Lithographic printing plate precursor, method for manufacturing lithographic printing plate, and printing method

Abstract

The present invention addresses the problem of providing: a lithographic printing plate precursor which exhibits excellent on-press developability, exhibits excellent printing durability when formed into a lithographic printing plate, and is capable of suppressing the occurrence of fouling; a method for producing a lithographic printing plate using the lithographic printing plate precursor; and a printing method. This lithographic printing plate precursor is provided with an aluminum support and an image recording layer, and is characterized in that the aluminum support comprises an aluminum plate and an anodized film of aluminum disposed on the aluminum plate, and the anodized film is positioned closer to the image recording layer side than the aluminum plate. The anodized film has micropores extending in the depth direction from the surface on the image recording layer side, the aperture ratio by the micropores is 20-70%, the gradient a45 at the surface on the image recording layer side of the anodized film is 3-25%, and the arithmetic average roughness Ra at the surface on the image recording layer side of the anodized film is 0.25-0.60 [mu] m.

Description

[0001] This application is a divisional application of the application number 202080088958.4 filed by the applicant and the invention name is “Lithographic printing plate precursor, method for manufacturing lithographic printing plate and printing method”. The filing date of the parent case of this application is December 25, 2020, and the priority date is December 27, 2019. Technical Field

[0002] The present invention relates to a lithographic printing plate precursor, a method for manufacturing a lithographic printing plate, and a printing method. Background Art

[0003] In recent years, planographic printing plates are obtained by CTP (computer to plate) technology, and a lot of research has been conducted accordingly.

[0004] For example, Patent Document 1 discloses a lithographic printing plate precursor using a lithographic printing plate support including an anodic oxide film having predetermined micropores.

[0005] Previous technical literature

[0006] Patent Literature

[0007] Patent Document 1: International Publication No. 2019 / 087516 Summary of the invention

[0008] Technical issues to be solved by the invention

[0009] As a result of studying the lithographic printing plate precursor described in Patent Document 1, the inventors of the present invention found that the on-press developability is excellent and the printing durability when made into a lithographic printing plate is also good. However, it is clear that if printing is performed with the rotation speed of the dampening roller slowed down relative to the rotation speed of the plate cylinder for the purpose of removing foreign matter on the lithographic printing plate precursor, spot-like stains (hereinafter also referred to as "slip stains") may sometimes be generated on the printed material.

[0010] Therefore, an object of the present invention is to provide a lithographic printing plate precursor having excellent on-press developability, good printing durability when made into a lithographic printing plate, and capable of suppressing the occurrence of smearing, and a method for producing a lithographic printing plate and a printing method using the lithographic printing plate precursor.

[0011] Means for solving technical problems

[0012] In order to achieve the above-mentioned problems, the present inventors conducted in-depth research and found that by using a lithographic printing plate precursor having an aluminum support body including an anodized film, the on-machine developability is excellent, the printing durability when the lithographic printing plate is made becomes good, and the occurrence of slippage can be suppressed. The anodized film contains micropores that meet the specified opening ratio, and the steepness a45 and the arithmetic mean roughness Ra at the surface on the image recording layer side are within the specified range, thereby completing the present invention.

[0013] That is, the present inventors have found that the above-mentioned problems can be achieved by the following configuration.

[0014] [1] A planographic printing plate precursor comprising an aluminum support and an image recording layer,

[0015] The aluminum support includes an aluminum plate and an aluminum anodized film disposed on the aluminum plate.

[0016] The anodized film is located closer to the image recording layer than the aluminum plate.

[0017] The anodic oxide film has micropores extending in the depth direction from the surface on the image recording layer side.

[0018] Based on the opening rate of micropores of 20-70%,

[0019] The steepness a45 indicating the area ratio of the portion having an inclination of 45° or more obtained by extracting a component with a wavelength of 0.2 to 2 μm on the image recording layer side of the anodic oxide film is 3 to 25%.

[0020] The arithmetic mean roughness Ra of the surface of the anodic oxide film on the image recording layer side was 0.25 to 0.60 μm.

[0021] [2] The lithographic printing plate precursor according to [1], wherein

[0022] The density of micropores is 400 to 2000 per μm. 2 .

[0023] [3] The lithographic printing plate precursor according to [1] or [2], wherein

[0024] The ratio of the value of the steepness a45 to the value of the arithmetic mean roughness Ra is 9-80.

[0025] [4] The lithographic printing plate precursor according to any one of [1] to [3], wherein

[0026] The density of recessed portions having a depth of 0.7 μm or more from the center line measured in a 400 μm×400 μm range on the image recording layer side surface of the anodic oxide film using a non-contact three-dimensional roughness meter was 900 or less.

[0027] [5] The lithographic printing plate precursor according to any one of [1] to [4], wherein

[0028] Al-Fe based intermetallic compounds are precipitated on the surface of the image recording layer side of the anodic oxide film.

[0029] The equivalent circle diameter of the Al-Fe-based intermetallic compound on the surface of the anodic oxide film on the image recording layer side is 0.5 to 3.0 μm.

[0030] The density of the Al-Fe-based intermetallic compounds having an equivalent circle diameter of 0.2 μm or more on the surface of the image recording layer side of the anodic oxide film is 3000 / mm 2 above.

[0031] [6] The lithographic printing plate precursor according to any one of [1] to [5], wherein

[0032] The aluminum plate contains 0.05 mass % or less of Cu, 0.1 to 0.4 mass % of Fe, 0.02 to 0.3 mass % of Si, and the remainder is composed of Al and inevitable impurities.

[0033] [7] The lithographic printing plate precursor according to any one of [1] to [6], wherein

[0034] The micropores are composed of a large-diameter pore portion and a small-diameter pore portion, wherein the large-diameter pore portion extends from the surface of the image recording layer side of the anodized film to a depth of 10 to 1000 nm, and the small-diameter pore portion is connected to the bottom of the large-diameter pore portion and extends from the connected position to a depth of 20 to 2000 nm.

[0035] The average diameter of the large-diameter pores on the surface of the image recording layer side of the anodic oxide film is 15 to 100 nm.

[0036] The average diameter of the small-diameter pores at the communication positions is 13 nm or less.

[0037] [8] The lithographic printing plate precursor according to [7], wherein

[0038] The depth of the large-diameter pores is 10 to 130 nm.

[0039] [9] The lithographic printing plate precursor according to [7] or [8], wherein

[0040] The average diameter of the large-diameter pores on the surface of the anodic oxide film on the image recording layer side is 30 to 100 nm.

[0041]

[10] The lithographic printing plate precursor according to any one of [7] to [9], wherein

[0042] The depth of the small-diameter pores is 650 to 2000 nm.

[0043]

[11] The lithographic printing plate precursor according to any one of [1] to

[10] , wherein

[0044] The image recording layer contains a leuco pigment.

[0045] The leuco pigment is a leuco pigment having a phthalide structure or a fluorane matrix structure.

[0046]

[12] The lithographic printing plate precursor according to

[11] , wherein

[0047] The leuco pigment is a compound represented by any one of the following formulas (Le-1) to (Le-3).

[0048] [Chemical formula 1]

[0049]

[0050] Among them, in the above formula (Le-1) to formula (Le-3),

[0051] ERG each independently represents an electron donating group, X1 to X4 each independently represents a hydrogen atom, a halogen atom or a dialkylphenylamino group, X5 to X 10 Each independently represents a hydrogen atom, a halogen atom or a monovalent organic group, Y1 and Y2 each independently represent C or N, when Y1 is N, X1 does not exist, when Y2 is N, X4 does not exist, Ra1 represents a hydrogen atom, an alkyl group or an alkoxy group, and Rb1~Rb4 each independently represent a hydrogen atom, an alkyl group or an aryl group.

[0052]

[13] The lithographic printing plate precursor according to

[11] , wherein

[0053] The leuco pigment is a compound represented by any one of the following formulas (Le-4) to (Le-6).

[0054] [Chemical formula 2]

[0055]

[0056] Among them, in the above formula (Le-4) to formula (Le-6),

[0057] ERG each independently represents an electron donating group, X1~X4 each independently represents a hydrogen atom, a halogen atom or a dialkylaniline group, Y1 and Y2 each independently represent C or N, when Y1 is N, X1 does not exist, when Y2 is N, X4 does not exist, Ra1 represents a hydrogen atom, an alkyl group or an alkoxy group, and Rb1~Rb4 each independently represent a hydrogen atom, an alkyl group or an aryl group.

[0058]

[14] The lithographic printing plate precursor according to

[11] , wherein

[0059] The leuco pigment is a compound represented by any one of the following formulas (Le-7) to (Le-9).

[0060] [Chemical formula 3]

[0061]

[0062] Among them, in the above formula (Le-7) to formula (Le-9),

[0063] X1~X4 each independently represent a hydrogen atom, a halogen atom or a dialkylaniline group, Y1 and Y2 each independently represent C or N, when Y1 is N, X1 does not exist, when Y2 is N, X4 does not exist, Ra1~Ra4 each independently represent a hydrogen atom, an alkyl group or an alkoxy group, Rb1~Rb4 each independently represent a hydrogen atom, an alkyl group or an aryl group, and Rc1 and Rc2 each independently represent an aryl group.

[0064]

[15] The lithographic printing plate precursor according to

[14] , wherein

[0065] In the above formulae (Le-7) to (Le-9), Ra1 to Ra4 each independently represent an alkoxy group.

[0066]

[16] The lithographic printing plate precursor according to

[14] , wherein

[0067] The leuco pigment is a compound represented by the above formula (Le-8).

[0068]

[17] The lithographic printing plate precursor according to

[16] , wherein

[0069] In the above formula (Le-8), X1 to X4 represent hydrogen atoms, and Y1 and Y2 represent C.

[0070]

[18] The lithographic printing plate precursor according to

[16] or

[17] , wherein

[0071] In the above formula (Le-8), Rb1 and Rb2 each independently represent a hydrogen atom or an alkyl group.

[0072]

[19] The lithographic printing plate precursor according to any one of [1] to

[18] , wherein

[0073] The image recording layer contains an infrared absorber, a polymerization initiator and a polymerizable compound.

[0074] The polymerization initiator includes an electron accepting polymerization initiator and an electron donating polymerization initiator.

[0075]

[20] The lithographic printing plate precursor according to

[19] , wherein

[0076] The difference between the HOMO of the infrared absorber and the HOMO of the electron donating polymerization initiator is 0.70 eV or less.

[0077]

[21] The on-press developing type planographic printing plate precursor according to

[19] or

[20] , wherein

[0078] The difference between the LUMO of the electron accepting polymerization initiator and the LUMO of the infrared absorber is 0.70 eV or less.

[0079]

[22] The lithographic printing plate precursor according to any one of

[19] to

[21] , wherein

[0080] The polymerizable compound has 7 or more functional polymerizable groups.

[0081]

[23] The lithographic printing plate precursor according to any one of

[19] to

[22] , wherein

[0082] The polymerizable compound has 10 or more functional polymerizable groups.

[0083]

[24] A method for manufacturing a lithographic printing plate, comprising:

[0084] an exposure step of exposing the lithographic printing plate precursor described in any one of [1] to

[23] in an imagewise manner to form exposed areas and unexposed areas; and

[0085] The removing step removes unexposed portions of the image-wise exposed planographic printing plate precursor.

[0086]

[25] A printing method, comprising:

[0087] an exposure step of exposing the lithographic printing plate precursor described in any one of [1] to

[23] in an imagewise manner to form exposed areas and unexposed areas; and

[0088] The printing step is to supply at least one of a printing ink and a fountain solution, remove unexposed portions of the planographic printing plate precursor imagewise exposed on a printing press, and perform printing.

[0089] Effects of the Invention

[0090] According to the present invention, there can be provided a lithographic printing plate precursor having excellent on-press developability, good printing durability when made into a lithographic printing plate, and capable of suppressing the occurrence of smearing, and a method for producing a lithographic printing plate and a printing method using the lithographic printing plate precursor. BRIEF DESCRIPTION OF THE DRAWINGS

[0091] Figure 1 This is a schematic cross-sectional view of one embodiment of the lithographic printing plate precursor of the present invention.

[0092] Figure 2 This is a schematic cross-sectional view of one embodiment of an aluminum support.

[0093] Figure 3 This is a graph showing an example of an alternating waveform current waveform diagram used in the electrochemical roughening treatment in the method for producing an aluminum support.

[0094] Figure 4 This is a side view showing an example of a radial type unit in the electrochemical roughening treatment using alternating current in the method for producing an aluminum support.

[0095] Figure 5 It is a schematic cross-sectional view of another embodiment of the aluminum support.

[0096] Figure 6 This is a schematic diagram of an anodizing treatment apparatus used for anodizing treatment in the production of an aluminum support. DETAILED DESCRIPTION

[0097] Hereinafter, the present invention will be described in detail.

[0098] The description of the constituent elements described below is based on typical embodiments of the present invention, but the present invention is not limited to these embodiments.

[0099] In addition, in this specification, the numerical range expressed using "to" means a range including the numerical values ​​described before and after "to" as the lower limit and the upper limit.

[0100] In addition, in this specification, each component can use a substance equivalent to each component alone, or can use two or more substances simultaneously. Here, when two or more substances are used simultaneously for each component, unless otherwise specified, the content of the component refers to the total content of the substances used simultaneously.

[0101] In addition, in this specification, when there is no description of substitution or unsubstituted, the group in the compound represented by the formula may also have a substituent, and unless otherwise specified, the group includes not only unsubstituted groups but also groups with substituents. For example, if there is a description of "R represents an alkyl group, an aryl group, or a heteroatom-containing cyclic group" in the formula, it means "R represents an unsubstituted alkyl group, a substituted alkyl group, an unsubstituted aryl group, a substituted aryl group, an unsubstituted heteroatom-containing cyclic group, or a substituted heteroatom-containing cyclic group".

[0102] [Original lithographic edition]

[0103] The lithographic printing plate precursor of the present invention comprises an aluminum support and an image recording layer. In the lithographic printing plate precursor, the aluminum support comprises an aluminum plate and an aluminum anodic oxide film disposed on the aluminum plate, and the anodic oxide film is located closer to the image recording layer than the aluminum plate.

[0104] Furthermore, in the planographic printing plate precursor of the present invention, the anodic oxide film has micropores extending in the depth direction from the surface on the image recording layer side, and the opening ratio based on the micropores is 20 to 70%.

[0105] Furthermore, in the lithographic printing plate precursor of the present invention, the surface on the image recording layer side of the anodized film (hereinafter also referred to as the "anodized film surface") has a steepness a45 of 3 to 25%, which represents the area ratio of the portion with an inclination of 45° or more obtained by extracting components with a wavelength of 0.2 to 2 μm.

[0106] Furthermore, in the planographic printing plate precursor of the present invention, the arithmetic mean roughness Ra of the surface of the anodic oxide film is 0.25 to 0.60 μm.

[0107] In the present invention, as described above, by using a lithographic printing plate precursor having an aluminum support including an anodized film, the on-machine developability is excellent, the printing durability when the lithographic printing plate is made becomes good, and the occurrence of slippage can be suppressed. The anodized film contains micropores that satisfy the above-mentioned opening ratio, and the steepness a45 and the arithmetic mean roughness Ra at the surface of the anodized film are respectively within the above-mentioned ranges.

[0108] Although the details are not yet clear, the present inventors speculate as follows.

[0109] That is, since the opening ratio of the micropores in the anodic oxide film is 20 to 70%, the ink is easily deposited and easily removed during on-press development, and thus the on-press developability is excellent, and the printing durability when made into a planographic printing plate becomes good.

[0110] Furthermore, since the steepness a45 of the anodic oxide film surface is 3 to 25% and the arithmetic mean roughness Ra is 0.25 to 0.60 μm, the ink jamming and accumulation on the frosted convex parts are suppressed, and therefore it is considered that the occurrence of slipping when making a planographic printing plate can be suppressed.

[0111] Figure 1 This is a schematic cross-sectional view of one embodiment of the lithographic printing plate precursor of the present invention.

[0112] Figure 1 The lithographic printing plate precursor 10 shown includes an aluminum support 12 a , an undercoat layer 14 , and an image-recording layer 16 .

[0113] Figure 21 is a schematic cross-sectional view of an embodiment of an aluminum support 12a. The aluminum support 12a has a laminated structure in which an aluminum plate 18 and an aluminum anodic oxide film 20a (hereinafter, also referred to as "anodic oxide film 20a") are laminated in sequence. In addition, the anodic oxide film 20a in the aluminum support 12a is located closer to the image recording layer 16 than the aluminum plate 18. That is, the planographic printing plate original 10 has an aluminum plate 18, an anodic oxide film 20a, a primer layer 14, and an image recording layer 16 in sequence.

[0114] The anodic oxide film 20a has micropores 22a extending from the surface thereof toward the aluminum plate 18. The term micropore is a general term for holes in the anodic oxide film, and does not define the size of the holes.

[0115] As will be described in detail later, the primer layer 14 is not an essential structure but a layer disposed as needed.

[0116] Hereinafter, each structure of the planographic printing plate precursor 10 will be described in detail.

[0117] 〔Aluminum sheet〕

[0118] The aluminum plate 18 (aluminum support) is a dimensionally stable metal having aluminum as a main component and contains aluminum or an aluminum alloy. Examples of the aluminum plate 18 include a pure aluminum plate, an alloy plate having aluminum as a main component and containing a trace amount of heterogeneous elements, or a plastic film or paper laminated or vapor-deposited with aluminum (alloy).

[0119] The heterogeneous elements contained in the aluminum alloy include silicon, iron, manganese, copper, magnesium, chromium, zinc, bismuth, nickel and titanium, and the content of the heterogeneous elements in the alloy is 10 mass % or less. As the aluminum plate 18, a pure aluminum plate is preferred, but from the perspective of smelting technology, it is difficult to produce completely pure aluminum, so a small amount of heterogeneous elements may be contained.

[0120] The composition of the aluminum plate 18 is not limited, and a known and publicly available material (for example, JIS A1050, JIS A 1100, JIS A 3103, and JIS A 3005) can be used as appropriate.

[0121] In the present invention, from the viewpoint of strength and electrolytic treatment, the aluminum plate 18 is preferably an aluminum alloy plate containing 0.05 mass % or less of Cu, 0.1 to 0.4 mass % of Fe, 0.02 to 0.3 mass % of Si, and the remainder consisting of Al and inevitable impurities.

[0122] The aluminum plate 18 preferably has a width of about 400 to 2000 mm and a thickness of about 0.1 to 0.6 mm. The width and thickness can be appropriately changed according to the size of the printing press, the size of the printing plate, and the needs of the user.

[0123] 〔Anodic oxide film〕

[0124] The anodized film 20a is a film generally produced on the surface of the aluminum plate 18 by anodizing treatment, and the film has ultrafine micropores 22a that are substantially perpendicular to the film surface and are uniformly distributed. The micropores 22a extend from the surface of the anodized film 20a on the image recording layer 16 side (the surface of the anodized film 20a on the side opposite to the aluminum plate 18 side) along the thickness direction (the aluminum plate 18 side).

[0125] The average diameter (average opening diameter) of the micropores 22a on the surface of the anodic oxide film 20a is preferably 15 to 100 nm, more preferably 30 to 100 nm. The diameter inside the pores may be wider or narrower than the surface layer.

[0126] The average diameter of the micropores 22a is the following value: the surface of the anodized film 20a was observed using a field emission scanning electron microscope (FE-SEM) with a magnification of 150,000 times with N=4 images, and 50 locations existing in the 400×600nm range were measured in the obtained 4 images. 2 The diameter of the micropores within the range of and the average value obtained.

[0127] When the shape of the micropore 22a is not circular, the equivalent circle diameter is used. The “equivalent circle diameter” refers to the diameter of a 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.

[0128] In the present invention, the density of the micropores 22a is not particularly limited, but is preferably 400 to 2000 pores / μm from the viewpoint of adhesion to the image recording layer. 2 , more preferably 500 to 1800 per μm 2 , more preferably 600 to 1500 per μm 2 .

[0129] In the present invention, the opening ratio based on the micropores 22a is 20 to 70%, preferably 30 to 70%, and more preferably 40 to 65%.

[0130] Here, the opening ratio refers to a value calculated by the following formula, which is obtained by multiplying the average area of ​​the openings of the micropores 22a calculated using the average radius obtained by dividing the average diameter of the micropores 22a by 2 and the density of the micropores 22a (total opening area) and the surface area of ​​the anodized film 20a.

[0131] Opening ratio (%) = 100 × total opening area / surface area of ​​anodic oxide film 20a

[0132] The depth of the micropores 22a is not particularly limited, but is preferably 10 to 3000 nm, more preferably 50 to 2000 nm, and further preferably 300 to 1600 nm.

[0133] The depth is a value obtained by taking a photograph (150,000 times) of a cross section of the anodic oxide film 20a, measuring the depths of 25 or more micropores 22a, and averaging the measured depths.

[0134] The shape of the micropores 22a is not particularly limited. Figure 2 The micropore 22a is generally straight (generally cylindrical), but may be conical in shape with a diameter decreasing toward the depth direction (thickness direction). Also, the shape of the bottom of the micropore 22a is not particularly limited, and may be curved (convex) or flat.

[0135] In the present invention, the steepness a45 of the surface of the image recording layer 16 side of the anodized film 20a, which represents the area ratio of the portion with an inclination of 45° or more obtained by extracting components with a wavelength of 0.2 to 2 μm, is 3 to 25%, preferably 4 to 23%, and more preferably 5 to 20%.

[0136] Here, the steepness a45 is one of the factors representing the surface shape and is a value obtained by the following steps (1) to (3).

[0137] (1) Measure the surface shape and obtain three-dimensional data.

[0138] First, the surface shape of the anodic oxide film 20 a side of the aluminum support 12 a is measured by an atomic force microscope (AFM), and three-dimensional data is obtained.

[0139] The measurement is performed, for example, under the following conditions. Specifically, the aluminum support 12a is cut into a size of 1 cm square, and is placed on a horizontal sample stage on a piezoelectric scanner. The cantilever is brought close to the sample surface, and when the area where the atomic force acts is reached, scanning is performed in the XY direction. At this time, the concavity and convexity of the sample are obtained by the displacement of the piezoelectric in the Z direction. For the piezoelectric scanner, a piezoelectric scanner capable of scanning 150 μm in the XY direction and 10 μm in the Z direction is used. For the cantilever, a cantilever with a resonance frequency of 120 to 150 kHz and a spring constant of 12 to 20 N / m (SI-DF20, manufactured by NANOPROBE) is used, and the measurement is performed in DFM mode (Dynamic Force Mode). In addition, the slight tilt of the sample is corrected by performing least squares approximation on the obtained three-dimensional data to obtain the reference surface.

[0140] During the measurement, 512×512 points were measured for 25×25 μm of the surface. The resolution in the XY direction was set to 1.9 μm, the resolution in the Z direction was set to 1 nm, and the scanning speed was set to 60 μm / sec.

[0141] (2) Perform calibration.

[0142] The calculation of the steepness a45 uses three-dimensional data that has been corrected by selecting components with a wavelength of 0.2 to 2 μm from the three-dimensional data obtained in (1). This correction can eliminate interference caused by the probe colliding with the edge of the convex part and bouncing, or the part other than the tip of the probe contacting the wall of the deep concave part when scanning a surface with deep concave and convex parts such as an aluminum support for a planographic printing plate precursor with an AFM probe.

[0143] The calibration is performed by performing a fast Fourier transform on the three-dimensional data obtained in (1) above to obtain a frequency distribution, and then selecting a component with a wavelength of 0.2 to 2 μm and performing an inverse Fourier transform.

[0144] (3) Calculate the steepness a45.

[0145] Using the three-dimensional data (f(x, y)) obtained by the calibration in (2) above, three adjacent points are extracted, and the angle between the small triangle formed by the three points and the reference plane is calculated for the total data, and the slope distribution curve is obtained. On the other hand, the sum of the areas of the small triangles is obtained as the actual area. Based on the slope distribution curve, the ratio of the area of ​​the portion with a slope of 45 degrees or more to the actual area, i.e., the steepness a45 (unit: %) is calculated.

[0146] The actual area S is obtained by the approximate three-point method using the following formula (i) using the atomic force microscope and the three-dimensional data obtained by measuring 512×512 points in a range of 25 μm×25 μm on the surface of the image recording layer 16 side of the anodized film 20a: x The range of the specific surface area ΔS, which is the value obtained by geometrically measuring the area S0, is not particularly limited, but is usually above 15%. From the viewpoint of better stain resistance, ink removal ability during paused printing, and image visual recognition, it is preferably above 20%, more preferably 20-40%, and further preferably 25-35%.

[0147] △S=(S x -S0) / S0×100(%)……(i)

[0148] In the measurement of the above ΔS, first, three-dimensional data (f(x, y)) is obtained according to the same procedure as (1) performed when calculating the above steepness a45.

[0149] Next, using the three-dimensional data (f(x, y)) obtained above, three adjacent points are extracted, and the sum of the areas of the small triangles formed by the three points is calculated as the actual area S x Regarding the surface area difference △S, according to the actual area S obtained x And the geometrically measured area S0 is calculated using the above formula (i).

[0150] In the present invention, the arithmetic mean roughness Ra of the surface of the anodic oxide film 20 a on the image recording layer 16 side is 0.25 to 0.60 μm, preferably 0.30 to 0.60 μm, and more preferably 0.35 to 0.55 μm.

[0151] Here, regarding the arithmetic mean roughness Ra, a stylus roughness meter (Surfcom575) was used to measure the two-dimensional roughness of the surface on the image recording layer 16 side of the anodized film 20a. The average roughness Ra specified in ISO04287 was measured 5 times under the following measurement conditions, and the average value was used.

[0152] <Measurement Conditions>

[0153] Cut-off value: 0.8mm

[0154] Tilt correction: FLAT-ML

[0155] Measuring length: 3mm

[0156] Scanning speed: 0.3mm / sec

[0157] Stylus tip diameter: 2μm

[0158] In the present invention, the ratio of the steepness a45 to the arithmetic mean roughness Ra of the surface of the anodic oxide film 20a on the image recording layer 16 side, that is, the ratio (a45 / Ra) is preferably 9-80, more preferably 20-70, and even more preferably 20-50.

[0159] In the present invention, for the reason that the printing durability when made into a lithographic printing plate becomes better, the density of the recesses with a depth of 0.7 μm or more from the center line obtained by measuring the range of 400 μm × 400 μm on the surface of the image recording layer 16 side of the anodized film 20a (hereinafter also referred to as "specific recesses") is preferably 900 or less, more preferably 400 to 900, and further preferably 500 to 850.

[0160] Here, the density of specific recessed portions refers to a value measured as follows.

[0161] First, a non-contact three-dimensional roughness meter (for example, VertScan, manufactured by Ryoka Systems Inc.) is used to non-contactly scan the anodic oxide film surface in an area of ​​400 μm×400 μm at a resolution of 0.01 μm to obtain three-dimensional data.

[0162] Next, the obtained three-dimensional data is subjected to image analysis using software (for example, SX Viewer, manufactured by Ryoka Systems Inc.), and the number of recessed portions having a depth of 0.70 μm or more from the center line is obtained.

[0163] In the present invention, it is preferred that Al-Fe based intermetallic compounds are precipitated on the surface of the image recording layer 16 side of the anodic oxide film 20a, and the equivalent circle diameter of the Al-Fe based intermetallic compounds on the surface of the image recording layer 16 side of the anodic oxide film 20a is 0.5 to 3.0 μm, and the density of the intermetallic compounds having an equivalent circle diameter of 0.2 μm or more on the surface of the image recording layer 16 side of the anodic oxide film 20a is 3000 pieces / mm 2 above.

[0164] Here, specific examples of Al-Fe based intermetallic compounds include Al3Fe, Al6Fe, Al m Fe, α-AlFeSi, β-AlFeSi, etc.

[0165] In addition, the density of the intermetallic compound was measured by the method shown below.

[0166] First, the surface of the anodic oxide film 20 a on the image recording layer 16 side was wiped clean of oil with acetone and used as a measurement sample.

[0167] Next, a reflected electron image of the surface of the aluminum alloy plate was captured using a scanning electron microscope (PC-SEM7401F, manufactured by JEOL Co., Ltd.) at an accelerating voltage of 12.0 kV and a magnification of 2000 times.

[0168] Next, images of five locations randomly selected from the obtained reflected electron image were saved in JPEG format and converted into bmf (bitmap file) format using MS-Paint (manufactured by Microsoft Corporation).

[0169] After reading the bmf format file into the image analysis software ImageFactory Ver.3.2 Japanese version (manufactured by Ash ahi Hi-tech Co., Ltd.) for image analysis, the image is statically binarized, the parts corresponding to the white spots of intermetallic compounds are counted, and the equivalent circle diameter (equivalent circle diameter) is specified as the characteristic quantity to obtain the particle size distribution.

[0170] Based on the results of the particle size distribution, the density of the intermetallic compound having an equivalent circle diameter of 0.2 μm or more was calculated. The calculation was performed by rounding off the average value of the densities calculated from the image data (particle size distribution) at five locations to the nearest hundred.

[0171] 〔Base coating〕

[0172] The undercoat layer 14 is a layer disposed between the aluminum support 12a and the image recording layer 16, and improves the adhesion between the two. As described above, the undercoat layer 14 is a layer provided as necessary, and may not be included in the planographic printing plate precursor.

[0173] The structure of the undercoat layer is not particularly limited, but it preferably contains a compound including a betaine structure from the viewpoint of being more excellent in stain resistance and ink removal ability during suspended printing.

[0174] First, the betaine structure refers to a structure having at least one cation and at least one anion. In addition, generally, the number of cations is equal to the number of anions, and the structure is neutral as a whole. However, in the present invention, when the number of cations is not equal to the number of anions, a structure having a required amount of counter ions in order to eliminate charges is also considered as a betaine structure.

[0175] The betaine structure is preferably any one of the structure represented by formula (1), the structure represented by formula (2), and the structure represented by formula (3) shown below.

[0176] [Chemical formula 4]

[0177]

[0178] In the formula, A - Indicates a structure with anions, B + Indicates a structure with cations, L 0 Indicates a linking group. * Indicates a linking site (linking position).

[0179] A - Preferably, it represents a structure having an anion such as carboxylate, sulfonate, phosphonate, or phosphite, and B + Preferably, it represents a structure having a cation such as ammonium, phosphonium, iodine, or sulfonium.

[0180] L 0 In formula (1) and formula (3), L 0 Examples of the divalent linking group include -CO-, -O-, -NH-, a divalent aliphatic group, a divalent aromatic group or a combination thereof. 0 A trivalent linking group may be mentioned.

[0181] The linking group is preferably a linking group having 30 or less carbon atoms including the carbon atoms of a substituent which may be described later.

[0182] Specific examples of the linking group include alkylene groups (preferably having 1 to 20 carbon atoms, more preferably 1 to 10 carbon atoms), and arylene groups such as phenylene and xylylene (preferably having 5 to 15 carbon atoms, more preferably 6 to 10 carbon atoms).

[0183] In addition, these linking groups may further have a substituent.

[0184] Examples of the substituent include a halogen atom, a hydroxyl group, a carboxyl group, an amino group, a cyano group, an aryl group, an alkoxy group, an aryloxy group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an acyloxy group, a monoalkylamino group, a dialkylamino group, a monoarylamino group, and a diarylamino group.

[0185] As the betaine structure, from the viewpoint of at least one of better printing durability, stain resistance, deinking ability during paused printing, and image visibility (hereinafter, also referred to as "the viewpoint that the effect of the present invention is better"), the structure represented by formula (i), the structure represented by formula (ii), or the structure represented by formula (iii) is preferred, and the structure represented by formula (i) is more preferred. * represents a linking site.

[0186] [Chemical formula 5]

[0187]

[0188] In formula (i), R 1 and R2 Each independently represents a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group or a heterocyclic group, and R 1 With R 2 They can be linked to each other to form a ring structure.

[0189] The ring structure may have a hetero atom such as an oxygen atom. The ring structure is preferably a 5- to 10-membered ring, more preferably a 5- or 6-membered ring.

[0190] R 1 and R 2 The number of carbon atoms in is preferably 1-30, more preferably 1-20.

[0191] As R 1 and R 2 From the viewpoint of more excellent effects of the present invention, a hydrogen atom, a methyl group or an ethyl group is preferred.

[0192] L 1 The divalent linking group is preferably -CO-, -O-, -NH-, a divalent aliphatic group (e.g., an alkylene group), a divalent aromatic group (e.g., a phenylene group), or a combination thereof.

[0193] As L 1 , preferably a straight-chain alkylene group having 3 to 5 carbon atoms.

[0194] In formula (i), A - It means a structure having an anion, preferably a carboxylate, a sulfonate, a phosphonate or a phosphite.

[0195] Specifically, the following structures can be mentioned.

[0196] [Chemical formula 6]

[0197]

[0198] In formula (i), preferably L 1 is a straight chain alkylene group having 4 or 5 carbon atoms and A - is a combination of sulfonates, more preferably L 1 A is a combination of a linear alkylene group having 4 carbon atoms and a sulfonate.

[0199] In formula (ii), L 2 The divalent linking group is preferably -CO-, -O-, -NH-, a divalent aliphatic group (e.g., an alkylene group), a divalent aromatic group (e.g., a phenylene group), or a combination thereof.

[0200] B + It means a structure having a cation, and preferably has an ammonium, phosphonium, iodine or sulfonium structure. Among them, an ammonium or phosphonium structure is preferred, and an ammonium structure is more preferred.

[0201] Examples of the structure having a cation include a trimethylammonium group, a triethylammonium group, a tributylammonium group, a benzyldimethylammonium group, a diethylhexylammonium group, a (2-hydroxyethyl)dimethylammonium group, a pyridinium group, an N-methylimidazolium group, an N-acridinium group, a trimethylphosphino group, a triethylphosphino group, and a triphenylphosphino group.

[0202] In formula (iii), L 3 The divalent linking group is preferably -CO-, -O-, -NH-, a divalent aliphatic group (e.g., an alkylene group), a divalent aromatic group (e.g., a phenylene group), or a combination thereof.

[0203] A represents a structure having an anion, preferably a carboxylate, a sulfonate, a phosphonate or a phosphite, and the details and preferred examples thereof are the same as those of A in formula (i).

[0204] R 3 ~R 7 Each independently represents a hydrogen atom or a substituent (preferably having 1 to 30 carbon atoms), R 3 ~R 7 At least one of them represents a connecting portion.

[0205] R as the connecting part 3 ~R 7 At least one of them can be passed as R 3 ~R 7 At least one of the substituents in the compound may be linked to another site in the compound, and may be directly linked to another site in the compound via a single bond.

[0206] As R 3 ~R 7 The substituent represented by ] includes a halogen atom, an alkyl group (including a cycloalkyl group and a bicycloalkyl group), an alkenyl group (including a cycloalkenyl group and a bicycloalkenyl group), an alkynyl group, an aryl group, a heterocyclic group, a cyano group, a hydroxyl group, a nitro group, a carboxyl group, an alkoxy group, an aryloxy group, a silyloxy group, a heterocyclic group, an acyloxy group, a carbamoyloxy group, an alkoxycarbonyloxy group, an aryloxycarbonyloxy group, an amino group (including a phenylamino group), an acylamino group, an aminocarbonylamino group, an alkoxycarbonylamino group, an aryloxycarbonylamino group, a sulfamoylamino group, an alkyl and arylsulfonylamino group, a mercapto group, an alkylthio group, an arylthio group, a heterocyclicthio group, a sulfamoyl group, a sulfo group, an alkyl and arylsulfinyl group, an alkyl and arylsulfonyl group, an acyl group, an aryloxycarbonyl group, an alkoxycarbonyl group, a carbamoyl group, an aryl and heterocyclic azo group, an imide group, a phosphinyl group, a phosphinyl group, a phosphinyloxy group, a phosphinylamino group, and a silyl group.

[0207] From the viewpoint of achieving more excellent effects of the present invention, the compound is preferably a polymer (hereinafter also referred to as a "specific polymer") comprising a repeating unit having a betaine structure. The repeating unit having a betaine structure is preferably a repeating unit represented by formula (A1).

[0208] [Chemical formula 7]

[0209]

[0210] In the formula, R 101 ~R 103 Each independently represents a hydrogen atom, an alkyl group or a halogen atom. L represents a single bond or a divalent linking group.

[0211] Examples of the divalent linking group include -CO-, -O-, -NH-, a divalent aliphatic group, a divalent aromatic group, and a combination thereof.

[0212] Specific examples of L including the above combination are given below. In the following examples, the left side is bonded to the main chain, and the right side is bonded to X.

[0213] L1: -CO-O-divalent aliphatic group-

[0214] L2: -CO-O- divalent aromatic group -

[0215] L3: -CO-NH- divalent aliphatic group -

[0216] L4: -CO-NH- divalent aromatic group -

[0217] L5: -CO-divalent aliphatic group-

[0218] L6: -CO- divalent aromatic group -

[0219] L7: -CO-divalent aliphatic group-CO-O-divalent aliphatic group-

[0220] L8: -CO-divalent aliphatic group-O-CO-divalent aliphatic group-

[0221] L9: -CO-divalent aromatic group-CO-O-divalent aliphatic group-

[0222] L10: -CO-divalent aromatic group-O-CO-divalent aliphatic group-

[0223] L11: -CO-divalent aliphatic group-CO-O-divalent aromatic group-

[0224] L12: -CO-divalent aliphatic group-O-CO-divalent aromatic group-

[0225] L13: -CO-divalent aromatic group-CO-O-divalent aromatic group-

[0226] L14: -CO-divalent aromatic group-O-CO-divalent aromatic group-

[0227] L15: -CO-O-divalent aromatic group-O-CO-NH-divalent aliphatic group-

[0228] L16: -CO-O-divalent aliphatic group-O-CO-NH-divalent aliphatic group-

[0229] Examples of the divalent aliphatic group include an alkylene group, an alkenylene group, and an alkynylene group.

[0230] Examples of the divalent aromatic group include an aryl group, and a phenylene group or a naphthylene group is preferred.

[0231] X represents a betaine structure. X is preferably the structure represented by the above-mentioned formula (i), the structure represented by the formula (ii), or the structure represented by the formula (iii).

[0232] In particular, in the formula (A1), preferably, L is L1 or L3, X is a structure represented by the formula (i), and A in the formula (i) is a sulfonate group.

[0233] The content of the repeating unit having a betaine structure in the specific polymer is not particularly limited, but is usually 20 to 95% by mass, preferably 50 to 95% by mass, more preferably 60 to 90% by mass, based on all the repeating units constituting the specific polymer, from the viewpoint of achieving better effects of the present invention.

[0234] The specific polymer may contain other repeating units in addition to the repeating unit having the above-mentioned betaine structure.

[0235] The specific polymer may include a repeating unit having a structure that interacts with the surface of the aluminum support 12 a (hereinafter, also simply referred to as an “interaction structure”).

[0236] Examples of the interaction structure include carboxylic acid structure, carboxylate structure, sulfonic acid structure, sulfonate structure, phosphonic acid structure, phosphonate structure, phosphate structure, phosphate ester structure, β-diketone structure, and phenolic hydroxyl group, and examples thereof include structures represented by the following formulas. Among them, carboxylic acid structure, carboxylate structure, sulfonic acid structure, sulfonate structure, phosphonic acid structure, phosphonate structure, phosphate ester structure, and phosphate ester structure are preferred.

[0237] [Chemical formula 8]

[0238]

[0239] In the above formula, R 11 ~R 13 Each independently represents a hydrogen atom, an alkyl group, an aryl group, an alkynyl group or an alkenyl group, M, M1 and M2 each independently represent a hydrogen atom, a metal atom (for example, an alkali metal atom such as Na or Li) or an ammonium group. B represents a boron atom.

[0240] The repeating unit having an interactive structure is preferably a repeating unit represented by formula (A2).

[0241] [Chemical formula 9]

[0242]

[0243] In the formula, R 201 ~R 203 Each independently represents a hydrogen atom, an alkyl group (preferably having 1 to 6 carbon atoms) or a halogen atom.

[0244] L represents a single bond or a divalent linking group. Examples of the divalent linking group include -CO-, -O-, -NH-, a divalent aliphatic group, a divalent aromatic group, and a combination thereof.

[0245] Specific examples of L including a combination include the same examples as those in the above formula (A1) and the following L17 and L18.

[0246] L17: -CO-NH-

[0247] L18: -CO-O-

[0248] Among L1 to L18, L1 to L4, L17 or L18 is preferred.

[0249] Q represents an interactive structure, and the preferred manner is the same as described above.

[0250] The content of the repeating unit having an interactive structure in the specific polymer is not particularly limited, but is preferably 1 to 40% by mass, more preferably 3 to 30% by mass, based on all repeating units constituting the specific polymer from the viewpoint of achieving more excellent effects of the present invention.

[0251] The specific polymer may include a repeating unit having a radical polymerizable group.

[0252] Examples of the radical polymerizable group include an addition polymerizable unsaturated bond group (e.g., a (meth)acryloyl group, a (meth)acrylamide group, a (meth)acrylonitrile group, an allyl group, a vinyl group, a vinyloxy group, and an alkynyl group) and a functional group capable of chain transfer (such as a mercapto group).

[0253] The specific polymer containing a repeating unit having a radical polymerizable group can be obtained by introducing a radical polymerizable group using the method described in Japanese Patent Application Laid-Open No. 2001-312068. By using a specific polymer containing a repeating unit having a radical polymerizable group, excellent developability is exhibited in the unexposed portion, and the permeability of the developer is suppressed by polymerization in the exposed portion, and the adhesion and adhesion between the aluminum support 12a and the image recording layer 16 are further improved.

[0254] The content of the repeating unit having a radical polymerizable group in the specific polymer is not particularly limited, but is preferably 1 to 30% by mass, more preferably 3 to 20% by mass, based on all repeating units constituting the specific polymer from the viewpoint of achieving more excellent effects of the present invention.

[0255] The content of the compound having the betaine structure in the primer layer 14 is not particularly limited, but is preferably 80% by mass or more, more preferably 90% by mass or more, relative to the total mass of the primer layer. The upper limit is 100% by mass.

[0256] In the above, the primer layer 14 including the compound having a betaine structure is described, but the primer layer may include other compounds.

[0257] For example, the primer layer may be in a form containing a compound having a hydrophilic group. Examples of the hydrophilic group include a carboxylic acid group and a sulfonic acid group.

[0258] The compound having a hydrophilic group may further have a radical polymerizable group.

[0259] 〔Image recording layer〕

[0260] The image recording layer 16 is preferably an image recording layer that can be removed by printing ink and / or fountain solution.

[0261] Hereinafter, each constituent component of the image recording layer 16 will be described.

[0262] <Infrared absorber>

[0263] The image recording layer 16 preferably contains an infrared absorber.

[0264] The infrared absorber preferably has a maximum absorption in the wavelength region of 750 to 1400 nm. In particular, in an on-press development type planographic printing plate precursor, on-press development is sometimes performed in a printing press under white light, so by using an infrared absorber having a maximum absorption in the wavelength region of 750 to 1400 nm that is not easily affected by white light, a planographic printing plate precursor with excellent developability can be obtained.

[0265] As the infrared absorber, a dye or a pigment is preferred.

[0266] Examples of the dye include commercially available dyes and known dyes described in documents such as "Dye Handbook" (edited by The Society of Synthetic Organic Chemistry, Japan, published in 1970).

[0267] Specific examples of the dye include cyanine dyes, leuco dyes, squarylium dyes, pyrylium salts, nickel thiol complexes, and indocyanine dyes. Among them, cyanine dyes, leuco dyes, and indocyanine dyes are preferred, and cyanine dyes and leuco dyes are more preferred.

[0268] (Anthocyanin)

[0269] As the cyanine dye, preferably, there is a cyanine dye represented by the following formula (a).

[0270] Formula (a)

[0271] [Chemical formula 10]

[0272]

[0273] In formula (a), X1 represents a hydrogen atom, a halogen atom, -N(R 9 )(R 10 ),-X 2 -L 1 or the groups shown below.

[0274] [Chemical formula 11]

[0275]

[0276] R 9 and R 10 Each independently represents an aromatic hydrocarbon group, an alkyl group or a hydrogen atom, and R 9 With R 10 They may be bonded to each other to form a ring. Among them, phenyl is preferred.

[0277] X 2 represents an oxygen atom or a sulfur atom, L 1 It represents a hydrocarbon group having 1 to 12 carbon atoms which may contain a heteroatom (N, S, O, a halogen atom, Se).

[0278] About X a - , to be combined with Z a - Defined in the same way, R a represents a hydrogen atom, an alkyl group, an aryl group, an amino group or a halogen atom.

[0279] R1 and R 2 Each independently represents a hydrocarbon group having 1 to 12 carbon atoms. 1 With R 2 They may be bonded to each other to form a ring, and when forming a ring, they preferably form a 5-membered ring or a 6-membered ring.

[0280] Ar 1 and Ar 2 Each independently represents an aromatic hydrocarbon group which may have a substituent (for example, an alkyl group). The aromatic hydrocarbon group is preferably a benzene ring group or a naphthyl ring group.

[0281] Y 1 and Y 2 Each independently represents a sulfur atom or a dialkylmethylene group having 12 or less carbon atoms.

[0282] R 3 and R 4 Each independently represents a hydrocarbon group having 20 or less carbon atoms which may have a substituent (for example, an alkoxy group).

[0283] R 5 , R 6 , R 7 and R 8 Each independently represents a hydrogen atom or a hydrocarbon group having 12 or less carbon atoms.

[0284] And, Za - The cyanine pigment represented by formula (a) has an anionic substituent in its structure, and when charge neutralization is not required, Za is not required. - As Za - Examples of the ion include halide ion, perchlorate ion, tetrafluoroborate ion, hexafluorophosphate ion and sulfonate ion, and preferably perchlorate ion, hexafluorophosphate ion or arylsulfonate ion.

[0285] (leuco pigment)

[0286] The leuco dye is not particularly limited as long as it has a colorless structure, but is preferably a leuco dye having a phthalide structure or a fluorane matrix structure from the viewpoint of color development and visibility of the exposed portion.

[0287] Moreover, from the perspective of color development and visual recognition of the exposed portion, the above-mentioned leuco dye having a phthalide structure or a fluoran matrix structure is preferably a compound represented by any one of the following formulas (Le-1) to (Le-3), and more preferably a compound represented by the following formula (Le-2).

[0288] [Chemical formula 12]

[0289]

[0290] In formula (Le-1) to formula (Le-3), ERG each independently represents an electron donating group, X1 to X4 each independently represents a hydrogen atom, a halogen atom or a dialkylphenylamino group, and X5 to X6 each independently represents an electron donating group. 10 Each independently represents a hydrogen atom, a halogen atom or a monovalent organic group, Y1 and Y2 each independently represent C or N, when Y1 is N, X1 does not exist, when Y2 is N, X4 does not exist, Ra1 represents a hydrogen atom, an alkyl group or an alkoxy group, and Rb1~Rb4 each independently represent a hydrogen atom, an alkyl group or an aryl group.

[0291] As the electron-donating group in the ERG of formula (Le-1) to formula (Le-3), from the viewpoint of color development and visual recognition of the exposed portion, it is preferably an amino group, an alkylamino group, an arylamino group, a dialkylamino group, a monoalkylmonoarylamino group, a diarylamino group, an alkoxy group, an aryloxy group or an alkyl group, more preferably an amino group, an alkylamino group, an arylamino group, a dialkylamino group, a monoalkylmonoarylamino group, a diarylamino group, an alkoxy group or an aryloxy group, further preferably a monoalkylmonoarylamino group or a diarylamino group, and especially preferably a monoalkylmonoarylamino group.

[0292] From the viewpoint of color development and visibility of the exposed portion, X1 to X4 in Formula (Le-1) to Formula (Le-3) are each independently preferably a hydrogen atom or a chlorine atom, and more preferably a hydrogen atom.

[0293] From the viewpoint of color development and visibility of the exposed portion, X5 to X6 in formula (Le-2) or formula (Le-3) are 10 Each of the above groups is independently preferably a hydrogen atom, a halogen atom, an alkyl group, an aryl group, an amino group, an alkylamino group, an arylamino group, a dialkylamino group, a monoalkylmonoarylamino group, a diarylamino group, a hydroxyl group, an alkoxy group, an aryloxy group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group or a cyano group, more preferably a hydrogen atom, a halogen atom, an alkyl group, an aryl group, an alkoxy group or an aryloxy group, further preferably a hydrogen atom, a halogen atom, an alkyl group or an aryl group, and particularly preferably a hydrogen atom.

[0294] From the viewpoint of color development and visibility of the exposed portion, at least one of Y1 and Y2 in Formula (Le-1) to Formula (Le-3) is preferably C, and both Y1 and Y2 are more preferably C.

[0295] From the viewpoint of color development and visibility of the exposed portion, Ra1 in Formula (Le-1) to Formula (Le-3) is preferably an alkyl group or an alkoxy group, more preferably an alkoxy group, and particularly preferably a methoxy group.

[0296] From the viewpoint of color development and visibility of the exposed portion, Rb1 to Rb4 in Formulae (Le-1) to (Le-3) are each independently preferably a hydrogen atom or an alkyl group, more preferably an alkyl group, and particularly preferably a methyl group.

[0297] Furthermore, from the perspective of color development and visual recognizability of the exposed portion, the above-mentioned leuco pigment having a phthalide structure or a fluoran matrix structure is more preferably a compound represented by any one of the following formulas (Le-4) to (Le-6), and is further preferably a compound represented by the following formula (Le-5).

[0298] [Chemical formula 13]

[0299]

[0300] In formula (Le-4) to formula (Le-6), ERG independently represents an electron donating group, X1 to X4 independently represent a hydrogen atom, a halogen atom or a dialkylaniline group, Y1 and Y2 independently represent C or N, when Y1 is N, X1 does not exist, and when Y2 is N, X4 does not exist, Ra1 represents a hydrogen atom, an alkyl group or an alkoxy group, and Rb1 to Rb4 independently represent a hydrogen atom, an alkyl group or an aryl group.

[0301] ERG, X1~X4, Y1, Y2, Ra1 and Rb1~Rb4 in formula (Le-4) to (Le-6) have the same meanings as ERG, X1~X4, Y1, Y2, Ra1 and Rb1~Rb4 in formula (Le-1) to (Le-3), and the preferred embodiments are also the same.

[0302] Moreover, from the perspective of color development and visual recognizability of the exposed portion, the above-mentioned leuco pigment having a phthalide structure or a fluoran matrix structure is further preferably a compound represented by any one of the following formulas (Le-7) to (Le-9), and is particularly preferably a compound represented by the following formula (Le-8).

[0303] [Chemical formula 14]

[0304]

[0305] In formula (Le-7) to formula (Le-9), X1 to X4 each independently represent a hydrogen atom, a halogen atom or a dialkylaniline group, Y1 and Y2 each independently represent C or N, when Y1 is N, X1 does not exist, and when Y2 is N, X4 does not exist, Ra1 to Ra4 each independently represent a hydrogen atom, an alkyl group or an alkoxy group, Rb1 to Rb4 each independently represent a hydrogen atom, an alkyl group or an aryl group, and Rc1 and Rc2 each independently represent an aryl group.

[0306] X1 to X4, Y1 and Y2 in formula (Le-7) to formula (Le-9) have the same meanings as X1 to X4, Y1 and Y2 in formula (Le-1) to formula (Le-3), and preferred aspects are also the same.

[0307] From the viewpoint of color development and visibility of the exposed portion, Ra1 to Ra4 in Formula (Le-7) to Formula (Le-9) are each independently preferably an alkyl group or an alkoxy group, more preferably an alkoxy group, and particularly preferably a methoxy group.

[0308] From the viewpoint of color development and visibility of the exposed portion, Rb1 to Rb4 in Formula (Le-7) to Formula (Le-9) are each independently preferably a hydrogen atom, an aryl group substituted with an alkyl group or an alkoxy group, more preferably an alkyl group, and particularly preferably a methyl group.

[0309] From the viewpoint of color development and visibility of the exposed portion, Rc1 and Rc2 in Formula (Le-7) to Formula (Le-9) are each independently preferably a phenyl group or an alkylphenyl group, and more preferably a phenyl group.

[0310] Furthermore, in formula (Le-8), from the viewpoint of color development and visibility of the exposed portion, it is preferred that X1 to X4 are hydrogen atoms and Y1 and Y2 are C.

[0311] Furthermore, in formula (Le-8), from the viewpoint of color development and visibility of the exposed portion, Rb1 and Rb2 are each independently preferably a hydrogen atom or an alkyl group.

[0312] The alkyl groups in formula (Le-1) to formula (Le-9) may be linear, branched, or have a ring structure.

[0313] Furthermore, the number of carbon atoms in the alkyl group in Formula (Le-1) to Formula (Le-9) is preferably 1 to 20, more preferably 1 to 8, further preferably 1 to 4, and particularly preferably 1 or 2.

[0314] The number of carbon atoms in the aryl group in Formula (Le-1) to Formula (Le-9) is preferably 6 to 20, more preferably 6 to 10, and particularly preferably 6 to 8.

[0315] Furthermore, each of the monovalent organic groups, alkyl groups, aryl groups, dialkylphenylamino groups, alkylamino groups, alkoxy groups, etc. in formula (Le-1) to formula (Le-9) may have a substituent. Examples of the substituent include alkyl groups, aryl groups, halogen atoms, amino groups, alkylamino groups, arylamino groups, dialkylamino groups, monoalkylmonoarylamino groups, diarylamino groups, hydroxyl groups, alkoxy groups, aryloxy groups, acyl groups, alkoxycarbonyl groups, aryloxycarbonyl groups, and cyano groups. Furthermore, these substituents may be further substituted by these substituents.

[0316] Specific examples of the leuco dye having a phthalide structure or a fluoran matrix structure that can be preferably used include the following compounds (S-1 to S-15).

[0317] [Chemical formula 15]

[0318]

[0319] [Chemical formula 16]

[0320]

[0321] [Chemical formula 17]

[0322]

[0323] [Chemical formula 18]

[0324]

[0325] The infrared absorbing dye may be used alone or in combination of two or more. Infrared absorbers other than infrared absorbing dyes such as pigments may also be used in combination. The pigment is preferably a compound described in paragraphs

[0072] to

[0076] of Japanese Patent Application Laid-Open No. 2008-195018.

[0326] The content of the infrared absorber is preferably 0.05 to 30% by mass, more preferably 0.1 to 20% by mass, based on the total mass of the image recording layer 16 .

[0327] <Polymerization Initiator>

[0328] The image recording layer 16 preferably contains a polymerization initiator.

[0329] The polymerization initiator is preferably a compound that generates radicals by light, heat, or both of these energies and initiates polymerization of a compound having a polymerizable unsaturated group (so-called radical polymerization initiator). Examples of the polymerization initiator include photopolymerization initiators and thermal polymerization initiators.

[0330] As the polymerization initiator, specifically, the polymerization initiators described in paragraphs

[0115] to

[0141] of JP-A-2009-255434 can be used.

[0331] In addition, as the polymerization initiator, from the viewpoint of reactivity and stability, an oxime ester compound or an onium salt such as a diazonium salt, an iodonium salt, and a sulfonium salt is preferred.

[0332] In the present invention, the polymerization initiator preferably contains an electron accepting polymerization initiator and / or an electron donating polymerization initiator, and more preferably contains both an electron accepting polymerization initiator and an electron donating polymerization initiator.

[0333] (Electron-accepting polymerization initiator)

[0334] The electron accepting polymerization initiator is a compound that generates polymerization initiating species such as radicals or cations by energy from light, heat, or both, and a known thermal polymerization initiator, a compound having a bond with low bond dissociation energy, a photopolymerization initiator, etc. can be appropriately selected and used.

[0335] As the electron accepting polymerization initiator, a radical polymerization initiator is preferred, and an onium compound is more preferred.

[0336] Furthermore, as the electron accepting polymerization initiator, an infrared-sensitive polymerization initiator is preferred.

[0337] The electron accepting polymerization initiator may be used alone or in combination of two or more.

[0338] Examples of the radical polymerization initiator include (a) organic halides, (b) carbonyl compounds, (c) azo compounds, (d) organic peroxides, (e) metallocene compounds, (f) azide compounds, (g) hexaarylbiimidazole compounds, (i) disulfone compounds, (j) oxime ester compounds, and (k) onium compounds.

[0339] (a) As the organic halide, for example, the compounds described in paragraphs 0022 to 0023 of JP-A-2008-195018 are preferred.

[0340] (b) As the carbonyl compound, for example, the compounds described in paragraph 0024 of JP-A-2008-195018 are preferred.

[0341] (c) As the azo compound, for example, the azo compounds described in Japanese Patent Application Laid-Open No. 8-108621 can be used.

[0342] (d) As the organic peroxide, for example, the compounds described in paragraph 0025 of JP-A-2008-195018 are preferred.

[0343] (e) As the metallocene compound, for example, the compounds described in paragraph 0026 of JP-A-2008-195018 are preferred.

[0344] (f) Examples of the azide compound include compounds such as 2,6-bis(4-azidobenzylidene)-4-methylcyclohexanone.

[0345] (g) As the hexaarylbiimidazole compound, for example, the compounds described in paragraph 0027 of JP-A-2008-195018 are preferred.

[0346] (i) Examples of the disulfone compound include compounds described in JP-A-61-166544 and JP-A-2002-328465.

[0347] (j) As the oxime ester compound, for example, the compounds described in paragraphs 0028 to 0030 of JP-A-2008-195018 are preferred.

[0348] Among the above-mentioned electron accepting polymerization initiators, preferred electron accepting polymerization initiators include oxime ester compounds and onium compounds from the viewpoint of curability. Among them, from the viewpoint of printing durability, especially printing durability when using an ink cured by ultraviolet (UV) irradiation as an ink in printing (hereinafter also referred to as "UV printing durability"), iodonium salt compounds, sulfonium salt compounds or azinium salt compounds are preferred, iodonium salt compounds or sulfonium salt compounds are more preferred, and iodonium salt compounds are further preferred.

[0349] Specific examples of these compounds are shown below, but the present invention is not limited thereto.

[0350] As examples of the iodonium salt compound, diaryliodonium salt compounds are preferred, and diphenyliodonium salt compounds substituted with an electron-donating group such as an alkyl group or an alkoxy group are more preferred, and asymmetric diphenyliodonium salt compounds are preferred. Specific examples include diphenyliodonium hexafluorophosphate, 4-methoxyphenyl-4-(2-methylpropyl)phenyliodonium hexafluorophosphate, 4-(2-methylpropyl)phenyl-p-tolyliodonium hexafluorophosphate, 4-hexyloxyphenyl-2,4,6-trimethoxyphenyliodonium hexafluorophosphate, 4-hexyloxyphenyl-2,4-diethoxyphenyliodonium tetrafluoroborate, 4-octyloxyphenyl-2,4,6-trimethoxyphenyliodonium 1-perfluorobutylsulfonate, 4-octyloxyphenyl-2,4,6-trimethoxyphenyliodonium hexafluorophosphate, and bis(4-tert-butylphenyl)iodonium tetraphenylborate.

[0351] As examples of sulfonium salt compounds, triarylsulfonium salt compounds are preferred, and particularly preferred are triarylsulfonium salt compounds in which at least a part of the electron withdrawing group, for example, the group on the aromatic ring is substituted with a halogen atom, and further preferred are triarylsulfonium salt compounds in which the total number of halogen atoms substituted on the aromatic ring is 4 or more. Specific examples include triphenylsulfonium hexafluorophosphate, triphenylsulfonium benzoylformate, bis(4-chlorophenyl)phenylsulfonium benzoylformate, bis(4-chlorophenyl)-4-methylphenylsulfonium tetrafluoroborate, tri(4-chlorophenyl)sulfonium 3,5-bis(methoxycarbonyl)benzenesulfonate, tri(4-chlorophenyl)sulfonium hexafluorophosphate, and tri(2,4-dichlorophenyl)sulfonium hexafluorophosphate.

[0352] Furthermore, as the counter anion of the iodonium salt compound and the sulfonium salt compound, a sulfonamide anion or a sulfonimide anion is preferred, and a sulfonimide anion is more preferred.

[0353] As the sulfonamide anion, an arylsulfonamide anion is preferred.

[0354] Furthermore, as the sulfonyl imide anion, a bisarylsulfonyl imide anion is preferred.

[0355] Specific examples of the sulfonamide anion or the sulfonimide anion are shown below, but the present invention is not limited thereto. In the following specific examples, Ph represents a phenyl group, Me represents a methyl group, and Ft represents an ethyl group.

[0356] [Chemical formula 19]

[0357]

[0358] Specific examples of the salt formation between the electron accepting polymerization initiator and the electron donating polymerization initiator described below are shown below, but the present invention is not limited to these.

[0359] [Chemical formula 20]

[0360]

[0361] The electron-accepting polymerization initiator may preferably be a compound represented by the following formula (I) from the viewpoints of color development, color development over time after exposure, developability of the obtained planographic printing plate precursor, and UV printing durability when the planographic printing plate is prepared.

[0362] [Chemical formula 21]

[0363]

[0364] In the formula, X represents a halogen atom, and specifically, a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom can be mentioned. Among these, a chlorine atom or a bromine atom is preferred because of its excellent sensitivity, and a bromine atom is particularly preferred.

[0365] A represents a divalent linking group selected from -CO-, -SO-, -SO2-, -PO- and -PO2-. Of these, -CO-, -SO- and -SO2- are more preferred, and -CO- and -SO2- are particularly preferred. X 1 and R X2 Each independently represents a hydrogen atom or a monovalent hydrocarbon group having 1 to 20 carbon atoms.

[0366] Examples of hydrocarbons constituting the hydrocarbon group include hydrocarbons described in paragraphs 0013 to 0014 of Japanese Patent Application Laid-Open No. 2002-162741, and specifically, examples of hydrocarbons include methane, ethane, propane, butane, hexane, nonane, decane, octadecane, cyclopentane, cyclohexane, adamantane, norbornane, decahydronaphthalene, tricyclo[5.2.1.0 2，6 ] aliphatic hydrocarbons having 1 to 30 carbon atoms, such as decane, ethylene, propylene, 1-butene, 1-hexene, 1-heptadecene, 2-butene, 2-hexene, 4-nonene, 7-tetradecene, butadiene, isoprene, 1,9-decadiene, cyclopentene, cyclohexene, cyclooctene, 1,4-cyclohexadiene, 1,5-cyclooctadiene, 1,5,9-cyclododecatriene, borneol, octahydronaphthalene, bicyclo[2.2.1]hept-2,5-diene, acetylene, 1-propyne, 2-hexyne, etc.; aromatic hydrocarbons, such as benzene, naphthalene, anthracene, indene, fluorene, etc.

[0367] The carbon atoms constituting such a hydrocarbon group may be substituted by one or more hetero atoms selected from the group consisting of an oxygen atom, a nitrogen atom and a sulfur atom.

[0368] As the substituent, a monovalent non-metallic atomic group excluding hydrogen can be mentioned, and a halogen atom (-F, -Br, -Cl, -I) can be mentioned, for example, a hydroxyl group, an alkoxy group, an aryloxy group, a mercapto group, an alkylthio group, an arylthio group, an alkyldisulfide group, an aryldisulfide group, an amino group, an N-alkylamino group, an N,N-dialkylamino group, an N-arylamino group, an N,N-diarylamino group, an N-alkyl-N-arylamino group, an acyloxy group, a carbamoyloxy group, an N-alkylcarbamoyloxy group, an N-arylcarbamoyloxy group, an N,N-dialkylcarbamoyloxy group, an N,N-diarylcarbamoyloxy group, an N-alkyl-N-arylamino group, an acyloxy group, a carbamoyloxy group, an N-alkylcarbamoyloxy group, an N-arylcarbamoyloxy group, an N,N-dialkylcarbamoyloxy group, an N,N-diarylcarbamoyloxy group, an N-alkyl-N-aryl carbamoyloxy, alkylthiooxy, arylthiooxy, acylthio, acylamino, N-alkylacylamino, N-arylacylamino, urea, N'-alkylurea, N',N'-dialkylurea, N'-arylurea, N',N'-diarylurea, N'-alkyl-N'-arylurea, N-alkylurea, N-arylurea, N'-alkyl-N-alkylurea, N'-alkyl-N-arylurea, N',N'-dialkyl-N-alkylurea, N',N'-dialkyl-N-arylurea, N'-aryl-N-alkylurea, N'-aryl-N-arylurea, N',N'-diaryl-N-alkylureido, N',N'-diaryl-N-arylureido, N'-alkyl-N'-aryl-N-alkylureido, N'-alkyl-N'-aryl-N-arylureido, alkoxycarbonylamino, aryloxycarbonylamino, N-alkyl-N-alkoxycarbonylamino, N-alkyl-N-aryloxycarbonylamino, N-aryl-N-alkoxycarbonylamino, N-aryl-N-aryloxycarbonylamino, formyl, acyl, carboxyl and its conjugate base, alkoxycarbonyl, aryloxycarbonyl, carbamoyl, N-alkylcarbamoyl, N,N-dialkylcarbamoyl , N-arylcarbamoyl, N,N-diarylcarbamoyl, N-alkyl-N-arylcarbamoyl, alkylsulfinyl, arylsulfinyl, alkylsulfonyl, arylsulfonyl, sulfo (-SO3H) and its conjugate base, alkoxysulfonyl, aryloxysulfonyl, sulfamoyl, N-alkylsulfamoyl, N,N-dialkylsulfamoyl, N-arylsulfamoyl, N,N-diarylsulfamoyl, N-alkyl-N-arylsulfamoyl, sulfamoyl, N-alkylsulfamoyl, N,N-dialkylsulfamoyl, N-arylsulfamoyl, N,N-diarylsulfamoyl, N-alkyl-N-arylsulfamoyl, N-acylsulfamoyl and its conjugated base, N-alkylsulfonylsulfamoyl (-SO2NHSO2(alkyl)) and its conjugated base, N-arylsulfonylsulfamoyl (-SO2NHSO2(aryl)) and its conjugated base, N-alkylsulfonylcarbamoyl (-CONHSO2(alkyl)) and its conjugated base, N-arylsulfonylcarbamoyl (-CONHSO2(aryl )) and its conjugate base, alkoxysilyl (-Si(Oalkyl)3), aryloxysilyl (-Si(Oaryl)3), hydroxysilyl (-Si(OH)3) and its conjugate base, phosphonyl (-PO3H2) and its conjugate base, dialkylphosphonyl (-PO3(alkyl)2), diarylphosphonyl (-PO3(aryl)2), alkylarylphosphonyl (-PO3(alkyl)(aryl)), monoalkylphosphonyl (-PO3H (alkyl)) and its conjugate base, monoarylphosphonyl (-P03H(ary])) and its conjugate base, phosphonooxy (-OPO3H2) and its conjugate base, dialkylphosphonooxy (-OPO3(alkyl)2), diarylphosphonooxy (-OPO3(aryl)2), alkylarylphosphonooxy (-OPO3(alkyl)(aryl)), monoalkylphosphonooxy (-OPO3H(alkyl)) and its conjugate base, monoarylphosphonooxy ( -OPO3H(aryl)) and its conjugated base, cyano, nitro, dialkylboryl (-B(alkyl)2), diarylboryl (-B(aryl)2), alkylarylboryl (-B(alkyl)(aryl)), dihydroxyboryl (-B(OH)2) and its conjugated base, alkylhydroxyboryl (-B(alkyl)(OH)) and its conjugated base, arylhydroxyboryl (-B(aryl)(OH)) and its conjugated base, aryl, alkyl, alkenyl, alkynyl. ,

[0369] If possible, these substituents may be bonded to each other or to a substituted hydrocarbon group to form a ring, and the substituents may be further substituted.

[0370] Preferred substituents include a halogen atom, an alkoxy group, an aryloxy group, an alkyl group, an alkenyl group, an alkynyl group and an aryl group.

[0371] m x and n x They represent integers from 1 to 3 respectively. x +n x = 2 to 4. From the viewpoint of sensitivity, m is preferably x =1 and n x =3 or m x =2 and nx =2. In m x and n x When m is 2 or more, (R1-A) and X may be different. x =1 and n x =1, R x2 They may also be different from each other.

[0372] Among the compounds represented by the above formula (I), compounds represented by the following formulae (II) and (III) are preferred because of their excellent visibility.

[0373] [Chemical formula 22]

[0374]

[0375] In formula (II) and (III), X has the same meaning as X in formula (I), and R 3 , R 4 and R 5 Each independently represents a monovalent hydrocarbon group having 1 to 20 carbon atoms.

[0376] Here, R 3 , R 4 and R 5 An aryl group is preferred, and a group in which the aryl group is substituted with an amide group is more preferred because of its excellent balance between sensitivity and storage stability.

[0377] Among the compounds represented by the following formulae (II) and (III), the compound represented by formula (IV) is particularly preferred.

[0378] [Chemical formula 23]

[0379]

[0380] In formula (IV), R 4 and R 5 Each independently represents a hydrogen atom or a monovalent hydrocarbon group having 1 to 20 carbon atoms. p and q represent integers from 1 to 5. However, p+q=2-6.

[0381] Specific examples of the electron accepting polymerization initiator represented by the above formula (I) include compounds represented by the following formulas, but the present invention is not limited thereto.

[0382] [Chemical formula 24]

[0383]

[0384] [Chemical formula 25]

[0385]

[0386] [Chemical formula 26]

[0387]

[0388] [Chemical formula 27]

[0389]

[0390] [Chemical formula 28]

[0391]

[0392] [Chemical formula 29]

[0393]

[0394] [Chemical formula 30]

[0395]

[0396] From the viewpoint of chemical resistance and UV printing durability, the lowest unoccupied molecular orbital (LUM0) of the electron-accepting polymerization initiator is preferably -3.00 eV or less, and more preferably -3.02 eV or less.

[0397] Furthermore, the lower limit is preferably -3.80 eV or more, and more preferably -3.60 eV or more.

[0398] The content of the electron accepting polymerization initiator is preferably 0.1 to 50% by mass, more preferably 0.5 to 30% by mass, and particularly preferably 0.8 to 20% by mass, based on the total mass of the image recording layer.

[0399] (Electron donating polymerization initiator)

[0400] From the viewpoint of contributing to improvement of chemical resistance and UV printing durability in the lithographic printing plate, the polymerization initiator preferably further contains an electron donating polymerization initiator, and more preferably contains both an electron donating polymerization initiator and the above-mentioned electron donating polymerization initiator.

[0401] Examples of the electron donating polymerization initiator include the following five types.

[0402] (i) Alkyl or aryl acid radical type complex: It is believed that the carbon-hetero bond is oxidatively cleaved to generate active radicals. Specific examples include borate compounds.

[0403] (ii) Aminoacetic acid compounds: It is believed that the CX bond on the carbon adjacent to nitrogen is cleaved by oxidation to generate an active free radical. X is preferably a hydrogen atom, a carboxyl group, a trimethylsilyl group or a benzyl group. Specifically, N-phenylglycine (the phenyl group may have a substituent) and N-phenyliminodiacetic acid (the phenyl group may have a substituent) are mentioned.

[0404] (iii) Sulfur-containing compounds: Compounds in which the nitrogen atom of the aminoacetic acid compound is replaced with a sulfur atom generate active radicals by the same action. Specific examples include phenylthioacetic acid (which may have a substituent in the phenyl group) and the like.

[0405] (iv) Tin-containing compounds: Compounds in which the nitrogen atom of the above-mentioned aminoacetic acid compound is replaced with a tin atom can generate active radicals by the same action.

[0406] (v) Sulfinates: They can generate active radicals by oxidation. Specific examples thereof include sodium arylsulfinate.

[0407] Among these electron donating polymerization initiators, it is also preferred that the image recording layer contain a borate compound. As the borate compound, a tetraaryl borate compound or a monoalkyl triaryl borate compound is preferred, and from the viewpoint of compound stability, a tetraaryl borate compound is more preferred, and a tetraphenyl borate compound is particularly preferred.

[0408] The counter cation of the borate compound is not particularly limited, but is preferably an alkali metal ion or a tetraalkylammonium ion, and more preferably a sodium ion, a potassium ion, or a tetrabutylammonium ion.

[0409] Specifically, as the borate compound, preferably, sodium tetraphenylborate is used.

[0410] Furthermore, from the viewpoint of chemical resistance and UV printing durability, the highest occupied molecular orbital (HOMO) of the electron donating polymerization initiator that can be used in the present invention is preferably -6.00 eV or more, more preferably -5.95 eV or more, and even more preferably -5.93 eV or more.

[0411] Furthermore, the upper limit is preferably -5.00 eV or less, and more preferably -5.40 eV or less.

[0412] In this specification, the calculation of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) is performed by the following method.

[0413] First, the counter anion in the compound to be calculated is ignored.

[0414] The structure was optimized using quantum chemical calculation software Gaussian09 under DFT (B3LYP / 6-31G(d)).

[0415] MO (molecular orbital) energy calculation was performed under DFT (B3LYP / 6-31+G(d, p) / CPCM (solvent=methanol)) using the structure obtained by the above-mentioned structural optimization.

[0416] The M0 energy Ebare (unit: Hartley) obtained by the above M0 energy calculation is converted into Escaled (unit: eV) used as the value of HOMO and LUM0 in this specification according to the following formula.

[0417] Escaled=0.823168×27.2114×Ebare-1.07634

[0418] In addition, 27.2114 is a coefficient used only for converting Hartley to eV, and 0.823168 and -1.07634 are adjustment coefficients for determining the HOMO and LUMO of the compound to be calculated so that the calculated values ​​match the measured values.

[0419] Hereinafter, B-1 to B-8 and other compounds are shown as preferred specific examples of the electron donating polymerization initiator, but the present invention is not limited to these compounds. In the following chemical formula, Bu represents an n-butyl group, and Z represents a counter cation.

[0420] As Z + The counter cation represented by + , K + 、N + (Bu) 4, etc. The above-mentioned Bu represents a normal butyl group.

[0421] And, as Z + The counter cation represented by is preferably the onium ion in the above-mentioned electron accepting polymerization initiator.

[0422] [Chemical formula 31]

[0423]

[0424] [Chemical formula 32]

[0425]

[0426] The electron donating polymerization initiator may be added alone or in combination of two or more.

[0427] The content of the electron donating polymerization initiator is preferably 0.01 to 30% by mass, more preferably 0.05 to 25% by mass, and even more preferably 0.1 to 20% by mass, based on the total mass of the image recording layer.

[0428] Furthermore, one of the preferred embodiments of the present invention is an embodiment in which the electron accepting polymerization initiator and the electron donating polymerization initiator form a salt.

[0429] Specifically, for example, the onium compound may be a salt of an onium ion and an anion (e.g., tetraphenylborate anion) in the electron donating polymerization initiator. More preferably, an iodonium borate compound may be an iodonium cation (e.g., di-p-tolyl iodonium cation) in the iodonium salt compound and a borate anion in the electron donating polymerization initiator to form a salt.

[0430] Specific examples of the form of the salt formed by the electron accepting polymerization initiator and the electron donating polymerization initiator are shown below, but the present invention is not limited to these.

[0431] [Chemical formula 33]

[0432]

[0433] The content of the polymerization initiator is preferably 0.1 to 50% by mass, more preferably 0.5 to 30% by mass, based on the total mass of the image recording layer 16 .

[0434] In the present invention, from the viewpoint of UV printing durability and chemical resistance, the difference between the HOMO of the electron donating polymerization initiator and the HOMO of the infrared absorber is preferably 1.00 eV or less, more preferably 0.700 eV or less. Also, from the same viewpoint, the difference between the HOMO of the electron donating polymerization initiator and the HOMO of the infrared absorber is preferably -0.200 eV or more, more preferably -0.100 eV or more.

[0435] From the same viewpoint, the difference between the HOMO of the electron donating polymerization initiator and the HOMO of the infrared absorber is preferably 1.00 eV to -0.200 eV, more preferably 0.700 eV to -0.100 eV. A negative value means that the HOMO of the electron donating polymerization initiator is higher than the HO M0 of the infrared absorber.

[0436] Furthermore, in the present invention, from the viewpoint of UV printing durability and chemical resistance, the difference between the LUMO of the infrared absorber and the LUMO of the electron accepting polymerization initiator is preferably 1.00 eV or less, more preferably 0.700 eV or less. Furthermore, from the same viewpoint, the difference between the LUMO of the infrared absorber and the LUMO of the electron accepting polymerization initiator is preferably -0.200 eV or more, more preferably -0.100 eV or more.

[0437] From the same viewpoint, the difference between the LUMO of the infrared absorber and the LUMO of the electron accepting polymerization initiator is preferably 1.00 eV to -0.200 eV, more preferably 0.700 eV to -0.100 eV. A negative value means that the LUMO of the infrared absorber is higher than the LUMO of the electron accepting polymerization initiator.

[0438] <Polymerizable Compound>

[0439] The image recording layer 16 preferably contains a polymerizable compound.

[0440] As the polymerizable compound, an addition polymerizable compound having at least one ethylenically unsaturated bond is preferred. Among them, a compound having at least one (preferably two) terminal ethylenically unsaturated bonds is more preferred. So-called free radical polymerizable compounds are more preferred.

[0441] As the polymerizable compound, for example, the polymerizable compounds exemplified in paragraphs

[0142] to

[0163] of JP-A-2009-255434 can be used.

[0442] In the present invention, from the viewpoint of UV printing durability, the polymerizable compound preferably contains a polymerizable compound having three or more functional groups, more preferably contains a polymerizable group having seven or more functional groups, and further preferably contains a polymerizable group having ten or more functional groups. Furthermore, from the viewpoint of UV printing durability in the obtained lithographic printing plate, the polymerizable compound preferably contains an ethylenically unsaturated compound having three or more functional groups (preferably seven or more functional groups, and more preferably ten or more functional groups), and further preferably contains a (meth)acrylate compound having three or more functional groups (preferably seven or more functional groups, and more preferably ten or more functional groups).

[0443] Furthermore, carbamate-based addition polymerizable compounds produced by the addition reaction of isocyanate and hydroxyl groups are also preferred. Specific examples thereof include vinyl carbamate compounds containing two or more polymerizable vinyl groups in one molecule, which are obtained by adding a polyisocyanate compound having two or more isocyanate groups in one molecule as described in Japanese Patent Gazette No. 48-41708 to a vinyl monomer containing a hydroxyl group represented by the following formula (A).

[0444] CH2=C(R 4 )COOCH2CH(R 5 )OH (A)

[0445] (Among them, R 4 and R 5 represents H or CH3. )

[0446] The content of the polymerizable compound is preferably 3 to 80% by mass, more preferably 10 to 75% by mass, based on the total mass of the image recording layer 16 .

[0447] <Binder Polymer>

[0448] The image-recording layer 16 preferably contains a binder polymer.

[0449] As the binder polymer, known binder polymers can be mentioned. Specifically, acrylic resins, polyvinyl acetal resins, polyurethane resins, polyurea resins, polyimide resins, polyamide resins, epoxy resins, methacrylic resins, polystyrene resins, novolac phenolic resins, polyester resins, synthetic rubbers, and natural rubbers can be mentioned.

[0450] In order to improve the film strength of the image part, the binder polymer may have crosslinking properties. To make the binder polymer crosslinkable, a crosslinking functional group such as an ethylenically unsaturated bond may be introduced into the main chain or side chain of the polymer. The crosslinking functional group may be introduced by copolymerization.

[0451] As the binder polymer, for example, the binder polymers disclosed in paragraphs

[0165] to

[0172] of JP-A-2009-255434 can be used.

[0452] The binder polymer may be a polymer compound in the form of microparticles. In other words, the binder polymer may be polymer particles.

[0453] Examples of the microparticle-shaped polymer compound (polymer constituting the polymer particles) include homopolymers, prepolymers, or mixtures thereof of monomers such as ethylene, styrene, vinyl chloride, methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate, vinylidene chloride, acrylonitrile, vinylcarbazole, and acrylates or methacrylates having a polyalkylene structure. More specifically, examples include copolymers of styrene-(meth)acrylonitrile-poly(ethylene glycol) monoalkyl ether (meth)acrylate compounds.

[0454] The content of the binder polymer is preferably 5 to 90% by mass, more preferably 5 to 70% by mass, based on the total mass of the image recording layer 16 .

[0455] <Surfactant>

[0456] The image recording layer 16 may contain a surfactant in order to promote on-press development at the start of printing and to improve the coating surface state.

[0457] Examples of the surfactant include nonionic surfactants, anionic surfactants, cationic surfactants, amphoteric surfactants, and fluorine-based surfactants.

[0458] As the surfactant, for example, the surfactant disclosed in paragraphs

[0175] to

[0179] of JP-A-2009-255434 can be used.

[0459] The content of the surfactant is preferably 0.001 to 10% by mass, more preferably 0.01 to 5% by mass, relative to the total mass of the image recording layer 16 .

[0460] The image recording layer 16 may further contain other compounds in addition to the above-mentioned ones as necessary.

[0461] Examples of other compounds include colorants disclosed in paragraphs

[0181] to

[0190] of JP-A-2009-255434, print-out agents, polymerization inhibitors, higher fatty acid derivatives, plasticizers, inorganic fine particles, and low-molecular hydrophilic compounds.

[0462] In addition, other compounds include hydrophobic precursors (microparticles capable of converting the image recording layer into hydrophobic properties when heat is applied) disclosed in paragraphs

[0191] to

[0217] of Japanese Patent Publication No. 2012-187907, low molecular weight hydrophilic compounds, sensitizers (for example, phosphonium compounds, nitrogen-containing low molecular weight compounds, ammonium group-containing polymers) and chain transfer agents.

[0463] Furthermore, as other compounds, an acid color developer can be mentioned.

[0464] The acid developer refers to a compound having the property of developing color by heating in a state where it receives protons of an electron accepting compound (e.g., an acid). The acid developer is particularly preferably a colorless compound having a partial skeleton such as lactone, lactam, sultone, spiropyran, ester, and amide, and the partial skeleton of which rapidly opens or cleaves when in contact with an electron accepting compound.

[0465] The acid color developer is preferably at least one compound selected from the group consisting of spiropyran compounds, spirooxazine compounds, spirolactone compounds, and spirolactam compounds.

[0466] 〔other〕

[0467] The lithographic printing plate precursor of the present invention may include other layers in addition to the aluminum support 12 a , the undercoat layer 14 , and the image-recording layer 16 described above.

[0468] For example, a protective layer may be included on the image recording layer 16 as necessary to prevent scratches or the like from being generated in the image recording layer 16 , block oxygen, and prevent ablation during high-intensity laser exposure.

[0469] Examples of the material used for the protective layer include materials described in paragraphs

[0213] to

[0227] of JP-A-2009-255434 (water-soluble polymer compounds, inorganic layered compounds, etc.).

[0470] [Method for producing lithographic printing plate precursor]

[0471] The above-mentioned lithographic printing plate precursor can be produced by combining known methods.

[0472] Among them, the above-mentioned lithographic printing plate precursor is preferably produced by a method in which the following steps are sequentially performed.

[0473] (Roughening treatment step) Step of roughening the aluminum plate

[0474] (Anodizing step) A step of anodizing the roughened aluminum plate

[0475] (Pore Enlarging Process) A process of bringing the aluminum plate having an anodic oxide film obtained in the anodizing process into contact with an acid aqueous solution or an alkali aqueous solution to enlarge the diameter of micropores in the anodic oxide film.

[0476] (Undercoat layer forming step) A step of forming an undercoat layer on the aluminum support obtained in the hole expansion treatment step

[0477] (Image Recording Layer Forming Step) Step of Forming an Image Recording Layer on the Undercoat Layer

[0478] Hereinafter, the steps of each process will be described in detail.

[0479] <Roughening process>

[0480] The roughening treatment step is a step of performing a roughening treatment including an electrochemical roughening treatment on the surface of the aluminum plate. This step is preferably performed before the anodizing treatment step described below, but if the surface of the aluminum plate already has a preferred surface shape, this step does not need to be performed.

[0481] Regarding the roughening treatment, only the electrochemical roughening treatment may be performed, but the electrochemical roughening treatment may be performed in combination with the mechanical roughening treatment and / or the chemical roughening treatment.

[0482] When the mechanical roughening treatment and the electrochemical roughening treatment are combined, it is preferred that the electrochemical roughening treatment be performed after the mechanical roughening treatment.

[0483] The electrochemical roughening treatment is preferably performed using direct current (DC) or alternating current (AC) in an aqueous solution mainly containing nitric acid or hydrochloric acid.

[0484] The method of mechanical roughening treatment is not particularly limited, and for example, the method described in Japanese Patent Publication No. 50-40047 can be mentioned.

[0485] The chemical roughening treatment is not particularly limited, and a known method may be used.

[0486] It is preferred that the following chemical etching treatment be performed after the mechanical roughening treatment.

[0487] The chemical etching treatment performed after the mechanical roughening treatment is performed for the following purposes: to smooth the edge portions of the concave and convex shapes on the surface of the aluminum plate, to prevent ink adhesion (catching on) during printing, thereby improving the contamination resistance of the lithographic printing plate, and to remove unnecessary substances such as abrasive material particles remaining on the surface.

[0488] As chemical etching treatment, etching using an acid and etching using an alkali are known. As a method that is particularly excellent in etching efficiency, chemical etching treatment using an alkali solution (hereinafter also referred to as “alkali etching treatment”) can be cited.

[0489] The alkali agent used in the alkali solution is not particularly limited, and examples thereof include caustic soda, caustic potash, sodium metasilicate, sodium carbonate, sodium aluminate, and sodium gluconate.

[0490] The alkaline solution may contain aluminum ions.

[0491] The concentration of the alkaline agent in the alkaline solution is preferably 0.01% by mass or more, more preferably 3% by mass or more, and is preferably 30% by mass or less, more preferably 25% by mass or less.

[0492] When the alkali etching treatment is performed, in order to remove the product generated by the alkali etching treatment, it is preferable to perform a chemical etching treatment (hereinafter also referred to as "desmear treatment") using a low-temperature acidic aqueous solution.

[0493] The acid used in the acidic aqueous solution is not particularly limited, and examples thereof include sulfuric acid, nitric acid, and hydrochloric acid. The acid concentration of the acidic aqueous solution is preferably 1 to 50% by mass. The temperature of the acidic aqueous solution is preferably 20°C to 80°C.

[0494] As the roughening treatment step, a method in which the treatment shown in the A mode or the B mode is carried out in the following order is preferred, and a method in which the treatment shown in the B mode is carried out in the following order is more preferred.

[0495] (Method A)

[0496] (2) Chemical etching using an alkaline aqueous solution (first alkaline etching)

[0497] (3) Chemical etching using an acidic aqueous solution (first desmear treatment)

[0498] (4) Electrochemical roughening treatment using an aqueous solution mainly containing nitric acid (first electrochemical roughening treatment)

[0499] (5) Chemical etching using an alkaline aqueous solution (second alkaline etching)

[0500] (6) Chemical etching using an acidic aqueous solution (second desmear treatment)

[0501] (7) Electrochemical roughening treatment in an aqueous solution containing hydrochloric acid as the main component (second electrochemical roughening treatment)

[0502] (8) Chemical etching using an alkaline aqueous solution (third alkaline etching treatment)

[0503] (9) Chemical etching using an acidic aqueous solution (third desmear treatment)

[0504] (Method B)

[0505] (10) Chemical etching using an alkaline aqueous solution (fourth alkaline etching treatment)

[0506] (11) Chemical etching using an acidic aqueous solution (the fourth desmear treatment)

[0507] (12) Electrochemical roughening treatment using an aqueous solution containing hydrochloric acid as the main component (third electrochemical roughening treatment)

[0508] (13) Chemical etching treatment using an alkaline aqueous solution (fifth alkaline etching treatment)

[0509] (14) Chemical etching using an acidic aqueous solution (fifth desmear treatment)

[0510] If necessary, (1) mechanical roughening treatment may be performed before the treatment (2) in the above-mentioned embodiment A or before the treatment (10) in the embodiment B.

[0511] The amount of aluminum plate dissolved in the first alkali etching treatment and the fourth alkali etching treatment is preferably 0.5 to 30 g / m 2 , more preferably 1.0 to 20 g / m2 .

[0512] As the aqueous solution mainly composed of nitric acid used in the first electrochemical roughening treatment in mode A, there can be mentioned an aqueous solution used in the electrochemical roughening treatment using direct current or alternating current. For example, there can be mentioned an aqueous solution obtained by adding aluminum nitrate, sodium nitrate, ammonium nitrate or the like to a 1 to 100 g / L nitric acid aqueous solution.

[0513] As the aqueous solution mainly composed of hydrochloric acid used in the second electrochemical roughening treatment in mode A and the third electrochemical roughening treatment in mode B, an aqueous solution used in an electrochemical roughening treatment using a conventional direct current or alternating current can be cited. For example, an aqueous solution obtained by adding 0 to 30 g / L of sulfuric acid to a 1 to 100 g / L hydrochloric acid aqueous solution can be cited. In addition, nitrate ions such as aluminum nitrate, sodium nitrate, and ammonium nitrate; and hydrochloric acid ions such as aluminum chloride, sodium chloride, and ammonium chloride can be further added to the solution.

[0514] In particular, in the present invention, as the aqueous solution mainly composed of hydrochloric acid used in the third electrochemical roughening treatment in mode B, it is preferred to use an aqueous solution obtained by adding 0.5 to 5 g / L of sulfuric acid to a 5 to 20 g / L hydrochloric acid aqueous solution, and it is more preferred to use an aqueous solution obtained by further adding aluminum chloride to the aqueous solution and adding 5 to 20 g / L of aluminum ions.

[0515] The AC power waveform for the electrochemical roughening treatment can be a sine wave, a rectangular wave, a trapezoidal wave, a triangular wave, etc. The frequency is preferably 0.1 to 250 Hz.

[0516] Figure 3 This is a graph showing an example of an alternating waveform current waveform diagram used in the electrochemical roughening treatment.

[0517] exist Figure 3 In the figure, ta is the anodic reaction time, tc is the cathodic reaction time, tp is the time until the current reaches the peak from 0, Ia is the current at the peak on the anodic circulation side, and Ic is the current at the peak on the cathode circulation side. In the trapezoidal wave, the time tp until the current reaches the peak from 0 is preferably 1 to 10 msec. The conditions for one cycle of alternating current used for electrochemical roughening are preferably: the ratio tc / ta of the anodic reaction time ta of the aluminum plate to the cathode reaction time tc is 1 to 20, the ratio Qc of the electric quantity when the aluminum plate is the anode to the electric quantity Qa when the aluminum plate is the anode is 0.3 to 20, and the anodic reaction time ta is in the range of 5 to 1000 msec. Regarding the current density, the anode circulation side Ia and the cathode circulation side Ic of the current peak of the trapezoidal wave are preferably 10 to 200 A / dm 2Ic / Ia is preferably 0.3 to 20. The total amount of electricity participating in the anodic reaction of the aluminum plate at the time of completion of electrochemical roughening is preferably 25 to 1000 C / dm 2 .

[0518] In particular, in the third electrochemical roughening treatment in the B mode of the present invention, the total amount of electricity participating in the anodic reaction of the aluminum plate at the time of completion of the electrochemical roughening is preferably 150 to 500 C / dm 2 .

[0519] Can be used in electrochemical roughening using alternating current Figure 4 The device shown.

[0520] Figure 4 This is a side view showing an example of a radial type unit in the electrochemical roughening treatment using alternating current.

[0521] exist Figure 4 In the figure, 50 is a main electrolytic cell, 51 is an AC power source, 52 is a radial drum roller, 53a and 53b are main electrodes, 54 is an electrolyte supply port, 55 is an electrolyte, 56 is a slit, 57 is an electrolyte channel, 58 is an auxiliary anode, 60 is an auxiliary anode tank, and W is an aluminum plate. When more than two electrolytic cells are used, the electrolysis conditions may be the same or different.

[0522] The aluminum plate W is wound on a radial drum roller 52 which is immersed in the main electrolytic tank 50 and is electrolytically treated through the main pole 53a and the main pole 53b connected to the AC power supply 51 during transportation. The electrolyte 55 is supplied from the electrolyte supply port 54 through the slit 56 to the electrolyte channel 57 between the radial drum roller 52 and the main pole 53a and the main pole 53b. The aluminum plate W treated in the main electrolytic tank 50 is then electrolytically treated in the auxiliary anode tank 60. In the auxiliary anode tank 60, the auxiliary anode 58 and the aluminum plate W are arranged opposite each other, and the electrolyte 55 is supplied in a manner that flows in the space between the auxiliary anode 58 and the aluminum plate W.

[0523] From the viewpoint of facilitating the production of a predetermined planographic printing plate precursor, the amount of aluminum plate dissolved in the second alkali etching treatment is preferably 1.0 g / m 2 More preferably 2.0 to 10 g / m 2 .

[0524] From the viewpoint of facilitating the production of a predetermined planographic printing plate precursor, the amount of aluminum plate dissolved in the third alkali etching treatment and the fifth alkali etching treatment is preferably 0.01 to 0.8 g / m 2 , more preferably 0.05 to 0.3 g / m 2 .

[0525] In the chemical etching treatment (first to fifth desmear treatments) using an acidic aqueous solution, an acidic aqueous solution containing phosphoric acid, nitric acid, sulfuric acid, chromic acid, hydrochloric acid, or a mixed acid containing two or more of these acids can be preferably used.

[0526] The acid concentration of the acidic aqueous solution is preferably 0.5 to 60% by mass.

[0527] <Anodizing Process>

[0528] The procedure of the anodizing treatment step is not particularly limited as long as the above-mentioned micropores can be obtained, and a known method can be used.

[0529] In the anodizing treatment step, an aqueous solution of sulfuric acid, phosphoric acid, oxalic acid, etc. can be used as an electrolytic cell. For example, the concentration of sulfuric acid is 100 to 300 g / L.

[0530] The conditions for the anodizing treatment can be appropriately set according to the electrolyte used, and examples thereof include a liquid temperature of 5 to 70° C. (preferably 10 to 60° C.), a current density of 0.5 to 60 A / dm 2 (preferably 5 to 60 A / dm2), voltage 1 to 100 V (preferably 5 to 50 V), electrolysis time 1 to 100 seconds (preferably 5 to 60 seconds) and film weight 0.1 to 5 g / m 2 (Preferably 0.2 to 3 g / m 2 In particular, in the present invention, the current density is preferably 5 to 20 A / dm 2 .

[0531] <Hole expansion treatment>

[0532] The pore expansion treatment is a treatment for increasing the diameter (pore size) of micropores present in the anodized film formed by the above-mentioned anodizing treatment step (pore size expansion treatment).

[0533] The pore expansion treatment can be performed by bringing the aluminum plate obtained by the above-mentioned anodizing treatment step into contact with an acid aqueous solution or an alkali aqueous solution. The contact method is not particularly limited, and examples thereof include a dipping method and a spraying method.

[0534] <Primer layer forming step>

[0535] The primer layer forming step is a step of forming a primer layer on the aluminum support body obtained in the pore expanding treatment step.

[0536] The method for producing the undercoat layer is not particularly limited, and examples thereof include a method in which a coating liquid for forming an undercoat layer containing a predetermined compound (eg, a compound having a betaine structure) is applied onto the anodized film of an aluminum support.

[0537] The undercoat layer-forming coating liquid preferably contains a solvent. Examples of the solvent include water and an organic solvent.

[0538] As a coating method for the undercoat layer-forming coating liquid, various known methods can be mentioned, for example, bar coater coating, spin coating, spray coating, curtain coating, dip coating, air knife coating, blade coating, and roll coating.

[0539] The coating amount (solid content) of the primer layer is preferably 0.1 to 100 mg / m 2 , more preferably 1 to 50 mg / m 2 .

[0540] <Image Recording Layer Forming Step>

[0541] The image recording layer forming step is a step of forming an image recording layer on the undercoat layer.

[0542] The method for forming the image recording layer is not particularly limited, and examples thereof include a method of applying an image recording layer-forming coating liquid containing predetermined components (the above-mentioned infrared absorber, polymerization initiator, polymerizable compound, etc.) onto the undercoat layer.

[0543] The coating liquid for forming an image recording layer preferably contains a solvent. Examples of the solvent include water and an organic solvent.

[0544] As for the coating method of the coating liquid for forming an image recording layer, the method exemplified as the coating method for forming an undercoat layer can be mentioned.

[0545] The coating amount (solid content) of the image recording layer varies depending on the application, but is usually preferably 0.3 to 3.0 g / m 2 .

[0546] When a protective layer is provided on the image recording layer, the method for producing the protective layer is not particularly limited, and examples thereof include a method of applying a protective layer-forming coating liquid containing predetermined components on the image recording layer.

[0547] In the above embodiment, the micropores 22a in the anodic oxide film 20a are described as being in a substantially straight tube shape. However, the micropores may have other structures as long as the average diameter of the micropores at the surface of the anodic oxide film is within a predetermined range.

[0548] For example, Figure 5 As shown, the aluminum support 12 b may be in the form of an aluminum plate 18 and an anodic oxide film 20 b having micropores 22 b composed of large-diameter pores 24 and small-diameter pores 26 .

[0549] The micropores 22b in the anodized film 20b are composed of a large-diameter pore portion 24 and a small-diameter pore portion 26. The large-diameter pore portion 24 extends from the surface of the anodized film to a depth of 10 to 1000 nm (depth D: reference 2). Figure 5 ) position, the small-diameter hole portion 26 is connected to the bottom of the large-diameter hole portion 24, and further extends from the connecting position to a position with a depth of 20 to 2000 nm.

[0550] Hereinafter, the large-diameter hole portion 24 and the small-diameter hole portion 26 will be described in detail.

[0551] The average diameter of the large-diameter pores 24 at the surface of the anodic oxide film 20 b is the same as the average diameter of the micropores 22 a at the surface of the anodic oxide film 20 a described above, and is preferably 15 to 100 nm, and more preferably 30 to 100 nm.

[0552] The method for measuring the average diameter of the large-diameter pores 24 at the surface of the anodic oxide film 20 b is the same as the method for measuring the average diameter of the micropores 22 a at the surface of the anodic oxide film 20 a .

[0553] The bottom of the large-diameter pores 24 is located at a depth of 10 to 1000 nm (hereinafter referred to as "depth D") from the surface of the anodic oxide film. That is, the large-diameter pores 24 are pores extending 10 to 1000 nm in the depth direction (thickness direction) from the surface of the anodic oxide film. The above depth is preferably 10 to 130 nm.

[0554] The depth is obtained by taking a photograph (150,000 times) of the cross section of the anodic oxide film 20 b , measuring the depths of 25 or more large-diameter pores 24 , and averaging the measured depths.

[0555] The shape of the large diameter hole portion 24 is not particularly limited, and examples thereof include a substantially straight tube shape (substantially cylindrical shape) and a conical shape whose diameter decreases toward the depth direction (thickness direction), and a substantially straight tube shape is preferred.

[0556] like Figure 5 As shown, the small-diameter hole portion 26 is a hole portion that communicates with the bottom of the large-diameter hole portion 24 and further extends in the depth direction (thickness direction) from the communication position.

[0557] The average diameter of the small-diameter pores 26 at the communicating positions is preferably 13 nm or less, more preferably 11 nm or less, and further preferably 10 nm or less. The lower limit is not particularly limited, but is usually 5 nm or more.

[0558] The average diameter of the small-diameter pores 26 is as follows: the surface of the anodized film 20a is observed using FE-SEM at a magnification of 150,000 times with N=4 images, and the number of small-diameter pores existing in the range of 400×600 nm is measured. 2In addition, when the large-diameter pores are deep, the upper portion of the anodized film 20b (the region having the large-diameter pores) can be cut (for example, by argon gas) as needed, and then the surface of the anodized film 20b can be observed with the above-mentioned FE-SEM to obtain the average diameter of the small-diameter pores.

[0559] When the shape of the small-diameter hole 26 is not circular, the equivalent circle diameter is used. The “equivalent circle diameter” refers to the diameter of a circle assuming the shape of the opening to have the same projected area as the opening.

[0560] The bottom of the small-diameter hole portion 26 is located at a position extending 20 to 2000 nm in the depth direction from the position communicating with the large-diameter hole portion 24. In other words, the small-diameter hole portion 26 is a hole portion extending in the depth direction (thickness direction) from the position communicating with the large-diameter hole portion 24, and the depth of the small-diameter hole portion 26 is 20 to 2000 nm. In addition, the above-mentioned depth is preferably 650 to 2000 nm.

[0561] The depth is obtained by taking a photograph (50,000 times) of the cross section of the anodic oxide film 20 b , measuring the depths of 25 or more small-diameter pores, and averaging the measured depths.

[0562] The shape of the small-diameter hole portion 26 is not particularly limited, and examples thereof include a substantially straight tube shape (substantially cylindrical shape) and a conical shape whose diameter decreases toward the depth direction, and a substantially straight tube shape is preferred.

[0563] In addition, the manufacturing method of the aluminum support 12b is not particularly limited, but a manufacturing method in which the following steps are performed in sequence is preferable.

[0564] (Roughening treatment step) Step of roughening the aluminum plate

[0565] (First anodizing step) Step of anodizing the roughened aluminum plate

[0566] (Pore Enlarging Process) A process of bringing the aluminum plate having an anodic oxide film obtained in the first anodic oxide treatment process into contact with an acid aqueous solution or an alkali aqueous solution to enlarge the diameter of micropores in the anodic oxide film.

[0567] (Second Anodizing Process) A process of anodizing the aluminum plate obtained in the hole expanding process

[0568] The procedures of each step can refer to known methods.

[0569] And, in the above Figure 1In the embodiment using the primer layer 14, however, as described above, the primer layer may not be included in the lithographic printing plate precursor.

[0570] When no primer layer is provided, the image recording layer may be formed after hydrophilization treatment is performed on the aluminum support.

[0571] As the hydrophilic treatment, the known methods disclosed in paragraphs

[0109] to

[0114] of Japanese Patent Application Laid-Open No. 2005-254638 can be cited. Among them, the hydrophilic treatment is preferably performed by immersing in an aqueous solution of an alkali metal silicate such as sodium silicate and potassium silicate, or by applying a hydrophilic vinyl polymer or a hydrophilic compound to form a hydrophilic primer layer.

[0572] The hydrophilization treatment using an aqueous solution of an alkali metal silicate such as sodium silicate or potassium silicate can be performed according to the method and procedure described in U.S. Pat. No. 2,714,066 and U.S. Pat. No. 3,181,461.

[0573] [Method for producing lithographic printing plate]

[0574] Next, a method for producing a lithographic printing plate using the lithographic printing plate precursor will be described.

[0575] The method for producing a lithographic printing plate generally includes: an exposure step of exposing a lithographic printing plate precursor imagewise (imagewise exposure) to form exposed areas and unexposed areas; and a step of removing the unexposed areas of the imagewise exposed lithographic printing plate precursor.

[0576] More specifically, one method for manufacturing a lithographic printing plate includes: an exposure step of exposing a lithographic printing plate original in an image-like manner (image exposure) to form an exposed portion and an unexposed portion; and a removal step of removing the unexposed portion of the lithographic printing plate original using a developer having a pH of 2 to 12.

[0577] Furthermore, another embodiment of the method for manufacturing a lithographic printing plate includes the following method for manufacturing a lithographic printing plate, which includes: an exposure step of exposing the lithographic printing plate original in an image-like manner (image exposure) to form an exposed portion and an unexposed portion; and an on-press development step of supplying at least one of a printing ink and a fountain solution to remove the unexposed portion of the lithographic printing plate original that has been exposed in an image-like manner on a printing press.

[0578] These methods are described in detail below.

[0579] The method for producing a lithographic printing plate includes exposing the lithographic printing plate precursor in an image form (image exposure). The image exposure is performed, for example, by laser exposure through a transparent original image having a line image or a halftone image or by laser scanning based on digital data.

[0580] The wavelength of the light source is preferably 750 to 1400 nm. In the case of a light source that emits light with a wavelength of 750 to 1400 nm, it is preferred to use as an image recording layer an infrared absorber that is a sensitizing dye having absorption in this wavelength region.

[0581] As the light source emitting light with a wavelength of 750 to 1400 nm, there can be cited solid lasers and semiconductor lasers that radiate infrared light. For infrared lasers, the output power is preferably 100 mW or more, the exposure time per pixel is preferably within 20 microseconds, and the irradiation energy is preferably 10 to 300 mJ / cm 2 In order to shorten the exposure time, it is preferable to use a multi-beam laser device. The exposure mechanism may be any of an inner drum method, an outer drum method and a flat plate method.

[0582] Image exposure can be performed by a conventional method using a plate-making machine, etc. In the case of an on-press development method described below, the image exposure of the lithographic printing plate precursor can be performed on the printing press after the lithographic printing plate precursor is mounted on the printing press.

[0583] The image-exposed planographic printing plate precursor is developed by removing the unexposed portion using a developer having a pH of 2 to 12 (developer treatment method) or by removing the unexposed portion using at least one of printing ink and fountain solution on a printing press (on-press development method).

[0584] (Developer treatment method)

[0585] In the developer treatment method, the image-exposed lithographic printing plate precursor is treated with a developer having a pH of 2 to 14 to remove the image recording layer in the non-exposed area to produce a lithographic printing plate.

[0586] The developer preferably contains a compound (specific compound) having at least one acid group selected from a phosphoric acid group, a phosphonic acid group, and a phosphinic acid group and one or more carboxyl groups and has a pH of 5 to 10.

[0587] As a method of development treatment, in the case of manual treatment, for example, a method of rubbing the entire lithographic printing plate precursor with a developer sufficiently contained in a sponge or absorbent cotton while treating, and fully drying after the treatment is completed. In the case of immersion treatment, for example, a method of immersing the lithographic printing plate precursor in a vat or deep tank filled with a developer for about 60 seconds and stirring, and then rubbing the lithographic printing plate precursor with absorbent cotton or a sponge while fully drying can be mentioned.

[0588] In the development process, it is preferable to use an apparatus with a simplified structure and a simplified process.

[0589] In the conventional development process, the protective layer is removed by a pre-washing step, then development is performed with an alkaline developer, then the alkali is removed by a post-washing step, a gum treatment is performed by a gum coating step, and drying is performed by a drying step.

[0590] In addition, development and gumming can be performed simultaneously with one liquid. As the gum, a polymer is preferred, and a water-soluble high molecular compound and a surfactant are more preferred.

[0591] Furthermore, it is preferred that the protective layer be removed, the development and the gumming be performed simultaneously with one liquid without performing a pre-washing step. Furthermore, it is preferred that after the development and the gumming, the excess developer be removed with a squeeze roller and then dried.

[0592] This treatment may be a method of immersing the substrate in a developer once or twice. Among them, a method of immersing the substrate in the developer once or twice is preferred.

[0593] For immersion, the exposed planographic printing plate precursor may be immersed in a developer tank storing a developer, or the developer may be sprayed onto the plate surface of the exposed planographic printing plate precursor using a sprayer or the like.

[0594] In addition, even in the case of immersion in a developer more than twice, when the same developer or a developer and a developer (fatigue solution) in which the components of the image recording layer are dissolved or dispersed by the development process are used for immersion more than twice, it is called a development process with one liquid (one liquid process).

[0595] Furthermore, in the development process, it is preferable to use a rubbing member, and it is preferable to place a rubbing member such as a brush in the developing bath for removing the non-image area of ​​the image recording layer.

[0596] The development process can be carried out in accordance with a conventional method, preferably at a temperature of 0°C to 60°C, more preferably at a temperature of 15°C to 40°C, by, for example, immersing the exposed lithographic printing plate precursor in a developer and wiping it with a brush, or by sucking the processing liquid injected into an external tank with a pump and spraying it from a nozzle and wiping it with a brush. These development processes can also be carried out multiple times in succession. For example, the processing liquid injected into an external tank can be sucked with a pump and sprayed from a nozzle and wiped with a brush, and then the processing liquid can be sprayed from the nozzle again and wiped with a brush. When an automatic developer is used for the development process, the developer becomes fatigued as the processing amount increases, so it is preferable to use a replenisher or a fresh developer to restore the processing capacity.

[0597] In the development process of the present invention, the glue coating machine and automatic developer known in the past for PS plate (Presensitized Plate) and CTP can also be used. When using an automatic developer, for example, a method of using a pump to suck the developer injected into the developer tank or the developer injected into the external tank and spraying it from the nozzle for processing, a method of immersing and conveying the printing plate in a tank filled with developer by a guide roller in the liquid and processing, and a so-called one-time processing method of supplying a required amount of substantially unused developer to each plate for processing can also be applied. Among any of the methods, a scrubbing mechanism based on a brush and double-sided fleece is more preferred. For example, commercially available automatic developers (Clean Out Unit C85 / C125, Clean-Out Unit+C85 / 120, FCF 85V, FCF 125V, FCF News (manufactured by Glunz & Jensen)) and Azura CX85, Azura CX125, Azura CX150 (manufactured by AGFAGRAPHICS) can be used. In addition, a device in which a laser exposure unit and an automatic developer are partially integrated can be used.

[0598] (On-press development method)

[0599] In the on-press development method, the image-exposed lithographic printing plate precursor is supplied with printing ink and fountain solution on a printing press, and the image recording layer in the non-image area is removed to produce a lithographic printing plate.

[0600] That is, if after the lithographic printing plate precursor is subjected to image exposure, it is directly mounted on a printing press without any developer treatment, or after the lithographic printing plate precursor is mounted on a printing press, image exposure is performed on the printing press, and then printing ink and fountain solution are supplied and printing is performed, then in the initial stage of printing, in the non-image part, the image recording layer of the unexposed part is dissolved or dispersed and removed by the supplied printing ink and / or fountain solution, so that the hydrophilic surface is exposed to the part. On the other hand, in the exposed part, the image recording layer solidified by exposure forms an oily ink receiving part with an oleophilic surface. The compound first supplied to the plate surface can be a printing ink or a fountain solution, but from the viewpoint of preventing contamination of the image recording layer components from which the fountain solution has been removed, it is preferred to supply the printing ink first.

[0601] In this way, the lithographic printing plate precursor is developed on the printing press and used directly in a plurality of printings. That is, as one aspect of the printing method of the present invention, the following printing method can be cited, which includes: an exposure step of exposing the lithographic printing plate precursor in an image-like manner to form an exposed portion and an unexposed portion; and a printing step of supplying at least one of a printing ink and a fountain solution, removing the unexposed portion of the lithographic printing plate precursor exposed in an image-like manner on the printing press, and performing printing.

[0602] In the method for producing a lithographic printing plate from a lithographic printing plate precursor according to the present invention, the entire surface of the lithographic printing plate precursor may be heated before image exposure, during image exposure, or from image exposure to development treatment as required, regardless of the development method.

[0603] Example

[0604] Below, give embodiment and the present invention is further described in detail.The material, usage amount, ratio, processing content, processing step etc. shown in the following embodiment can be appropriately changed without departing from the scope of the gist of the present invention.Therefore, the scope of the present invention should not be interpreted restrictively by the embodiment shown below.

[0605] [Example 1 to Example 30 and Comparative Example 1 to Comparative Example 7]

[0606] [Method for producing aluminum support]

[0607] An aluminum plate of material 1S with a thickness of 0.3 mm (1050-H18 material, Cu: 0.0014 mass %, Fe: 0.345 mass %, Si: 0.082 mass %) was subjected to the following alkali etching treatment, decontamination treatment using an acidic aqueous solution, electrochemical roughening treatment, alkali etching treatment, decontamination treatment using an acidic aqueous solution, first-stage anodizing treatment (first anodizing treatment), pore expansion treatment and second-stage anodizing treatment (second anodizing treatment) to manufacture an aluminum support.

[0608] (1) Alkali etching treatment

[0609] The aluminum plate was etched by spraying a caustic soda aqueous solution with a caustic soda concentration of 26 mass % and an aluminum ion concentration of 6.5 mass % at a temperature of 70°C. Then, it was rinsed with water using a spray. Then, the aluminum dissolution amount of the surface subjected to electrochemical roughening treatment was 5 g / m 2 .

[0610] (2) Decontamination treatment using an acidic aqueous solution

[0611] Next, decontamination treatment was performed using an acidic aqueous solution. Specifically, the acidic aqueous solution was sprayed onto the aluminum plate using a sprayer and decontamination treatment was performed for 3 seconds. As the acidic aqueous solution used for decontamination treatment, an aqueous solution of 150 g / L sulfuric acid was used. The liquid temperature was 30°C.

[0612] (3) Electrochemical roughening treatment

[0613] Next, electrochemical roughening treatment was performed using alternating current using a hydrochloric acid electrolyte having a concentration and liquid temperature shown in Table 1 below. Aluminum chloride was added to adjust the aluminum ion concentration. The waveform of the alternating current was a sine wave with symmetrical positive and negative waveforms, a frequency of 50 Hz, and a 1:1 ratio between the anodic reaction time and the cathodic reaction time in one cycle of the alternating current. A carbon electrode was used as the counter electrode of the aluminum plate. Then, a water washing treatment was performed. In addition, for the current density in the electrochemical roughening treatment, the peak value of the alternating current waveform was adjusted to the value shown in Table 1 below, and the total amount of electricity involved in the anodic reaction of the aluminum plate at the end of the electrochemical roughening treatment was adjusted to the value shown in Table 1 below.

[0614] (4) Alkali etching treatment

[0615] The aluminum plate after electrochemical roughening treatment was etched by spraying a caustic soda aqueous solution having a caustic soda concentration of 5 mass % and an aluminum ion concentration of 0.5 mass % at a temperature of 45°C. Then, it was washed with water. In addition, the amount of aluminum dissolved on the surface subjected to electrochemical roughening treatment was adjusted to the value shown in Table 1 below.

[0616] (5) Decontamination treatment using an acidic aqueous solution

[0617] Next, a decontamination treatment was performed using an acidic aqueous solution. Specifically, the acidic aqueous solution was sprayed onto the aluminum plate using a sprayer and the decontamination treatment was performed for 3 seconds. As the acidic aqueous solution used for the decontamination treatment, an aqueous solution with a sulfuric acid concentration of 170 g / L and an aluminum ion concentration of 5 g / L was used. The liquid temperature was 35°C.

[0618] (6) First stage anodizing treatment (first anodizing treatment)

[0619] Utilize based Figure 6 The first stage of anodizing treatment was carried out using a direct current electrolytic anodizing device having the structure shown. Furthermore, anodizing treatment was carried out under the conditions shown in Table 1 below to form an anodic oxide film having a predetermined film thickness.

[0620] (7) Hole expansion

[0621] The anodized aluminum plate was immersed in a caustic soda aqueous solution having a temperature of 40° C., a caustic soda concentration of 5% by mass, and an aluminum ion concentration of 0.5% by mass to perform pore expansion treatment, and then washed with water using a spray.

[0622] (8) Second stage anodizing treatment (second anodizing treatment)

[0623] Utilize based Figure 6 The first stage of anodizing treatment was performed using a direct current electrolytic anodizing apparatus having the structure shown. Furthermore, anodizing treatment was performed under the conditions shown in Table 1 below to form an anodized film having a predetermined film thickness, thereby producing an aluminum support.

[0624] [Table 1]

[0625]

[0626] For the aluminum support body produced, the arithmetic mean roughness Ra, steepness a45, density of specific recesses, ratio (a45 / Ra), opening ratio based on micropores, density of micropores, average diameter and depth of large-diameter pores, and average diameter and depth of small-diameter pores of the surface of the anodized film on the side opposite to the aluminum plate side were measured by the above method. These results are shown in Table 2 below.

[0627] [Formation of base coat]

[0628] The anodic oxide film of each aluminum support was coated on the surface of the prepared aluminum support in a dry coating amount of 20 mg / m 2 The primer layer-forming coating liquid 1 was applied in a manner to form a primer layer.

[0629] The undercoat layer-forming coating liquid 1 contains a polymer (0.5 g) of the following structural formula, a 1 mass % aqueous solution (0.86 g) of a surfactant (EMALEX 710) manufactured by NIHON EMULSION Co., Ltd., and water (500 g). The numerical value at the lower right of the parentheses of each structural unit represents mass %.

[0630] [Chemical formula 34]

[0631]

[0632] [Formation of image recording layer (Examples 1 to 28 and Comparative Examples 1 to 7)]

[0633] The coating liquid A for forming an image recording layer having the following composition was applied by bar coating on the aluminum support having the undercoat layer, and then dried at 100° C. for 60 seconds to form a dry coating weight of 1.0 g / m 2 image recording layer.

[0634] The image recording layer forming coating liquid A is obtained by mixing and stirring the following photosensitive liquid (1) and microgel liquid (1) immediately before coating.

[0635] <Photosensitive liquid>

[0636]

[0637] Sodium tetraphenylborate

[0638] Free radical polymerizable compounds

[0639] Tris(acryloyloxyethyl)isocyanurate

[0640] (NK Ester A-9300, manufactured by Shin-Nakamura Chemical Co., Ltd.) 0.192 g

[0641] · Low molecular weight hydrophilic compound 0.062g

[0642] Tris(2-hydroxyethyl)isocyanurate

[0643] ·Low molecular weight hydrophilic compound (1)〔as follows〕 0.050 g

[0644] Sensitizer 0.055g

[0645] Phosphonium compound (1) [described below]

[0646] Sensitizer 0.018g

[0647] Benzyl-dimethyl-octylammonium PF6 salt

[0648] Sensitizer 0.035g

[0649] Ammonium-containing polymers (1)

[0650] [As follows, reduced viscosity 44 ml / g]

[0651] Fluorine-based surfactant (1) [as follows] 0.008 g

[0652] 2-Butane 1.091g

[0653] ·1-O-oxy-2-propanol 8.609g

[0654] <Microsol>

[0655] Microsol (1) 2.640g

[0656] · Distilled water 2.425 g

[0657] The structures of the binder polymer (1), polymerization initiator (2), infrared absorber (2), low molecular weight hydrophilic compound (1), phosphonium compound (1), ammonium group-containing polymer (1) and fluorine-based surfactant (1) used in the above-mentioned photosensitive liquid are shown below.

[0658] [Chemical formula 35]

[0659]

[0660] [Chemical formula 36]

[0661]

[0662]

[0663] -Synthesis of microgel (1)-

[0664] An oil phase component was obtained by adding 4.46 g of a polyfunctional isocyanate having the following structure (manufactured by Mitsui Chemicals, Inc.; 75% by mass ethyl acetate solution), trimethylolpropane (6 mol) and xylene diisocyanate (18 mol), and then adding an adduct (manufactured by Mitsui Chemicals, Inc.; 50% by mass ethyl acetate solution) to the adduct (manufactured by Mitsui Chemicals, Inc.; 50% by mass ethyl acetate solution) 10 g, pentaerythritol triacrylate (manufactured by Nippon Kayaku Co., Ltd., SR444) 3.15 g and PIONIN A-41C (manufactured by Takemoto Oil & Fat Co., Ltd.) 0.1 g were dissolved in 17 g of ethyl acetate. In addition, 40 g of a 4% by mass aqueous solution of polyvinyl alcohol (PVA-205 manufactured by KURARAY CO., LTD.) was prepared to obtain a water phase component.

[0665] The oil phase component and the water phase component were mixed and emulsified at 12000 rpm for 10 minutes using a homogenizer. The obtained emulsion was added to 25 g of distilled water, and the obtained solution was stirred at room temperature for 30 minutes and then further stirred at 50° C. for 3 hours. The obtained microgel was diluted with distilled water so that the solid content concentration of the obtained microgel became 15% by mass, and was used as microgel (1). The average particle size of the microgel (1) was measured by light scattering method, and the average particle size was 0.2 μm.

[0666] [Chemical formula 37]

[0667]

[0668] [Formation of image recording layer (Examples 29 and 30)]

[0669] The coating liquid B for forming an image recording layer having the following composition was applied by bar coating on the aluminum support having the undercoat layer, and then dried at 100° C. for 60 seconds to form a dry coating amount of 1.0 g / m 2 image recording layer.

[0670] <Image Recording Layer Forming Coating Liquid B>

[0671] Electron-accepting polymerization initiator Int-3 (described below): 0.041 parts

[0672] Infrared absorber IR-4 (described below): 0.027 parts

[0673] Infrared absorber IR-5 (described below): 0.015 parts

[0674] Polymerizable compound M-4 [described below]: 0.100 parts

[0675] Polymerizable compound M-5 [described below]: 0.096 parts

[0676] Polymerizable compound M-6 [described below]: 0.096 parts

[0677] Polymer particles 1 [described below]: 0.300 parts

[0678] Color developer (leuco pigment) S-2 (described below): 0.041 parts

[0679] Hydroxypropyl cellulose: 0.030 parts

[0680] n-Propanol: 5.168 parts

[0681] 2-Butanone: 6.460 parts

[0682] 1-Methoxy-2-propanol: 1.615 parts

[0683] Methanol: 2.907 parts

[0684] Electron-accepting polymerization initiator Int-3

[0685] [Chemical formula 38]

[0686]

[0687] Int-3 is a salt composed of 0.5 molar equivalents of each of the two cations and 1 molar equivalent of the one anion.

[0688] Infrared absorber IR-4 and infrared absorber IR-5

[0689] [Chemical formula 39]

[0690]

[0691] Polymerizable compound M-4 and polymerizable compound M-5

[0692] [Chemical formula 40]

[0693]

[0694] Polymerizable compound M-6

[0695] [Chemical formula 41]

[0696]

[0697] Polymer particles 1: Resin particles containing the following resin (n=45, Mw=50,000)

[0698] [Chemical formula 42]

[0699]

[0700] -Synthesis of polymer particles 1-

[0701] A dispersing unit: 10.0 parts of the following compound B-1 (n=45), 85.0 parts of distilled water, and 240.0 parts of n-propanol were placed in a four-necked flask, and heated and stirred at 70° C. under a nitrogen atmosphere.

[0702] Next, a mixture of 20.0 parts of the following compound A-1, 70.0 parts of the following compound A-2, and 0.7 parts of 2,2′-azobisisobutyronitrile, which had been mixed in advance, was added dropwise to the four-necked flask over 2 hours.

[0703] After the dropwise addition, the reaction was continued for 5 hours as it was, and then 0.5 parts of 2,2'-azobisisobutyronitrile was added, and the temperature was raised to 80° C. 0.4 parts of 2,2'-azobisisobutyronitrile was added every 6 hours, and the reaction was carried out for a total of 19 hours.

[0704] The reaction solution was naturally cooled to room temperature (25° C.) to obtain a dispersion of polymer particles 1 (solid content: 23%).

[0705] [Chemical formula 43]

[0706]

[0707] The median particle size of polymer particles 1 was 150 nm, and the coefficient of variation was 23%.

[0708] Furthermore, as a result of confirming the dispersibility of the polymer particles 1 by the method described above, the polymer particles 1 are particles that are dispersible in water and particles that are dispersible in an organic solvent.

[0709] Color developer (leuco pigment) S-2

[0710] [Chemical formula 44]

[0711]

[0712] 〔Formation of protective layer〕

[0713] The protective layer coating liquid (1) having the following composition was further coated on the image recording layer by a bar coater and then dried at 120°C for 60 seconds to form a dry coating weight of 0.15 g / m 2 A protective layer is formed on the surface of the substrate to produce a lithographic printing plate master.

[0714] <Protective layer coating liquid (1)>

[0715] Inorganic layered compound dispersion (1) 1.5 g

[0716] · Polyvinyl alcohol (CKS50 manufactured by Nippon Synthetic Chemical Industry Co., Ltd., sulfonic acid modified, saponification degree of 99 mol% or more, polymerization degree of 300) 6 mass % aqueous solution 0.55 g

[0717] 0.03 g of a 6 mass % aqueous solution of polyvinyl alcohol (PVA-405 manufactured by Kuraray Co., Ltd., degree of saponification 81.5 mol %, degree of polymerization 500)

[0718] - Preparation of Inorganic Layered Compound Dispersion (1) -

[0719] 6.4 parts by mass of synthetic mica SOMASIF ME-100 (manufactured by Co-op Chemical Co., Ltd.) was added to 193.6 parts by mass of ion exchange water and dispersed using a homogenizer until the volume average particle size (laser scattering method) became 3 μm. The aspect ratio of the obtained dispersed particles was 100 or more.

[0720] [Evaluation method]

[0721] 〔Printing durability〕

[0722] The obtained planographic printing plate precursor was exposed using an exposure machine equipped with an infrared semiconductor laser (Luxel PLATESETTER T-6000III, manufactured by Fujifilm Corporation) at an external drum rotation speed of 1,000 rpm, a laser output of 70%, and a resolution of 2,400 dpi (dot per inch). The exposure image was made to include a solid image, 3% dots of TAFFETA20 (frequency modulation screening), and a Ming Dynasty 7-character hollow text image. In addition, 1 inch = 25.4 mm.

[0723] The exposed planographic printing plate precursor thus obtained was not subjected to development treatment, but was mounted on the plate cylinder of a DAIYA IF2 printing press manufactured by Mitsubishi Heavy Industries, Ltd. Using a fountain solution of IF102 (manufactured by Fujifilm Corporation) / tap water = 3 / 97 (volume ratio) and GE cart on black ink (manufactured by T&K TOKA CO., LTD.), the fountain solution and ink were supplied by the standard automatic printing start method of DAIYA IF2 to perform on-press development, and then printing was performed using Tokubishi Art (continuous amount: 76.5 kg) paper at a printing speed of 10,000 sheets per hour.

[0724] After the above-mentioned on-machine development, printing was further continued. As the number of printed sheets increased, the image recording layer gradually wore away, so the ink concentration on the printed matter decreased. The number of printed sheets when the value obtained by measuring the dot area ratio of 3% dots of frequency modulation screening in the printed matter using a Gretag densitometer decreased by 5% from the measured value of the 100th printed sheet was taken as the number of printed sheets to evaluate the printing durability. The results are shown in Table 2 below.

[0725] 〔Slippery and Dirty〕

[0726] Using a Heidelberg printing press SX-74, the Vario system (sliding damping mechanism) was turned on to slow down the rotation speed of the dampening roller relative to the rotation speed of the plate cylinder. Printing was performed under the following conditions, and the contamination of the paper surface after printing 500 sheets was measured using a spectrophotometer (eXact) to measure the a value in the color difference Lab.

[0727] <Printing conditions>

[0728] Ink: DIC Fusion G Red S

[0729] Ink concentration: 1.45±0.05

[0730] Fountain solution: IF102 (4%)

[0731] Temperature setting: 25℃

[0732] Rubber cloth: Day3000-4 (1.95)

[0733] Paper: Tokubishi Art (made by MITSUBISHIPAPER MILLS LIMITED.)

[0734] <Evaluation Criteria>

[0735] The evaluation was carried out based on the following criteria in order from good to poor slip properties. The results are shown in Table 2 below.

[0736] 10 points: a value is less than 0.4

[0737] 9 points: a value is 0.5 or more and 0.6 or less

[0738] 8 points: a value is 0.7 or more and 0.8 or less

[0739] 7 points: a value is 0.9 or more and 1.0 or less

[0740] 6 points: a value is greater than 1.0 and less than 1.1

[0741] 5 points: a value is greater than 1.1 and less than 1.2

[0742] 4 points: a value is 1.3 or more and 1.4 or less

[0743] 3 points: a value is 1.5 or more and 1.6 or less

[0744] 2 points: a value is 1.7 or more and 1.8 or less

[0745] 1 point: a value is 1.9 or above

[0746] 〔On-press development〕

[0747] The obtained planographic printing plate precursor was exposed using an exposure machine equipped with an infrared semiconductor laser (Luxel PLATESETTER T-6000III, manufactured by Fujifilm Corporation) at an external drum speed of 1000 rpm, a laser output of 70%, and a resolution of 2400 dpi. The exposure image included a solid image and a 50% dot pattern of 20 μm dot FM (Frequency Modulation) screening.

[0748] The exposed planographic printing plate precursor thus obtained was not subjected to development treatment, but was mounted on the plate cylinder of a printing press LITHRONE 26 manufactured by KOMORI Corporation. Using a fountain solution of Ecolity-2 (manufactured by Fujifilm Corporation) / tap water = 2 / 98 (volume ratio) and Values-G (N) black ink (manufactured by Dainippon Ink and Chemicals, Inc.), the fountain solution and ink were supplied by the standard automatic printing start method of LITHRONE 26 to perform on-press development, and then 100 sheets were printed on Tokubishi Art (76.5 kg) paper at a printing speed of 10,000 sheets per hour. After the on-press development of the unexposed portion of the 50% halftone dot pattern was completed, the number of waste sheets of printing paper required until the ink was not transferred to the halftone dot non-image portion was measured as the on-press development property, and the evaluation was carried out in the following standards in order from the best on-press development property. The results are shown in Table 2 below.

[0749] 10 points: less than 5 damaged sheets of paper

[0750] 9 points: 6 to 10 pieces of paper are damaged

[0751] 8 points: 11 to 15 pieces of paper damaged

[0752] 7 points: 16 to 19 pieces of paper damaged

[0753] 6 points: 20 to 25 pieces of paper damaged

[0754] 5 points: 26 to 29 pieces of paper damaged

[0755] 4 points: 30 to 34 pieces of paper damaged

[0756] 3 points: 35 to 39 pieces of paper damaged

[0757] 2 points: 40 to 50 pieces of paper damaged

[0758] 1 point: more than 51 pieces of paper are damaged

[0759] [Table 2]

[0760]

[0761] As shown in Table 2, it is known that when the arithmetic mean roughness Ra of the anodic oxide film surface is larger than 0.60 μm, the printing durability is poor and the occurrence of slipping cannot be sufficiently suppressed (Comparative Example 1).

[0762] Furthermore, it is known that when the steepness a45 at the surface of the anodic oxide film exceeds 25% and the arithmetic mean roughness Ra is less than 0.25 μm, the on-press developability is poor and the occurrence of slipping cannot be sufficiently suppressed (Comparative Example 2).

[0763] Furthermore, it is known that if the steepness a45 at the surface of the anodic oxide film is greater than 25%, the occurrence of slipping cannot be fully suppressed (Comparative Examples 3 and 4). In addition, Comparative Example 3 is an example equivalent to Patent Document 1 (International Publication No. 2019 / 087516).

[0764] Furthermore, it is known that when the steepness a45 at the surface of the anodic oxide film is less than 3%, the printing durability is poor (Comparative Example 5).

[0765] Furthermore, it is known that if the opening ratio based on micropores is not within the range of 20 to 70%, the printing durability is poor (Comparative Examples 6 and 7).

[0766] In contrast, it is known that if the opening rate based on the micropores is 20 to 70%, the steepness a45 at the surface of the anodized film is 3 to 25%, and the arithmetic mean roughness Ra is 0.25 to 0.60 μm, the on-machine developability is excellent, the printing durability when made into a lithographic printing plate becomes good, and the occurrence of slippage can be suppressed (Examples 1 to 30).

[0767] Furthermore, from the comparison between Examples 1 and 8 to 28 and Examples 29 and 30, it is known that if the image recording layer contains a leuco dye having a phthalide structure or a fluoran matrix structure, the occurrence of slipping tends to be further suppressed.

[0768] Explanation of symbols

[0769] ta-anodic reaction time, tc-cathodic reaction time, tp-time from 0 to peak current, Ia-peak current on the anode circulation side, Ic-peak current on the cathode circulation side, 10-lithographic printing plate precursor, 12a, 12b-aluminum support, 14-undercoat layer, 16-image recording layer, 18-aluminum plate, 20a, 20b-anodic oxide film, 22a, 22b-micropores, 24-large diameter pores, 26-small diameter pores, 50-main electrolytic cell, 5 1-AC power supply, 52-radial drum roller, 53a, 53b-main pole, 54-electrolyte supply port, 55-electrolyte, 56-auxiliary anode, 60-auxiliary anode tank, W-aluminum plate, 610-anodizing treatment device, 612-power supply tank, 614-electrolytic treatment tank, 616-aluminum plate, 618, 626-electrolyte, 620-power supply electrode, 622, 628-roller, 624-roller, 630-electrolytic electrode, 632-tank wall, 634-DC power supply.

Claims

1. A lithographic printing plate precursor comprising an aluminum support and an image recording layer, The aluminum support includes an aluminum plate and an aluminum anodized film disposed on the aluminum plate. The anodized film is located closer to the image recording layer than the aluminum plate. The anodic oxide film has micropores extending in the depth direction from the surface on the image recording layer side. Based on the opening rate of the micropores being 20% ​​to 70%, The steepness a45 of the surface of the anodic oxide film on the image recording layer side, which represents the area ratio of a portion having an inclination of 45° or more obtained by extracting a component with a wavelength of 0.2 μm to 2 μm, is 3% to 25%. The arithmetic mean roughness Ra of the surface of the anodic oxide film on the image recording layer side is 0.25 μm to 0.60 μm.

2. The lithographic printing plate precursor according to claim 1, wherein The density of the micropores is 400 / μm 2 ~2000 / μm 2 .

3. The lithographic printing plate precursor according to claim 1 or 2, wherein The ratio of the value of the steepness a45 to the value of the arithmetic mean roughness Ra is 9-80.

4. The lithographic printing plate precursor according to claim 1 or 2, wherein The density of recessed portions having a depth of 0.7 μm or more from the center line measured in a range of 400 μm×400 μm on the surface of the image recording layer side of the anodic oxide film using a non-contact three-dimensional roughness meter was 900 or less.

5. The lithographic printing plate precursor according to claim 1 or 2, wherein An Al-Fe based intermetallic compound is precipitated on the surface of the anodic oxide film on the image recording layer side. The Al—Fe-based intermetallic compound has an equivalent circle diameter of 0.5 μm to 3.0 μm on the surface of the anodic oxide film on the image recording layer side. The density of the Al-Fe-based intermetallic compounds having an equivalent circle diameter of 0.2 μm or more on the surface of the anodic oxide film on the image recording layer side is 3000 / mm 2 above.

6. The lithographic printing plate precursor according to claim 1 or 2, wherein The aluminum plate contains 0.05 mass % or less of Cu, 0.1 mass % to 0.4 mass % of Fe, 0.02 mass % to 0.3 mass % of Si, and the remainder is composed of Al and inevitable impurities.

7. The lithographic printing plate precursor according to claim 1 or 2, wherein The micropores are composed of a large-diameter pore portion and a small-diameter pore portion, the large-diameter pore portion extends from the surface of the image recording layer side of the anodized film to a position with a depth of 10nm to 1000nm, and the small-diameter pore portion is connected to the bottom of the large-diameter pore portion and extends from the connected position to a position with a depth of 20nm to 2000nm. The average diameter of the large-diameter pores on the surface of the anodic oxide film on the image recording layer side is 15 nm to 100 nm, The average diameter of the small-diameter pores at the communication positions is 13 nm or less.

8. The lithographic printing plate precursor according to claim 7, wherein The depth of the large-diameter pore portion is 10 nm to 130 nm.

9. The lithographic printing plate precursor according to claim 7, wherein The average diameter of the large-diameter pores on the surface of the anodic oxide film on the image recording layer side is 30 nm to 100 nm.

10. The lithographic printing plate precursor according to claim 7, wherein The depth of the small-diameter pores is 650 nm to 2000 nm.

11. The lithographic printing plate precursor according to claim 1 or 2, wherein The image recording layer contains a leuco pigment, The leuco pigment is a leuco pigment having a phthalide structure or a fluorane matrix structure.

12. The lithographic printing plate precursor according to claim 11, wherein The leuco pigment is a compound represented by any one of the following formulas (Le-1) to (Le-3), Among them, in the formula (Le-1) to the formula (Le-3), ERG each independently represents an electron donating group, X1 to X4 each independently represents a hydrogen atom, a halogen atom or a dialkylphenylamino group, X5 to X 10 Each independently represents a hydrogen atom, a halogen atom or a monovalent organic group, Y1 and Y2 each independently represent C or N, when Y1 is N, X1 does not exist, when Y2 is N, X4 does not exist, Ra1 represents a hydrogen atom, an alkyl group or an alkoxy group, and Rb1~Rb4 each independently represent a hydrogen atom, an alkyl group or an aryl group.

13. The lithographic printing plate precursor according to claim 11, wherein The leuco pigment is a compound represented by any one of the following formulas (Le-4) to (Le-6), Among them, in the formula (Le-4) to the formula (Le-6), ERG each independently represents an electron donating group, X1~X4 each independently represents a hydrogen atom, a halogen atom or a dialkylaniline group, Y1 and Y2 each independently represent C or N, when Y1 is N, X1 does not exist, when Y2 is N, X4 does not exist, Ra1 represents a hydrogen atom, an alkyl group or an alkoxy group, and Rb1~Rb4 each independently represent a hydrogen atom, an alkyl group or an aryl group.

14. The lithographic printing plate precursor according to claim 11, wherein The leuco pigment is a compound represented by any one of the following formulas (Le-7) to (Le-9), Among them, in the formula (Le-7) to the formula (Le-9), X1~X4 each independently represent a hydrogen atom, a halogen atom or a dialkylaniline group, Y1 and Y2 each independently represent C or N, when Y1 is N, X1 does not exist, when Y2 is N, X4 does not exist, Ra1~Ra4 each independently represent a hydrogen atom, an alkyl group or an alkoxy group, Rb1~Rb4 each independently represent a hydrogen atom, an alkyl group or an aryl group, and Rc1 and Rc2 each independently represent an aryl group.

15. The lithographic printing plate precursor according to claim 14, wherein In the above formulae (Le-7) to (Le-9), Ra1 to Ra4 each independently represent an alkoxy group.

16. The lithographic printing plate precursor according to claim 14, wherein The leuco pigment is a compound represented by the formula (Le-8).

17. The lithographic printing plate precursor according to claim 16, wherein In the formula (Le-8), X1 to X4 represent hydrogen atoms, and Y1 and Y2 represent C.

18. The lithographic printing plate precursor according to claim 16, wherein In the above formula (Le-8), Rb1 and Rb2 each independently represent a hydrogen atom or an alkyl group.

19. The lithographic printing plate precursor according to claim 1 or 2, wherein The image recording layer contains an infrared absorber, a polymerization initiator and a polymerizable compound. The polymerization initiator includes an electron accepting polymerization initiator and an electron donating polymerization initiator.

20. The lithographic printing plate precursor according to claim 19, wherein The difference between the HOMO of the infrared absorber and the HOMO of the electron donating polymerization initiator is 0.70 eV or less.

21. The lithographic printing plate precursor according to claim 19, wherein The difference between the LUMO of the electron accepting polymerization initiator and the LUMO of the infrared absorber is 0.70 eV or less.

22. The lithographic printing plate precursor according to claim 19, wherein The polymerizable compound has 7 or more functional polymerizable groups.

23. The lithographic printing plate precursor according to claim 19, wherein The polymerizable compound has a polymerizable group having ten or more functional groups.

24. A method for manufacturing a lithographic printing plate, comprising: An exposure step of exposing the planographic printing plate precursor according to any one of claims 1 to 23 in an image-wise manner to form exposed areas and unexposed areas; and The removing step is to remove the unexposed portion of the image-wise exposed planographic printing plate precursor.

25. A printing method comprising: An exposure step of exposing the planographic printing plate precursor according to any one of claims 1 to 23 in an image-wise manner to form exposed areas and unexposed areas; and The printing step is to supply at least one of a printing ink and a fountain solution, remove unexposed portions of the planographic printing plate precursor imagewise exposed on a printing press, and perform printing.

Images