxide film is more than 10 nm and not more than 100 nm.
(4) The lithographic printing plate precursor as described in any one of (1) to (3), wherein an average diameter of the small diameter holes (ii) at the communication position is 15 nm or less.
(5) A polymer containing an acid group selected from a phosphonic acid group, a phosphoric acid group, a sulfonic acid group, and a carboxylic acid group is contained between the aluminum support having the anodized film and the positive type image recording layer. The lithographic printing plate precursor as described in any one of (1) to (4), which has a subbing layer.
(6) The lithographic printing plate precursor as described in any one of (1) to (5) above, wherein the positive type image recording layer contains an infrared absorber.
(7) The lithographic printing plate precursor as described in (6) above, wherein the positive type image recording layer has a two-layer structure, and an alkali-soluble polymer compound is contained in a layer close to the aluminum support having the anodic oxide film.

According to the present invention, it is possible to provide a lithographic printing plate precursor which can provide a positive-working lithographic printing plate which is excellent in printing durability, leaving-to-standability and stain resistance.

FIG. 1 is a schematic cross-sectional view of an embodiment of a lithographic printing plate precursor according to the present invention. FIG. 1 is a schematic cross-sectional view of an embodiment of an aluminum support having an anodized film. It is a schematic cross section of the aluminum support body which has an anodized film which shows a 1st anodizing treatment process to a 2nd anodizing treatment process in order of a process. It is a schematic cross section of the aluminum support body which has an anodized film which shows a 1st anodizing treatment process to a 2nd anodizing treatment process in order of a process. It is a schematic cross section of the aluminum support body which has an anodized film which shows a 1st anodizing treatment process to a 2nd anodizing treatment process in order of a process. It is a graph which shows an example of an alternating waveform current waveform chart used for the electrochemical roughening process in the manufacturing method of the aluminum support body which has an anodic oxide film. It is a side view which shows an example of the radial type cell in the electrochemical surface-roughening process using alternating current in the manufacturing method of the aluminum support body which has an anodic oxide film. It is a side view which shows the concept of the process of the brush graining used for the mechanical surface-roughening process in the manufacturing method of the aluminum support body which has an anodic oxide film. It is the schematic of the anodizing treatment apparatus used for the anodizing treatment in the manufacturing method of the aluminum support body which has an anodic oxidation film.

Hereinafter, modes for carrying out the invention will be described in detail.
In the present specification, a numerical range represented using “to” means a range including numerical values described before and after “to” as the lower limit value and the upper limit value.
Further, in the present specification, with regard to the notation of a group in a compound represented by the formula, in the case where substitution or non-substitution is not described, when the group can further have a substituent, other particular definition is Unless otherwise stated, the group includes not only unsubstituted groups but also groups having substituents. For example, in the formula, if "R represents an alkyl group, an aryl group or a heterocyclic group", "R represents an unsubstituted alkyl group, a substituted alkyl group, an unsubstituted aryl group, a substituted aryl group, an unsubstituted group. And "representing a heterocyclic group or a substituted heterocyclic group".

[Planar printing plate original plate]
The lithographic printing plate precursor of the present invention is a lithographic printing plate precursor having an aluminum support having an anodized film and a positive-working image recording layer.
A schematic cross-sectional view of an embodiment of a lithographic printing plate precursor according to the present invention is shown in FIG. In FIG. 1, a lithographic printing plate precursor 10 has an aluminum support 12 having an anodized film, an undercoat layer 14 and a positive type image recording layer 16.

[Aluminum support having an anodic oxide film]
An aluminum support having an anodized film in a lithographic printing plate precursor according to the present invention is described.
A schematic cross-sectional view of an embodiment of an aluminum support having an anodized film is shown in FIG. In FIG. 2, the aluminum support 12 having the anodized film has an aluminum plate 18 and an anodized film 20 of aluminum (hereinafter, also simply referred to as “anodized film 20”) in this order. The anodized film 20 in the aluminum support 12 is located on the positive image recording layer 16 side of the lithographic printing plate precursor 10 in FIG. That is, the lithographic printing plate precursor 10 has an aluminum plate 18, an anodized film 20, an undercoat layer 14, and a positive type image recording layer 16.

In FIG. 2, the anodized film 20 has micropores 22 extending from the surface thereof toward the aluminum plate 18, and the micropores 22 are constituted of large diameter holes 24 and small diameter holes 26. Here, the term "micropore" is a commonly used term that represents the pore in the anodized film, and does not define the size of the pore.

(Aluminum plate)
The aluminum plate 18 (aluminum support) is made of a dimensionally stable aluminum-based metal, that is, aluminum or an aluminum alloy. The aluminum plate 18 is made of a pure aluminum plate or an alloy plate containing aluminum as a main component and a small amount of different elements.

The different elements contained in the aluminum alloy include silicon, iron, manganese, copper, magnesium, chromium, zinc, bismuth, nickel, titanium and the like. The content of foreign elements in the alloy is 10% by mass or less. Although a pure aluminum plate is preferable as the aluminum plate 18, completely pure aluminum may contain a slight amount of different elements because it is difficult to manufacture due to smelting technology. The composition of the aluminum plate 18 is not limited, and materials of known and commonly used materials (for example, JIS A 1050, JIS A 1100, JIS A 3103, and JIS A 3005) can be appropriately used.

The width of the aluminum plate 18 is preferably about 400 to 2,000 mm, and the thickness is preferably about 0.1 to 0.6 mm. The width or thickness can be appropriately changed according to the size of the printing press, the size of the printing plate, and the user's request.

(Anode oxide film)
The anodized film 20 is generally prepared on the surface of the aluminum plate 18 by anodizing treatment, and is anodized aluminum film which is substantially perpendicular to the film surface and has extremely fine micropores 22 uniformly distributed. Point to. The micropores 22 extend from the surface of the anodized film along the thickness direction (aluminum plate 18 side).
The thickness of the anodized film is 200 to 2,000 nm, preferably 500 to 1,800 nm, and more preferably 750 to 1,500 nm.

The micropores 22 in the anodized film 20 communicate with the large diameter hole 24 extending from the surface of the anodized film to a position where the depth (depth A: see FIG. 2) exceeds 60 nm, and the bottom of the large diameter hole 24 And a small diameter hole 26 extending from the communication position to a position of a depth of 200 to 2,000 nm.
The large diameter hole 24 and the small diameter hole 26 will be described in detail below.

(Large diameter hole)
It is preferable that the average diameter (average opening diameter) in the anodic oxide film surface of the large diameter hole part 24 is 100 nm or less larger than 10 nm. The average diameter is more preferably 15 to 60 nm, still more preferably 18 to 40 nm, in that the effect of the present invention is more excellent.
If the average diameter is 10 nm or less, the printing durability may be poor. In addition, when the average diameter exceeds 100 nm, there may be cases in which the chargeability on standing is inferior.
The average diameter of the large diameter holes 24 is 400 in the obtained four images obtained by observing N of the surface of the anodized film 20 with a field-emission scanning electron microscope (FE-SEM) at a magnification of 150,000. The diameter (diameter) of the micropores (large diameter holes) present in the range of × 600 nm ² was measured and averaged.
When the shape of the large diameter hole portion 24 is not circular, the equivalent circle diameter is used. The “equivalent circle diameter” is the diameter of the circle when the shape of the opening is assumed to be a circle having the same projected area as the projected area of the opening.

The bottom of the large diameter hole portion 24 is at a position where the depth (hereinafter also referred to as depth A) from the surface of the anodized film exceeds 60 nm. That is, the large diameter hole portion 24 is a hole portion that extends more than 60 nm in the depth direction (thickness direction) from the surface of the anodized film. Among them, the depth A is preferably 65 to 200 nm, and more preferably 70 to 100 nm in that the effect of the present invention is more excellent.
When the depth A is 60 nm or less, the printing durability is poor. In the case where the depth A exceeds 200 nm, there are cases in which the chargeability on standing is inferior.
The depth from the surface of the anodized film is obtained by observing the cross section of the anodized film 20 with FE-SEM (150,000 times), and measuring the depth of 25 large diameter holes in the obtained image, It is an averaged value.

The shape of the large diameter hole portion 24 is not particularly limited. For example, the substantially straight tubular shape (substantially cylindrical shape), a conical shape whose diameter decreases in the depth direction (thickness direction), and the depth direction (thickness direction) There is an inverted conical shape in which the diameter is increased, and a substantially straight tubular shape is preferable. The diameter at the bottom of the large diameter hole may generally be about 1 to 10 nm different from the diameter of the opening. The shape of the bottom of the large diameter hole portion 24 is not particularly limited, and may be curved (concave) or planar.

(Small diameter hole)
As shown in FIG. 2, the small diameter hole 26 communicates with the bottom of the large diameter hole 24 and extends in the depth direction (thickness direction) from the communication position. One small diameter hole 26 normally communicates with one large diameter hole 24, but two or more small diameter holes 26 may communicate with the bottom of one large diameter hole 24.
The average diameter at the communication position of the small diameter holes 26 is not particularly limited, but is preferably less than 20 nm, more preferably 15 nm or less, still more preferably 13 nm or less, and particularly preferably 10 nm or less. The average diameter is preferably 5 nm or more. In the case where the average diameter is 20 nm or more, there may be a case where the leaving property is inferior.

The average diameter of the small-diameter hole portion 26 is a micro image existing in the range of 400 × 600 nm ² in four images obtained by observing the surface of the anodized film 20 with N = four sheets by FE-SEM at a magnification of 150,000. The diameter (diameter) of the pores (small diameter holes) was measured and averaged. When the large diameter hole is deep, the upper part of the anodized film 20 (area with the large diameter hole) is cut (for example, cut with argon gas) as necessary, and then the anodic oxide film 20 is cut. The surface may be observed by the above-described FE-SEM to determine the average diameter of the small diameter holes.
When the shape of the small diameter hole 26 is not circular, the equivalent circle diameter is used. The “equivalent circle diameter” is the diameter of the circle when the shape of the opening is assumed to be a circle having the same projected area as the projected area of the opening.

The bottom of the small diameter hole portion 26 is preferably located at a position further extending 100 to less than 1,940 nm in the depth direction from the communication position with the large diameter hole portion 24 (corresponding to the depth A described above). In other words, the depth of the small diameter holes 26 is preferably 100 to less than 1,940 nm. Among them, the small diameter hole 26 preferably extends from the communication position to a position 300 to 1600 nm deep from the communication position, and the small diameter hole 26 extends from the communication position to a depth 900 to 1300 nm from the point of more excellent effect of the present invention. Is more preferred.
When the depth is less than 100 nm, the scratch resistance may be poor. When the depth is more than 1,940 nm, the processing time may be prolonged and the productivity and economy may be inferior.
The depth of the small diameter holes was obtained by observing the cross section of the anodized film 20 with FE-SEM (50,000 times), measuring the depth of 25 small diameter holes in the obtained image, and averaging the values. It is.

The shape of the small diameter hole portion 26 is not particularly limited. For example, a substantially straight pipe (substantially cylindrical shape), a conical shape whose diameter decreases in the depth direction, and a dendritic shape branching in the depth direction And a substantially straight tubular shape is preferred. The diameter at the bottom of the small diameter hole portion 26 may normally have a difference of about 1 to 5 nm from the diameter at the communication position. The shape of the bottom of the small diameter hole 26 is not particularly limited, and may be curved (concave) or planar.

It is important that in the aluminum support having the anodized film, the average diameter of the small diameter holes at the communication position is smaller than the average diameter of the large diameter holes on the surface of the anodized film. When the average diameter of the small diameter holes is the same as or larger than the average diameter of the large diameter holes, the stain resistance is poor.
With regard to the average diameter of the large diameter holes and the average diameter of the small diameter holes, the ratio, that is, the average diameter of the large diameter holes / the average diameter of the small diameter holes is preferably 1.1 to 12.5. 5-10 are more preferred.

<Method of producing aluminum support having anodized film>
Hereinafter, a method of producing an aluminum support having an anodized film in the lithographic printing plate precursor according to the present invention will be described.
Although the manufacturing method of the aluminum support body which has an anodic oxide film is not specifically limited, The manufacturing method which implements the following processes in order is preferable. (Roughening treatment step) Step of roughening the aluminum plate (first anodizing treatment step) Step of anodizing the roughened aluminum plate (pore wide treatment step) In the first anodizing treatment step The step of contacting the obtained aluminum plate having an anodic oxide film with an aqueous acid solution or an alkaline aqueous solution to enlarge the diameter of the micropores in the anodic oxide film (second anodizing treatment step) aluminum obtained in the pore wide treatment step Step of Anodizing Plate (Hydrophilizing Treatment Step) Step of Hydrophilizing the Aluminum Plate Obtained in the Second Anodizing Step Below, each of the above steps will be described in detail. The roughening treatment step and the hydrophilization treatment step may not be carried out if not necessary.
FIGS. 3A to 3C show schematic cross-sectional views of an aluminum support having an anodized film showing a first anodizing treatment step to a second anodizing treatment step in the order of steps.

(Roughening treatment process)
The surface roughening treatment step is a step of subjecting the surface of the aluminum plate to a surface roughening treatment including electrochemical graining treatment. The surface roughening treatment step is preferably performed before the first anodizing treatment step described later, but may not be performed if the surface of the aluminum plate already has a preferable surface shape.

The surface roughening may be performed only by electrochemical surface roughening, but it is performed by combining electrochemical surface roughening with mechanical surface roughening and / or chemical surface roughening. It is also good.
When mechanical graining treatment and electrochemical graining treatment are combined, it is preferable to apply electrochemical graining treatment after mechanical graining treatment.

The electrochemical graining treatment is preferably performed in an aqueous solution of nitric acid or hydrochloric acid.

The mechanical surface roughening treatment is generally applied in order to make the surface of the aluminum plate have a surface roughness Ra of 0.35 to 1.0 μm.
The conditions of the mechanical surface-roughening treatment are not particularly limited, but can be applied, for example, according to the method described in Japanese Patent Publication No. 50-40047. The mechanical graining treatment can be performed by brush graining using pumice stone suspension or in a transfer method.
The chemical surface-roughening treatment is also not particularly limited, and can be performed according to known methods.

After mechanical graining treatment, the following chemical etching treatment is preferably applied.
The chemical etching treatment applied after the mechanical surface roughening treatment smoothes the uneven edge portion of the surface of the aluminum plate, prevents the ink from being caught during printing, and improves the stain resistance of the lithographic printing plate In addition, it is performed to remove unnecessary substances such as abrasive particles remaining on the surface.
As the chemical etching treatment, etching with an acid and etching with an alkali are known, but as a method particularly excellent in terms of etching efficiency, chemical etching treatment using an alkali solution (hereinafter, also referred to as “alkali etching treatment”). Can be mentioned.

The alkaline agent to be used for the alkaline solution is not particularly limited, but for example, caustic soda, caustic potash, sodium metasilicate, sodium carbonate, sodium aluminate, sodium gluconate and the like are preferably mentioned.
The alkali agent may contain an aluminum ion. 0.01 mass% or more is preferable, 3 mass% or more is more preferable, 30 mass% or less is preferable, and, as for the density | concentration of an alkaline solution, 25 mass% or less is more preferable.
The temperature of the alkaline solution is preferably room temperature or more, more preferably 30 ° C. or more, and preferably 80 ° C. or less, more preferably 75 ° C. or less.

0.1 g / m ² or more is preferable, 1 g / m ² or more is more preferable, 20 g / m ² or less is preferable, and 10 g / m ² or less is more preferable.
The processing time is preferably 2 seconds to 5 minutes in accordance with the etching amount, and more preferably 2 to 10 seconds from the viewpoint of improving the productivity.

When alkali etching is performed after mechanical surface roughening, chemical etching (hereinafter also referred to as "desmutting") is performed using a low temperature acidic solution in order to remove a product generated by the alkali etching. It is preferable to apply.
The acid used for the acidic solution is not particularly limited, and examples thereof include sulfuric acid, nitric acid and hydrochloric acid. The concentration of the acidic solution is preferably 1 to 50% by mass. Also, the temperature of the acidic solution, 20 to 80 ° C., is preferable. When the concentration and temperature of the acidic solution are in this range, the stain resistance of the lithographic printing plate is further improved.

The above-mentioned surface roughening treatment is a treatment to which electrochemical surface roughening treatment is carried out after mechanical surface roughening treatment and chemical etching treatment, if desired. Even when the surface roughening treatment is performed, the chemical etching treatment can be performed using an alkaline aqueous solution such as caustic soda before the electrochemical surface roughening treatment. Thus, impurities and the like present in the vicinity of the surface of the aluminum plate can be removed.

The electrochemical graining treatment is suitable for making a lithographic printing plate excellent in printability because it is easy to impart fine asperities (pits) to the surface of an aluminum plate.
Electrochemical graining treatment is carried out using direct current or alternating current in an aqueous solution mainly comprising nitric acid or hydrochloric acid.

After electrochemical graining treatment, the following chemical etching treatment is preferably carried out. Smut and intermetallic compounds are present on the surface of the aluminum plate after electrochemical graining treatment. In the chemical etching treatment performed after the electrochemical surface roughening treatment, it is preferable to first carry out a chemical etching treatment (alkali etching treatment) using an alkaline solution in order to remove particularly the smut efficiently. As conditions for chemical etching using an alkaline solution, the processing temperature is preferably 20 to 80 ° C., and the processing time is preferably 1 to 60 seconds. It is preferable to contain aluminum ion in the alkaline solution.

After electrochemical graining treatment followed by chemical etching treatment using an alkaline solution, it is preferable to carry out chemical etching treatment (desmutting treatment) using a low temperature acidic solution in order to remove the resulting products .
Even in the case where alkaline etching is not performed after electrochemical graining treatment, desmutting is preferably performed in order to efficiently remove smut.

The chemical etching process described above can be performed by a dipping method, a shower method, a coating method, or the like, and is not particularly limited.

<First anodizing treatment step>
In the first anodizing treatment step, an oxide film of aluminum having micropores extending in the depth direction (thickness direction) on the surface of the aluminum plate by anodizing the aluminum plate subjected to the above-mentioned surface roughening treatment Is a process of forming By this first anodizing treatment, as shown in FIG. 3A, an anodized film 32a of aluminum having micropores 33a is formed on the surface of the aluminum plate 31.

The first anodizing treatment can be performed by a method conventionally performed in this field, but the manufacturing conditions are appropriately set so that the above-mentioned micropores can be finally formed.
Specifically, the average diameter (average opening diameter) of the micropores 33a formed in the first anodizing treatment step is usually about 4 to 14 nm, preferably 5 to 10 nm. If it is in the said range, it will be easy to form the micropore which has the predetermined | prescribed shape mentioned above, and the performance of the obtained lithographic printing plate precursor is more excellent.
The depth of the micropores 33a is usually about 60 to less than 200 nm, preferably 70 to 100 nm. If it is in the said range, it will be easy to form the micropore which has the predetermined | prescribed shape mentioned above, and the performance of the obtained lithographic printing plate precursor is more excellent.

The pore density of the micropores 33a is not particularly limited, but the pore density is preferably 50 to 4000 / μm ² , and more preferably 100 to 3000 / μm ² . Within the above range, the printing durability and leaving-off properties of the resulting lithographic printing plate, and the developability of the lithographic printing plate precursor are excellent.

The thickness of the anodized film obtained by the first anodizing treatment step is preferably 70 to 300 nm, more preferably 80 to 150 nm. If it is in the above-mentioned range, the printing durability, leaving-to-stand property, stain resistance, and developability of the lithographic printing plate precursor obtained from the lithographic printing plate obtained are excellent.
The film amount of the anodized film obtained by the first anodizing treatment step is preferably 0.1 to 0.3 g / m ² , more preferably 0.1 ² to 0.25 g / m ² . If it is in the above-mentioned range, the printing durability, leaving-to-stand property, stain resistance, and developability of the lithographic printing plate precursor obtained from the lithographic printing plate obtained are excellent.

In the first anodizing treatment step, an aqueous solution of sulfuric acid, oxalic acid or the like can be mainly used as an electrolytic bath. In some cases, an aqueous solution or a non-aqueous solution in which chromic acid, sulfamic acid, benzenesulfonic acid or the like or a combination of two or more of them can be used. An anodized film can be formed on the surface of the aluminum plate by applying direct current or alternating current to the aluminum plate in the above-mentioned electrolytic bath.
The electrolytic bath may contain aluminum ions. The content of aluminum ion is not particularly limited, but is preferably 1 to 10 g / L.

The conditions of the anodizing treatment are appropriately set depending on the electrolyte to be used, but generally, the concentration of the electrolyte is 1 to 80% by mass (preferably 5 to 20% by mass), the solution temperature is 5 to 70 ° C. 10 to 60 ° C., current density 0.5 to 60 A / dm ² (preferably 5 to 50 A / dm ² ), voltage 1 to 100 V (preferably 5 to 50 V), electrolysis time 1 to 100 seconds (preferably) A range of 5 to 60 seconds is appropriate.

Among the above anodizing treatments, in particular, the method of anodizing at a high current density in sulfuric acid, which is described in British Patent No. 1,412,768, is preferable.

(Pore wide processing process)
The pore widening process is a process (pore diameter enlarging process) for enlarging the diameter (pore diameter) of the micropores present in the anodized film formed by the first anodizing process described above. By this pore-widening process, as shown in FIG. 3B, the diameter of the micropores 33a is enlarged, and an anodic oxide film 32b having the micropores 33b having a larger average diameter is formed.
By the pore-widening process, the average diameter of the micropores 33b is expanded to the range of 10 to 100 nm (preferably, 15 to 60 nm, more preferably, 18 to 40 nm). The micropores 33b correspond to the large diameter holes 24 (FIG. 2) described above.
It is preferable to adjust the depth from the surface of the micropores 33b to the same degree as the depth A (FIG. 2) described above by the pore widening process.

The pore-widening process is performed by bringing the aluminum plate obtained by the above-described first anodizing process into contact with an aqueous acid solution or an aqueous alkali solution. The method for contacting is not particularly limited, and examples thereof include a dipping method and a spraying method. Among them, the immersion method is preferred.

When using an aqueous alkali solution in the pore-widening step, it is preferable to use at least one aqueous alkali solution selected from sodium hydroxide, potassium hydroxide and lithium hydroxide. The concentration of the aqueous alkali solution is preferably 0.1 to 5% by mass.
After adjusting the pH of the aqueous alkaline solution to 11 to 13, the aluminum plate is brought into contact with the aqueous alkaline solution for 1 to 300 seconds (preferably 1 to 50 seconds) under conditions of 10 to 70 ° C. (preferably 20 to 50 ° C.) Is appropriate.
The alkali treatment solution may contain metal salts of polyvalent weak acids such as carbonates, borates and phosphates.

When using an aqueous acid solution in the pore-widening step, it is preferable to use an aqueous solution of an inorganic acid such as sulfuric acid, phosphoric acid, nitric acid, hydrochloric acid or a mixture thereof. The concentration of the aqueous acid solution is preferably 1 to 80% by mass, more preferably 5 to 50% by mass.
It is appropriate to bring the aluminum plate into contact with the aqueous acid solution for 1 to 300 seconds (preferably 1 to 150 seconds) under the conditions of a liquid temperature of 5 to 70 ° C. (preferably 10 to 60 ° C.).
The aqueous alkali solution or the aqueous acid solution may contain aluminum ions. The content of aluminum ion is not particularly limited, but is preferably 1 to 10 g / L.

(Second anodizing process)
The second anodizing treatment step is a step of forming micropores extending in the depth direction (thickness direction) by anodizing the aluminum plate to which the above-described pore-widening treatment has been applied. By this second anodizing treatment step, as shown in FIG. 3C, an anodized film 32c having micropores 33c extending in the depth direction is formed.
It communicates with the bottom of the micropores 33b whose average diameter is expanded by the second anodizing treatment step, the average diameter is smaller than the average diameter of the micropores 33b (corresponding to the large diameter holes 24), and the depth direction from the communication position A new hole is formed which extends to the surface. The said hole corresponds to the small diameter hole 26 mentioned above.

In the second anodizing treatment step, the average diameter of the newly formed hole is larger than 0 and less than 20 nm, and the depth from the communication position with the large diameter hole 20 is within the above-described predetermined range. Will be implemented. The electrolytic bath used for the treatment is the same as the first anodizing treatment step described above, and the treatment conditions are appropriately set according to the material to be used.
The conditions of the anodizing treatment are appropriately set depending on the electrolyte to be used, but generally, the concentration of the electrolyte is 1 to 80% by mass (preferably 5 to 20% by mass), the solution temperature is 5 to 70 ° C. Preferably, the current density is 0.5 to 60 A / dm ² (preferably 1 to 30 A / dm ² ), the voltage is 1 to 100 V (preferably 5 to 50 V), and the electrolysis time is 1 to 100 seconds (preferably) A range of 5 to 60 seconds is appropriate.

The thickness of the anodized film obtained by the second anodizing treatment step is usually 200 to 2,000 nm, preferably 750 to 1,500 nm. If it is in the said range, it will be excellent in the printing resistance and leaving-to-stand property of the lithographic printing plate obtained.
The film amount of the anodized film obtained by the second anodizing treatment step is usually 2.2 to 5.4 g / m ² , preferably 2.2 to 4.0 g / m ² . Within the above range, the printing durability and leaving-off properties of the resulting lithographic printing plate, and the developability and scratch resistance of the lithographic printing plate precursor are excellent.

Ratio (coating thickness 1 / coating thickness) of the thickness (coating thickness 1) of the anodized film obtained by the first anodizing treatment step and the thickness (coating thickness 2) of the anodized film obtained by the second anodizing treatment step 0.01 to 0.15 is preferable, and 0.02 to 0.10 is more preferable. Within the above range, the scratch resistance of the lithographic printing plate support is excellent.

In order to manufacture the shape of the small diameter holes 26 (see FIG. 2) described above, the voltage to be applied may be increased stepwise or continuously during the processing of the second anodizing treatment step. As the voltage to be applied is increased, the diameter of the hole to be formed is increased, and as a result, a shape like the above-described small diameter hole 26 is obtained.

(Hydrophilization treatment process)
The manufacturing method of the aluminum support body which has an anodic oxidation film may have the hydrophilization treatment process which performs a hydrophilization treatment after the 3rd anodizing treatment process mentioned above. As the hydrophilization treatment, known methods disclosed in paragraphs [0109] to [0114] of JP-A-2005-254638 can be used.

It is preferable to perform the hydrophilization treatment by a method of immersing in an aqueous solution of an alkali metal silicate such as sodium silicate and potassium silicate.

Hydrophilization treatment with an aqueous solution of an alkali metal silicate such as sodium silicate and potassium silicate is described in U.S. Pat. Nos. 2,714,066 and 3,181,461. It can be performed according to the method and procedure.

As the aluminum support having an anodized film, a support obtained by sequentially performing the treatments shown in the following A mode or B mode on the above-mentioned aluminum plate is preferable, and from the viewpoint of printing durability, In particular, the A mode is preferred. It is desirable to wash with water between each of the following treatments. However, in the case where a solution having the same composition is used in two successive steps (treatments), the water washing may be omitted.

<A mode>
(2) Chemical etching process in alkaline aqueous solution (first alkali etching process)
(3) Chemical etching process in acidic aqueous solution (first desmutting process)
(4) Electrochemical graining treatment in an aqueous solution mainly comprising nitric acid (first electrochemical graining treatment)
(5) Chemical etching process in alkaline aqueous solution (second alkali etching process)
(6) Chemical etching process in acidic aqueous solution (second desmutting process)
(7) Electrochemical graining treatment in an aqueous solution mainly composed of hydrochloric acid (second electrochemical graining treatment)
(8) Chemical etching process in alkaline aqueous solution (third alkali etching process)
(9) Chemical etching process in acidic aqueous solution (third desmutting process)
(10) Anodizing treatment (first anodizing treatment, pore widening treatment, second anodizing treatment)
(11) Hydrophilization treatment

<B mode>
(2) Chemical etching process in alkaline aqueous solution (first alkali etching process)
(3) Chemical etching process in acidic aqueous solution (first desmutting process)
(12) Electrochemical graining treatment in an aqueous solution mainly composed of hydrochloric acid (5) Chemical etching treatment in an aqueous alkali solution (second alkali etching treatment)
(6) Chemical etching process in acidic aqueous solution (second desmutting process)
(10) Anodizing treatment (first anodizing treatment, pore widening treatment, second anodizing treatment)
(11) Hydrophilization treatment

Prior to the treatment of (2) of the above-mentioned A mode and B mode, (1) mechanical surface roughening treatment may be carried out, if necessary. From the viewpoint of printing durability and the like, the treatment of (1) is preferably not included in each embodiment.
Here, the mechanical surface-roughening treatment, electrochemical surface-roughening treatment, chemical etching treatment, anodizing treatment and hydrophilization treatment in the above (1) to (12) are the same as the treatment methods and conditions described above. It is preferable to apply the treatment method and conditions described below.

The mechanical surface-roughening treatment is preferably performed by mechanical surface-roughening treatment using a rotating nylon brush roll having a hair diameter of 0.2 to 1.6 mm and a slurry solution supplied to the surface of the aluminum plate. Although a well-known thing can be used as an abrasives, a silica sand, quartz, aluminum hydroxide or these mixtures are preferable. The specific gravity of the slurry is preferably 1.05 to 1.3. Of course, a method of spraying a slurry liquid, a method of using a wire brush, or a method of transferring the surface shape of a roughened rolling roll to an aluminum plate may be used.

The concentration of the aqueous alkaline solution used for the chemical etching process (first to third alkaline etching processes) in the aqueous alkaline solution is preferably 1 to 30% by mass, and contains 0 to 10% by mass of aluminum and alloy components contained in the aluminum alloy. You may
As the alkaline aqueous solution, an aqueous solution mainly comprising caustic soda is particularly preferable. The liquid temperature is preferably room temperature to 95 ° C. for 1 to 120 seconds.
After the etching process is completed, it is preferable to perform the liquid removal by the nip roller and the water washing by the spray in order not to bring the processing solution into the next step.

Dissolution amount of the aluminum plate in the first alkali etching treatment is preferably 0.5 ~ 30g / ^{m 2,} more preferably 1.0 ~ 20g / ^{m 2,} more preferably 3.0 ~ 15g / ^{m 2.}
Dissolution amount of the aluminum plate in the second alkali etching treatment is preferably 0.001 ~ 30 g / ^{m 2,} more preferably 0.1 ~ 4g / ^{m 2,} more preferably 0.2 ~ 1.5g / ^{m 2.}
The dissolution amount of the aluminum plate in the third alkali etching treatment is preferably 0.001 to 30 g / m ² , more preferably 0.01 to 0.8 g / m ² , and further preferably 0.02 to 0.3 g / m ^2. preferable.

Phosphoric acid, nitric acid, sulfuric acid, chromic acid, hydrochloric acid or a mixed acid containing two or more of these acids is preferably used in the chemical etching process (first to third desmutting processes) in an acidic aqueous solution. The concentration of the acidic aqueous solution is preferably 0.5 to 60% by mass. In the acidic aqueous solution, 0 to 5% by mass of alloy components contained in aluminum and aluminum alloy may be dissolved.
The solution temperature is from room temperature to 95 ° C., and the treatment time is preferably 1 to 120 seconds. After the desmutting treatment is completed, it is preferable to carry out drainage with a nip roller and washing with a spray in order to prevent the treatment liquid from being carried to the next step.

The aqueous solution used for electrochemical graining treatment is described.
The aqueous solution mainly composed of nitric acid used in the first electrochemical graining treatment may be an aqueous solution used in electrochemical graining treatment using a conventional direct current or alternating current, and an aqueous solution of 1 to 100 g / L nitric acid And nitrate ion such as aluminum nitrate, sodium nitrate and ammonium nitrate; hydrochloric acid ion such as aluminum chloride, sodium chloride and ammonium chloride; and one or more of hydrochloric acid or nitrate compound having 1 etc. to 1 g / L to saturation. be able to.
In the aqueous solution mainly composed of nitric acid, metals contained in an aluminum alloy such as iron, copper, manganese, nickel, titanium, magnesium and silica may be dissolved.
Specifically, it is preferable to use a solution obtained by adding aluminum chloride or aluminum nitrate so that the amount of aluminum ions is 3 to 50 g / L in a 0.5 to 2% by mass aqueous solution of nitric acid.
The liquid temperature is preferably 10 to 90 ° C., and more preferably 40 to 80 ° C.

The aqueous solution mainly composed of hydrochloric acid used in the second electrochemical graining treatment may be an aqueous solution used in electrochemical graining treatment using a conventional direct current or alternating current, and is 1 to 100 g / L hydrochloric acid aqueous solution And nitrate ion such as aluminum nitrate, sodium nitrate and ammonium nitrate; hydrochloric acid ion such as aluminum chloride, sodium chloride and ammonium chloride; and one or more of hydrochloric acid or nitrate compound having 1 etc. to 1 g / L to saturation. be able to.
A metal contained in an aluminum alloy such as iron, copper, manganese, nickel, titanium, magnesium, and silica may be dissolved in an aqueous solution containing hydrochloric acid as a main component.
Specifically, it is preferable to use a solution obtained by adding aluminum chloride or aluminum nitrate so as to have an aluminum ion concentration of 3 to 50 g / L in a 0.5 to 2% by mass aqueous solution of hydrochloric acid.
The solution temperature is preferably 10 to 60 ° C., and more preferably 20 to 50 ° C. Hypochlorous acid may be added.

On the other hand, as the aqueous solution mainly composed of hydrochloric acid used in electrochemical graining treatment in a hydrochloric acid aqueous solution in B mode, an aqueous solution used for electrochemical graining treatment using normal direct current or alternating current can be used, Sulfuric acid can be used by adding 0 to 30 g / L to a 1 to 100 g / L aqueous hydrochloric acid solution. To this aqueous solution, add one or more of hydrochloric acid or nitrate compound having nitrate ion such as aluminum nitrate, sodium nitrate, ammonium nitrate; hydrochloric acid ion such as aluminum chloride, sodium chloride, ammonium chloride etc. to 1 g / L to saturation It can be used.
A metal contained in an aluminum alloy such as iron, copper, manganese, nickel, titanium, magnesium, and silica may be dissolved in an aqueous solution containing hydrochloric acid as a main component.
Specifically, it is preferable to use a solution obtained by adding aluminum chloride, aluminum nitrate or the like to an aqueous solution of 0.5 to 2% by mass of nitric acid so that the amount of aluminum ions is 3 to 50 g / L.
The solution temperature is preferably 10 to 60 ° C., and more preferably 20 to 50 ° C. Hypochlorous acid may be added.

Sine waves, square waves, trapezoidal waves, triangular waves or the like can be used as the alternating current power source waveform of the electrochemical surface roughening treatment. The frequency is preferably 0.1 to 250 Hz.

A graph showing an example of an alternating waveform current waveform diagram used for electrochemical graining treatment in a method of manufacturing an aluminum support having an anodic oxide film is shown in FIG.
In FIG. 4, ta is the anode reaction time, tc is the cathode reaction time, tp is the time until the current reaches a peak from 0, Ia is the peak current on the anode cycle side, and Ic is the peak current on the cathode cycle side It is. In the trapezoidal wave, the time tp for the current to reach a peak from 0 is preferably 1 to 10 msec. Due to the influence of the impedance of the power supply circuit, if tp is less than 1, a large power supply voltage is required at the rise of the current waveform, and the facility cost of the power supply becomes high. When it becomes larger than 10 msec, it becomes easy to receive to the influence of the trace component in electrolyte solution, and it becomes difficult to perform uniform roughening. The conditions of one cycle of alternating current used for electrochemical surface roughening are the ratio tc / ta of anode reaction time ta of aluminum plate to cathode reaction time tc of 1 to 20, and the amount of electricity Qc when the aluminum plate is anode Preferably, the ratio Qc / Qa of the quantity of electricity Qa at this time is in the range of 0.3 to 20, and the anode reaction time ta is in the range of 5 to 1000 msec. The tc / ta is more preferably 2.5-15. Qc / Qa is more preferably 2.5-15. The current density is preferably 10 to 200 A / dm ² on both the anode cycle side Ia and the cathode cycle side Ic of the current at the peak value of the trapezoidal wave. The Ic / Ia is preferably in the range of 0.3 to 20. The total amount of electricity involved in the anodic reaction of the aluminum plate at the end of the electrochemical surface roughening is preferably 25 to 1000 C / dm ² .

As an electrolytic cell used for electrochemical roughening using alternating current, an electrolytic cell used for known surface treatment such as vertical type, flat type and radial type can be used, but it is described in JP-A-5-195300. Particularly preferred is a radial type electrolytic cell as described above.

The apparatus shown in FIG. 5 can be used for electrochemical roughening using alternating current. FIG. 5 is a side view showing an example of a radial type cell in electrochemical graining treatment using alternating current in the method for producing an aluminum support having an anodized film.
In FIG. 5, 50 is a main electrolytic cell, 51 is an AC power supply, 52 is a radial drum roller, 53a and 53b are main electrodes, 54 is an electrolytic solution supply port, 55 is an electrolytic solution, 56 is a slit, 57 is an electrolytic solution passage, 58 is an auxiliary anode, 60 is an auxiliary anode tank, and W is an aluminum plate. When two or more electrolytic cells are used, the electrolytic conditions may be the same or different.
The aluminum plate W is wound around a radial drum roller 52 disposed so as to be immersed in the main electrolytic cell 50, and is electrolyzed by the main electrodes 53a and 53b connected to the AC power supply 51 in the transportation process. The electrolytic solution 55 is supplied from the electrolytic solution supply port 54 through the slit 56 to the electrolytic solution passage 57 between the radial drum roller 52 and the main electrodes 53a and 53b. The aluminum plate W treated in the main electrolytic cell 50 is then electrolytically treated in the auxiliary anode cell 60. An auxiliary anode 58 is disposed opposite to the aluminum plate W in the auxiliary anode tank 60, and the electrolyte solution 55 is supplied to flow in the space between the auxiliary anode 58 and the aluminum plate W.

[Positive image recording layer]
The positive-working image recording layer in the lithographic printing plate precursor according to the invention is described.
The positive type image recording layer comprises an image recording layer comprising a single layer or a plurality of layers. An infrared absorbing agent is contained in the image recording layer, and a thermal positive type image recording layer capable of imagewise exposure with an infrared laser is preferable, but a conventional positive type image recording layer using ultraviolet light can also be used.

<Thermal positive type image recording layer>
The thermal positive type image recording layer (hereinafter also referred to as a thermal positive type heat sensitive layer) preferably contains an alkali-soluble polymer compound and an infrared absorber. Here, the alkali-soluble polymer compound includes homopolymers containing an acidic group in the main chain and / or side chain in the polymer, copolymers thereof, and mixtures thereof. Therefore, the thermal positive type heat sensitive layer has the property of dissolving when it comes in contact with an alkali developer. Among alkali-soluble polymer compounds, those having at least one of the following acidic groups (1) to (6) in the main chain and / or side chain of the polymer are preferred in terms of solubility in an alkaline developer: preferable.

(1) phenolic hydroxyl group (-Ar-OH)
(2) Sulfonamide group (-SO ₂ NH-R)
(3) Substituted sulfonamide group acid group (-SO ₂ NHCOR, -SO ₂ NHSO ₂ R, -CONHSO ₂ R) (hereinafter referred to as "active imide group")
(4) Carboxyl group (-CO ₂ H)
(5) Sulfo group (-SO ₃ H)
(6) Phosphoric acid group (-OPO ₃ H ₂ )

In the above (1) to (6), Ar represents a divalent aryl group which may have a substituent, and R represents a hydrocarbon group which may have a substituent.

Among the alkali-soluble polymer compounds having an acid group selected from the above (1) to (6), an alkali-soluble polymer compound having (1) a phenol group, (2) a sulfonamide group or (3) an active imido group An alkali-soluble polymer compound having (1) a phenol group or (2) a sulfonamide group is particularly preferable from the viewpoint of sufficiently securing the solubility in an alkali developer and the film strength.

Representative examples of the polymerization component in the alkali-soluble polymer compound will be described.
(1) Examples of the polymerizable monomer having a phenolic hydroxyl group include polymerizable monomers consisting of low molecular weight compounds each having one or more phenolic hydroxyl groups and a polymerizable unsaturated bond, and examples thereof include phenolic Acrylamides having a hydroxyl group, methacrylamides, acrylic acid esters or methacrylic acid esters, hydroxystyrene and the like can be mentioned.
The monomer having a phenolic hydroxyl group may be used in combination of two or more.

(2) As a polymerizable monomer having a sulfonamide group, a sulfonamide group (—NH—SO ₂ —) in which at least one hydrogen atom is bonded to a nitrogen atom in one molecule, and a polymerizable unsaturated bond The polymerizable monomer which consists of a low molecular weight compound which each has one or more is mentioned, For example, the low molecular weight compound which has an acryloyl group, an allyl group or vinyloxyl group, and a mono-substituted aminosulfonyl group or a substituted sulfonylimino group is preferable. Examples of such compounds include the compounds represented by the general formulas (I) to (V) described in JP-A-8-123029. Specifically, m-aminosulfonylphenyl methacrylate, N- (p-aminosulfonylphenyl) methacrylamide, N- (p-aminosulfonylphenyl) acrylamide, etc. are suitably used as the polymerizable monomer having a sulfonamide group. be able to.

As a polymer obtained from the polymerizable monomer which has a sulfonamide group, the polymer which has at least 1 sort (s) among the structural unit represented by following formula S-1 and the structural unit represented by following formula S-2 is mentioned preferably .

In formulas S-1 and S-2, R ^s1 represents a hydrogen atom or an alkyl group. Z represents -O- or -NR ^s2 , wherein R ^s2 represents a hydrogen atom, an alkyl group, an alkenyl group or an alkynyl group. Ar ¹ and Ar ² each independently represent an aromatic group, and at least one is a heteroaromatic group. sa and sb each independently represent 0 or 1;

In the formula S-1, R ^s1 represents a hydrogen atom or an alkyl group, and the alkyl group is a substituted or unsubstituted alkyl group, preferably one having no substituent. ^Examples of the alkyl group represented by R ^s1 include lower alkyl groups such as methyl group, ethyl group, propyl group and butyl group. R ^s1 is preferably a hydrogen atom or a methyl group.
Z represents -O- or -NR ^s2- , preferably -NR ^s2- . Here, R ^s2 represents a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, or a substituted or unsubstituted alkynyl group, preferably a hydrogen atom or an unsubstituted alkyl group, Preferably it is a hydrogen atom.
sa and sb each independently represent 0 or 1, and a preferred embodiment is a case where sa is 0 and sb is 1, more preferably a case where both sa and sb are 0, particularly preferably sa. And sb are both 1.
More specifically, in the above structural unit, when sa is 0 and sb is 1, Z is preferably O. In addition, when sa and sb are both 1, Z is preferably NR ^s2 , where R ^s2 is preferably a hydrogen atom.

Ar ¹ and Ar ² each independently represent an aromatic group, and at least one is a heteroaromatic group. Ar ¹ is a divalent aromatic group, and Ar ² is a monovalent aromatic group. The aromatic group is a substituent formed by replacing one or two of the hydrogen atoms constituting the aromatic ring with a linking group.
The aromatic ring and heteroaromatic ring in the aromatic group may be selected from hydrocarbon aromatic rings such as benzene, naphthalene and anthracene, and may be furan, thiophene, pyrrole, imidazole or 1,2,3-triazole 1,2,4-triazole, tetrazole, oxazole, isoxazole, thiazole, isothiazole, thiadiazole, oxadiazole, pyridine, pyridazine, pyrimidine, pyrazine, 1,3,5-triazine, 1,2,4-triazine Or a heteroaromatic ring such as 1,2,3-triazine.
A plurality of rings may be fused, for example, in the form of a fused ring such as benzofuran, benzothiophene, indole, indazole, benzoxazole, quinoline, quinazoline, benzimidazole or benzotriazole.

The aromatic group and the heteroaromatic group may further have a substituent, and as the substituent which can be introduced, an alkyl group, a cycloalkyl group, an alkenyl group, a cycloalkenyl group, an aryl group, a heteroaryl group Hydroxy group, mercapto group, carboxy group or alkyl ester thereof, sulfonic acid group or alkyl ester thereof, phosphinic acid group or alkyl ester thereof, amino group, sulfonamide group, amido group, nitro group, halogen atom, or the like The substituent etc. which are formed by combining two or more may be mentioned, and the substituent may further have the substituent mentioned here.

Ar ² is preferably a heteroaromatic group which may have a substituent, more preferably pyridine, pyridazine, pyrimidine, pyrazine, 1,3,5-triazine, 1,2,4-triazine, And heteroaromatic rings containing a nitrogen atom selected from 1,2,3-triazines, tetrazoles, oxazoles, isoxazoles, thiazoles, isothiazoles, thiadiazoles, and oxadiazoles.

The content of the constituent unit represented by the formula S-1 or the formula S-2 (but converted as a monomer unit) is preferably 10 mol% to 100 mol% with respect to the total amount of the monomer units in the polymer. 20 mol% to 90 mol% is more preferable, 30 mol% to 80 mol% is more preferable, and 30 mol% to 70 mol% is particularly preferable.

The polymer may be a copolymer containing other structural units in addition to the structural units represented by the above-mentioned formula S-1 or formula S-2.
As another structural unit, a hydrophobic monomer having a substituent such as an alkyl group or an aryl group in the side chain structure of the monomer, or an acid group, an amide group, a hydroxy group or an ethylene oxide group in the side chain structure of the monomer It is important to select the kind of monomer to be copolymerized in the range which does not impair the alkali solubility of the above-mentioned polymer. .

Other copolymerization components include (meth) acrylamide, N-substituted (meth) acrylamide, N-substituted maleimide, (meth) acrylic acid ester, (meth) acrylic acid ester having a polyoxyethylene chain, 2-hydroxyethyl (Meth) acrylate, styrene, styrene sulfonic acid, o-, p-, or m-vinylbenzene acid, vinylpyridine, N-vinylcaprolactam, N-vinylpyrrolidine, (meth) acrylic acid, itaconic acid, maleic acid, glycidyl (Meth) acrylate, hydrolyzed vinyl acetate, vinyl phosphonic acid and the like. As preferable copolymerization components, N-benzyl (meth) acrylamide, (meth) acrylic acid and the like can be mentioned.

The number average molecular weight (Mn) of the polymer having at least one of the constitutional unit represented by the above formula S-1 and the constitutional unit represented by the above formula S-2 is preferably 10,000 to 500,000, 10,000 to 200,000 are more preferable, and 10,000 to 100,000 are particularly preferable. The weight average molecular weight (Mw) is preferably 10,000 to 1,000,000, more preferably 20,000 to 500,000, and particularly preferably 20,000 to 200,000.

(3) As the polymerizable monomer having an active imide group, a compound having an active imide group in the molecule described in JP-A-11-84657 is preferable, and an active imide group can be polymerized in one molecule. And polymerizable monomers comprising low molecular weight compounds each having one or more unsaturated bonds. Specifically, N- (p-toluenesulfonyl) methacrylamide, N- (p-toluenesulfonyl) acrylamide and the like can be suitably used as the polymerizable monomer having an active imide group.

The polymeric compound which copolymerized 2 or more types in the polymerizable monomer which has the said phenolic hydroxyl group, the polymerizable monomer which has a sulfonamide group, and the polymerizable monomer which has an active imide group, or these 2 or more types It is preferable to use a polymer compound obtained by copolymerizing the polymerizable monomer with another polymerizable monomer. When the polymerizable monomer having a phenolic hydroxyl group is copolymerized with a polymerizable monomer having a sulfonamide group and / or a polymerizable monomer having an active imido group, the blending mass ratio of these components is 50: 50 to 5: It is preferably in the range of 95, and more preferably in the range of 40:60 to 10:90.

When the alkali-soluble polymer compound is a copolymer of the above-mentioned polymerizable monomer having a phenolic hydroxyl group, a polymerizable monomer having a sulfonamide group, or a polymerizable monomer having an active imido group and another polymerizable monomer In view of the effect of improving alkali solubility and development latitude, the monomer imparting alkali solubility is preferably contained in an amount of 10 mol% or more, preferably 20 mol% or more, based on the total molar amount of monomers used for copolymerization. Is more preferred.

As the monomer component to be copolymerized with the polymerizable monomer having a phenolic hydroxyl group, the polymerizable monomer having a sulfonamide group, or the polymerizable monomer having an active imide group, the compounds listed in the following (m1) to (m12) are exemplified Although it can do, it is not limited to these.
(M1) Acrylic acid esters having an aliphatic hydroxyl group such as 2-hydroxyethyl acrylate or 2-hydroxyethyl methacrylate, and methacrylic acid esters.
(M2) Alkyl acrylates such as methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, amyl acrylate, hexyl acrylate, octyl acrylate, benzyl acrylate, 2-chloroethyl acrylate, glycidyl acrylate and the like.
(M3) Alkyl methacrylates such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, amyl methacrylate, hexyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, 2-chloroethyl methacrylate, glycidyl methacrylate and the like.
(M4) Acrylamide, methacrylamide, N-methylol acrylamide, N-ethyl acrylamide, N-hexyl methacrylamide, N-cyclohexyl acrylamide, N-hydroxyethyl acrylamide, N-phenyl acrylamide, N-nitrophenyl acrylamide, N-ethyl- Acrylamide or methacrylamide such as N-phenyl acrylamide.

(M5) Vinyl ethers such as ethyl vinyl ether, 2-chloroethyl vinyl ether, hydroxyethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, octyl vinyl ether, phenyl vinyl ether and the like.
(M6) Vinyl esters such as vinyl acetate, vinyl chloroacetate, vinyl butyrate and vinyl benzoate.
(M7) Styrenes such as styrene, α-methylstyrene, methylstyrene and chloromethylstyrene.
(M8) Vinyl ketones such as methyl vinyl ketone, ethyl vinyl ketone, propyl vinyl ketone, phenyl vinyl ketone and the like.
(M9) Olefins such as ethylene, propylene, isobutylene, butadiene and isoprene.
(M10) N-vinylpyrrolidone, acrylonitrile, methacrylonitrile and the like.
(M11) Unsaturated imides such as maleimide, N-acryloyl acrylamide, N-acetyl methacrylamide, N-propionyl methacrylamide, N- (p-chlorobenzoyl) methacrylamide and the like.
(M12) Unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic anhydride and itaconic acid.

The infrared absorber contained in the heat-sensitive layer of the thermal positive type is a substance that absorbs light and generates heat. The infrared absorbing agent can convert exposure energy into heat to efficiently release interaction between the exposed area of the heat sensitive layer. The infrared absorbing agent is preferably a pigment or dye having a light absorbing region in the infrared region of a wavelength of 700 to 1200 nm from the viewpoint of recording sensitivity.

As pigments, commercially available pigments, as well as Color Index (CI) Handbook, "Latest Pigment Handbook" (edited by Japan Pigment Technology Association, published in 1977), "latest pigment applied technology" (CMC publication, published in 1986) and Pigments described in "Printing Ink Technology", CMC Publishing, 1984) can be used.

Types of pigments include, for example, black pigments, yellow pigments, orange pigments, brown pigments, red pigments, purple pigments, blue pigments, green pigments, fluorescent pigments, metal powder pigments, polymer-bound dyes. Specifically, insoluble azo pigments, azo lake pigments, condensed azo pigments, chelate azo pigments, phthalocyanine pigments, anthraquinone pigments, perylene and perinone pigments, thioindigo pigments, quinacridone pigments, dioxazine pigments, isoindolinone pigments Quinophthalone pigments, dyed lake pigments, azine pigments, nitroso pigments, nitro pigments, natural pigments, fluorescent pigments, inorganic pigments, carbon black can be used.

The pigment may be used without surface treatment, or may be used after being subjected to conventionally known surface treatment.

The particle size of the pigment is preferably 0.01 to 10 μm, more preferably 0.05 to 1 μm, and still more preferably 0.1 to 1 μm. Within the above range, it is preferable in view of the stability of the pigment dispersion in the heat-sensitive layer coating solution, the uniformity of the heat-sensitive layer, and the like.

As a method of dispersing the pigment, for example, known dispersion techniques used for ink production and toner production described in "Latest Pigment Application Technology" (CMC Publishing, 1986) etc. can be used.

As dyes, commercially available dyes and known dyes described in the literature (for example, "Dye Handbook" Kodansha (1986), "Dye Handbook" edited by the Society of Synthetic Organic Chemistry, published in 1945) are used. it can. Specifically, azo dyes, metal complex salts azo dyes, pyrazolone azo dyes, naphthoquinone dyes, anthraquinone dyes, phthalocyanine dyes, carbonium dyes, azulenium dyes, quinoneimine dyes, methine dyes, cyanine dyes, squalilium dyes, pyrilium salts, metal-metal complexes Dyes such as (for example, dithiol metal complex, metal-containing phthalocyanine) can be used.

Among these pigments or dyes, those absorbing infrared light or near infrared light are particularly preferable in that they are suitable for use of a laser emitting infrared light or near infrared light.

As a pigment which absorbs such infrared light or near-infrared light, phthalocyanine (including metal-containing phthalocyanine) and carbon black are suitably used. Moreover, as a dye which absorbs infrared light or near infrared light, for example, cyanine dyes, merocyanine dyes, iminium dyes, oxonol dyes, pyrylium (including thiopyrylium, selenapyrilium, ternapyrylium) dyes, naphthoquinone dyes, Examples include squarylium dyes, phthalocyanines (including metal-containing phthalocyanines) dyes, organic metal complexes (metal complex compounds with dithiols, diamines and the like, etc.) and the like. Specifically, for example, compounds described in paragraph Nos. [0020] to [0021] of JP-A-7-285275, and “Electronics related dyes-present state and future prospects-” Chapter 16 Examples thereof include compounds described in known materials such as CMC (1998).

As another preferred example of the dye, a near infrared absorbing dye described as formula (I) or (II) in US Pat. No. 4,756,993 is described in JP-A-2000-267265. An infrared absorbing dye which becomes soluble in an alkaline aqueous solution, an infrared absorbing dye containing a functional group which changes to hydrophilicity by heat as described in JP-A-11-309952, JP-A-2000-160131 The polymethine dyes described in JP-A-2000-330271, JP-A-2001-117216 and JP-A-2001-174980, and the phthalocyanine dyes described in JP-A-2000-352817. However, the dye as the infrared absorber used in the present invention is not limited to these.

The content of the infrared absorber is preferably 0.01 to 50% by mass, more preferably 0.01 to 30% by mass, still more preferably 0.1 to 10% by mass, based on the total solid content of the heat-sensitive layer. In the case of dyes, particularly preferably 0.5 to 10% by weight, in the case of pigments particularly preferably 1 to 10% by weight. When the content of the infrared absorbing agent is less than 0.01% by mass, the sensitivity may be lowered, and when it exceeds 50% by mass, the uniformity of the heat-sensitive layer is lost and the durability of the heat-sensitive layer is deteriorated. There is.

The heat-sensitive layer of the thermal positive type may further contain other components such as an acid generator, an acid multiplying agent, a development accelerator, a surfactant, a print-out agent / colorant, a plasticizer, a wax agent and the like. With regard to these components, the description in paragraphs [0119] to [0147] of JP-A-2003-1956 can be referred to.

The thermal positive type image recording layer may have a two-layer structure consisting of a lower layer close to the aluminum support having the anodized film and an upper layer present thereon. An image recording layer having a two-layer structure is described, for example, in JP-A-11-218914.
The upper layer contains an alkali-soluble polymer compound, an infrared absorber, and other components contained in the heat-sensitive layer of the thermal positive type.
The lower layer preferably contains an alkali-soluble polymer compound. The lower layer may further contain an infrared absorber and other components.

With respect to the composition ratio of each component in the lower layer and the upper layer, the content of the alkali-soluble polymer compound is preferably 10% by mass to 90% by mass with respect to the total mass of the lower layer and the upper layer. 01% by mass to 50% by mass is preferable, the content of the acid generator is preferably 0% by mass to 30% by mass, the content of the acid multiplying agent is preferably 0% by mass to 20% by mass, and the content of the development accelerator Is preferably 0% by mass to 20% by mass, the content of surfactant is preferably 0% by mass to 5% by mass, and the content of printout agent / coloring agent is preferably 0% by mass to 10% by mass, and the plasticizer The content of is preferably 0% by mass to 10% by mass, and the content of the wax agent is preferably 0% by mass to 10% by mass.

The lower layer and the upper layer can be formed by dissolving the above-described components in a solvent and coating. The solvents to be used include ethylene dichloride, cyclohexanone, methyl ethyl ketone, methanol, ethanol, propanol, ethylene glycol monomethyl ether, 1-methoxy-2-propanol, 2-methoxyethyl acetate, 1-methoxy-2-propyl acetate, dimethoxyethane, Methyl lactate, ethyl lactate, N, N-dimethylacetamide, N, N-dimethylformamide, tetramethylurea, N-methylpyrrolidone, dimethylsulfoxide, sulfolane, γ-butyrolactone, toluene, 1,3-dimethyl-2-imidazolidinone Etc., but are not limited to these. The solvents are used alone or in combination.

The content of the alkali-soluble polymer compound in the lower and upper layers is preferably 10% by mass to 90% by mass, more preferably 50% by mass to 88% by mass, and more preferably 60% by mass with respect to the total mass of the contained layer. 85 mass% is more preferable. When the content is in this range, the patternability upon development becomes good.

Coating amount after drying of the lower layer components is preferably 0.5 ~ 4.0g / ^{m 2,} more preferably 0.6 ~ 2.5g / ^{m 2.} When it is 0.5 g / m ² or more, the printing durability is excellent, and when it is 4.0 g / m ² or less, the image reproducibility and the sensitivity are excellent.
Coating amount after drying of the upper layer component is preferably 0.05 ~ 1.0g / ^{m 2,} more preferably 0.08 ~ 0.7g / ^{m 2.} If it is 0.05 g / ^{m 2} or more, excellent in development latitude and scratch resistance, if it is 1.0 g / ^{m 2} or less, excellent sensitivity.
Lower layer and the coating amount after drying of the combined upper layer is preferably 0.6 ~ 4.0g / ^{m 2,} more preferably 0.7 ~ 2.5g / ^{m 2.} When it is 0.6 g / m ² or more, the printing durability is excellent, and when it is 4.0 g / m ² or less, the image reproducibility and the sensitivity are excellent.

It is preferable that the lower layer and the upper layer are basically formed by separating two layers.
As a method for forming two layers separately, for example, as described in paragraphs [0068] to [0069] of JP 2011-209343 A, a component contained in the lower layer, and an element contained in the upper layer are included. The method of utilizing the difference in solvent solubility with the components, or the method of rapidly drying and removing the solvent after applying the upper layer, and the like can be mentioned. It is preferable to use the latter method in combination because the separation between layers is further improved.

<Conventional positive type image recording layer>
The conventional positive type image recording layer is typically a photosensitive layer containing an alkali-soluble polymer compound and an o-quinonediazide compound. With respect to the conventional positive type image recording layer, the description in paragraphs [0042] to [0066] of JP-A-2003-1956 can be referred to.

Subbing layer
In the lithographic printing plate precursor of the invention, a subbing layer can be provided, as required, between the aluminum support having an anodized film and the positive-working image recording layer.
The component contained in the undercoat layer is not particularly limited, but various organic compounds described in paragraph [0151] of JP-A-2003-1956 can be used. Alternatively, a polymer compound having an acid group-containing component and an onium group-containing component described in JP-A-2000-105462 is also suitably used. When this subbing layer is provided, it has sufficient alkali developability, and a large number of prints of clear images can be obtained without causing a decrease in stain resistance and image strength at the time of printing.

As the undercoat layer component having higher hydrophilicity, a polymer containing an acid group selected from phosphonic acid group, phosphoric acid group, sulfonic acid group and carboxylic acid group is preferably used. It is preferable that it is a copolymer containing the monomer unit which has the said acidic radical. Moreover, you may also include the monomer unit which has a highly hydrophilic betaine structure at the terminal. Examples of more preferable copolymers include those described in paragraphs [0012] to [0036] of JP-A-2010-284963.

The undercoat layer components may be used singly or in combination of two or more.
The formation of the undercoat layer can be carried out in the following manner. That is, a method in which a solution obtained by dissolving the undercoat layer component in water or an organic solvent such as methanol, ethanol, methyl ethyl ketone or the like or a mixed solvent thereof is coated on an anodized aluminum support and dried, Alternatively, the aluminum support having the anodized film is immersed in a solution in which the undercoat layer component is dissolved in an organic solvent such as methanol, ethanol, methyl ethyl ketone or the like, or a mixed solvent thereof, and the undercoat layer component is adsorbed. It is a method of forming by washing and drying by the like. In the former method, a solution with a concentration of preferably 0.005 to 10% by weight of the primer layer component can be applied by various methods. In the latter method, the concentration of the solution is preferably 0.01 to 20% by mass, more preferably 0.05 to 5% by mass, and the immersion temperature is preferably 20 to 90 ° C., more preferably 25 to 50 ° C. The immersion time is preferably 0.1 seconds to 20 minutes, more preferably 2 seconds to 1 minute. The solution used in the above method can also be adjusted to a pH range of 1 to 12 with a basic substance such as ammonia, triethylamine or potassium hydroxide, or an acidic substance such as hydrochloric acid or phosphoric acid. In addition, a yellow dye may be contained to improve tone reproduction of the lithographic printing plate precursor. The coverage of the undercoat layer, ² ~ 200mg / ^m 2 is is suitable, preferably 5 ~ 100mg / ^{m 2.}

<Back coat layer>
If necessary, a backcoat layer may be provided on the back side of the support of the lithographic printing plate precursor. The backcoat layer is formed of a metal oxide obtained by hydrolysis and polycondensation of an organic polymer compound described in JP-A-5-45885 and an organic or inorganic metal compound described in JP-A-6-35174. Is preferably used. In particular, alkoxy compounds of silicon such as Si (OCH ₃ ) ₄ , Si (OC ₂ H ₅ ) ₄ , Si (OC ₃ H ₇ ) ₄ and Si (OC ₄ H ₉ ) ₄ are inexpensive and easily obtainable, and are obtained from these The metal oxide coating layer is preferable to the developer-resistant solution.

<Method of preparing lithographic printing plate>
The lithographic printing plate precursor of the present invention can produce a lithographic printing plate by performing conventionally known image formation (for example, exposure) and development depending on the type of positive-working image recording layer. The light source of the actinic ray used for image exposure can be selected appropriately according to the type of positive image recording layer. Specifically, the light source described in paragraph [0268] of JP-A-2003-1956 can be used.

It is preferable that the thermal type planographic printing plate precursor which is irradiated with a laser beam based on digital data and exposed like a desired image is developed by a method using an alkaline developer. In this way, when exposure and development processing is performed, the laser light is efficiently absorbed by the infrared absorber contained in the image recording layer of the exposed portion, and only the image recording layer of the exposed portion is stored due to the accumulation of energy absorbed by exposure. The heat is generated to be alkali-soluble, and the development processing using an alkali developer removes only the image recording layer in the exposed area to form a desired image.
When the image recording layer is of the conventional positive type, it can be similarly developed using an alkaline developer.

The alkaline developing solution used for development is an alkaline aqueous solution, and can be appropriately selected and used from conventionally known alkaline aqueous solutions. For example, an aqueous alkali solution containing an alkali silicate or a nonreducing sugar and a base is suitably mentioned, and in particular, one having a pH of 12.5 to 14.0 is more suitably mentioned. The description of paragraphs [0270] to [0292] in JP-A No. 2003-1956 can be referred to for the above-mentioned alkali developer.

Hereinafter, the present invention will be described in detail by way of examples, but the present invention is not limited thereto.

[Examples 1 to 38 and Comparative Examples 1 to 9]
[Production of an aluminum support having an anodized film]
Surface treatment A, surface treatment C or surface treatment D of the following aluminum support was applied to an aluminum alloy plate of a material 1S having a thickness of 0.3 mm to produce an aluminum support having an anodized film. In addition, the water washing process was performed during all the treatment processes, and the liquid was removed by the nip roller after the water washing process.

<Surface treatment A>
The following treatments (A-a) to (A-l) were performed.
(Aa) Mechanical roughening treatment (brush grain method)
Using a device as shown in FIG. 6, mechanical roughening is carried out by rotating bunching brushes while supplying a suspension of pumice (specific gravity: 1.1 g / cm 3) to the surface of the aluminum plate as a polishing slurry liquid. I did the processing. In FIG. 6, 1 is an aluminum plate, 2 and 4 are roller brushes (in this embodiment, bundle brushes), 3 is an abrasive slurry, and 5, 6, 7 and 8 are support rollers.
In the mechanical surface roughening treatment, the median diameter (μm) of the abrasive was 30 μm, the number of brushes was four, and the rotational speed (rpm) of the brush was 250 rpm. The material of the bundle planting brush was 6 · 10 nylon, and the diameter of the bristles was 0.3 mm and the bristle length was 50 mm. The brush was flocked so as to be dense by drilling a hole in a 300 300 mm stainless steel cylinder. The distance between the two support rollers (φ 200 mm) at the lower part of the bundle planting brush was 300 mm. The bunching brush was pressed until the load of the drive motor for rotating the brush became 10 kW plus to the load before pressing the bunching brush to the aluminum plate. The rotation direction of the brush was the same as the moving direction of the aluminum plate.

(A-b) Alkali etching treatment An etching treatment was carried out by spraying an aqueous caustic soda solution having a concentration of 26 mass% caustic soda and a concentration of 6.5 mass% aluminum ion onto an aluminum plate at a temperature of 70 ° C with a spray pipe. The amount of dissolved aluminum was 10 g / m ² .

(A-c) Desmut treatment in acidic aqueous solution Desmut treatment was performed in nitric acid aqueous solution. As the nitric acid aqueous solution used for the desmutting treatment, the nitric acid waste solution used for the electrochemical graining treatment in the next step was used. The liquid temperature was 35 ° C. The desmut solution was sprayed by spray and desmutted for 3 seconds.

(A-d) Electrochemical surface roughening treatment Electrochemical surface roughening treatment was performed continuously using an alternating voltage of nitric acid electrolysis 60 Hz. The electrolyte used was an electrolyte prepared by adding aluminum nitrate to an aqueous solution containing 10.4 g / L of nitric acid at a temperature of 35 ° C. to adjust the aluminum ion concentration to 4.5 g / L. The AC power supply waveform is the waveform shown in FIG. 4, and a carbon electrode is used as a counter electrode by using a trapezoidal rectangular wave AC with a time tp of 0.8 msec for a current value to reach a peak and a duty ratio of 1: 1. Electrochemical graining treatment was performed. Ferrite was used for the auxiliary anode. The electrolytic cell shown in FIG. 5 was used. The current density was 30 A / dm ² at the peak value of the current, and 5% of the current flowing from the power supply was diverted to the auxiliary anode. Amount of electricity (C / dm ²⁾ the aluminum plate was 185C / dm ² as the total quantity of electricity when the anode.

(Ae) Alkali etching treatment An etching treatment was carried out by spraying a caustic soda aqueous solution having a sodium hydroxide concentration of 27% by mass and an aluminum ion concentration of 2.5% by mass onto an aluminum plate at a temperature of 50 ° C with a spray pipe. The amount of dissolved aluminum was 3.5 g / m ² .

(A-f) Desmut treatment in acidic aqueous solution Desmut treatment was performed in a sulfuric acid aqueous solution. As a sulfuric acid aqueous solution used for desmutting treatment, a solution having a sulfuric acid concentration of 170 g / L and an aluminum ion concentration of 5 g / L was used. The liquid temperature was 30.degree. The desmut solution was sprayed by spray and desmutted for 3 seconds.

(Ag) Electrochemical Surface Roughening Treatment Electrochemical surface roughening treatment was carried out continuously using an alternating voltage of 60 Hz in hydrochloric acid electrolysis. The electrolyte used was an electrolyte prepared by adding aluminum chloride to an aqueous solution of hydrochloric acid 6.2 g / L at a liquid temperature of 35 ° C. and adjusting the aluminum ion concentration to 4.5 g / L. The AC power supply waveform is the waveform shown in FIG. 4, and a carbon electrode is used as a counter electrode by using a trapezoidal rectangular wave AC with a time tp of 0.8 msec for a current value to reach a peak and a duty ratio of 1: 1. Electrochemical graining treatment was performed. Ferrite was used for the auxiliary anode. The electrolytic cell shown in FIG. 5 was used.
The current density was 25A / dm ² at the peak of electric current amount of hydrochloric acid electrolysis (C / dm ²⁾ the aluminum plate was 63C / dm ² as the total quantity of electricity when the anode.

(Ah) Alkali etching treatment An etching treatment was carried out by spraying a caustic soda aqueous solution having a caustic soda concentration of 5% by mass and an aluminum ion concentration of 0.5% by mass onto an aluminum plate at a temperature of 60 ° C. using a spray pipe. The amount of dissolved aluminum was 0.2 g / m ² .

(Ai) Desmut Treatment in Acidic Aqueous Solution Desmut treatment was performed in a sulfuric acid aqueous solution. The waste liquid generated in the anodizing treatment step (dissolving aluminum ion 5 g / L in sulfuric acid 170 g / L aqueous solution) was subjected to desmutting treatment at a liquid temperature of 35 ° C. for 4 seconds.

(A-j) Anodizing Treatment in the First Step Anodizing treatment in the first step was performed using an anodizing device by direct current electrolysis having the structure shown in FIG. The electrolytic solution was anodized under the conditions shown in Table 1 using a 170 g / L aqueous solution of sulfuric acid.
In the anodizing apparatus 610, the aluminum plate 616 is transported as shown by the arrow in FIG. The aluminum plate 616 is charged to (+) by the feeding electrode 620 in the feeding tank 612 in which the electrolytic solution 618 is stored. The aluminum plate 616 is conveyed upward by the roller 622 in the power supply tank 612 and is turned downward by the nip roller 624, and then conveyed toward the electrolytic treatment tank 614 where the electrolytic solution 626 is stored. Turn to Next, the aluminum plate 616 is charged to (−) by the electrolytic electrode 630 to form an anodic oxide film on the surface thereof, and the aluminum plate 616 leaving the electrolytic treatment tank 614 is transported to a later step. In the anodizing apparatus 610, the direction changing means is constituted by the roller 622, the nip roller 624 and the roller 628, and the aluminum plate 616 is formed between the rollers 622, 624 and 628 in the space between the power supply tank 612 and the electrolytic treatment tank 614. The sheet is transported in a mountain shape and a reverse U shape. The feed electrode 620 and the electrolytic electrode 630 are connected to a DC power supply 634.

(A-k) Pore-Wide Treatment An aluminum plate was immersed in an aqueous caustic soda solution having a sodium hydroxide concentration of 5% by mass and an aluminum ion concentration of 0.5% by mass under the conditions shown in Table 1 to perform pore-wide treatment.

(A-l) Second Step Anodizing Treatment The second step anodizing treatment was performed using a direct current electrolytic anodizing apparatus having the structure shown in FIG. The electrolytic solution was anodized under the conditions shown in Table 1 using a 170 g / L aqueous solution of sulfuric acid.

<Surface treatment C>
The following treatments (C-a) to (C-k) were performed.
(C-a) Alkali etching treatment An etching treatment was carried out by spraying a caustic soda aqueous solution having a sodium hydroxide concentration of 26% by mass and an aluminum ion concentration of 6.5% by mass onto an aluminum plate at a temperature of 70 ° C with a spray pipe. The amount of dissolved aluminum was 5 g / m ² .

(Cb) Desmut treatment in acidic aqueous solution Desmut treatment was performed in nitric acid aqueous solution. As the nitric acid aqueous solution used for the desmutting treatment, the nitric acid waste solution used for the electrochemical roughening in the next step was used. The liquid temperature was 35 ° C. The desmut solution was sprayed by spray and desmutted for 3 seconds.

(C-c) Electrochemical surface roughening treatment Electrochemical surface roughening treatment was carried out continuously using an alternating voltage of nitric acid electrolysis 60 Hz. The electrolyte used was an electrolyte prepared by adding aluminum nitrate to an aqueous solution containing 10.4 g / L of nitric acid at a temperature of 35 ° C. to adjust the aluminum ion concentration to 4.5 g / L. The AC power supply waveform is the waveform shown in FIG. 4, and a carbon electrode is used as a counter electrode by using a trapezoidal rectangular wave AC with a time tp of 0.8 msec for a current value to reach a peak and a duty ratio of 1: 1. An electrochemical roughening treatment was performed. Ferrite was used for the auxiliary anode. The electrolytic cell shown in FIG. 5 was used. The current density was 30 A / dm ² at the peak value of the current, and 5% of the current flowing from the power supply was diverted to the auxiliary anode. Amount of electricity (C / dm ²⁾ the aluminum plate was 230C / dm ² as the total quantity of electricity when the anode.

(Cd) Alkali etching treatment An etching treatment was carried out by spraying a caustic soda aqueous solution having a sodium hydroxide concentration of 27% by mass and an aluminum ion concentration of 2.5% by mass at a temperature of 50 ° C. onto an aluminum plate. The amount of dissolved aluminum was 3.5 g / m ² .

(C-e) Desmut treatment in acidic aqueous solution Desmut treatment was performed in a sulfuric acid aqueous solution. As a sulfuric acid aqueous solution used for desmutting treatment, a solution having a sulfuric acid concentration of 170 g / L and an aluminum ion concentration of 5 g / L was used. The solution temperature was 30.degree. The desmut solution was sprayed by spray and desmutted for 3 seconds.

(Cf) Electrochemical surface roughening treatment Electrochemical surface roughening treatment was continuously performed using an alternating voltage of hydrochloric acid electrolysis 60 Hz. The electrolyte used was an electrolyte prepared by adding aluminum chloride to an aqueous solution of hydrochloric acid 6.2 g / L at a liquid temperature of 35 ° C. and adjusting the aluminum ion concentration to 4.5 g / L. The AC power supply waveform is the waveform shown in FIG. 4, and a carbon electrode is used as a counter electrode by using a trapezoidal rectangular wave AC with a time tp of 0.8 msec for a current value to reach a peak and a duty ratio of 1: 1. An electrochemical roughening treatment was performed. Ferrite was used for the auxiliary anode. The electrolytic cell shown in FIG. 5 was used.
The current density was 25A / dm ² at the peak of electric current amount of hydrochloric acid electrolysis (C / dm ²⁾ the aluminum plate was 63C / dm ² as the total quantity of electricity when the anode.

(Cg) Alkali etching treatment An etching treatment was carried out by spraying a caustic soda aqueous solution having a caustic soda concentration of 5% by mass and an aluminum ion concentration of 0.5% by mass onto an aluminum plate at a temperature of 60 ° C. using a spray pipe. The amount of dissolved aluminum was 0.2 g / m ² .

(C-h) Desmut treatment in acidic aqueous solution Desmut treatment was performed in an aqueous sulfuric acid solution. The waste liquid generated in the anodizing treatment step (dissolving aluminum ion 5 g / L in sulfuric acid 170 g / L aqueous solution) was subjected to desmutting treatment at a liquid temperature of 35 ° C. for 4 seconds.

(Ci) Anodizing Treatment in the First Step Anodizing treatment in the first step was performed using an anodizing device by direct current electrolysis having a structure shown in FIG. The electrolytic solution was anodized under the conditions shown in Table 1 using a 170 g / L aqueous solution of sulfuric acid.
In the anodizing apparatus 610, the aluminum plate 616 is transported as shown by the arrow in FIG. The aluminum plate 616 is charged to (+) by the feeding electrode 620 in the feeding tank 612 in which the electrolytic solution 618 is stored. The aluminum plate 616 is conveyed upward by the roller 622 in the power supply tank 612 and is turned downward by the nip roller 624, and then conveyed toward the electrolytic treatment tank 614 where the electrolytic solution 626 is stored. Turn to Next, the aluminum plate 616 is charged to (−) by the electrolytic electrode 630 to form an anodic oxide film on the surface thereof, and the aluminum plate 616 leaving the electrolytic treatment tank 614 is transported to a later step. In the anodizing apparatus 610, the direction changing means is constituted by the roller 622, the nip roller 624 and the roller 628, and the aluminum plate 616 is formed between the rollers 622, 624 and 628 in the space between the power supply tank 612 and the electrolytic treatment tank 614. The sheet is transported in a mountain shape and a reverse U shape. The feed electrode 620 and the electrolytic electrode 630 are connected to a DC power supply 634.

(C-j) Pore-Wide Treatment An aluminum plate was immersed in an aqueous caustic soda solution having a sodium hydroxide concentration of 5% by mass and an aluminum ion concentration of 0.5% by mass under the conditions shown in Table 1 to perform pore-wide treatment.

(CK) Second Step Anodizing Treatment The second step anodizing treatment was performed using a direct current electrolytic anodizing device having the structure shown in FIG. The electrolytic solution was anodized under the conditions shown in Table 1 using a 170 g / L aqueous solution of sulfuric acid.

<Surface treatment D>
The following treatments (D-a) to (D-h) were performed.
(D-a) Alkali etching treatment An etching treatment was carried out by spraying a caustic soda aqueous solution having a concentration of 26 mass% caustic soda and 6.5 mass% aluminum ion onto an aluminum plate at a temperature of 70 ° C with a spray pipe. The amount of dissolved aluminum was 1.0 g / m ² .

(D-b) Desmut treatment in acidic aqueous solution (first desmut treatment)
Desmut treatment was performed in an acidic aqueous solution. The acidic aqueous solution used for desmutting was an aqueous solution of 150 g / L of sulfuric acid. The liquid temperature was 30.degree. The desmut solution was sprayed by spraying and desmutted for 3 seconds.

(D-c) Electrochemical surface roughening treatment in hydrochloric acid aqueous solution Using an electrolytic solution having a hydrochloric acid concentration of 14 g / L, an aluminum ion concentration of 13 g / L, and a sulfuric acid concentration of 3 g / L, electrochemical roughening using an alternating current The flattening process was performed. The temperature of the electrolytic solution was 30.degree. The aluminum ion concentration was adjusted by adding aluminum chloride. The alternating current waveform is a sine wave with a positive and negative waveform symmetrical, the frequency is 50 Hz, the anodic reaction time and the cathodic reaction time in one alternating current cycle are 1: 1, and the current density is the peak current value of the alternating current waveform. It was 75 A / dm ² . Further, the amount of electricity was 450 C / dm ² in total of the amount of electricity that the aluminum plate was subjected to the anode reaction, and the electrolytic treatment was divided into four steps at 125 C / dm ² every four seconds. A carbon electrode was used as the counter electrode of the aluminum plate.

(D-d) Alkali etching treatment An etching treatment was carried out by spraying a caustic soda aqueous solution having a caustic soda concentration of 5% by mass and an aluminum ion concentration of 0.5% by mass onto an aluminum plate at a temperature of 45 ° C. using a spray pipe. The amount of aluminum dissolved was 0.2 g / m ² .

(D-e) Desmut treatment in acidic aqueous solution Desmut treatment in acidic aqueous solution was performed. As the acidic aqueous solution used for the desmutting treatment, the waste solution generated in the anodizing treatment step (5.0 g / L of aluminum ion dissolved in an aqueous solution of 170 g / L of sulfuric acid) was used. The liquid temperature was 30.degree. The desmut solution was sprayed by spray and desmutted for 3 seconds.

(D-f) Anodizing Treatment in the First Step Anodizing treatment in the first step was performed using an anodizing device by direct current electrolysis having a structure shown in FIG. The electrolytic solution was anodized under the conditions shown in Table 1 using a 170 g / L aqueous solution of sulfuric acid.

(D-g) Pore-Wide Treatment An aluminum plate was immersed in an aqueous caustic soda solution having a sodium hydroxide concentration of 5% by mass and an aluminum ion concentration of 0.5% by mass under the conditions shown in Table 1 to perform pore-wide treatment.

(Dh) Second Step Anodizing Treatment The second step anodizing treatment was performed using a direct current electrolytic anodizing device having the structure shown in FIG. The electrolytic solution was anodized under the conditions shown in Table 1 using a 170 g / L aqueous solution of sulfuric acid.

With respect to an aluminum support having an anodized film produced by applying the above surface treatment A, surface treatment C or surface treatment D, the thickness of the anodized film, the depth of the large diameter hole, the anodization of the large diameter hole The average diameter on the surface of the coating and the average diameter at the communication position of the small diameter holes are shown in Table 2.
The average diameter of the micropores (average diameter of the large diameter hole portion and the small diameter hole portion) was obtained by observing the surface of the large diameter hole portion and the surface of the small diameter hole portion with N = 4 sheets by FE-SEM at 150,000 magnification. In the four images, the diameters of the micropores (large diameter holes and small diameter holes) present in the range of 400 × 600 nm 2 were measured and averaged. When the depth of the large diameter hole was deep and the diameter of the small diameter hole was difficult to measure, the upper part of the anodized film was cut and then the diameter of the small diameter hole was determined.
The depth of the micropore (the depth of the large diameter hole and the small diameter hole) is observed by the cross section of the anodized film by FE-SEM (large diameter hole depth observation: 150,000 times, the small diameter hole depth Observation: 50,000 times) In the obtained image, the depths of 25 micropores were measured and averaged.

<Hydrophilization treatment>
As described in Table 2, the following hydrophilization treatments A to B were performed.

<Hydrophilization treatment A>
The aluminum support having the anodized film is immersed in an aqueous solution at 40 ° C. (pH = 1.9) containing 4 g / L of polyvinylphosphonic acid for 10 seconds, and washed with desalted water containing calcium ions at 20 ° C. for 2 seconds And dried. After treatment, the amounts of P and Ca on the support were 25 mg / m ² and 1.9 mg / m ² , respectively.

<Hydrophilization treatment B>
The aluminum support having the anodized film was immersed in a treatment tank of a 1% by mass aqueous solution of sodium silicate No. 3 at a temperature of 30 ° C. for 10 seconds to perform alkali metal silicate treatment (silicate treatment). Thereafter, it was rinsed with a well water spray and dried.

<Formation of undercoat layer>
As described in Table 2, the following undercoating solutions for forming undercoat layers A to F were applied to a dry coating amount of 20 mg / m ² to form undercoat layers A to F.

(Coating solution A for forming undercoat layer)
・ Following copolymer UP-1: 0.3 g
・ Methanol: 100 g
Water: 1 g

(Coating solution B for forming undercoat layer)
・ Following copolymer UP-2: 0.3 g
・ Methanol: 100 g
Water: 1 g

(Coating solution for forming undercoat layer C)
・ Following copolymer UP-3: 0.3 g
・ Methanol: 10 g
Water: 90 g

(Coating liquid for forming undercoat layer D)
・ Following copolymer UP-4: 0.3 g
・ Methanol: 10 g
Water: 90 g

(Coating solution E for forming undercoat layer)
・ The following copolymer UP-5: 0.3 g
・ Methanol: 10 g
Water: 90 g

(Coating solution F for forming undercoat layer)
・ Β-alanine: 0.3 g
・ Methanol: 100 g
Water: 1 g

In the copolymers UP-1 to UP-5 contained in the undercoat layer-forming coating solutions A to E, the composition ratio of each constituent unit is mol%, and the molecular weight is a mass average molecular weight.

<Formation of image recording layer>
As described in Table 2, the following coating solutions A to F for forming an image recording layer were applied by a bar coater to form image recording layers A to F.
When the image recording layer is a single layer, the coating solution for forming an image recording layer is applied so that the dry coating amount is 1.0 g / m ^2, and oven drying is performed at 100 ° C. for 60 seconds to form an image recording layer. did.
When the image recording layer is two layers, after applying the coating solution for forming the first image recording layer, oven drying at 100 ° C. for 60 seconds, and then, coating for the second image recording layer The solution is applied and oven-dried at 120 ° C for 40 seconds, and the first layer and the second layer have a dry coating amount of 0.5 g / m ² each, and the total of the two layer dry coating amount is 1.0 g / m ² The image recording layer was formed as follows.

(Coating solution A for forming an image recording layer)
M, p-cresol novolac resin (m / p ratio = 6/4, 1.12 g
Mass average molecular weight 5,000)
-The following IR dye (1) 0.03 g
-0.015 g of the following diazonium salt 1
Tetrahydrophthalic anhydride 0.04 g
・ 0.03 g of bis-p-hydroxyphenyl sulfone
・ 0.02 g of chloride ion of ethyl violet counter ion
Dye-fluorinated surfactant (Megafuck F-780, 0.01 g)
DIC Corporation)
・ 13 g of methyl ethyl ketone

(Coating solution B for forming an image recording layer)
・ 0.3 g of copolymer P-1
N- (p-aminosulfonylphenyl) methacrylamide / methyl methacrylate / acrylonitrile = 35/35/30 (molar ratio) copolymer (mass average molecular weight 65,000)
・ M, p-cresol novolak resin (m / p ratio = 6/4, 0.1 g
Mass average molecular weight 5,000)
・ The above IR dye (1) 0.03 g
・ 0.02 g of 6-hydroxynaphthalene counter ion of ethyl violet
Dye, bis-p-hydroxyphenyl sulfone converted to sulfonate anion, 0.02 g
・ 0.003 g of p-toluenesulfonic acid
・ Fluorinated surfactant (Megafuck F-780,
DIC (manufactured by DIC Corporation) 0.005 g
・ 30 g of methyl ethyl ketone
・ 15 g of 1-methoxy-2-propanol
・ 15 g of γ-butyrolactone

(Coating solution C for forming an image recording layer)
・ Fluorinated surfactant (Megafuck F-780, 0.01 g
DIC Corporation)
・ The above IR dye (1) 0.013 g
・ 0.05g of hydroxynaphthalene counter ion of crystal violet
Dye, m, p-cresol novolak resin (m / p ratio = 6/4, 0.6 g) converted to sulfonate anion
Mass average molecular weight 5,000)
・ 15.0 g of methyl ethyl ketone
・ 30.0 g of 1-methoxy-2-propanol

(Coating solution D for forming an image recording layer)
The composition is the same as the coating solution B for forming an image recording layer except that the copolymer P-1 of the coating solution B for forming an image recording layer is changed to the following copolymer P-2.
Copolymer P-2
N-phenylmaleimide / N-methylphenylmaleimide / acrylonitrile / N-hydroxyphenylmaleimide = 30/20/20/30 (molar ratio) copolymer (mass average molecular weight 61,000)

(Coating solution E for forming an image recording layer)
The composition is the same as that of the coating solution B for forming an image recording layer except that the copolymer P-1 of the coating solution B for forming an image recording layer is changed to the following copolymer P-3.

<Synthesis of Copolymer P-3>
First, Hofmann et al. The following monomers were synthesized by the method described in K., Makromolekulare Chemie, Volume 177, P1791-1813 (1976).

Then, in a 250 ml reaction vessel, add the above monomer having 160 mmol of sulfonamide group, 20.6 g (132 mmol) of benzylacetamide, 2.31 g (32 mmol) of acrylic acid and 104 g of γ-butyrolactone, The mixture was heated to 140 ° C. while stirring at 200 rpm. The reaction was carried out under nitrogen reflux. After the solids dissolved, the reaction vessel was cooled to 100 ° C. A solution of 0.37 ml of Trigonox DC50 (manufactured by AKZO NOBEL) and 1.48 ml of Trigonox 141 (manufactured by AKZO NOBEL) in 3.66 ml of butyrolactone was sequentially added. After the reaction started, the reaction vessel temperature was raised to 143 ° C., and 1.87 ml of Trigonox DC50 was added over 2 hours. The reaction mixture was allowed to react at 140 ° C. for 2 hours while stirring at 400 rpm. The reaction mixture was cooled to 120 ° C. and the stirring conditions were raised to 500 rpm. 86.8 ml of 1-methyl-2-propanol was added, and the temperature was lowered to room temperature to obtain the desired polymer.
The structure of the polymer was confirmed by ¹ H-NMR spectrography and size exclusion chromatography using dimethylacetamide / 0.21% LiCl as a mark and using a mixed column in terms of polystyrene.
Copolymer P-3 was a sulfonamide group-containing acrylic resin represented by the following formula, and the mass average molecular weight was 66,000. In the following formulas, the numerical value at the lower right of the parentheses represents the content ratio (molar ratio) of the constituent units.

(Coating solution F for forming an image recording layer)
・ Naphthoquinone-1,2-diazide-5-sulfonyl black 0.90 g
Ester compound of Ryde and pyrogallol-acetate resin (Note 1)
・ Cresol-formaldehyde resin 2.00 g
-0.05 g of t-butylphenol-formaldehyde resin (Note 2)
・ Aisen ・ spirone ・ Yellow (Aizen Spilon 0.04g
Yellow) GRH (manufactured by Hodogaya Chemical Industry Co., Ltd.)
・ Naphthoquinone-1,2-diazide-4-sulfonic acid chloride 0.03 g
-Oil Blue # 603 (manufactured by Orient Chemical Industry Co., Ltd.) 0.05 g
・ Methyl ethyl ketone 8 g
・ Methyl cellosolve acetate 15 g
Note 1: Ester compounds described in US Pat. No. 3,635,709, Example 1 Note 2: Resins described in US Pat. No. 4,123,279

<Preparation of a lithographic printing plate precursor>
The lithographic printing plate precursor used in Examples 1 to 38 and Comparative Examples 1 to 12 by combining the aluminum support having the anodized film, the hydrophilization treatment, the undercoat layer, and the image recording layer as shown in Tables 1 to 2 Was produced.

For Examples and Comparative Examples other than Example 36 and Comparative Example 10, the lithographic printing plate precursor was exposed with an energy of 80 mJ / cm ² using a Lotem 400 Quantum imager manufactured by CREO, and a developer Goldstar Premium manufactured by Kodak. Using Plate Developer (pH 13.0), development was carried out at 25 ° C. for 30 seconds in an InterPlater 85 HD processor manufactured by Glunz & Jensen, and gumging was performed with Finisher FP2W (1: 1 dilution) manufactured by Fujifilm Corporation.
The exposed image included a solid image and 50% halftone dots and 3% halftone dots of TAFFET A20 (FM screen) manufactured by Fuji Film Co., Ltd., and a 7-character blank morning letter chart.

For Example 36 and Comparative Example 10, a mask film including a solid image, 50% halftone dots and 3% halftone dots of TAFFET A 20 (FM screen), and a 7-point blank letter chart on an image recording layer was formed on the image recording layer. After installation, the lithographic printing plate precursor was exposed from a distance of 70 cm with a 3 KW metal halide lamp light, and an 8-fold dilution of DP-4 (manufactured by Fuji Photo Film Co., Ltd.) was used to make the product from Fuji Photo Film Co., Ltd. It was developed at 25 ° C. for 40 seconds by an automatic developing machine (800 U) and gummed with a finisher FP2W (1: 1 dilution) manufactured by Fujifilm Corporation.
Thus, the lithographic printing plates in Examples 1 to 38 and Comparative Examples 1 to 12 were produced.

<Evaluation of lithographic printing plate precursor>
(Printing durability)
The lithographic printing plate obtained by the above exposure and development was attached to a plate cylinder of a printing machine LITHRONE 26 manufactured by Komori Corporation. Using dampening water of Ecolity-2 (Fuji Film Co., Ltd.) / Tap water = 2/98 (volume ratio) and Values-G (N) ink ink (Dainippon Ink Chemical Co., Ltd.), The dampening water and the ink were supplied by the standard automatic printing start method of LITHRNE 26, printing was started, and printing was performed on Tokiwa Art (76.5 kg unit weight) paper at a printing speed of 10,000 sheets per hour. .
As the number of printed sheets increased, the image recording layer was gradually worn away, and the ink density on the printed matter decreased. The printing durability is evaluated using the number of copies as the number of copies when the value obtained by measuring the halftone dot area rate of the 50% halftone screen of the FM screen with a Gretag densitometer is 5% lower than the measured value of the 100th print. did. The number of printed sheets (about 40,000 sheets) of Comparative Example 3 was used as a reference (100%), and the number of printed sheets of the other examples and comparative examples was expressed as an index. The larger the value, the better the printing durability.

(Never pay)
The lithographic printing plate obtained by the above exposure and development was attached to a plate cylinder of a printing machine LITHRONE 26 manufactured by Komori Corporation. Using dampening water of Ecolity-2 (Fuji Film Co., Ltd.) / Tap water = 2/98 (volume ratio) and Values-G (N) ink ink (Dainippon Ink Chemical Co., Ltd.), We supply dampening water and ink by LITHRNE26's standard automatic printing start method, and print over 100 sheets on Tokishi art (continuous mass 76.5 kg) paper, and confirm that good printed materials can be obtained After printing, the printing was temporarily stopped, and left on a printing press for 4 hours in a room at a temperature of 25 ° C. and a humidity of 50%. After that, when printing was resumed, the number of printing sheets required until a good printed product without stains was obtained was measured, and the free-standing property was evaluated. According to the following criteria, it was evaluated as 10 points to 1 point in order from the smaller number of printing paper (damaged paper) required for obtaining a good printed product without stains (that is, the one with better leaving-to-stand). Six points or more are acceptable ranges for the free payment.
10 points: 30 broken sheets or less 9 points: broken sheets 31 to 50 sheets 8 points: broken sheets 51 to 75 sheets or less 7 points: broken sheets 76 to 100 sheets 6 points: broken sheets 101 to 125 5 sheets or less: broken sheet 126 sheets to 150 sheets or less 4 points: broken sheets 151 sheets to 175 sheets or less 3 points: broken sheets 176 sheets to 200 sheets or less 2 points: broken sheets 200 sheets to 250 sheets or less 1 point: loss More than 301 sheets of paper

(Stain resistance)
The lithographic printing plate obtained by the above exposure and development was scratched using a scratch tester under the environment of temperature 25 ° C. and humidity 70%. The scratch tester used was a Heidon Scratching Intensity Tester HEIDEN-18 manufactured by Shinto Scientific Co., Ltd., and a 0.1 mm sapphire needle was used, and the scratching load was 50 (g). Using the lithographic printing plate after scratching, printing was carried out in the same manner as in the above evaluation of printing durability, and it was evaluated whether the scratched part would be a printing stain. Three or more points are acceptable for stain resistance.
5 points: no print stains 4 points: slight print stains not visually discernable 3 points: slight print stains visually recognized but acceptable range 1 point: print stains clearly recognized

The above evaluation results are shown in Table 2. The description of "D (to D-f)" of Comparative Example 3 in the "support surface treatment" column of Tables 1 and 2 is the surface treatment of the aluminum plate according to <D-process> (D-f) It means that the steps up to the anodizing treatment step were performed, and the subsequent steps were not performed. The same applies to “A (to A−j)” of Comparative Example 11 and “C (to C−i)” of Comparative Example 12.
In the "image recording layer" column, the description including "/" indicates that the image recording layer has a two-layer structure, the left side of / indicates the lower image recording layer, and the right side indicates the upper image recording layer. Show. For example, the display of “B / C” in Example 32 means that the lower image recording layer is the image recording layer B and the upper image recording layer is the image recording layer C.

As shown in Tables 1 and 2 above, the lithographic printing plate precursor according to the present invention can achieve desired effects with regard to all of printing durability, leaving-to-stand property and stain resistance.
In addition, even when the hydrophilization treatment and the undercoat layer are variously changed, desired effects can be obtained with regard to all of the printing resistance, the release resistance and the stain resistance.
Furthermore, even when the positive-type image recording layer is variously changed to a single-layer or two-layer thermal positive-type image recording layer or a conventional positive-type image recording layer, The desired effect is obtained for all.
On the other hand, in Comparative Example 1 in which the thickness of the anodized film is less than 200 nm, the stain resistance is inferior. Moreover, in Comparative Examples 3 and 4 in which the depth of the large diameter hole portion is 60 nm or less, the printing durability is poor. Furthermore, the printing durability is poor even in Comparative Examples 5 to 9 in which the average diameter of the small diameter holes is not smaller than the average diameter of the large diameter holes. Thus, in the comparative example which does not satisfy the predetermined requirements, the desired effects can not be obtained with respect to all of the printing durability, leaving-to-stand and dirt resistance.

According to the present invention, it is possible to provide a lithographic printing plate precursor which can provide a positive-working lithographic printing plate which is excellent in printing durability, leaving-to-standability and stain resistance.

Although the invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention.
This application is based on Japanese Patent Application (Application No. 2017-167856) filed on Aug. 31, 2017, the contents of which are incorporated herein by reference.

1 aluminum plate 2 roller-like brush (in this embodiment, bunching brush)
3 Abrasive Slurry Liquid 4 Roller Brush (In this Example, Bundled Brush)
5 support roller 6 support roller 7 support roller 8 support roller 10 planographic printing plate precursor 12 aluminum support with anodized film 14 undercoat layer 16 positive type image recording layer 18 aluminum plate 20 anodized film of aluminum 22 micropore 24 large diameter Holes 26 Small-diameter holes 31 Aluminum plate 32a Anodized film 32b Anodized film 32c Anodized film 32c Anodized film 33a Micropore 33b Micropore 33c Micropore 50 Main electrolytic cell 51 AC power supply 52 Radial drum roller 53a Main pole 53b Main pole 54 Electrolyte solution supply port 55 Electrolyte solution 56 Slit 57 Electrolyte passage 58 Auxiliary anode 60 Auxiliary anode tank W Aluminum plate 610 Anodizing treatment apparatus 612 Power feed tank 614 Electrolytic treatment tank 616 Aluminum plate 618 Electrolyte solution 62 Feeding electrode 622 roller 624 nip roller 626 electrolyte 628 roller 630 electrolytic electrode 632 tank wall 634 a DC power source

Claims (7)

1. A lithographic printing plate precursor comprising: an aluminum support having an anodized film; and a positive-working image recording layer, wherein the anodized film has a thickness of 200 nm to 2,000 nm, and the anodized film comprises A large-diameter hole (i) having micropores extending in the depth direction from the surface on the positive-type image recording layer side, the micropores extending from the surface of the anodized film to a position exceeding 60 nm in depth; It has a small diameter hole (ii) communicating with the bottom of the diameter hole and extending further in the depth direction from the communication position, and the average diameter of the small diameter hole (ii) at the communication position is the surface of the anodic oxide film A lithographic printing plate precursor which is smaller than the average diameter of the large diameter holes (i) in.
2. The lithographic printing plate precursor as claimed in claim 1, wherein the depth of the small diameter holes (ii) from the communication position is 100 nm to less than 1940 nm.
3. The lithographic printing plate precursor as claimed in claim 1 or 2, wherein the mean diameter of the large diameter pores (i) on the surface of the anodized film is more than 10 nm and not more than 100 nm.
4. The lithographic printing plate precursor as claimed in any one of claims 1 to 3, wherein an average diameter of the small diameter holes (ii) at the communication position is 15 nm or less.
5. A subbing layer containing a polymer containing an acid group selected from a phosphonic acid group, a phosphoric acid group, a sulfonic acid group, and a carboxylic acid group, between the aluminum support having the anodized film and the positive type image recording layer The lithographic printing plate precursor according to any one of claims 1 to 4, which has
6. The lithographic printing plate precursor as claimed in any one of claims 1 to 5, wherein the positive-working image recording layer contains an infrared absorber.
7. The lithographic printing plate precursor as claimed in claim 6, wherein the positive-working image recording layer has a two-layer structure, and an alkali-soluble polymer compound is contained in a layer close to the aluminum support having the anodized film.
   

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