Lithographic printing plate master and method for producing printing plates

Abstract

To provide a lithographic print plate original plate capable of achieving preferable visibility and suppressing edge pollution, and a production method of a print plate using the lithographic print plate original plate.SOLUTION: There is provided a lithographic print plate original plate comprising one or more layers including an image recording layer on an aluminum support comprising an anodic oxide film, and in at least one of the layers, including an oxo acid salt whose molecular weight is 1000 or smaller. The image recording layer includes an acid coloring agent, the content of the oxo acid salt is substantially equal in at least one plane in the one or more layers, and the lithographic print plate original plate has, on its end part, an R-shaped part. There is also provided a production method of a print plate.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a lithographic printing plate master and a method for producing a printing plate. [Background technology]

[0002] Generally, a lithographic printing plate consists of an oil-based image area that receives ink during the printing process and a hydrophilic non-image area that receives dampening solution. Lithographic printing utilizes the property that water and oil-based inks repel each other, by designating the oil-based image area of ​​the lithographic printing plate as the ink-receiving area and the hydrophilic non-image area as the dampening solution-receiving area (non-ink-receiving area). This creates a difference in ink adhesion on the surface of the lithographic printing plate, allowing ink to adhere only to the image area, and then transferring the ink to a substrate such as paper to print. To produce these lithographic printing plates, conventionally, lithographic printing plates (PS plates) made by providing an oil-lipophilic photosensitive resin layer (image recording layer) on a hydrophilic support have been widely used. Typically, the lithographic printing plate is produced by exposing the lithographic printing plate to an original image such as lithographic film, leaving the image portion of the image recording layer intact, and dissolving and removing the other unnecessary parts of the image recording layer with an alkaline developer or organic solvent, thereby exposing the surface of the hydrophilic support and forming the non-image portion.

[0003] Furthermore, with growing concern for the global environment, environmental issues related to wastewater from wet processing such as developing have come into focus. In response to the environmental challenges mentioned above, efforts are being made to simplify or eliminate the processing of developing or platemaking. One such simplified method is called "on-press development." In this method, after exposing the lithographic printing plate, conventional developing is not performed; instead, the plate is mounted directly onto the printing press, and the removal of unwanted parts of the image recording layer is carried out in the early stages of the normal printing process. In the present invention, a lithographic printing plate that can be used for such on-press development is referred to as an "on-press development type lithographic printing plate".

[0004] When printing using a lithographic printing plate, if printing on paper smaller than the size of the plate, as with a standard sheet-fed printing press, the edges of the plate are outside the paper surface and therefore do not affect the print quality. However, when printing continuously on rolls of paper using a rotary press, such as in newspaper printing, the edges of the plate are within the roll surface. As a result, ink adhering to the edges transfers to the paper, causing linear stains (edge ​​stains) that significantly impair the commercial value of the printed material.

[0005] One example of an attempt to suppress the occurrence of edge staining is the one described in Patent Document 1. Patent Document 1 describes a lithographic printing plate master having a layer on a support containing a color-developing compound having a group that cleaves upon exposure to heat or infrared radiation, and having a sag shape at the ends of at least two opposing sides of the support, with a sag amount X of 25 μm to 150 μm and a sag width Y of 70 μm to 300 μm. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] International Publication No. 2021 / 171862 [Overview of the project] [Problems that the invention aims to solve]

[0007] Furthermore, as an attempt to suppress the occurrence of edge fouling, the addition of support-adsorbing compounds to the constituent layers of the lithographic printing plate is being considered. Incidentally, when mounting a lithographic printing plate onto a printing press, the image in the exposed area is usually visually inspected. In conventional wet development processes, the lithographic printing plate with the non-image areas removed is mounted onto the printing press, making it easier to visually inspect the image in the exposed area of ​​the lithographic printing plate. On the other hand, when developing on a press, the printing press is fitted with a lithographic printing plate that still has the non-image areas removed, making it difficult to visually confirm the image on the lithographic plate. Based on the above, and with consideration for improving color development in the exposed areas, a lithographic printing plate containing an acid colorant in the image recording layer has been developed. However, it has been found that it is extremely difficult to suppress edge staining while maintaining visibility in lithographic printing plates containing acid colorants in the image recording layer.

[0008] The present invention has been made in view of the above, and its purpose is to provide a lithographic printing plate master that has good visibility and suppresses edge staining, and a method for producing a printing plate using a lithographic printing plate master. [Means for solving the problem]

[0009] The means to solve the above problems are described below. <1> An aluminum support having an anodized film has one or more layers including an image recording layer, A lithographic printing plate original containing an oxoate with a molecular weight of 1000 or less in at least one of the above one or more layers, The above image recording layer contains an acid colorant. The content of the above oxo salt is substantially the same in at least one plane of the one or more layers, The above oxo salt comprises at least one selected from the group consisting of phosphates, phosphonates, phosphinates, sulfates, sulfites, sulfonates, sulfinates, nitrates, nitrites, and silicates. The above-mentioned lithographic printing plate is a lithographic printing plate with a drooping shape at its edges. <2> The above oxo salt comprises at least one selected from the group consisting of phosphates, phosphonates, phosphinates, sulfates, sulfites, sulfinates, nitrates, and nitrites. <1> The lithographic printing plate described above. <3> The above oxo salt comprises at least one selected from the group consisting of phosphates, phosphonates, and phosphinates. <1> or <2> The lithographic printing plate described above. <4> The above image recording layer has a protective layer, and the protective layer contains the above oxo salt. <1> ~ <3> A lithographic printing plate as described in any one of the items. <5> The above oxo salt content is 5 mg / m² 2 ~100mg / m 2 That is, <1> ~ <4> A lithographic printing plate as described in any one of the items. <6> An aluminum support having an anodized film has one or more layers including an image recording layer, A lithographic printing plate original containing an oxoate with a molecular weight of 1000 or less in at least one of the above one or more layers, The above image recording layer contains an acid colorant. The content of the above oxo salt is substantially the same in at least one plane of the one or more layers, The above oxo salt comprises at least one selected from the group consisting of phosphates, phosphonates, phosphinates, sulfates, sulfites, sulfonates, sulfinates, nitrates, nitrites, and silicates. The above-mentioned lithographic printing plate has a drooping shape at the edges. The above lithographic printing plate original plate 50cm 2 A lithographic printing plate master in which the pH of the solution obtained by immersing the plate in 5 mL of water is between 6.5 and 9.0. <7> The above acid colorant has a structure that undergoes ring opening or leaving group elimination upon decomposition of a decomposable group, and the structure that undergoes ring opening or leaving group elimination upon decomposition of the decomposable group is represented by any of the following formulas 1a to 1d. <1> ~ <6> A lithographic printing plate as described in any one of the items.

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[19] below) are also described below.

[0010] [1] An aluminum support having an anodized film has one or more layers including an image recording layer, A lithographic printing plate original containing an oxoate with a molecular weight of 1000 or less in at least one of the above one or more layers, The above image recording layer contains an acid colorant. The content of the above oxo salt is substantially the same in at least one plane of the one or more layers, The above-mentioned lithographic printing plate is a lithographic printing plate with a drooping shape at its edges.

[0011] [2] The lithographic printing plate according to [1], wherein the oxo salt comprises at least one selected from the group consisting of phosphates, phosphonates, phosphinates, carboxylates, sulfates, sulfites, sulfonates, sulfinates, nitrates, nitrites, and silicates.

[0012] [3] The lithographic printing plate according to [1] or [2], wherein the oxo salt comprises at least one selected from the group consisting of phosphates, phosphonates, phosphinates, carboxylates, sulfates, sulfites, sulfinates, nitrates, and nitrites.

[0013] [4] A lithographic printing plate according to any one of [1] to [3], wherein the oxo salt is selected from the group consisting of phosphates, phosphonates, and phosphinates.

[0014] [5] A lithographic printing plate according to any one of [1] to [4], having a protective layer on the image recording layer, wherein the protective layer contains the oxoate salt.

[0015] [6] The above oxo salt content is 5 mg / m² 2 ~100mg / m 2 The lithographic printing plate described in any one of items [1] to [5].

[0016] [7] An aluminum support having an anodized film has one or more layers including an image recording layer, A lithographic printing plate master containing a support-adsorbing compound with a molecular weight of 1000 or less in at least one of the above one or more layers, The above image recording layer contains an acid colorant. The content of the above-mentioned support adsorbent compound is substantially the same in at least one plane of the one or more layers, The above-mentioned lithographic printing plate has a drooping shape at the edges. The above lithographic printing plate original plate 50cm 2A lithographic printing plate master in which the pH of the solution obtained by immersing the plate in 5 mL of water is between 6.5 and 9.0.

[0017] [8] The lithographic printing plate according to any one of items [1] to [7], wherein the above-mentioned acid colorant has a structure that undergoes ring opening or elimination of a leaving group by decomposition of a decomposable group, and the structure that undergoes ring opening or elimination of a leaving group by decomposition of the decomposable group is represented by any one of the following formulas 1a to 1d.

[0018] [ka]

[0019] In formulas 1a to 1d, R 1 and R 2 This represents the portion that connects to the parent structure of the acid colorant described above. R 3 and R 4 Each of these independently represents either an aryl group or a heteroaryl group. R 5 This represents a hydrocarbon group. X represents the leaving group described above.

[0020] [9] The lithographic printing plate according to [8], wherein the above-mentioned acid colorant has a core structure represented by any of the following formulas 2a to 2f.

[0021] [ka]

[0022] In formulas 2a to 2f, structure b represents a structure that opens up the ring upon decomposition of the above-mentioned decomposable group, and R1-R9 each independently represent a hydrogen atom, an alkyl group, or an alkoxy group. The structures represented by formulas 2a to 2f have one or more of the above-mentioned decomposable groups on the aromatic ring in formulas 2a to 2f.

[0023]

[10] A lithographic printing plate according to any one of the following [1] to [7], wherein the above-mentioned acid colorant is a compound represented by either formula 3a or 3b below.

[0024] [ka]

[0025] In formula (3a), Ar1 and Ar2 each independently represent an aryl group or a heteroaryl group. R 10 , R 11 These independently represent a hydrogen atom, an alkyl group, an aryl group, and a heteroaryl group, respectively. In formula (3b), ERG each independently represents an electron-donating group, n represents an integer from 1 to 5, X1 to X4 each independently represents a hydrogen atom, a halogen atom, or a monovalent organic group, Y1 and Y2 each independently represent C or N, if Y1 is N, then X1 does not exist, if Y2 is N, then X4 does not exist, and R 12 and R 13 Each of these independently represents a hydrogen atom, an alkyl group, an aryl group, or a heteroaryl group.

[0026]

[11] The above acid colorant content is 5 mg / m² 2 ~50mg / m 2 The lithographic printing plate described in any one of items [1] to

[10] .

[0027]

[12] A lithographic printing plate according to any one of [1] to

[11] , wherein the image recording layer comprises a polymerizable compound, a polymerization initiator, and an infrared absorber.

[0028]

[13] A lithographic printing plate according to

[12] , comprising the above-mentioned infrared absorber compound represented by the following formula 4.

[0029] [ka]

[0030] In formula 4, R 14 and R 15 Each of these independently represents a hydrogen atom or an alkyl group, and R 14 and R 15 They may be connected to each other to form a ring, R 16 ~R 19 Each of these independently represents a hydrogen atom or an alkyl group, and R 20 and R 21 Each of the following independently represents an alkyl group or an aryl group, Y3 and Y4 each independently represent an oxygen atom, a sulfur atom, a -NR0- or a dialkylmethylene group, R0 represents a hydrogen atom, an alkyl group or an aryl group, Ar3 and Ar4 each independently represent a group that forms a benzene ring or naphthalene ring which may have a group represented by formula 5 described later, and A1 is -NR 22 R 23 , represents -X5-L1 or a halogen atom, R 22 and R 23 Each of the following independently represents an alkyl group, an aryl group, an alkoxycarbonyl group, or an arylsulfonyl group; X5 represents an oxygen atom or a sulfur atom; L1 represents a hydrocarbon group or a heteroaryl group; and Za represents a counterion that neutralizes the charge. -X6 formula 5 In equation 5, X6 is a halogen atom, -C(=O)-X7-R 24 -C(=O)-NR 25 R 26 -OC(=O)-R 27 -CN, -SO2NR 28 R 29 , or represents a perfluoroalkyl group, where X7 represents a single bond or oxygen atom, R 24 and R 27 Each of these independently represents an alkyl group or an aryl group, and R 25 , R 26 , R 28 and R 29 Each of these independently represents a hydrogen atom, an alkyl group, or an aryl group.

[0031]

[14] A lithographic printing plate according to any one of [1] to

[13] , wherein the image recording layer contains an electron-donating polymerization initiator.

[0032]

[15] The lithographic printing plate according to

[14] , wherein the electron-donating polymerization initiator is a borate compound.

[0033]

[16] The amount of anodic oxide in the above anodic oxide coating is 3.0 g / m². 2 A lithographic printing plate as described in any one of the following items [1] to

[15] .

[0034]

[17] A lithographic printing plate as described in any one of items [1] to

[16] , wherein the sag shape is such that the sag amount X is 25 to 150 μm and the sag width Y is 70 to 300 μm.

[0035]

[18] The lithographic printing plate according to

[17] , wherein the crack area ratio present on the surface of the anodic oxide film in the region corresponding to the sag width Y is 10% or less.

[0036]

[19] A method for producing a printing plate, comprising the steps of: exposing a lithographic printing plate described in any one of items [1] to

[18] to an image; and supplying at least one of printing ink and dampening water to remove unexposed portions of the image recording layer in the lithographic printing plate. [Effects of the Invention]

[0037] According to the present invention, it is possible to provide a lithographic printing plate master that has good visibility and suppresses edge staining, and a method for producing a printing plate using a lithographic printing plate master. [Brief explanation of the drawing]

[0038] [Figure 1] This graph shows an example of an alternating waveform current diagram used in electrochemical surface roughening treatment. [Figure 2]This is a side view showing an example of a radial cell used in electrochemical surface roughening treatment using alternating current. [Figure 3] This is a schematic diagram showing the cross-sectional shape of the edge of a lithographic printing plate. [Figure 4] This is a conceptual diagram showing an example of the cutting section of a slittering machine. [Figure 5] This is a side view illustrating the concept of the brush graining process used for mechanical surface roughening in the fabrication of aluminum supports. [Figure 6] This is a schematic diagram of an anodizing apparatus used in anodizing treatment. [Modes for carrying out the invention]

[0039] The details of the present invention will be described below. The following descriptions of the constituent elements may be based on representative embodiments of the present invention, but the present invention is not limited to such embodiments. In this specification, the "~" symbol indicating a numerical range is used to mean that the numbers before and after it are included as the lower and upper limits, respectively. Furthermore, in the notation of groups (atomic groups) in this specification, the notation that does not specify whether they are substituted or unsubstituted includes both those with and without substituents. For example, "alkyl group" includes not only alkyl groups without substituents (unsubstituted alkyl groups) but also alkyl groups with substituents (substituted alkyl groups). In this specification, "(meth)acrylic" is a term used to encompass both acrylic and methacrylic, and "(meth)acryloyl" is a term used to encompass both acryloyl and methacryloyl. Furthermore, the term "process" as used in this specification includes not only independent processes, but also processes that cannot be clearly distinguished from other processes, as long as their intended purpose is achieved. Furthermore, in this invention, "mass%" and "weight%" are synonymous, and "parts by mass" and "parts by weight" are synonymous. Unless otherwise specified, each component in the composition or each structural unit in the polymer in the present invention may be included alone or in combination of two or more types. Furthermore, in the present invention, the amount of each component in the composition, or each constituent unit in the polymer, means the total amount of the multiple substances or constituent units corresponding to each component or constituent unit in the composition, unless otherwise specified, if there are multiple such substances or constituent units in the composition. Furthermore, in the present invention, a combination of two or more preferred embodiments is a more preferred embodiment. Furthermore, unless otherwise specified, the weight-average molecular weight (Mw) and number-average molecular weight (Mn) in this invention are determined by detecting the molecular weight using a differential refractometer with THF (tetrahydrofuran) as the solvent, using a gel permeation chromatography (GPC) analyzer with TSKgel GMHxL, TSKgel G4000HxL, or TSKgel G2000HxL (all product names of Tosoh Corporation) columns, and converting them using polystyrene as a standard substance. In this invention, the term "lithographic printing plate" includes not only the lithographic printing plate but also the sacrificial plate. Furthermore, the term "lithographic printing plate" includes not only the lithographic printing plate produced from the lithographic printing plate through operations such as exposure and development as needed, but also the sacrificial plate. In the case of a sacrificial plate, exposure and development operations are not necessarily required. A sacrificial plate is, for example, a lithographic printing plate used to attach to a printing cylinder that is not in use when printing some pages in single color or two colors in color newspaper printing. The present invention will be described in detail below.

[0040] [Lithographic printing plate original plate] The first lithographic printing plate according to the present invention (hereinafter also simply referred to as the first lithographic printing plate) is, An aluminum support having an anodized film has one or more layers including an image recording layer, A lithographic printing plate original containing an oxoate with a molecular weight of 1000 or less in at least one of the above one or more layers, The above image recording layer contains an acid colorant. The content of the above oxo salt is substantially the same in at least one plane of the one or more layers, The above-mentioned lithographic printing plate is a lithographic printing plate that has a drooping shape at its edges.

[0041] The second lithographic printing plate according to the present invention (hereinafter also simply referred to as the second lithographic printing plate) is, An aluminum support having an anodized film has one or more layers including an image recording layer, A lithographic printing plate master containing a support-adsorbing compound with a molecular weight of 1000 or less in at least one of the above one or more layers, The above image recording layer contains an acid colorant. The content of the above-mentioned support adsorbent compound is substantially the same in at least one plane of the one or more layers, The above-mentioned lithographic printing plate has a drooping shape at the edges. The above lithographic printing plate original plate 50cm 2 This is a lithographic printing plate whose pH is between 6.5 and 9.0 when immersed in 5 mL of water.

[0042] Furthermore, according to the first and second lithographic printing plates of the present invention, by adopting the above configuration, it is possible to obtain a lithographic printing plate that has good visibility and suppresses edge staining. The reason is not clear, but it is presumed to be as follows.

[0043] As mentioned above, in an attempt to suppress the occurrence of edge staining, the addition of support-adsorbing compounds to the constituent layers of the lithographic printing plate is being considered. Also, as mentioned above, when developing on the press, the printing press is fitted with a lithographic printing plate from which the non-image areas have not yet been removed, making it difficult to visually confirm the image on the lithographic printing plate. Therefore, in consideration of improving the color development in the exposed areas, lithographic printing plates containing an acid colorant in the image recording layer have been developed. However, it was found that when a lithographic printing plate containing a support-adsorbing compound and an acid colorant was used, the lithographic printing plate developed color during storage over time before exposure. When the lithographic printing plate developed color before exposure, the difference in color between the exposed and unexposed areas decreased, making it difficult to visually inspect the exposed image. This made it difficult to achieve both suppression of edge staining and good visibility. Through diligent research, the inventors discovered that when lithographic printing plates are stored over time, the support-adsorbing compounds contained in the plates react with the acid colorants, making the acid colorants more likely to develop color. This led to the completion of the present invention.

[0044] The first lithographic printing plate of the present invention contains an acid colorant in the image recording layer, and one or more layers including the image recording layer contain an oxo salt with a molecular weight of 1000 or less. Oxoacids are equivalent to support-adsorbing compounds, and by including oxoate salts, the reaction with acid colorants is suppressed during the storage of lithographic printing plates over the aforementioned period, compared to when strong acids such as oxoacids are used. As a result, the color development on the plate surface can be suppressed before exposure. Consequently, the difference in color development between the exposed and unexposed areas does not decrease significantly after exposure, and the exposed areas can be clearly seen. Based on the above, it is believed that a lithographic printing plate with good visibility and suppressed edge smudging can be obtained.

[0045] The second lithographic printing plate according to the present invention contains an acid colorant in the image recording layer, and one or more layers including the image recording layer contain a support-adsorbing compound with a molecular weight of 1000 or less, and the above lithographic printing plate 50 cm 2 The pH of the solution obtained by immersing the material in 5 mL of water is between 6.5 and 9.0. The pH of the lithographic printing plate, specifically the pH of one or more layers including the image recording layer present on the support, is adjusted. In this way, by adjusting the pH of the lithographic printing plate, compared to when the pH is below 6.5, the acid-developing agent is less likely to decompose due to acid during storage of the lithographic printing plate over time, thus suppressing the development of color on the plate surface before exposure. As a result, the difference in color between the exposed and unexposed areas does not decrease significantly after exposure, and the exposed areas can be clearly seen. On the other hand, by adjusting the pH of the lithographic printing plate to 9.0 or lower, the adsorption capacity of the support-adsorbing compound is higher compared to when the pH is higher than 9.0, and a higher edge fouling suppression effect can be obtained. Based on the above, it is believed that a lithographic printing plate with good visibility and suppressed edge smudging can be obtained.

[0046] The first and second lithographic printing plates according to the present invention (hereinafter collectively referred to simply as "lithographic printing plates") will be described in detail below. The first and second lithographic printing plates are typically press-developed lithographic printing plates. On-press development is a method in which, after image exposure, the lithographic printing plate is mounted directly onto the printing press without the conventional wet development process, and the removal of non-image areas of the image recording layer is performed in the early stages of the normal printing process. A lithographic printing plate that can be developed on press is called an on-press development type lithographic printing plate.

[0047] (First lithographic printing plate) First, the first lithographic printing plate of the present invention will be described.

[0048] (Aluminum support) The support is an aluminum support. The aluminum plate used for such an aluminum support is made of a dimensionally stable metal mainly composed of aluminum, i.e., aluminum or an aluminum alloy. It is preferable to select from pure aluminum plates and alloys mainly composed of aluminum containing trace amounts of other elements.

[0049] The foreign elements contained in aluminum alloys include silicon, iron, manganese, copper, magnesium, chromium, zinc, bismuth, nickel, and titanium. The content of foreign elements in the alloy is 10% by mass or less. Pure aluminum sheets are preferred, but since it is difficult to manufacture completely pure aluminum due to smelting technology, alloys containing small amounts of foreign elements are also acceptable. The composition of the aluminum sheet used for the aluminum support is not specified, and conventionally known aluminum sheets, such as JIS A 1050, JIS A 1100, JIS A 3103, and JIS A 3005, can be used as appropriate. The thickness of the support (preferably an aluminum plate) is preferably about 0.1 to 0.6 mm.

[0050] (Anodized coating) The above support has an anodic oxide coating. The term "anodic oxide film" refers to an anodic oxide film (preferably an anodized aluminum film) having extremely fine pores (also called micropores) formed on the surface of a support (preferably an aluminum plate) by an anodizing treatment. The micropores extend from the surface of the anodic oxide film opposite the support along the thickness direction (support side, depth direction). The average diameter (average aperture diameter) on the surface of the anodic oxide film of the micropore is preferably 7 nm to 150 nm, more preferably 10 nm to 100 nm, even more preferably 10 nm to 60 nm, particularly preferably 15 nm to 60 nm, and most preferably 18 nm to 40 nm, from the viewpoint of tone reproducibility, print resistance, and blanket stain resistance. The depth of the micropore is preferably 10 nm to 3,000 nm, more preferably 10 nm to 2,000 nm, and even more preferably 10 nm to 1,000 nm.

[0051] The shape of a micropore is usually that of a nearly straight tube (or nearly cylindrical) with a diameter that remains almost constant in the depth direction (thickness direction), but it may also be conical in shape, where the diameter decreases continuously in the depth direction (thickness direction). Alternatively, it may be a shape in which the diameter decreases discontinuously in the depth direction (thickness direction). Examples of micropores with a shape in which the diameter becomes discontinuously smaller in the depth direction (thickness direction) include micropores composed of a large-diameter pore portion extending in the depth direction from the surface of the anodic oxide film and a small-diameter pore portion communicating with the bottom of the large-diameter pore portion and extending in the depth direction from the communication point.

[0052] Specifically, a micropore is preferred that consists of a large-diameter pore extending 10 nm to 1,000 nm in depth from the surface of the anodic oxide film, and a small-diameter pore communicating with the bottom of the large-diameter pore and extending a further 20 to 2,000 nm in depth from the communication point. The large-diameter and small-diameter hole sections are described in detail below.

[0053] -Large diameter hole- The average diameter (average aperture diameter) of the anodic oxide film surface in the large-diameter pores is preferably 7 nm to 150 nm, more preferably 10 nm to 100 nm, even more preferably 15 nm to 100 nm, particularly preferably 15 nm to 60 nm, and most preferably 18 nm to 40 nm, from the viewpoint of tone reproducibility, print resistance, and blanket stain resistance. The average diameter of the large-diameter pores is calculated by observing the surface of the anodic oxide film with a field emission scanning electron microscope (FE-SEM) at a magnification of 150,000x (N=4 images), measuring the diameter of micropores (large-diameter pores) in a 400nm × 600nm area in the four images obtained, and calculating the arithmetic mean of the diameters. If the shape of the large-diameter opening is not circular, the equivalent diameter of the circle is used. The "equivalent diameter of the circle" is the diameter of the circle when the shape of the opening is assumed to be a circle with the same projected area as the projected area of ​​the opening.

[0054] The bottom of the large-diameter pore is preferably located at a depth of 70 nm to 1,000 nm (hereinafter also referred to as depth A) from the surface of the anodic oxide film. In other words, the large-diameter pore is preferably a pore that extends 70 nm to 1,000 nm in the depth direction (thickness direction) from the surface of the anodic oxide film. Among these, in terms of the superior effect of the manufacturing method of the lithographic printing plate, depth A is more preferably 90 nm to 850 nm, even more preferably 90 nm to 800 nm, and particularly preferably 90 nm to 600 nm. The above depth is calculated as the arithmetic mean value by taking a photograph (150,000 times magnification) of the cross-section of the anodic oxide film and measuring the depths of 25 or more large-diameter holes.

[0055] The shape of the large-diameter hole is not particularly limited, and examples thereof include a substantially straight tube shape (substantially cylindrical shape) and a conical shape in which the diameter decreases in the depth direction (thickness direction), and a substantially straight tube shape is preferable. Further, the shape of the bottom of the large-diameter hole is not particularly limited, and may be a curved surface shape (convex shape) or a flat surface shape. The inner diameter of the large-diameter hole is not particularly limited, but it is preferably approximately the same size as the diameter of the opening or smaller than the diameter of the opening. Note that the inner diameter of the large-diameter hole may have a difference of about 1 nm to 10 nm from the diameter of the opening.

[0056] - Small-diameter hole - The small-diameter hole is a hole that communicates with the bottom of the large-diameter hole and extends further in the depth direction (thickness direction) from the communication position. Usually, one small-diameter hole communicates with one large-diameter hole, but two or more small-diameter holes may communicate with the bottom of one large-diameter hole. The average diameter at the communication position of the small-diameter hole is preferably 15 nm or less, more preferably 13 nm or less, still more preferably 11 nm or less, and particularly preferably 10 nm or less. The lower limit is not particularly limited, but 5 nm is preferable.

[0057] The average diameter of the small-diameter hole is calculated by observing the surface of the anodic oxide film with a FE-SEM at a magnification of 150,000 times for N = 4 sheets, measuring the diameter (diameter) of the micropores (small-diameter holes) existing in the range of 400 nm × 600 nm in the obtained 4 images, and obtaining the arithmetic mean value of the diameters. Note that when the depth of the large-diameter hole is deep, if necessary, the upper part of the anodic oxide film (the region with the large-diameter hole) may be cut (for example, cut with argon gas), and then the surface of the anodic oxide film may be observed with the above FE-SEM to obtain the average diameter of the small-diameter hole. Note that when the shape of the small-diameter hole is not circular, the equivalent circle diameter is used. The "equivalent circle diameter" is 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.

[0058] The bottom of the small-diameter hole portion is preferably located at a position extending 20 nm to 2,000 nm in the depth direction from the communication position with the large-diameter hole portion (corresponding to the depth A described above). In other words, the small-diameter hole portion is a hole portion extending in the depth direction (thickness direction) from the communication position with the large-diameter hole portion. The depth of the small-diameter hole portion is preferably 20 nm to 2,000 nm, more preferably 100 nm to 1,500 nm, and particularly preferably 200 nm to 1,000 nm. Note that the above depth is obtained by taking a photograph (150,000 times magnification) of the cross-section of the anodic oxide film, measuring the depths of 25 or more small-diameter hole portions, and calculating the arithmetic average value.

[0059] The shape of the small-diameter hole portion is not particularly limited, and examples thereof include a substantially straight tubular shape (substantially cylindrical shape) and a conical shape in which the diameter decreases in the depth direction. A substantially straight tubular shape is preferred. Also, the shape of the bottom of the small-diameter hole portion is not particularly limited, and it may be a curved surface shape (convex shape) or a flat surface shape. The inner diameter of the small-diameter hole portion is not particularly limited, and it may be approximately the same size as the diameter at the communication position, or may be smaller or larger than the above diameter. Note that the inner diameter of the small-diameter hole portion may usually have a difference of about 1 nm to 10 nm from the diameter of the opening portion.

[0060] The ratio of the average diameter on the surface of the anodic oxide film of the large-diameter hole portion to the average diameter at the communication position of the small-diameter hole portion, (average diameter on the surface of the anodic oxide film of the large-diameter hole portion) / (average diameter at the communication position of the small-diameter hole portion), is preferably 1.1 to 13, and more preferably 2.5 to 6.5. Also, the ratio of the depth of the large-diameter hole portion to the depth of the small-diameter hole portion, (depth of the large-diameter hole portion) / (depth of the small-diameter hole portion), is preferably 0.005 to 50, and more preferably 0.025 to 40.

[0061] Also, the shape of the micropore is a substantially straight tubular shape (substantially cylindrical shape) in which the diameter of the micropore hardly changes in the depth direction (thickness direction), but it may also be a conical shape in which the diameter continuously increases in the depth direction (thickness direction). Also, it may be a shape in which the diameter increases discontinuously in the depth direction (thickness direction). Examples of micropores with a shape in which the diameter increases discontinuously in the depth direction (thickness direction) include micropores composed of a small-diameter pore extending in the depth direction from the surface of the anodic oxide film and a large-diameter pore communicating with the bottom of the small-diameter pore and extending in the depth direction from the point of communication.

[0062] Specifically, a micropore is preferred that consists of a small-diameter pore extending 10 nm to 1,000 nm in depth from the surface of the anodic oxide film, and a large-diameter pore communicating with the bottom of the small-diameter pore and extending a further 20 to 2,000 nm in depth from the communication point.

[0063] -Small diameter hole- The average diameter (average aperture diameter) of the small-diameter pores on the surface of the anodic oxide film is not particularly limited, but is preferably 35 nm or less, more preferably 25 nm or less, and particularly preferably 20 nm or less. There is no particular lower limit, but 15 nm is preferred. The average diameter of the small-diameter pores is calculated by observing the surface of the anodic oxide film with a field emission scanning electron microscope (FE-SEM) at a magnification of 150,000x (N=4 images), measuring the diameter of micropores (large-diameter pores) in the 400nm × 600nm range in the four images obtained, and calculating the arithmetic mean of the diameters. If the shape of the small-diameter hole is not circular, the equivalent diameter is used. The "equivalent diameter" is the diameter of the circle when the shape of the opening is assumed to be a circle with the same projected area as the projected area of ​​the opening.

[0064] The bottom of the small-diameter pore is preferably located at a depth of 70 nm to 1,000 nm (hereinafter also referred to as depth A') from the surface of the anodic oxide film. In other words, the small-diameter pore is preferably a pore that extends 70 nm to 1,000 nm in the depth direction (thickness direction) from the surface of the anodic oxide film. The above depth is calculated by taking a cross-sectional photograph (150,000x magnification) of the anodic oxide film, measuring the depth of 25 or more large-diameter pores, and taking the arithmetic mean.

[0065] The shape of the small-diameter hole is not particularly limited; for example, it can be approximately straight (approximately cylindrical) or conical, with the diameter increasing in the depth direction (thickness direction), and an approximately straight shape is preferred. Furthermore, the shape of the bottom of the small-diameter hole is not particularly limited and may be curved (convex) or flat. The inner diameter of the small-diameter hole is not particularly limited, but it is preferable that it be about the same size as the diameter of the opening, or smaller than the diameter of the opening. The inner diameter of the small-diameter hole may differ from the diameter of the opening by about 1 nm to 10 nm.

[0066] -Large diameter hole- The large-diameter hole is a hole that communicates with the bottom of the small-diameter hole and extends further in the depth direction (thickness direction) beyond the point of communication. Typically, one large-diameter hole may have two or more small-diameter holes communicating with the bottom of one large-diameter hole. The average diameter at the communication position of the large-diameter hole is preferably 20 nm to 400 nm, more preferably 40 nm to 300 nm, even more preferably 50 nm to 200 nm, and particularly preferably 50 nm to 100 nm.

[0067] The average diameter of the large-diameter pores is calculated by observing the surface of the anodized film with FE-SEM at a magnification of 150,000x (N=4 images), measuring the diameter of micropores (large-diameter pores) in the 400nm × 600nm range in the four obtained images, and calculating the arithmetic mean of the diameters. If the depth of the small-diameter holes is deep, the upper part of the anodic oxide film (the region containing the small-diameter holes) may be cut (for example, by cutting with argon gas), and then the surface of the anodic oxide film may be observed with the FE-SEM described above to determine the average diameter of the large-diameter holes. If the shape of the large-diameter opening is not circular, the equivalent diameter of the circle is used. The "equivalent diameter of the circle" is the diameter of the circle when the shape of the opening is assumed to be a circle with the same projected area as the projected area of ​​the opening.

[0068] The bottom of the large-diameter hole is preferably located 20 nm to 2,000 nm further in the depth direction from the communication point with the small-diameter hole (corresponding to the depth A' described above). In other words, the large-diameter hole is a hole that extends further in the depth direction (thickness direction) from the communication point with the small-diameter hole, and the depth of the large-diameter hole is preferably 20 nm to 2,000 nm, more preferably 100 nm to 1,500 nm, and particularly preferably 200 nm to 1,000 nm. The above depth is calculated by taking a cross-sectional photograph (150,000x magnification) of the anodic oxide film, measuring the depth of 25 or more large-diameter pores, and taking the arithmetic mean.

[0069] The shape of the large-diameter hole is not particularly limited; for example, it can be approximately straight (approximately cylindrical) or conical, with the diameter decreasing towards the depth. A nearly straight shape is preferred. The shape of the bottom of the large-diameter hole is also not particularly limited; it may be curved (convex) or flat. The inner diameter of the large-diameter hole is not particularly limited, but it may be about the same size as the diameter at the communication position, or it may be smaller or larger than the above diameter. In general, the inner diameter of the large-diameter hole may differ from the diameter of the opening by about 1 nm to 10 nm.

[0070] The above support has an anodic oxide film, The above anodic oxide film is applied sequentially from the surface of the anodic oxide film toward the depth, The upper layer has a thickness of 30-500 nm and has micropores with an average diameter of 20-100 nm. An intermediate layer with a thickness of 100 to 300 nm having micropores whose average diameter is 1 / 2 to 5 times the average diameter of the micropores in the above-mentioned upper micropore layer, and A sublayer with a thickness of 300-2000 nm, having micropores with an average diameter of 15 nm or less. It is preferable that it has

[0071] In press-developed lithographic printing plates, high brightness on the surface of the anodic oxide coating of the support (the surface on which the image recording layer is formed) is useful from the viewpoint of improving image visibility. In the printing process of a lithographic printing plate, usually, a plate inspection operation is performed for the purpose of checking whether image recording has been performed as intended before attaching the printing plate to a printing press. In an on-machine developing type lithographic printing plate original plate, since it is required to check the image at the stage where the image has been exposed, means for generating a so-called baked-out image in the image-exposed area is applied. As a method for quantitatively evaluating the visibility (image visibility) of the image portion of an on-machine developing type lithographic printing plate original plate that has been image-exposed, there is a method of measuring the lightness of the image-exposed area and the lightness of the unexposed area and obtaining the difference between the two. Here, as the lightness, the value of lightness L* in the CIEL*a*b* color system can be used, and the measurement can be performed using a color difference meter (SpectroEye, manufactured by X-Rite Co., Ltd.). The larger the difference between the lightness of the image-exposed area and the lightness of the unexposed area obtained by the measurement, the easier it is to see the image portion. In order to increase the difference between the lightness of the image-exposed area and the lightness of the unexposed area, it has been found that it is effective for the value of lightness L* in the CIEL*a*b* color system on the surface of the anodic oxide film to be large. That is, the value of lightness L* is preferably 60 to 100.

[0072] The support having an anodic oxide film may have a back coat layer containing an organic polymer compound described in JP-A-5-45885 or a silicon alkoxy compound described in JP-A-6-35174 on the surface opposite to the side where a constituent layer containing a hydroxy acid compound having two or more hydroxyl groups is formed, if necessary.

[0073] (Manufacture of an aluminum support having an anodic oxide film) As an example of the support, a method for manufacturing an aluminum support having an anodic oxide film will be described. Aluminum supports having an anodized coating can be manufactured using known methods. The method for manufacturing aluminum supports having an anodized coating is not particularly limited. A preferred embodiment of the method for manufacturing aluminum supports having an anodized coating includes a step of roughening an aluminum plate (roughening step), an anodizing step of anodic oxidizing the roughened aluminum plate (anodic oxidation step), and a step of contacting the aluminum plate having the anodized coating obtained in the anodizing step with an acidic aqueous solution or an alkaline aqueous solution to enlarge the diameter of micropores in the anodized coating (pore widening step).

[0074] The following describes each step in detail.

[0075] <Surface roughening process> The surface roughening process involves applying a surface roughening treatment, including electrochemical surface roughening, to the surface of the aluminum plate. While it is preferable to perform the surface roughening process before the anodic oxidation process described later, it may be omitted if the aluminum plate already has a desirable surface shape.

[0076] The surface roughening treatment may consist solely of electrochemical roughening, or it may be a combination of electrochemical roughening, mechanical roughening, and at least one of chemical roughening. When combining mechanical surface roughening and electrochemical surface roughening, it is preferable to perform the electrochemical surface roughening after the mechanical surface roughening.

[0077] Electrochemical surface roughening treatment is preferably carried out in an aqueous solution of nitric acid or hydrochloric acid.

[0078] Mechanical surface roughening treatment is generally performed with the aim of achieving a surface roughness Ra: 0.35 to 1.0 μm on the surface of an aluminum plate. The conditions for the mechanical surface roughening treatment are not particularly limited, but can be carried out, for example, according to the method described in Japanese Patent Publication No. 50-40047. The mechanical surface roughening treatment can be carried out by brush grain treatment using a pumstone suspension or by a transfer method. Furthermore, the chemical surface roughening treatment is not particularly limited and can be carried out according to known methods.

[0079] Following the mechanical surface roughening treatment, it is preferable to perform the following chemical etching treatment. The chemical etching process, which follows the mechanical surface roughening treatment, is performed to smooth the edges of the uneven surface of the aluminum plate, prevent ink from sticking during printing, improve the stain resistance of the lithographic printing plate, and remove unwanted materials such as abrasive particles remaining on the surface. Chemical etching processes include etching with acids and etching with alkalis, but chemical etching using alkaline solutions (hereinafter also referred to as "alkaline etching") is particularly superior in terms of etching efficiency.

[0080] The alkaline agent used in the alkaline solution is not particularly limited, but examples of suitable alkaline agents include caustic soda, caustic potassium, sodium metasilicate, sodium carbonate, sodium aluminate, and sodium gluconate. The alkaline solution may contain aluminum ions. 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, preferably 30% by mass or less, and more preferably 25% by mass or less. Furthermore, the temperature of the alkaline solution is preferably above room temperature, more preferably above 30°C, more preferably below 80°C, and more preferably below 75°C.

[0081] The etching rate is 0.01 g / m². 2 The above is preferable, and 0.05 g / m 2 The above is more preferable, and also 30g / m 2 The following is preferable: 20 g / m 2 The following are preferable. The processing time is preferably 2 seconds to 5 minutes, depending on the etching amount, and more preferably 2 to 10 seconds from the viewpoint of improving productivity.

[0082] When alkaline etching is performed after mechanical surface roughening, it is preferable to perform chemical etching (hereinafter also referred to as "de-matt treatment") using a low-temperature acidic solution to remove the products generated by the alkaline etching. The acid used in the acidic solution is not particularly limited, but examples include sulfuric acid, nitric acid, and hydrochloric acid. The concentration of the acidic solution is preferably 1 to 50% by mass. The temperature of the acidic solution is preferably 20 to 80°C. When the concentration and temperature of the acidic solution are within this range, the resistance to spot-like stains in the lithographic printing plate using an aluminum support is further improved.

[0083] A preferred embodiment of the surface roughening process is illustrated below. -Pattern SA- An embodiment in which the processes shown in (1) to (8) are carried out in this order. (1) Chemical etching treatment using an alkaline aqueous solution (first alkaline etching treatment) (2) Chemical etching treatment using an acidic aqueous solution (first desmatt treatment) (3) Electrochemical roughening treatment using an aqueous solution mainly composed of nitric acid (first electrochemical roughening treatment) (4) Chemical etching treatment using an alkaline aqueous solution (second alkaline etching treatment) (5) Chemical etching treatment using an acidic aqueous solution (second desmatt treatment) (6) Electrochemical roughening treatment using an aqueous solution mainly composed of hydrochloric acid (second electrochemical roughening treatment) (7) Chemical etching treatment using an alkaline aqueous solution (third alkaline etching treatment) (8) Chemical etching treatment using an acidic aqueous solution (third desmatt treatment)

[0084] -Mode SB- An embodiment in which the processes shown in (11) to (15) are carried out in this order. (11) Chemical etching treatment using an alkaline aqueous solution (fourth alkaline etching treatment) (12) Chemical etching treatment using an acidic aqueous solution (fourth desmatt treatment) (13) Electrochemical roughening treatment using an aqueous solution mainly composed of hydrochloric acid (third electrochemical roughening treatment) (14) Chemical etching treatment using an alkaline aqueous solution (5th alkaline etching treatment) (15) Chemical etching treatment using an acidic aqueous solution (5th desmatt treatment)

[0085] Mechanical surface roughening treatment may be performed before the treatment described in (1) of embodiment SA, or before the treatment described in (11) of embodiment SB, if necessary.

[0086] The amount of aluminum plate dissolved in the first and fourth alkaline etching treatments is 0.5 g / m². 2 ~30g / m 2 Preferably, 1.0 g / m 2 ~20g / m 2 This is preferable.

[0087] Examples of aqueous solutions mainly composed of nitric acid used in the first electrochemical roughening treatment in embodiment SA include aqueous solutions used in electrochemical roughening treatment using direct current or alternating current. For example, aqueous solutions obtained by adding aluminum nitrate, sodium nitrate, or ammonium nitrate to an aqueous solution of 1 g / L to 100 g / L of nitric acid include aqueous solutions. The aqueous solution mainly composed of hydrochloric acid used in the second electrochemical roughening treatment in embodiment SA and the third electrochemical roughening treatment in embodiment SB includes aqueous solutions used for electrochemical roughening treatment using direct current or alternating current. For example, an aqueous solution obtained by adding 0 g / L to 30 g / L of sulfuric acid to an aqueous hydrochloric acid solution of 1 g / L to 100 g / L is included. In addition, nitrate ions such as aluminum nitrate, sodium nitrate, or ammonium nitrate; chloride ions such as aluminum chloride, sodium chloride, or ammonium chloride may be further added to this aqueous solution.

[0088] The alternating current power supply waveform for the electrochemical roughening treatment can use a sine wave, square wave, trapezoidal wave, triangular wave, etc. The frequency is preferably 0.1 Hz to 250 Hz. Figure 1 is a graph showing an example of an alternating waveform current waveform diagram used in the electrochemical roughening treatment. In Figure 1, ta is the anode reaction time, tc is the cathode reaction time, tp is the time for the current to reach the peak from 0, Ia is the current at the peak on the anode cycle side, and Ic is the current at the peak on the cathode cycle side. In the trapezoidal wave, the time tp for the current to reach the peak from 0 is preferably 1 msec to 10 msec. The conditions for one cycle of the alternating current used in the electrochemical roughening treatment are such that the ratio tc / ta of the cathode reaction time tc to the anode reaction time ta of the aluminum plate is 1 to 20, the ratio Qc / Qa of the electric quantity Qc at the cathode and the electric quantity Qa at the anode of the aluminum plate is 0.3 to 20, and the anode reaction time ta is preferably in the range of 5 msec to 1,000 msec. The current density is such that both the anode cycle side Ia and the cathode cycle side Ic of the current at the peak value of the trapezoidal wave are 10 to 200 A / dm 2 is preferred. Ic / Ia is preferably 0.3 to 20. The total electric quantity involved in the anode reaction of the aluminum plate at the time when the electrochemical roughening treatment is completed is 25 C / dm 2 ~1,000 C / dm 2 is preferred.

[0089] For the electrochemical roughening treatment using alternating current, the apparatus shown in Figure 2 can be used. Figure 2 is a side view showing an example of a radial type cell in the electrochemical roughening treatment using alternating current. In Figure 2, 50 is the main electrolytic cell, 51 is the alternating current power supply, 52 is the radial drum roller, 53a and 53b are the main electrodes, 54 is the electrolyte supply port, 55 is the electrolyte, 56 is the slit, 57 is the electrolyte passage, 58 is the auxiliary anode, 60 is the auxiliary anode tank, and W is the aluminum plate. When two or more electrolytic cells are used, the electrolytic conditions may be the same or different. The aluminum plate W is wound around a radial drum roller 52 immersed in the main electrolytic cell 50 and is electrolytically treated by main electrodes 53a and 53b connected to an AC power supply 51 during the conveyance process. The electrolytic solution 55 is supplied from an electrolytic solution supply port 54 through a slit 56 to an electrolytic solution passage 57 between the radial drum roller 52 and the main electrodes 53a and 53b. The aluminum plate W processed in the main electrolytic cell 50 is then electrolytically treated in an auxiliary anode cell 60. An auxiliary anode 58 is disposed opposite to the aluminum plate W in this auxiliary anode cell 60, and the electrolytic solution 55 is supplied so as to flow through the space between the auxiliary anode 58 and the aluminum plate W.

[0090] The dissolution amount of the aluminum plate in the second alkali etching treatment is 1.0 g / m 2 ~20 g / m 2 which is preferable, and 2.0 g / m 2 ~10 g / m 2 which is more preferable.

[0091] The dissolution amount of the aluminum plate in the third alkali etching treatment and the fifth alkali etching treatment is 0.01 g / m 2 ~0.8 g / m 2 which is preferable, and 0.05 g / m 2 ~0.3 g / m 2 which is more preferable.

[0092] In the chemical etching treatment (first to fifth desmuttreatment) 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 is preferably used. The concentration of the acid in the acidic aqueous solution is preferably 0.5 mass% to 60 mass%.

[0093] <Anodic oxidation treatment step> The anodizing process involves applying an anodizing treatment to the aluminum plate that has undergone the surface roughening treatment described above, thereby forming an aluminum oxide film on the surface of the aluminum plate. The anodizing treatment forms an aluminum anodic oxide film having micropores on the surface of the aluminum plate. Anodizing can be carried out by setting appropriate manufacturing conditions, taking into consideration the desired micropore shape, etc., according to methods conventionally known in this field.

[0094] In the anodizing process, aqueous solutions of sulfuric acid, phosphoric acid, oxalic acid, etc., can be mainly used as the electrolyte. In some cases, aqueous solutions or non-aqueous solutions of chromic acid, sulfamic acid, benzenesulfonic acid, or combinations of two or more of these can also be used. When direct current or alternating current is passed through an aluminum plate in the electrolyte, an anodic oxide film can be formed on the surface of the aluminum plate. The electrolyte may contain aluminum ions. The aluminum ion content is not particularly limited, but 1 to 10 g / L is preferred.

[0095] The conditions for anodizing are set appropriately depending on the electrolyte used, but generally, the electrolyte concentration is 1 to 80% by mass (preferably 5 to 20% by mass), the liquid temperature is 5 to 70°C (preferably 10 to 60°C), and the current density is 0.5 to 60 A / dm². 2 (preferably 5-50 A / dm 2 A suitable range is 1 to 100V (preferably 5 to 50V) for the voltage and 1 to 100 seconds (preferably 5 to 60 seconds) for the electrolysis time.

[0096] The method of anodic oxidation in sulfuric acid at a high current density, as described in British Patent No. 1,412,768, is a preferred example of an anodizing treatment.

[0097] Anodizing can be performed multiple times. One or more conditions, such as the type, concentration, temperature, current density, voltage, and electrolysis time of the electrolyte used in each anodizing process, can be changed. If the anodizing process is performed twice, the first process may be called the first anodizing process, and the second anodizing process may be called the second anodizing process. By performing both the first and second anodizing processes, it is possible to form anodized films with different shapes, making it possible to provide lithographic printing plates with superior printing performance. Furthermore, it is also possible to perform the pore-widening treatment described below following the anodizing treatment, and then perform the anodizing treatment again. In this case, the process will involve the first anodizing treatment, the pore-widening treatment, and the second anodizing treatment. By utilizing the method of performing the first anodic oxidation treatment, pore widening treatment, and second anodic oxidation treatment described above, it is possible to form micropores consisting of large-diameter pores extending in the depth direction from the surface of the aforementioned anodic oxidation film, and small-diameter pores communicating with the bottom of the large-diameter pores and extending in the depth direction from the communication point.

[0098] <Pore-wide processing process> The pore widening process is a process (pore diameter enlargement process) that enlarges the diameter of micropores (pore diameter) present in the anodic oxide film formed by the above anodic oxidation process. This pore widening process enlarges the diameter of the micropores, resulting in the formation of an anodic oxide film with micropores having a larger average diameter.

[0099] Pore ​​widening can be performed by contacting the aluminum plate obtained by the above anodic oxidation process with an acidic aqueous solution or an alkaline aqueous solution. The method of contact is not particularly limited and examples include immersion and spraying. Among these, the immersion method is preferred.

[0100] When using an alkaline aqueous solution in the pore-widening process, it is preferable to use at least one alkaline aqueous solution selected from the group consisting of sodium hydroxide, potassium hydroxide, and lithium hydroxide. The concentration of the alkaline aqueous solution is preferably 0.1 to 5% by mass. It is appropriate to adjust the pH of the alkaline aqueous solution to 11 to 13 and contact the aluminum plate with the alkaline aqueous solution for 1 to 300 seconds (preferably 1 to 50 seconds) under conditions of 10 to 70°C (preferably 20 to 50°C). In this case, the alkaline treatment solution may also contain metal salts of polyvalent weak acids such as carbonates, borates, and phosphates.

[0101] When using an aqueous acid solution in the pore-widening process, it is preferable to use an aqueous solution of an inorganic acid such as sulfuric acid, phosphoric acid, nitric acid, hydrochloric acid, or a mixture thereof. The concentration of the aqueous acid solution is preferably 1 to 80% by mass, and more preferably 5 to 50% by mass. It is appropriate to contact the aluminum plate with the aqueous acid solution for 1 to 300 seconds (preferably 1 to 150 seconds) under conditions where the temperature of the aqueous acid solution is 5 to 70°C (preferably 10 to 60°C). Alkaline aqueous solution or acidic aqueous solution may contain aluminum ions. The aluminum ion content is not particularly limited, but 1 to 10 g / L is preferred.

[0102] A method for producing an aluminum support having an anodic oxide film may include a hydrophilization treatment step in which a hydrophilization treatment is performed after the pore-widening treatment step described above. For the hydrophilization treatment, a known method described in paragraphs 0109 to 0114 of Japanese Patent Application Publication No. 2005-254638 can be used.

[0103] Hydrophilization treatment is preferably carried out by methods such as immersion in an aqueous solution of alkali metal silicates such as sodium silicate or potassium silicate, or by applying a hydrophilic vinyl polymer or hydrophilic compound to form a hydrophilic undercoat layer.

[0104] Hydrophilization treatment with aqueous solutions of alkali metal silicates such as sodium silicate and potassium silicate can be carried out by the methods and procedures described in U.S. Patent No. 2,714,066 and U.S. Patent No. 3,181,461.

[0105] The amount of anodic oxide coating in the above anodic oxide coating is not particularly limited, but is 3.0 g / m². 2 Preferably, it is 2.5 g / m 2 It is more preferable that the following conditions apply: 2.0 g / m 2 The following is even more preferable: The amount of anodic oxide coating in the above anodic oxide coating is not particularly limited, but is 0.5 g / m². 2 It is preferable that the above conditions are met.

[0106] The amount of anodized film is calculated using the following method. The constituent layers (undercoat layer, image recording layer, protective layer) of the lithographic printing plate are removed using a PlasmaReactor PR300 manufactured by Yamato Scientific Co., Ltd. The surface of the exposed aluminum support with an anodized coating is measured using an X-ray fluorescence analyzer (ZSX PrimusII manufactured by Rigaku Corporation), and the amount of anodized coating (g / m²) is determined using a calibration curve prepared separately. 2 The following parameters were used to calculate the anodic oxide film amount. The calibration curve was created from the relationship between the Compton scattered radiation intensity obtained from the X-ray fluorescence analyzer and the amount of anodic oxide film calculated by the Mason method. To improve the measurement accuracy of the Mason method, all Mason solutions used were fresh. The conditions for X-ray fluorescence analysis were as follows: X-ray tube: Rh, measurement spectrum: RhLα, tube voltage: 50kV, tube current: 60mA, slit: S2, spectroscopic crystal: Ge, detector: PC, analysis area: 30mmφ, peak position (2θ): 89.510deg., background (2θ): 87.000deg. and 92.000deg., integration time: 60 seconds / sample

[0107] The first lithographic printing plate of the present invention is The aluminum support having an anodized coating has one or more layers, including an image recording layer.

[0108] <Image recording layer> The image recording layer contains an acid chromogen. The acid chromogen is described below.

[0109] [Acid coloring agent] In this invention, "acid colorant" refers to a compound that changes the color of an image recording layer by developing or decolorizing when heated while accepting an electron-accepting compound (e.g., a proton such as an acid). As an acid colorant, a colorless compound having a partial skeleton such as a lactone, lactam, salton, spiropyran, ester, or amide is particularly preferred, in which these partial skeletons rapidly open or cleave when in contact with an electron-accepting compound.

[0110] Specific examples of acid colorants include those described in International Publication No. 2020 / 158138.

[0111] In particular, the acid colorant used in the present invention is preferably at least one compound selected from the group consisting of spiropyran compounds, spirooxazine compounds, spirolactone compounds, and spirolactam compounds, from the viewpoint of color development. From the viewpoint of visibility, the hue of the pigment after color development is preferably green, blue, or black.

[0112] Furthermore, the above-mentioned acid colorant preferably contains a leuco dye from the viewpoint of color development and visibility. The above-mentioned leuco dye is not particularly limited as long as it has a leuco structure, but it is preferable that it has a spiro structure, and more preferably that it has a spirolactone ring structure. Furthermore, from the viewpoint of color development and visibility of the exposed area, the leuco dye is preferably a leuco dye having a phthalide structure or a fluorane structure. Furthermore, the leuco dye having the phthalide structure or fluorane structure described above is preferably a compound represented by any of the following formulas (Le-1) to (Le-3), and more preferably a compound represented by the following formula (Le-2), from the viewpoint of color development and visibility of the exposed area.

[0113] [ka]

[0114] In formulas (Le-1) to (Le-3), ERG each independently represents an electron-donating group, X1 to X4 each independently represents a hydrogen atom, a halogen atom, or a dialkylanilino group, and X5 to X 10 Each of the following independently represents a hydrogen atom, a halogen atom, or a monovalent organic group; Y1 and Y2 independently represent C or N; if Y1 is N, X1 is absent; if Y2 is N, X4 is absent; Ra1 represents a hydrogen atom, an alkyl group, or an alkoxy group; and Rb1 to Rb4 independently represent a hydrogen atom, an alkyl group, an aryl group, or a heteroaryl group.

[0115] In the ERG of formulas (Le-1) to (Le-3), the electron-donating group is preferably an amino group, alkylamino group, arylamino group, heteroarylamino group, dialkylamino group, monoalkylmonoarylamino group, monoalkylmonoheteroarylamino group, diarylamino group, diheteroarylamino group, monoarylmonoheteroarylamino group, alkoxy group, allyloxy group, heteroaryloxy group, or alkyl group, more preferably an amino group, alkylamino group, arylamino group, heteroarylamino group, dialkylamino group, monoalkylmonoarylamino group, monoalkylmonoheteroarylamino group, diarylamino group, diheteroarylamino group, monoarylmonoheteroarylamino group, alkoxy group, or allyloxy group, even more preferably a monoalkylmonoarylamino group, diarylamino group, diheteroarylamino group, or monoarylmonoheteroarylamino group, and particularly preferably a monoalkylmonoarylamino group. Furthermore, as the electron-donating group in the above ERG, from the viewpoint of color development and visibility of the exposed area, it is preferable that the disubstituted amino group has an aryl group having a substituent at least one ortho position or a heteroaryl group having a substituent at least one ortho position, more preferably that the disubstituted amino group has a substituent at least one ortho position and a phenyl group having an electron-donating group at the para position, even more preferably that the amino group has a substituent at least one ortho position and a phenyl group having an electron-donating group at the para position and an aryl group or heteroaryl group, and particularly preferably that the amino group has a substituent at least one ortho position and a phenyl group having an electron-donating group at the para position and an aryl group having an electron-donating group or a heteroaryl group having an electron-donating group. In this invention, the ortho position in an aryl group or heteroaryl group other than a phenyl group refers to the bond position adjacent to position 1 (for example, position 2) when the bond position to another structure of the aryl group or heteroaryl group is defined as position 1. Furthermore, from the viewpoint of color development and visibility of the exposed area, the electron-donating group of the aryl group or heteroaryl group is preferably an amino group, alkylamino group, arylamino group, heteroarylamino group, dialkylamino group, monoalkylmonoarylamino group, monoalkylmonoheteroarylamino group, diarylamino group, diheteroarylamino group, monoarylmonoheteroarylamino group, alkoxy group, allyloxy group, heteroaryloxy group, or alkyl group, more preferably an alkoxy group, allyloxy group, heteroaryloxy group, or alkyl group, and particularly preferably an alkoxy group.

[0116] In formulas (Le-1) to (Le-3), X1 to X4 are each independently preferably hydrogen atoms or chlorine atoms, and more preferably hydrogen atoms, from the viewpoint of color development and visibility of the exposed area. X5~X in equation (Le-2) or equation (Le-3) 10Each of these groups is preferably, from the viewpoint of color development and visibility of the exposed area, a hydrogen atom, halogen atom, alkyl group, aryl group, amino group, alkylamino group, arylamino group, heteroarylamino group, dialkylamino group, monoalkylmonoarylamino group, monoalkylmonoheteroarylamino group, diarylamino group, diheteroarylamino group, monoarylmonoheteroarylamino group, hydroxyl group, alkoxy group, allyloxy group, heteroallyloxy group, acyl group, alkoxycarbonyl group, allyloxycarbonyl group, heteroallyloxycarbonyl group, or cyano group; more preferably a hydrogen atom, halogen atom, alkyl group, aryl group, alkoxy group, or allyloxy group; even more preferably a hydrogen atom, halogen atom, alkyl group, or aryl group; and particularly preferably a hydrogen atom. In formulas (Le-1) to (Le-3), at least one of Y1 and Y2 is preferably C, and more preferably both Y1 and Y2 are C, from the viewpoint of color development and visibility of the exposed area. In formulas (Le-1) to (Le-3), Ra1 is preferably an alkyl group or an alkoxy group, more preferably an alkoxy group, and particularly preferably a methoxy group, from the viewpoint of color development and visibility of the exposed area. In formulas (Le-1) to (Le-3), Rb1 to Rb4 are each independently preferably a hydrogen atom or an alkyl group, more preferably an alkyl group, and particularly preferably a methyl group, from the viewpoint of color development and visibility of the exposed area.

[0117] Furthermore, the leuco dye having the phthalide structure or fluorane structure described above is more preferably a compound represented by any of the following formulas (Le-4) to (Le-6), and even more preferably a compound represented by the following formula (Le-5), from the viewpoint of color development and visibility of the exposed area.

[0118] [ka]

[0119] In formulas (Le-4) to (Le-6), ERG independently represents an electron-donating group, X1 to X4 independently represent a hydrogen atom, a halogen atom, or a dialkylanilino group, Y1 and Y2 independently represent C or N, if Y1 is N, then X1 is absent, if Y2 is N, then X4 is absent, Ra1 represents a hydrogen atom, an alkyl group, or an alkoxy group, and Rb1 to Rb4 independently represent a hydrogen atom, an alkyl group, an aryl group, or a heteroaryl group.

[0120] In equations (Le-4) to (Le-6), ERG, X1 to X4, Y1, Y2, Ra1, and Rb1 to Rb4 are equivalent to ERG, X1 to X4, Y1, Y2, Ra1, and Rb1 to Rb4 in equations (Le-1) to (Le-3), and the same applies to the preferred embodiment.

[0121] Furthermore, the leuco dye having the phthalide structure or fluorane structure described above is more preferably a compound represented by any of the following formulas (Le-7) to (Le-9), and is particularly preferably a compound represented by the following formula (Le-8), from the viewpoint of color development and visibility of the exposed area.

[0122] [ka]

[0123] In formulas (Le-7) to (Le-9), X1 to X4 each independently represent a hydrogen atom, a halogen atom, or a dialkylanilino group; Y1 and Y2 each independently represent C or N; if Y1 is N, X1 is absent; if Y2 is N, X4 is absent; 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, an aryl group, or a heteroaryl group; and Rc1 and Rc2 each independently represent an aryl group or a heteroaryl group.

[0124] In equations (Le-7) to (Le-9), X1 to X4, Y1 and Y2 are equivalent to X1 to X4, Y1 and Y2 in equations (Le-1) to (Le-3), and the preferred embodiment is also equivalent. In formula (Le-7) or formula (Le-9), Ra1 to Ra4 are each independently preferably alkyl groups or alkoxy groups, more preferably alkoxy groups, and particularly preferably methoxy groups, from the viewpoint of color development and visibility of the exposed area. In formulas (Le-7) to (Le-9), Rb1 to Rb4 are each independently preferably substituted with a hydrogen atom, an alkyl group, or an alkoxy group, more preferably an alkyl group, and particularly preferably a methyl group, from the viewpoint of color development and visibility of the exposed area. In formula (Le-8), Rc1 and Rc2 are each preferably a phenyl group or an alkylphenyl group, and more preferably a phenyl group, from the viewpoint of color development and visibility of the exposed area. Furthermore, Rc1 and Rc2 in formula (Le-8) are each preferably, from the viewpoint of color development and visibility of the exposed area, an aryl group having a substituent at least one ortho position, or a heteroaryl group having a substituent at least one ortho position, more preferably an aryl group having a substituent at least one ortho position, even more preferably a phenyl group having a substituent at least one ortho position, and particularly preferably a phenyl group having a substituent at least one ortho position and an electron-donating group at the para position. Examples of substituents in Rc1 and Rc2 are those described later. Furthermore, in formula (Le-8), from the viewpoint of color development and visibility of the exposed area, it is preferable that X1 to X4 are hydrogen atoms and Y1 and Y2 are carbon. Furthermore, in formula (Le-8), from the viewpoint of color development and visibility of the exposed area, it is preferable that Rb1 and Rb2 are each independently substituted with an alkyl group or an alkoxy group aryl group. Furthermore, in formula (Le-8), from the viewpoint of color development and visibility of the exposed area, it is preferable that Rb1 and Rb2 are each independently an aryl group or a heteroaryl group, more preferably an aryl group, even more preferably an aryl group having an electron-donating group, and particularly preferably a phenyl group having an electron-donating group at the para position. Furthermore, the electron-donating groups in Rb1, Rb2, Rc1, and Rc2 are preferably amino groups, alkylamino groups, arylamino groups, heteroarylamino groups, dialkylamino groups, monoalkylmonoarylamino groups, monoalkylmonoheteroarylamino groups, diarylamino groups, diheteroarylamino groups, monoarylmonoheteroarylamino groups, alkoxy groups, allyloxy groups, heteroaryloxy groups, or alkyl groups, more preferably alkoxy groups, allyloxy groups, heteroaryloxy groups, or alkyl groups, and particularly preferably alkoxy groups.

[0125] Furthermore, as an acid colorant, it is preferable to include a compound represented by the following formula (Le-10) from the viewpoint of color development and visibility of the exposed area.

[0126] [ka]

[0127] In formula (Le-10), each Ar1 independently represents an aryl group or a heteroaryl group, and each Ar2 independently represents an aryl group having a substituent at least one ortho position, or a heteroaryl group having a substituent at least one ortho position.

[0128] In equation (Le-10), Ar1 is equivalent to Rb1 and Rb2 in equations (Le-7) to (Le-9), and the same applies to the preferred embodiment. In equation (Le-10), Ar2 is synonymous with Rc1 and Rc2 in equations (Le-7) to (Le-9), and the preferred embodiment is similar.

[0129] Furthermore, as an acid colorant, it is preferable to include a compound represented by the following formula (Le-11) from the viewpoint of color development and visibility of the exposed area.

[0130] [ka]

[0131] In formula (Le-11), ERG each independently represents an electron-donating group, n11 represents an integer from 1 to 5, X1 to X4 each independently represents a hydrogen atom, a halogen atom, or a dialkylanilino group, Y1 and Y2 each independently represent C or N, if Y1 is N, then X1 is absent, if Y2 is N, then X4 is absent, and Rb2 and Rb4 each independently represent a hydrogen atom, an alkyl group, an aryl group, or a heteroaryl group.

[0132] In formula (Le-11), ERG, X1-X4, Y1, Y2, Rb2, and Rb4 are equivalent to ERG, X1-X4, Y1, Y2, Rb2, and Rb4 in formulas (Le-1) to (Le-3), respectively, and the same applies to the preferred embodiment. In equation (Le-11), n11 is preferably an integer between 1 and 3, and more preferably 1 or 2.

[0133] The alkyl groups in formulas (Le-1) to (Le-9) or (Le-11) may be linear, branched, or have a ring structure. Furthermore, the number of carbon atoms in the alkyl group in formulas (Le-1) to (Le-9) or (Le-11) is preferably 1 to 20, more preferably 1 to 8, even more preferably 1 to 4, and particularly preferably 1 or 2. In formulas (Le-1) to (Le-11), the number of carbon atoms in the aryl group is preferably 6 to 20, more preferably 6 to 10, and particularly preferably 6 to 8. Specific examples of aryl groups in formulas (Le-1) to (Le-11) include phenyl groups, naphthyl groups, anthracenyl groups, and phenantrenyl groups, which may have substituents. Specific examples of heteroaryl groups in formulas (Le-1) to (Le-11) include furyl groups, pyridyl groups, pyrimidyl groups, pyrazoyl groups, and thiophenyl groups, which may have substituents.

[0134] Furthermore, each of the monovalent organic groups, alkyl groups, aryl groups, heteroaryl groups, dialkylanilino groups, alkylamino groups, alkoxy groups, etc. in formulas (Le-1) to (Le-11) may have substituents. Examples of substituents include alkyl groups, aryl groups, heteroaryl groups, halogen atoms, amino groups, alkylamino groups, arylamino groups, heteroarylamino groups, dialkylamino groups, monoalkylmonoarylamino groups, monoalkylmonoheteroarylamino groups, diarylamino groups, diheteroarylamino groups, monoarylmonoheteroarylamino groups, hydroxyl groups, alkoxy groups, allyloxy groups, heteroallyloxy groups, acyl groups, alkoxycarbonyl groups, allyloxycarbonyl groups, heteroallyloxycarbonyl groups, cyano groups, etc. Moreover, these substituents may be further substituted with other substituents.

[0135] Furthermore, from the viewpoint of color development and visibility of the exposed area, the acid colorant preferably contains a compound represented by either of the following formulas 3a or 3b. In one preferred embodiment, the acid colorant is preferably a compound represented by either of the following formulas 3a or 3b.

[0136] [ka]

[0137] In formula (3a), Ar1 and Ar2 each independently represent an aryl group or a heteroaryl group. R 10 , R11 These independently represent a hydrogen atom, an alkyl group, an aryl group, and a heteroaryl group, respectively. In formula (3b), ERG each independently represents an electron-donating group, n represents an integer from 1 to 5, X1 to X4 each independently represents a hydrogen atom, a halogen atom, or a monovalent organic group, Y1 and Y2 each independently represent C or N, if Y1 is N, then X1 does not exist, if Y2 is N, then X4 does not exist, and R 12 and R 13 Each of these independently represents a hydrogen atom, an alkyl group, an aryl group, or a heteroaryl group.

[0138] The alkyl groups in formulas (3a) to (3b) may be linear, branched, or have a ring structure. Furthermore, the number of carbon atoms in the alkyl group in formulas (3a) to (3b) is preferably 1 to 20, more preferably 1 to 8, even more preferably 1 to 4, and particularly preferably 1 or 2. The number of carbon atoms in the aryl group in formulas (3a) to (3b) is preferably 6 to 20, more preferably 6 to 10, and particularly preferably 6 to 8. Specific examples of aryl groups in formulas (3a) to (3b) include phenyl groups, naphthyl groups, anthracenyl groups, and phenantrenyl groups, which may have substituents. Specific examples of heteroaryl groups in formulas (3a) to (3b) include furyl groups, pyridyl groups, pyrimidyl groups, pyrazoyl groups, and thiophenyl groups, which may have substituents. In equation (3b), ERG is synonymous with ERG in equations (Le-1) to (Le-3), and the preferred embodiment is also the same. In equation (3b), n is preferably an integer between 1 and 3, and more preferably 1 or 2. The monovalent organic group in equation (3b) is X5~X in equations (Le-2)~(Le-3). 10 This is synonymous with a monovalent organic group, and the preferred embodiment is similar.

[0139] Furthermore, each of the monovalent organic groups, alkyl groups, aryl groups, heteroaryl groups, etc. in formulas (3a) to (3b) may have substituents. Examples of substituents include alkyl groups, aryl groups, heteroaryl groups, halogen atoms, amino groups, alkylamino groups, arylamino groups, heteroarylamino groups, dialkylamino groups, monoalkylmonoarylamino groups, monoalkylmonoheteroarylamino groups, diarylamino groups, diheteroarylamino groups, monoarylmonoheteroarylamino groups, hydroxyl groups, alkoxy groups, allyloxy groups, heteroaryloxy groups, acyl groups, alkoxycarbonyl groups, allyloxycarbonyl groups, heteroaryloxycarbonyl groups, cyano groups, and the like. Moreover, these substituents may be further substituted with other substituents.

[0140] The following compounds are examples of leuco dyes having the above-mentioned phthalide structure or fluorane structure that are preferably used.

[0141] [ka]

[0142] [ka]

[0143] [ka]

[0144] [ka]

[0145] [ka]

[0146] [ka]

[0147] [ka]

[0148] [ka] TIFF0007830125000023.tif5651

[0149] [ka]

[0150] [ka]

[0151] Furthermore, in a preferred embodiment, the acid colorant preferably contains a compound (specific dye compound) having a decomposable group that is decomposed by acid and a structure that opens a ring or detaches a leaving group upon decomposition of the decomposable group.

[0152] From the viewpoint of color development and visibility of the exposed area, the above-mentioned decomposable group is preferably a group that decomposes with acid to produce an amino group or a hydroxyl group, and more preferably a group that decomposes with acid to produce an amino group. Furthermore, the amino group produced by the decomposition of the above-mentioned decomposable group may be an unsubstituted amino group or a monosubstituted amino group, but from the viewpoint of color development and visibility of the exposed area, it is preferable that it be a monosubstituted amino group, and more preferably an alkylamino group. Furthermore, the above-mentioned degradable group is preferably a group represented by the following formula 2a or formula 2b, and more preferably a group represented by the following formula 2a, from the viewpoint of color development and visibility of the exposed area.

[0153] [ka]

[0154] In equations 2a and 2b, R a R represents a hydrogen atom or an alkyl group. b R represents a hydrogen atom, alkyl group, aryl group, heteroaryl group, alkoxy group, or aryloxy group. c The symbol represents a protecting group for the hydroxyl group, and the wavy lines indicate the bonding position with other structures.

[0155] R a From the viewpoint of color development and visibility of the exposed area, it is preferably an alkyl group, more preferably an alkyl group having 1 to 8 carbon atoms, even more preferably an alkyl group having 1 to 4 carbon atoms, and particularly preferably a methyl group or an ethyl group. R b From the viewpoint of color development and visibility of the exposed area, it is preferably an alkoxy group or an aryloxy group, more preferably an alkoxy group, and even more preferably a tertiary alkoxy group, an arylmethoxy group, or a 2-trialkylsilylethoxy group. R c From the viewpoint of color development and visibility of the exposed area, it is preferably an acetal protecting group, an oxycarbonyl protecting group, an acyl group, or a silyl group; more preferably a tetrahydrofuranyl group, a tetrahydropyranyl group, a 1-alkoxyalkyl group, a tertiary alkoxycarbonyl group, an acyl group, or a trialkylsilyl group; even more preferably a tetrahydrofuranyl group, a tetrahydropyranyl group, a 1-alkoxyalkyl group, a tertiary alkoxycarbonyl group, or a trialkylsilyl group; and particularly preferably a tetrahydrofuranyl group, a tetrahydropyranyl group, or a trialkylsilyl group.

[0156] The specific dye compound only needs to have one or more degradable groups, but from the viewpoint of color development, the number of degradable groups in the specific dye compound is preferably 1 to 4, more preferably 1 or 2, and particularly preferably 1. Furthermore, from the viewpoint of color development and visibility of the exposed area, the above-mentioned degradable group is preferably a group having at least one structure selected from the group consisting of a urethane bond and a carbonate bond.

[0157] Furthermore, the groups formed by the decomposition of the above-mentioned decomposable groups preferably have a Hammett value of 0 or less, more preferably -0.3 or less, and even more preferably -1.0 or more and -0.5 or less. The method for calculating the Hammett value of a group in this invention shall be based on Chem. Rev., 1991, 97, 165-195. For example, the para and meta positions in each of the parent nuclear structures described later are defined as follows.

[0158] [ka]

[0159] When calculating the Hammett value for a group not described in the above literature, the value obtained by the following simplified formula using the equilibrium constant pKx of the corresponding substituted benzoic acid at 25°C and the equilibrium constant pKH = 4.201 for unsubstituted benzoic acid (J. Org. Chem., 1958, 23(3), pp420-427) shall be used. σ = pKx - pKH The value of substituted benzoic acid may be one known from literature, or it may be calculated experimentally using the method described below. A substituted benzoic acid is added to an ethanol / water = 50 / 50 solution, and the solution is titrated with a 0.1N NaOH aqueous solution at 25°C. The pKx is calculated from the pH at the half-neutralization point. Since it is a weak acid, the pH at the half-neutralization point can be assumed to be equal to the pKx.

[0160] Specifically, as the above-mentioned degradable group, from the viewpoint of color development and visibility of the exposed area, a group represented by any of the following formulas D-1 to D-5 is preferred, a group represented by any of the following formulas D-1 to D-4 is more preferred, a group represented by any of the following formulas D-1 to D-3 is even more preferred, and a group represented by the following formula D-1 is preferred. The dashed lines indicate the bonding position with other structures.

[0161] [ka]

[0162] In formulas D-1 to D-5, R D1 R represents an alkyl group. D2 R represents an alkyl group or aryl group. D3 R represents an alkyl group. D4 R represents a hydrogen atom or an alkyl group. D5 R represents an alkyl group. D4 and R D5 The doves may be bonded together to form a ring, R D6 Each of these independently represents an alkyl group or an aryl group, and R D7 represents an alkyl group or aryl group.

[0163] R D1 From the viewpoint of color development and visibility of the exposed area, it is preferably an alkyl group having 1 to 8 carbon atoms, more preferably an alkyl group having 1 to 4 carbon atoms, and particularly preferably a methyl group or an ethyl group. R D2 From the viewpoint of color development and visibility of the exposed area, it is preferably an alkyl group, and more preferably a tertiary alkyl group, an arylmethyl group, or a 2-trialkylsilylethyl group. R D3 From the viewpoint of color development and visibility of the exposed area, it is preferable that it be a tertiary alkyl group. R D4 and R D5From the viewpoint of color development and visibility of the exposed area, it is preferable that the elements are bonded to form a ring, and more preferably that they are bonded to form a 5- or 6-membered ring. Furthermore, from the viewpoint of color development and visibility of the exposed area, R D4 R is a hydrogen atom, D5 An embodiment in which is an alkyl group is also preferred. R D6 Each of these groups is preferably an alkyl group, and particularly preferably a methyl group, from the viewpoint of color development and visibility of the exposed area. R D7 From the viewpoint of color development and visibility of the exposed area, it is preferably an alkyl group, more preferably an alkyl group having 1 to 4 carbon atoms, and even more preferably a methyl group.

[0164] From the viewpoint of color development, the structure that opens a ring or has a leaving group removed by the decomposition of the above-mentioned decomposable group is preferably the structure that opens a ring by the decomposition of the above-mentioned decomposable group. Furthermore, from the viewpoint of color development and visibility of the exposed area, the specific dye compound is preferably a compound having three carbon atoms and one heteroatom (preferably a nitrogen atom or an oxygen atom, more preferably an oxygen atom) bonded to a quaternary carbon atom as the portion that opens the ring or detaches a leaving group.

[0165] As for the structure that opens the ring or detaches the leaving group upon decomposition of the above-mentioned decomposable group, it is preferable that the structure is represented by any of the following formulas 1a to 1d, more preferably by any of the following formulas 1a to 1c, and particularly preferably by the structure represented by the following formula 1a, from the viewpoint of color development and suppression of fading over time. In one preferred embodiment, the acid colorant has a structure that undergoes ring-opening or leaving group elimination by decomposition of a decomposable group, and it is preferable that the structure that undergoes ring-opening or leaving group elimination by decomposition of the decomposable group is represented by any of the following formulas 1a to 1d.

[0166] [ka]

[0167] In formulas 1a to 1d, R 1 and R 2 This represents the portion that connects to the core structure of the acid colorant (e.g., a specific dye compound), R 3 and R 4 R represents an aryl group or a heteroaryl group. 5 represents a hydrocarbon group, and X represents the above-mentioned leaving group.

[0168] R 3 and R 4 From the viewpoint of color development, it is preferably an aryl group having 6 to 12 carbon atoms or a heteroaryl group having 2 to 12 carbon atoms, more preferably an aryl group having 6 to 12 carbon atoms, and even more preferably a phenyl group. R 5 From the viewpoint of color development, it is preferably an alkyl group or an aryl group, more preferably an aryl group, even more preferably an aryl group having 6 to 12 carbon atoms, and particularly preferably a phenyl group. X is not particularly limited as long as it is a group that can be removed by the decomposition of the above-mentioned decomposable group, but it is preferably an acyloxy group, more preferably an acyloxy group having 1 to 8 carbon atoms, and even more preferably an acetyloxy group.

[0169] From the viewpoint of color development, the acid colorant (preferably a specific dye compound) preferably has a core structure represented by any of the following formulas 2a to 2f, and more preferably has a structure represented by the following formula 2a.

[0170] [ka]

[0171] In formulas 2a to 2f, structure b represents a structure that opens up the ring upon decomposition of the above-mentioned decomposable group, and R1-R9 each independently represent a hydrogen atom, an alkyl group, or an alkoxy group. The structures represented by formulas 2a to 2f have one or more of the above-mentioned decomposable groups on the aromatic ring in formulas 2a to 2f.

[0172] The alkyl groups R1 to R9 are not particularly limited, but are more preferably alkyl groups having 1 to 8 carbon atoms, even more preferably alkyl groups having 1 to 4 carbon atoms, and are particularly preferably methyl or ethyl groups. The alkoxy groups R1 to R9 are not particularly limited, but are more preferably alkoxy groups having 1 to 8 carbon atoms, even more preferably alkoxy groups having 1 to 4 carbon atoms, and particularly preferably alkoxy groups having 1 to 2 carbon atoms.

[0173] In formulas 2a to 2f, structure b represents a structure that opens its ring upon decomposition of the above-mentioned decomposable group, and the structures represented by formulas 2a to 2f have one or more of the above-mentioned decomposable groups on the aromatic ring in formulas 2a to 2f.

[0174] Structure b is preferably a structure represented by any of formulas 1a to 1d, from the viewpoint of color development and visibility of the exposed area. The structures represented by formulas 2a to 2f above have one or more of the above-mentioned decomposable groups on the aromatic ring in formulas 2a to 2f, and may also have substituents on the aromatic ring. Preferred substituents include alkyl groups, aryl groups, alkoxy groups, allyloxy groups, dialkylamino groups, diarylamino groups, alkylarylamino groups, arylamino groups, and alkylamino groups. In particular, from the viewpoint of color development and visibility of the exposed area, it is preferable that the substituent has at least one dialkylamino group.

[0175] The specific dye compound is particularly preferably a compound represented by the following formula D-6, from the viewpoint of color development and visibility of the exposed area.

[0176] [ka]

[0177] In formula D-6, R D8 R represents the above-mentioned decomposable group, D9 Each of these independently represents an alkyl group or an aryl group, and R D10 Each of the characters independently represents an alkyl group or an aryl group, and each of the characters independently represents an integer from 0 to 3.

[0178] R D9 Each of these groups is preferably an alkyl group having 1 to 12 carbon atoms or an aryl group having 6 to 12 carbon atoms, more preferably an alkyl group having 1 to 4 carbon atoms, a benzyl group or a phenyl group, and even more preferably an alkyl group having 1 to 4 carbon atoms, from the viewpoint of color development and visibility of the exposed area. R D10 Each of these is preferably an alkyl group, and more preferably a methyl group. Each of nd is preferably 0 or 1, and more preferably 0.

[0179] The following are preferred examples of specific dye compounds, but it goes without saying that the list is not limited to these. Note that "Ph" represents a phenyl group.

[0180] [ka]

[0181] [ka]

[0182] [ka]

[0183] [ka]

[0184] [ka]

[0185] [ka]

[0186] [ka]

[0187] There are no particular restrictions on the method for preparing specific dye compounds; they can be prepared by referring to known methods for preparing leuco dyes and methods for introducing degradable groups.

[0188] It is also possible to use commercially available acid colorants, such as ETAC, RED500, RED520, CVL, S-205, BLACK305, BLACK400, BLACK100, BLACK500, H-7001, GREEN300, NIRBLACK78, BLUE220, H-3035, BLUE203, ATP, H-1046, H-2114 (all manufactured by Fukui Yamada Chemical Industry Co., Ltd.), ORANGE-DCF, and Vermilio. Examples include n-DCF, PINK-DCF, RED-DCF, BLMB, CVL, GREEN-DCF, TH-107 (all manufactured by Hodogaya Chemical Co., Ltd.), ODB, ODB-2, ODB-4, ODB-250, ODB-BlackXV, Blue-63, Blue-502, GN-169, GN-2, Green-118, Red-40, Red-8 (all manufactured by Yamamoto Kasei Co., Ltd.), and Crystal Violet Lactone (manufactured by Tokyo Chemical Industry Co., Ltd.). Among these commercially available products, ETAC, S-205, BLACK305, BLACK400, BLACK100, BLACK500, H-7001, GREEN300, NIRBLACK78, H-3035, ATP, H-1046, H-2114, GREEN-DCF, Blue-63, GN-169, and Crystal Violet Lactone are preferred because the resulting film has good visible light absorption.

[0189] These acid colorants may be used individually or in combination of two or more components. The acid colorant content should be 5-100 mg / m² from the perspective of visibility and print durability. 2 Preferably, 10-70 mg / m² 2 More preferably, 15-50 mg / m² 2 That is even more preferable.

[0190] The image recording layer may contain components other than acid colorants as appropriate. Details of each component included in the image recording layer will be described later.

[0191] [Oxo salts with a molecular weight of 1,000 or less] In the first lithographic printing plate according to the present invention, at least one of the one or more layers including the image recording layer contains an oxo salt with a molecular weight of 1,000 or less. Preferably, the compound does not have an unsaturated double bond group in its molecule. The content of the compound is substantially the same in at least one plane of one or more layers, including the image recording layer.

[0192] This document describes oxo salts with a molecular weight of 1,000 or less (hereinafter also referred to as "specific low molecular weight compounds" or "oxo salts") that are contained in at least one of one or more layers, including an image recording layer. The specific low molecular weight compound efficiently adsorbs to cracks during on-board development and has the property of making the cracks hydrophilic, thus contributing to the prevention of edge fouling. The specific low molecular weight compound is an oxo salt and has support adsorption properties.

[0193] The molecular weight of the specific low molecular weight compound is 1,000 or less. Having a molecular weight of 1,000 or less allows it to easily move to the surface of the anodic oxide film during on-pressure development, resulting in excellent edge fouling prevention. The molecular weight is preferably 50 to 1,000, more preferably 50 to 800, and even more preferably 50 to 600.

[0194] It is preferable that the specific low molecular weight compound does not have an unsaturated double bond group in its molecule. An unsaturated double bond group is a polymerizable group and includes ethylenically unsaturated groups such as (meth)acrylic groups, vinyl groups, allyl groups, and styryl groups. By the specific low molecular weight compound not having an unsaturated double bond group in its molecule, it is possible to suppress the curing of the specific low molecular weight compound together with at least one of the one or more layers, including the image recording layer, during exposure.

[0195] As a specific low molecular weight compound, oxo salts are used. Oxo acids are compounds in which a hydroxyl group (-OH) and an oxo group (=O) are bonded to the same atom, and the hydroxyl group provides an acidic proton. Examples of salts that make up oxoacids include alkali metal salts, alkaline earth metal salts, and ammonium salts. The countercation in oxo salts is not particularly limited, but metal ions and onium ions are preferably used. Among these, sodium ions, potassium ions, calcium ions, lithium ions, ammonium ions, and sulfonium ions are preferably used as countercations due to their ease of handling and solubility in coating solutions.

[0196] The above oxo salt preferably contains at least one selected from the group consisting of phosphates, phosphonates, phosphinates, carboxylates, sulfates, sulfites, sulfonates, sulfinates, nitrates, nitrites, and silicates.

[0197] Examples of phosphates include monosodium phosphate, disodium phosphate, trisodium phosphate, monopotassium phosphate, dipotassium phosphate, tripotassium phosphate, monoammonium phosphate, disammonium phosphate, sodium hexametaphosphate, sodium phytate, sodium pyrophosphate, sodium polyphosphate, and sodium metaphosphate.

[0198] Examples of phosphonates include phosphonic acid, ethylphosphonic acid, propylphosphonic acid, i-propylphosphonic acid, butylphosphonic acid, hexylphosphonic acid, octylphosphonic acid, dodecylphosphonic acid, octadecylphosphonic acid, 2-hydroxyethylphosphonic acid, 1,5-pentanediphosphonic acid, and sodium, potassium, or ammonium salts of aminomethylphosphonic acid. Examples of phosphinates include sodium salts, potassium salts, or ammonium salts of phosphinic acid, phenylphosphonic acid, and diphenylphosphonic acid.

[0199] Examples of carboxylate salts include citric acid, glutaric acid, glyceric acid, gluconic acid, tartaric acid, mevalonic acid, pantoic acid, quinic acid, shikimic acid, gallic acid, caffeic acid, 2,3-dihydroxybenzoic acid, 2,4-dihydroxybenzoic acid, 2,5-dihydroxybenzoic acid, 2,6-dihydroxybenzoic acid, 3,4-dihydroxybenzoic acid, 3,5-dihydroxybenzoic acid, 2,3,4-trihydroxybenzoic acid, and sodium, potassium, or ammonium salts of 3,4,5-trihydroxybenzoic acid. Examples of sulfates include sodium sulfate, potassium sulfate, and ammonium sulfate.

[0200] Examples of sulfites include ammonium sulfite, potassium sulfite, sodium sulfite, sodium bisulfite, calcium sulfite, and calcium bisulfite. Examples of sulfonates include p-toluenesulfonic acid, methanesulfonic acid, and sodium, potassium, or ammonium salts of 10-camphorsulfonic acid. Examples of sulfinates include methanesulfinic acid, p-toluenesulfinic acid, and sodium, potassium, or ammonium salts of benzenesulfinic acid.

[0201] Examples of nitrates include sodium nitrate, potassium nitrate, and ammonium nitrate. Examples of nitrites include potassium nitrite, calcium nitrite, and sodium nitrite. Examples of silicates include sodium silicate and potassium silicate.

[0202] The above oxo salt more preferably contains at least one selected from the group consisting of phosphates, phosphonates, phosphinates, carboxylates, sulfates, sulfites, sulfinates, nitrates, and nitrites, and even more preferably contains at least one selected from the group consisting of phosphates, phosphonates, and phosphinates.

[0203] Particularly preferred low molecular weight compounds include monosodium phosphate, monoammonium phosphate, disammonium phosphate, sodium hexametaphosphate, sodium phytate, sodium phosphinate, sodium gluconate, sodium citrate, sodium p-toluenesulfonate, trisodium phosphate, sodium pyrophosphate, sodium phosphonate, sodium 2-hydroxyethylphosphonate, sodium ethylphosphonate, and sodium phenylphosphinate.

[0204] Specific low molecular weight compounds may be used individually or in combination of two or more. The content of specific low molecular weight compounds is 10-200 mg / m², from the viewpoint of suppressing edge staining and improving print resistance. 2 Preferably, 30-150 mg / m² 2 More preferably, 50-100 mg / m² 2 That is even more preferable.

[0205] In the present invention, the content of the specific low molecular weight compound is substantially the same within at least one plane of one or more layers including the image recording layer. Here, "the content of the specific low molecular weight compound is substantially the same within at least one plane of one or more layers including the image recording layer" means that the specific low molecular weight compound is distributed almost uniformly within at least one plane of one or more layers including the image recording layer, and there is no substantial difference in the content of the specific low molecular weight compound between the center and the edges of the lithographic printing plate. In other words, it means that there is no difference in content other than the difference in the content of the specific low molecular weight compound within at least one plane of one or more layers including the image recording layer, which may normally occur when at least one of the one or more layers including the image recording layer is coated. Therefore, the present invention is different from intentionally applying a specific low molecular weight compound only to the edges of a lithographic printing plate to create a state in which the content of the specific low molecular weight compound at the edges is greater than the content of the specific low molecular weight compound in areas other than the edges.

[0206] The oxo salt additive layer is not particularly limited, but from the viewpoint of print resistance, it is preferable to add it to the protective layer. In one preferred embodiment, it is preferable that at least one of the one or more layers including the image recording layer is a protective layer.

[0207] (Second lithographic printing plate) The second lithographic printing plate of the present invention will now be described. The aluminum support is the same as the aluminum support in the first lithographic printing plate described above. The image recording layer in the second lithographic printing plate contains an acid colorant. The acid colorant is the same as the acid colorant in the image recording layer of the first lithographic printing plate described above. The second lithographic printing plate contains a support-adsorbing compound with a molecular weight of 1000 or less in at least one of the one or more layers described above.

[0208] [Support-adsorbing compounds with a molecular weight of 1,000 or less] In the second lithographic printing plate of the present invention, at least one of the one or more layers including the image recording layer contains a support-adsorbing compound with a molecular weight of 1,000 or less (hereinafter also simply referred to as "compound A"). The support-adsorbing compound preferably does not have an unsaturated double bond group in its molecule. The content of the support-adsorbing compound is substantially the same in at least one plane of one or more layers, including the image recording layer.

[0209] One characteristic of compound A is its ability to adsorb to a support. Here, "support adsorption" refers to its ability to adsorb to the anodic oxide film on the aluminum support. The presence or absence of adsorption to the anodic oxide film can be easily determined by the following method. Specifically, a solution is prepared by dissolving the test compound in an easily soluble solvent (e.g., water). The coating amount after drying of this solution is 30 mg / m². 2 The test compound is applied to an aluminum support having an anodic oxide coating and dried. Next, the aluminum support coated with the test compound is washed and dried five times using the above-mentioned easily soluble solvent, and the amount of test compound remaining that was not removed by washing is measured. The amount of remaining compound can be measured either by directly quantifying the amount of remaining test compound or by quantifying the amount of test compound dissolved in the washing solution. The quantification of the test compound can be performed, for example, by X-ray fluorescence measurement or reflectance spectroscopic absorbance measurement. The remaining amount is 1 mg / m². 2 If the above conditions are met, the test compound is determined to have support adsorption properties.

[0210] Compound A preferably has a support adsorption property and therefore has a group that exhibits adsorption to the anodic oxide film on the aluminum support. Examples of groups that exhibit adsorption to the anodic oxide film on the aluminum support include functional groups that can form chemical bonds (e.g., ionic bonds, hydrogen bonds, coordination bonds) with substances (e.g., metals, metal oxides) or functional groups (e.g., hydroxyl groups) present on the surface of the anodic oxide film. Among such functional groups, salts of acidic groups are preferred. Examples of acidic groups include phenolic hydroxyl groups, carboxyl groups, -SO3H, -OSO3H, -PO3H2, -OPO3H2, -CONHSO2-, -SO2NHSO2-, and -COCH2COCH3. -OPO3H2 and -PO3H2 are particularly preferred. Examples of salts formed by acidic groups include alkali metal salts, alkaline earth metal salts, and ammonium salts.

[0211] The compound A described above is not particularly limited, but specifically, it can be described as an "oxo salt" contained in "at least one of the one or more layers" of the first lithographic printing plate described above. The same applies to preferred ranges, content, etc.

[0212] In the second lithographic printing plate, the content of compound A is substantially the same in at least one plane of one or more layers including the image recording layer. Here, "the content of compound A is substantially the same in at least one plane of one or more layers including the image recording layer" means that compound A is distributed almost uniformly in at least one plane of one or more layers including the image recording layer, and there is no substantial difference in the content of compound A between the center and the edges of the lithographic printing plate. In other words, it means that there is no difference in content other than the difference in the content of compound A in at least one plane of one or more layers including the image recording layer, which can normally occur when at least one of the layers including the image recording layer is coated. Therefore, the present invention differs from intentionally applying compound A only to the edges of a lithographic printing plate to create a state in which the content of compound A at the edges is greater than the content of compound A in areas other than the edges.

[0213] In the second lithographic printing plate of the present invention, the lithographic printing plate 50 cm 2 The pH of the solution obtained by immersing the substance in 5 mL of water is between 6.5 and 9.0. The above-mentioned gel is measured as follows: The resulting lithographic printing plate was 50 cm in diameter. 2 1cm 2 The material was cut into 50 small pieces and placed in a glass bottle. 5.0 mL of pure water was added, and the glass bottle was treated in an ultrasonic cleaner for 1 hour. After that, the pH of the water in which the lithographic printing plate was immersed was measured. The water temperature at this time was 25°C.

[0214] The pH range is between 6.5 and 9.0. To adjust the pH in this way, one possible method, though not limited to, is to use the oxoate salt used in the first lithographic printing plate as compound A contained in the second lithographic printing plate.

[0215] The pH is 6.5 or higher, preferably 6.8 or higher, and more preferably 7.0 or higher. Furthermore, the pH is 9.0 or lower, preferably 8.7 or lower, and more preferably 8.5 or lower.

[0216] If the pH is set below 6.5, the acid-based coloring agent will be more susceptible to degradation by acid during the long-term storage of the lithographic printing plates, making it difficult to suppress the development of color on the plate surface before exposure. Furthermore, if the pH is set above 9.0, the adhesion of compound A to the support decreases compared to a lithographic printing plate with a pH of 9.0 or lower, making it difficult to obtain the edge stain suppression effect.

[0217] In the first lithographic printing plate and the second lithographic printing plate of the present invention, "one or more layers including an image recording layer" includes at least an image recording layer. Other layers besides the image recording layer are not particularly limited, but examples include a primer layer and a protective layer. The above-mentioned undercoat layer is formed on the above-mentioned support, and the above-mentioned protective layer is formed on the image recording layer. "One or more layers including an image recording layer" includes the following four embodiments: <1> Image recording layer only <2> Undercoat layer and image recording layer <3> Image recording layer and protective layer <4> Undercoat layer, image recording layer, and protective layer

[0218] One of the above-mentioned layers is, for example, at least one layer selected from the group consisting of an image recording layer, an undercoat layer, and a protective layer. Furthermore, at least one of the above-mentioned layers may include, for example, two or more layers selected from the group consisting of an image recording layer, an undercoat layer, and a protective layer.

[0219] The first lithographic printing plate according to the present invention contains an oxo salt with a molecular weight of 1000 or less in at least one of the one or more layers. In a preferred embodiment, the image recording layer contains the above-mentioned oxo salt. This is the case where at least one of the one or more layers is an image recording layer. In another preferred embodiment, the first lithographic printing plate of the present invention has a primer layer on a support, and the primer layer contains the oxoate salt. Furthermore, in a preferred embodiment, the first lithographic printing plate of the present invention has a protective layer on an image recording layer, wherein the protective layer contains the oxoate salt.

[0220] The second lithographic printing plate according to the present invention contains compound A in at least one of the one or more layers. In a preferred embodiment, the image recording layer contains the compound A. This is the case where at least one of the one or more layers is an image recording layer. In another preferred embodiment, the second lithographic printing plate of the present invention has a primer layer on a support, wherein the primer layer contains compound A. Furthermore, in a preferred embodiment, the second lithographic printing plate of the present invention has a protective layer on top of the image recording layer, wherein the protective layer contains the compound A.

[0221] The lithographic printing plate of the present invention has one or more layers, including an image recording layer. Furthermore, the image recording layer is preferably a negative-type image recording layer, and more preferably a water-soluble or water-dispersible negative-type image recording layer. From the viewpoint of on-press developmentability, it is preferable that the lithographic printing plate used in the present invention allows for the removal of unexposed portions of the image recording layer by at least one of dampening solution and printing ink. The lithographic printing plate of the present invention has an aluminum support and the image recording layer described above, but any of the following configurations can also be preferred. (1) The lithographic printing plate has an aluminum support, an image recording layer, and a protective layer in that order. (2) The lithographic printing plate has an aluminum support, an undercoat layer, and an image recording layer in that order. (3) The lithographic printing plate has an aluminum support, an undercoat layer, an image recording layer, and a protective layer in this order.

[0222] The image recording layer may contain components other than acid colorants as appropriate. In the lithographic printing plate of the present invention, the image recording layer preferably contains a polymerizable compound, a polymerization initiator, and an infrared absorber.

[0223] [Polymerizable compound] The image recording layer in the present invention preferably contains a polymerizable compound. In this invention, a polymerizable compound refers to a compound having a polymerizable group. The polymerizable group is not particularly limited and any known polymerizable group is acceptable, but it is preferably an ethylenically unsaturated group. Furthermore, the polymerizable group may be a radical polymerizable group or a cationic polymerizable group, but it is preferably a radical polymerizable group. Examples of radical polymerizable groups include (meth)acryloyl groups, allyl groups, vinylphenyl groups, and vinyl groups, with (meth)acryloyl groups being preferred from the viewpoint of reactivity. The molecular weight of the polymerizable compound (or weight-average molecular weight if it has a molecular weight distribution) is preferably 50 or more and less than 2,500.

[0224] The polymerizable compound used in the present invention may be, for example, a radical polymerizable compound or a cationic polymerizable compound, but it is preferable that it be an addition polymerizable compound (ethylenically unsaturated compound) having at least one ethylenically unsaturated bond. The ethylenically unsaturated compound is preferably a compound having at least one terminal ethylenically unsaturated bond, and more preferably a compound having two or more terminal ethylenically unsaturated bonds. The polymerizable compound may have chemical forms such as monomers, prepolymers, i.e., dimers, trimers or oligomers, or mixtures thereof. In particular, from the viewpoint of print resistance, the polymerizable compound preferably contains a polymerizable compound with three or more functions, more preferably a polymerizable compound with seven or more functions, and even more preferably a polymerizable compound with ten or more functions. Furthermore, from the viewpoint of print resistance in the resulting lithographic printing plate, the polymerizable compound preferably contains an ethylenically unsaturated compound with three or more functions (preferably seven or more functions, more preferably ten or more functions), and even more preferably a (meth)acrylate compound with three or more functions (preferably seven or more functions, more preferably ten or more functions).

[0225] Furthermore, from the viewpoint of on-pressure developability and stain suppression, the polymerizable compound preferably contains a polymerizable compound with two or fewer functions, more preferably a bifunctional polymerizable compound, and particularly preferably a bifunctional (meth)acrylate compound. The content of a bifunctional polymerizable compound (preferably a bifunctional polymerizable compound) is preferably 5% to 100% by mass, more preferably 10% to 100% by mass, and particularly preferably 15% to 100% by mass, relative to the total mass of polymerizable compounds in the image recording layer, from the viewpoint of print resistance, on-press developability, and stain suppression.

[0226] -Oligomer- It is preferable that the polymerizable compound contained in the image recording layer is an oligomeric polymerizable compound (hereinafter also simply referred to as "oligomer"). In the present invention, an oligomer refers to a polymerizable compound having a molecular weight (or weight-average molecular weight if it has a molecular weight distribution) of 600 or more and 40,000 or less, and containing at least one polymerizable group. From the viewpoint of excellent chemical resistance and print resistance, the molecular weight of the oligomer is preferably between 1,000 and 25,000.

[0227] Furthermore, from the viewpoint of improving print resistance, the number of polymerizable groups in one oligomer molecule is preferably 2 or more, more preferably 3 or more, even more preferably 6 or more, and particularly preferably 10 or more. Furthermore, there is no particular upper limit on the number of polymerizable groups in the oligomer, but it is preferable that the number of polymerizable groups be 20 or less.

[0228] From the viewpoint of print resistance and on-press developability, the oligomer preferably has 7 or more polymerizable groups and a molecular weight of 1,000 to 40,000, and more preferably has 7 to 20 polymerizable groups and a molecular weight of 1,000 to 25,000. Furthermore, the product may contain polymer components that may be generated during the manufacturing process of the oligomer.

[0229] From the viewpoint of print resistance, visibility, and on-press developability, the oligomer preferably has at least one compound selected from the group consisting of compounds having a urethane bond, compounds having an ester bond, and compounds having an epoxy residue, and it is preferable that it has a compound having a urethane bond. In this invention, the term "epoxy residue" refers to a structure formed by an epoxy group, and means a structure similar to that obtained by a reaction between an acid group (such as a carboxylic acid group) and an epoxy group.

[0230] As for compounds having a urethane bond, those described in International Publication No. 2020 / 262692 can be suitably used.

[0231] Furthermore, as a compound having a urethane bond, a compound obtained by introducing polymerizable groups through a polymer reaction into a polyurethane obtained by the reaction of a polyisocyanate compound and a polyol compound may be used. For example, a compound having a urethane bond may be obtained by reacting a polyurethane oligomer, which is obtained by reacting a polyol compound having an acid group with a polyisocyanate compound, with a compound having an epoxy group and a polymerizable group.

[0232] In a compound having an ester bond, which is an example of an oligomer, the number of polymerizable groups is preferably 3 or more, and more preferably 6 or more.

[0233] As examples of oligomers containing epoxy residues, compounds containing a hydroxyl group within the compound are preferred. Furthermore, the number of polymerizable groups in the compound having epoxy residues is preferably 2 to 6, and more preferably 2 to 3. Compounds having the above-mentioned epoxy residue can be obtained, for example, by reacting a compound having an epoxy group with acrylic acid.

[0234] Specific examples of oligomers are shown in the table below, but the oligomers used in the present invention are not limited to these. Commercial oligomers may be used, including, but are not limited to, UA510H, UA-306H, UA-306I, UA-306T (all manufactured by Kyoeisha Chemical Co., Ltd.), UV-1700B, UV-6300B, UV7620EA (all manufactured by Nippon Synthetic Chemical Industry Co., Ltd.), U-15HA (manufactured by Shin Nakamura Chemical Industry Co., Ltd.), EBECRYL450, EBECRYL657, EBECRYL885, EBECRYL800, EBECRYL3416, EBECRYL860 (all manufactured by Daicel Ornex Co., Ltd.).

[0235] From the viewpoint of improving chemical resistance, print resistance, and suppression of on-press development residue, the oligomer content is preferably 30% to 100% by mass, more preferably 50% to 100% by mass, and even more preferably 80% to 100% by mass, based on the total mass of polymerizable compounds in the image recording layer.

[0236] -Low molecular polymerizable compounds- The polymerizable compound may further contain polymerizable compounds other than the above-mentioned oligomer. From the viewpoint of chemical resistance, polymerizable compounds other than oligomers are preferably low-molecular-weight polymerizable compounds. Low-molecular-weight polymerizable compounds may be in chemical forms such as monomers, dimers, trimers, or mixtures thereof. Furthermore, from the viewpoint of chemical resistance, the low molecular weight polymerizable compound is preferably at least one polymerizable compound selected from the group consisting of polymerizable compounds having three or more ethylenically unsaturated groups and polymerizable compounds having an isocyanuric ring structure.

[0237] In this invention, a low molecular weight polymerizable compound refers to a polymerizable compound with a molecular weight (or weight-average molecular weight, if it has a molecular weight distribution) of 50 or more and less than 800. The molecular weight of the low molecular weight polymerizable compound is preferably 100 or more and less than 800, more preferably 300 or more and less than 800, and even more preferably 400 or more and less than 800, from the viewpoint of excellent chemical resistance, print resistance, and suppression of on-press developer residue.

[0238] When the polymerizable compound includes low molecular weight polymerizable compounds as polymerizable compounds other than oligomers (the total amount if it includes two or more types of low molecular weight polymerizable compounds), from the viewpoint of chemical resistance, print resistance, and suppression of on-press developer residue, the ratio of the oligomer to the low molecular weight polymerizable compound (oligomer / low molecular weight polymerizable compound) is preferably 10 / 1 to 1 / 10 by mass, more preferably 10 / 1 to 3 / 7, and even more preferably 10 / 1 to 7 / 3.

[0239] Furthermore, as low molecular weight polymerizable compounds, polymerizable compounds described in paragraphs 0082 to 0086 of International Publication No. 2019 / 013268 can also be suitably used.

[0240] The structure of the polymerizable compound, whether it is used alone or in combination, and the amount added, as well as other details of its usage, can be arbitrarily determined. In particular, the image recording layer preferably contains two or more polymerizable compounds from the viewpoint of print resistance. The content of polymerizable compounds (or the total content of polymerizable compounds if two or more polymerizable compounds are included) is preferably 5% to 75% by mass, more preferably 10% to 70% by mass, and even more preferably 15% to 60% by mass, relative to the total solid content of the image recording layer.

[0241] [Polymerization initiator] The image recording layer in the present invention preferably contains a polymerization initiator. Furthermore, from the viewpoint of sensitivity, print resistance, on-press developability, and ink adhesion, the polymerization initiator preferably includes an electron-donating polymerization initiator, and more preferably includes both an electron-accepting polymerization initiator and an electron-donating polymerization initiator.

[0242] -Electron-accepting polymerization initiator- The image recording layer described above preferably contains an electron-accepting polymerization initiator as a polymerization initiator. Electron-accepting polymerization initiators are compounds that, when electrons in an infrared absorber are excited by infrared exposure, accept one electron through intermolecular electron transfer, thereby generating polymerization initiator species such as radicals. The electron-accepting polymerization initiator used in the present invention is a compound that generates polymerization initiator species such as radicals or cations in response to light, heat, or both of these energies, and can be appropriately selected and used from known thermal polymerization initiators, compounds having bonds with low bond dissociation energy, photopolymerization initiators, and the like. As electron-accepting polymerization initiators, radical polymerization initiators are preferred, and onium compounds are more preferred. Furthermore, an infrared photosensitive polymerization initiator is preferred as the electron-accepting polymerization initiator. Examples of electron-accepting radical polymerization initiators 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.

[0243] (a) As organic halides, for example, the compounds described in paragraphs 0022 to 0023 of Japanese Patent Publication No. 2008-195018 are preferred. (b) As a carbonyl compound, for example, the compound described in paragraph 0024 of Japanese Patent Publication No. 2008-195018 is preferred. (c) As the azo compound, for example, the azo compound described in Japanese Patent Publication No. 8-108621 can be used. (d) As for the organic peroxide, for example, the compound described in paragraph 0025 of Japanese Patent Application Publication No. 2008-195018 is preferred. (e) As a metallocene compound, for example, the compound described in paragraph 0026 of Japanese Patent Publication No. 2008-195018 is preferred. (f) Examples of azide compounds include 2,6-bis(4-azidobenzylidene)-4-methylcyclohexanone. (g) As a hexaarylbiimidazole compound, for example, the compound described in paragraph 0027 of Japanese Patent Publication No. 2008-195018 is preferred. (i) Examples of disulfone compounds include those described in Japanese Patent Publication No. 61-166544 and Japanese Patent Publication No. 2002-328465. (j) As oxime ester compounds, for example, the compounds described in paragraphs 0028 to 0030 of Japanese Patent Publication No. 2008-195018 are preferred.

[0244] Among the electron-accepting polymerization initiators mentioned above, oxime ester compounds and onium compounds are preferred from the viewpoint of curability. In particular, iodonium salt compounds, sulfonium salt compounds, or azinium salt compounds are preferred from the viewpoint of print resistance, iodonium salt compounds or sulfonium salt compounds are more preferred, and iodonium salt compounds are especially preferred. Specific examples of these compounds are shown below, but the present invention is not limited thereto.

[0245] Examples of iodonium salt compounds include diaryliodonium salt compounds, more preferably diphenyliodonium salt compounds substituted with electron-donating groups, such as alkyl or alkoxyl groups, and asymmetric diphenyliodonium salt compounds. Specific examples include diphenyliodonium = hexafluorophosphate, 4-methoxyphenyl-4-(2-methylpropyl)phenyliodonium = hexafluorophosphate, 4-(2-methylpropyl)phenyl-p-tolylliodonium = hexafluorophosphate, 4-hexyloxyphenyl-2,4,6-trimethoxyphenyliodonium = hexafluorophosphate, 4-hexyloxyphenyl-2,4-diethoxyphenyliodonium = tetrafluoroborate, 4-octyloxyphenyl-2,4,6-trimethoxyphenyliodonium = 1-perfluorobutanesulfonate, 4-octyloxyphenyl-2,4,6-trimethoxyphenyliodonium = hexafluorophosphate, and bis(4-t-butylphenyl)iodonium = hexafluorophosphate.

[0246] Examples of sulfonium salt compounds include triarylsulfonium salt compounds, and particularly preferred are triarylsulfonium salt compounds in which at least a portion of the electron-withdrawing group, for example, the group on the aromatic ring, is substituted with a halogen atom. Triarylsulfonium salt compounds in which the total number of halogen atom substitutions on the aromatic ring is 4 or more are even more preferred. Specific examples include triphenylsulfonium=hexafluorophosphate, triphenylsulfonium=benzoylformate, bis(4-chlorophenyl)phenylsulfonium=benzoylformate, bis(4-chlorophenyl)-4-methylphenylsulfonium=tetrafluoroborate, tris(4-chlorophenyl)sulfonium=3,5-bis(methoxycarbonyl)benzenesulfonate, tris(4-chlorophenyl)sulfonium=hexafluorophosphate, and tris(2,4-dichlorophenyl)sulfonium=hexafluorophosphate.

[0247] Furthermore, as counter anions for iodonium salt compounds and sulfonium salt compounds, sulfonamide anions or sulfonimide anions are preferred, with sulfonimide anions being more preferred. As the sulfonamide anion, an aryl sulfonamide anion is preferred. Furthermore, bisarylsulfonimide anions are preferred as sulfonimide anions. Specific examples of sulfonamide anions or sulfonimide anions are preferably those described in International Publication No. 2020 / 262692.

[0248] Furthermore, the electron-accepting polymerization initiator may also contain a compound represented by the following formula (II) from the viewpoint of developability and print durability of the resulting lithographic printing plate.

[0249] [ka]

[0250] In formula (II), X A represents a halogen atom, R A This represents an aryl group.

[0251] X in equation (II) A Specifically, these include fluorine atoms, chlorine atoms, bromine atoms, and yo A chlorine atom is one example. Of these, a chlorine atom or a bromine atom is preferred because of its excellent sensitivity, and a bromine atom is particularly preferred. Furthermore, in equation (II), R A From the perspective of having an excellent balance between sensitivity and storage stability. Therefore, an aryl group substituted with an amide group is preferred.

[0252] A specific example of the electron-accepting polymerization initiator represented by the above formula (II) is International Publication No. 2020. The material described in No. 262692 can be suitably used.

[0253] The lowest unoccupied orbital (LUMO) of the electron-accepting polymerization initiator is preferably -3.00 eV or less, and more preferably -3.02 eV or less, from the viewpoint of improving sensitivity and reducing the occurrence of plate skipping. Furthermore, the lower limit is preferably -3.80 eV or higher, and more preferably -3.60 eV or higher.

[0254] Electron-accepting polymerization initiators may be used alone or in combination of two or more. 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, relative to the total solid content of the image recording layer.

[0255] -Electron-donating polymerization initiator- From the viewpoint of contributing to improved chemical resistance and print resistance in lithographic printing plates, the polymerization initiator preferably includes an electron-donating polymerization initiator, and more preferably includes both an electron-donating polymerization initiator and the above-mentioned electron-donating polymerization initiator. Examples of electron-donating polymerization initiators include the following five types: (i) Alkyl or arylate complexes: These are thought to oxidatively break the carbon-heterobond and generate active radicals. Specifically, borate compounds are examples of such complexes. (ii) Aminoacetic acid compounds: It is thought that oxidation causes the CX bond on the carbon adjacent to the nitrogen to break, generating an active radical. X is preferably a hydrogen atom, a carboxyl group, a trimethylsilyl group, or a benzyl group. Specifically, examples include N-phenylglycines (which may have substituents on the phenyl group) and N-phenyliminodiacetic acid (which may have substituents on the phenyl group). (iii) Sulfur-containing compounds: Compounds obtained by replacing the nitrogen atom of the above-mentioned aminoacetic acid compounds with a sulfur atom can generate active radicals through a similar mechanism. Specifically, examples include phenylthioacetic acid (which may have substituents on the phenyl group). (iv) Tin-containing compounds: Compounds in which the nitrogen atoms of the above-mentioned aminoacetic acid compounds are replaced with tin atoms can generate active radicals through a similar mechanism. (v) Sulfinates: These can generate active radicals upon oxidation. Examples include sodium arylsulfinate.

[0256] Among these electron-donating polymerization initiators, the image recording layer preferably contains a borate compound from the viewpoint of print resistance and sensitivity. As the borate compound, tetraarylborate compounds or monoalkyltriarylborate compounds are preferred, tetraarylborate compounds are more preferred from the viewpoint of compound stability, and tetraphenylborate compounds are particularly preferred. The countercation 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.

[0257] Sodium tetraphenylborate is a preferred example of the borate compound.

[0258] Preferred examples of electron-donating polymerization initiators include those described in International Publication No. 2020 / 262692.

[0259] Furthermore, from the viewpoint of visibility, print resistance, and stability over time, the image recording layer preferably contains at least one compound selected from the group consisting of an onium compound as the electron-accepting polymerization initiator and a borate compound as the electron-donating polymerization initiator, and more preferably contains an onium compound as the electron-accepting polymerization initiator and a borate compound as the electron-donating polymerization initiator. Furthermore, the image recording layer preferably contains a borate compound as the electron-donating polymerization initiator. In one preferred embodiment, the electron-donating polymerization initiator is preferably a borate compound.

[0260] Electron-donating polymerization initiators may be added individually or in combination of two or more. 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, relative to the total solid content of the image recording layer.

[0261] Furthermore, one preferred embodiment of the present invention is one in which the electron-accepting polymerization initiator and the electron-donating polymerization initiator form a salt. Specifically, for example, the onium compound may be a salt of an onium ion and an anion in the electron-donating polymerization initiator (e.g., tetraphenylborate anion). More preferably, an iodonium borate salt compound may be formed in which an iodonium cation (e.g., di-p-tolylodonium cation) in the iodonium salt compound and a borate anion in the electron-donating polymerization initiator form a salt. A specific example of the embodiment in which the above-mentioned electron-accepting polymerization initiator and the above-mentioned electron-donating polymerization initiator form a salt is preferably the one described in International Publication No. 2020 / 262692.

[0262] In the present invention, if the image recording layer contains an onium ion and an anion in the electron-donating polymerization initiator described above, the image recording layer shall contain an electron-accepting polymerization initiator and the electron-donating polymerization initiator.

[0263] [Infrared absorber] The lithographic printing plate used in the present invention preferably contains an infrared absorbent in the image recording layer. There are no particular restrictions on the infrared absorber; for example, pigments and dyes can be used. Dyes used as infrared absorbers include commercially available dyes and known dyes listed in literature such as the "Dye Handbook" (edited by the Society of Synthetic Organic Chemistry, published in 1970). Specifically, examples of dyes include azo dyes, metal complex azo dyes, pyrazolone azo dyes, naphthoquinone dyes, anthraquinone dyes, phthalocyanine dyes, carbonium dyes, quinone imine dyes, methine dyes, cyanine dyes, squarylium dyes, pyryllium salts, and metal thiolate complexes.

[0264] Among these dyes, particularly preferred are cyanine dyes, squarylium dyes, pyryllium salts, nickel thiolate complexes, and indorenine-cyanine dyes. Furthermore, cyanine dyes and indorenine-cyanine dyes are also preferred. Of these, cyanine dyes are particularly preferred.

[0265] The infrared absorber described above is preferably a cationic polymethine dye having an oxygen or nitrogen atom at the meso position. Examples of cationic polymethine dyes include cyanine dyes, pyrylium dyes, thiopyrillium dyes, and azulenium dyes, with cyanine dyes being preferred from the viewpoint of ease of acquisition and solvent solubility during the introduction reaction.

[0266] Specific examples of cyanine dyes include the compounds described in paragraphs 0017 to 0019 of Japanese Patent Publication No. 2001-133969, the compounds described in paragraphs 0016 to 0021 of Japanese Patent Publication No. 2002-023360, the compounds described in paragraphs 0012 to 0037 of Japanese Patent Publication No. 2002-040638, preferably the compounds described in paragraphs 0034 to 0041 of Japanese Patent Publication No. 2002-278057, the compounds described in paragraphs 0080 to 0086 of Japanese Patent Publication No. 2008-195018, particularly preferably the compounds described in paragraphs 0035 to 0043 of Japanese Patent Publication No. 2007-90850, and the compounds described in paragraphs 0105 to 0113 of Japanese Patent Publication No. 2012-206495. Furthermore, the compounds described in paragraphs 0008 to 0009 of Japanese Patent Publication No. 5-5005 and paragraphs 0022 to 0025 of Japanese Patent Publication No. 2001-222101 can also be preferably used. As pigments, compounds described in paragraphs 0072 to 0076 of Japanese Patent Publication No. 2008-195018 are preferred.

[0267] The above infrared absorber preferably contains a compound represented by the following formula 4.

[0268] [ka]

[0269] In formula 4, R 14 and R 15 Each of these independently represents a hydrogen atom or an alkyl group, and R 14 and R 15 They may be connected to each other to form a ring, R 16 ~R 19 Each of these independently represents a hydrogen atom or an alkyl group, and R 20 and R 21 Each of the following independently represents an alkyl group or an aryl group, Y3 and Y4 each independently represent an oxygen atom, a sulfur atom, a -NR0- or a dialkylmethylene group, R0 represents a hydrogen atom, an alkyl group or an aryl group, Ar3 and Ar4 each independently represent a group that forms a benzene ring or naphthalene ring which may have a group represented by formula 5 described later, and A1 is -NR 22 R 23 , represents -X5-L1 or a halogen atom, R 22 and R 23 Each of these independently represents an alkyl group, an aryl group, an alkoxycarbonyl group, or an arylsulfonyl group; X5 represents an oxygen atom or a sulfur atom; L1 represents a hydrocarbon group or a heteroaryl group; and Za represents a counterion that neutralizes the charge. -X6 formula 5 In equation 5, X6 is a halogen atom, -C(=O)-X7-R 24 -C(=O)-NR 25 R 26 -OC(=O)-R 27 -CN, -SO2NR 28 R 29, or represents a perfluoroalkyl group, where X7 represents a single bond or oxygen atom, R 24 and R 27 Each of these independently represents an alkyl group or an aryl group, and R 25 , R 26 , R 28 and R 29 Each of these independently represents a hydrogen atom, an alkyl group, or an aryl group.

[0270] Ar3 and Ar4 each independently represent a group that forms a benzene ring or a naphthalene ring. The benzene ring and naphthalene ring may have substituents other than -X6. Examples of substituents include alkyl groups, alkoxy groups, aryloxy groups, amino groups, alkylthio groups, arylthio groups, carboxyl groups, carboxylate groups, sulfo groups, sulfonate groups, and combinations thereof, but alkyl groups are preferred. Furthermore, in a preferred embodiment, it is preferable that in formula 4, at least one of Ar3 and Ar4 has the group represented by formula 5.

[0271] In equation 5, X6 is a halogen atom, -C(=O)-X7-R 24 -C(=O)-NR 25 R 26 -OC(=O)-R 27 -CN, -SO2NR 28 R 29 , or represents a perfluoroalkyl group, and from the viewpoint of print resistance, visibility and long-term stability, halogen atoms, -C(=O)-X7-R 24 -C(=O)-NR 25 R 26 -OC(=O)-R 27 , CN, or -SO2NR 28 R 29 Preferably, it is a halogen atom, -C(=O)-OR 24 -C(=O)-NR 25 R 26 , or -OC(=O)-R 27 Preferably, it is a halogen atom, -C(=O)-OR 24, or -OC(=O)-R 27 It is even more preferable that the atom be a fluorine atom, a chlorine atom, a bromine atom, or -C(=O)OR 30 It is even more preferable that it be a chlorine atom or a bromine atom. Furthermore, the X6 that is substituted for Ar3 and the X6 that is substituted for Ar4 may be the same group or different groups. However, from the viewpoint of print resistance, visibility, and stability over time, it is preferable that the X6 that is substituted for Ar3 and the X6 that is substituted for Ar4 are the same group.

[0272] X7 represents a single bond or an oxygen atom, and is preferably an oxygen atom. R 24 and R 27 Each of these independently represents an alkyl group or an aryl group, preferably an alkyl group having 1 to 12 carbon atoms or an aryl group having 6 to 12 carbon atoms, and more preferably an alkyl group having 1 to 12 carbon atoms. R 25 , R 26 , R 28 and R 29 Each of these independently represents a hydrogen atom, an alkyl group, or an aryl group, preferably a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, or an aryl group having 6 to 12 carbon atoms; more preferably a hydrogen atom or an alkyl group having 1 to 12 carbon atoms; and even more preferably an alkyl group having 1 to 12 carbon atoms. R 30 This represents an alkyl group or an aryl group, preferably an alkyl group having 1 to 12 carbon atoms or an aryl group having 6 to 12 carbon atoms, and more preferably an alkyl group having 1 to 12 carbon atoms.

[0273] A1 is -NR 22 R 23 , -X5-L1 or represents a halogen atom, and from the viewpoint of print resistance, visibility and stability over time, -NR 22 R 23 Alternatively, -X5-L1 is preferred, and -NR 31 R 32 , -SR 33 It is preferable that it be so. Furthermore, from the viewpoint of suppressing UV plate skipping and UV print resistance, A1 is preferably a halogen atom, more preferably a chlorine atom or a bromine atom, and particularly preferably a chlorine atom. R 22 and R 23 Each of these independently represents an alkyl group, an aryl group, an alkoxycarbonyl group, or an arylsulfonyl group, preferably an alkyl group having 1 to 12 carbon atoms or an aryl group having 6 to 12 carbon atoms, and more preferably an alkyl group having 1 to 12 carbon atoms. X5 represents an oxygen atom or a sulfur atom, and if L1 is a hydrocarbon group or a heteroaryl group, it is preferably a sulfur atom. L1 represents a hydrocarbon group or a heteroaryl group. From the viewpoint of print resistance, a hydrocarbon group or a heteroaryl group is preferred, an aryl group or a heteroaryl group is more preferred, and a heteroaryl group is even more preferred. R 31 and R 32 Each of these independently represents an aryl group, preferably an aryl group having 6 to 20 carbon atoms, and more preferably a phenyl group. R 33 represents a hydrocarbon group or a heteroaryl group, with an aryl group or a heteroaryl group being preferred, and a heteroaryl group being more preferred.

[0274] L1 and R 33 The following groups are preferred as heteroaryl groups in this compound.

[0275] [ka]

[0276] R 14 ~R 23 The alkyl group in R0 is preferably an alkyl group having 1 to 30 carbon atoms, more preferably an alkyl group having 1 to 15 carbon atoms, and even more preferably an alkyl group having 1 to 10 carbon atoms. The alkyl group may be linear, branched, or have a ring structure. Specifically, examples include methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, hexadecyl group, octadecyl group, eicosyl group, isopropyl group, isobutyl group, s-butyl group, t-butyl group, isopentyl group, neopentyl group, 1-methylbutyl group, isohexyl group, 2-ethylhexyl group, 2-methylhexyl group, cyclohexyl group, cyclopentyl group, and 2-norbornyl group. Among these alkyl groups, methyl, ethyl, propyl, or butyl groups are particularly preferred.

[0277] Furthermore, the alkyl group may have substituents. Examples of substituents include alkoxy groups, aryloxy groups, amino groups, alkylthio groups, arylthio groups, halogen atoms, carboxyl groups, carboxylate groups, sulfo groups, sulfonate groups, alkyloxycarbonyl groups, aryloxycarbonyl groups, and groups that combine these.

[0278] R 22 , R 23 , R 31 , R 32 In R0, the aryl group is preferably an aryl group having 6 to 30 carbon atoms, more preferably an aryl group having 6 to 20 carbon atoms, and even more preferably an aryl group having 6 to 12 carbon atoms. Furthermore, the aryl group may have substituents. Examples of substituents include alkyl groups, alkoxy groups, aryloxy groups, amino groups, alkylthio groups, arylthio groups, halogen atoms, carboxyl groups, carboxylate groups, sulfo groups, sulfonate groups, alkyloxycarbonyl groups, aryloxycarbonyl groups, and groups that combine these. Examples of the above-mentioned aryl groups include, for example, phenyl group, naphthyl group, p-tolyl group, p-chlorophenyl group, p-fluorophenyl group, p-methoxyphenyl group, p-dimethylaminophenyl group, p-methylthiophenyl group, and p-phenylthiophenyl group. Among these aryl groups, phenyl, p-methoxyphenyl, p-dimethylaminophenyl, or naphthyl groups are preferred.

[0279] R 14 and R 15 It is preferable that they are connected to form a ring. R 14 and R 15 When they are linked to form a ring, a preferred number of ring members is a 5- or 6-membered ring, with a 6-membered ring being more preferred. Also, R 14 and R 15 The ring formed by the linking of these elements is preferably a hydrocarbon ring which may have ethylenically unsaturated bonds.

[0280] Y3 and Y4 each independently represent an oxygen atom, a sulfur atom, -NR0-, or a dialkylmethylene group, with -NR0- or a dialkylmethylene group being preferred, and a dialkylmethylene group being more preferred. R0 represents a hydrogen atom, an alkyl group, or an aryl group, and is preferably an alkyl group.

[0281] R 20 and R 21 It is preferable that they be the same group. Also, R 20 and R 21 Each of these is preferably a linear alkyl group or an alkyl group having a sulfonate group at the terminal, and more preferably a methyl group, an ethyl group, or a butyl group having a sulfonate group at the terminal. Furthermore, the countercation of the sulfonate group may be the cation on the nitrogen atom in formula 4, or it may be an alkali metal cation or an alkaline earth metal cation. Furthermore, from the viewpoint of making the compound represented by formula 4 water-soluble, R 20 and R 21 Each of these groups is preferably an alkyl group having an anionic structure, more preferably an alkyl group having a carboxylate group or a sulfonate group, and even more preferably an alkyl group with a sulfonate group attached to its terminus. Furthermore, the maximum absorption wavelength of the compound represented by Equation 4 is increased to a longer wavelength, and from the viewpoint of visibility and print durability in lithographic printing plates, R 20 and R 21 Each of these groups is preferably an alkyl group having an aromatic ring, more preferably an alkyl group having an aromatic ring at its terminal end, and particularly preferably a 2-phenylethyl group, a 2-naphthalenylethyl group, or a 2-(9-anthracenyl)ethyl group.

[0282] R 16 ~R 19 Each of these independently represents either a hydrogen atom or an alkyl group, and a hydrogen atom is preferred.

[0283] Za represents a counterion that neutralizes the charge. When an anionic species is indicated, examples include sulfonate ions, carboxylate ions, tetrafluoroborate ions, hexafluorophosphate ions, chloride ions, perchlorate ions, sulfonamide anions, and sulfonimide anions. When a cationic species is indicated, alkali metal ions, alkaline earth metal ions, ammonium ions, pyridinium ions, or sulfonium ions are preferred, sodium ions, potassium ions, ammonium ions, pyridinium ions, or sulfonium ions are more preferred, sodium ions, potassium ions, or ammonium ions are even more preferred, and sodium ions, potassium ions, or trialkylammonium ions are particularly preferred. R 14 ~R 21 R0, A1, Ar3, Ar4, Y3 and Y4 may have anionic or cationic structures, 14 ~R 21 If R0, A1, Ar3, Ar4, Y3, and Y4 are all charge-neutral groups, then Za is a monovalent counteranion, but for example, R 14 ~R 21 If R0, A1, Ar3, Ar4, Y3, and Y4 have two or more anionic structures, Za can also act as a countercation. Furthermore, in equation 4, Za may be omitted if the parts other than Za are electrically neutral.

[0284] Infrared absorbers may be used individually or in combination of two or more types. Furthermore, pigments and dyes may be used in combination as infrared absorbers. The total content of the infrared absorber in the image recording layer is preferably 0.1% to 10.0% by mass, and more preferably 0.5% to 5.0% by mass, relative to the total solid content of the image recording layer.

[0285] 〔particle〕 The above image recording layer preferably contains particles from the viewpoint of print resistance. The particles may be organic or inorganic, but from the viewpoint of print resistance, it is preferable to include organic particles, and more preferable to include polymer particles. As inorganic particles, known inorganic particles can be used, and metal oxide particles such as silica particles and titania particles can be suitably used.

[0286] The polymer particles are preferably selected from the group consisting of thermoplastic resin particles, heat-reactive resin particles, polymer particles having polymerizable groups, microcapsules containing hydrophobic compounds, and microgels (crosslinked polymer particles). Among these, polymer particles having polymerizable groups or microgels are preferred. In a particularly preferred embodiment, the polymer particles contain at least one ethylenically unsaturated group. The presence of such polymer particles provides the effect of improving the print resistance of the exposed areas and the on-press developability of the unexposed areas. Furthermore, from the viewpoint of print resistance and on-press developability, the polymer particles are preferably thermoplastic resin particles.

[0287] As thermoplastic resin particles, thermoplastic polymer particles described in Research Disclosure No. 33303 of January 1992, Japanese Patent Publication No. 9-123387, 9-131850, 9-171249, 9-171250, and European Patent No. 931647 are preferred. Specific examples of polymers constituting thermoplastic resin particles include homopolymers or copolymers 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, or mixtures thereof. Preferably, copolymers containing polystyrene, styrene, and acrylonitrile, or polymethyl methacrylate are used. The average particle size of the thermoplastic resin particles is preferably 0.01 μm to 3.0 μm.

[0288] Examples of heat-reactive resin particles include polymer particles having heat-reactive groups. Heat-reactive polymer particles form hydrophobic regions through crosslinking due to thermal reactions and the resulting changes in functional groups.

[0289] In polymer particles having a heat-reactive group, any functional group that undergoes any reaction as long as a chemical bond is formed may be used as the heat-reactive group, but it is preferably a polymerizable group. Examples of such groups include ethylenically unsaturated groups that undergo radical polymerization (e.g., acryloyl group, methacryloyl group, vinyl group, allyl group, etc.), cationic polymerizable groups (e.g., vinyl group, vinyloxy group, epoxy group, oxetanyl group, etc.), isocyanate groups or their blocks, epoxy groups, vinyloxy groups and functional groups having active hydrogen atoms that react with these groups (e.g., amino group, hydroxyl group, carboxyl group, etc.), carboxyl groups and their hydroxyl or amino groups that undergo condensation reactions, and acid anhydrides and their amino or hydroxyl groups that undergo ring-opening addition reactions.

[0290] As microcapsules, for example, as described in Japanese Patent Publication No. 2001-277740 and Japanese Patent Publication No. 2001-277742, at least a portion of the constituent components of the image recording layer are encapsulated within the microcapsules. The constituent components of the image recording layer can also be contained outside the microcapsules. In the image recording layer containing microcapsules, a preferred configuration is one in which hydrophobic constituent components are encapsulated within the microcapsules and hydrophilic constituent components are contained outside the microcapsules.

[0291] Microgels (crosslinked polymer particles) may contain a portion of the components of the image recording layer on at least one of their surface or interior. In particular, reactive microgels having radical polymerizable groups on their surface are preferred from the viewpoint of the sensitivity of the resulting lithographic printing plate and the print resistance of the resulting lithographic printing plate.

[0292] Known methods can be applied to microencapsulate or microgel the components of the image recording layer.

[0293] Furthermore, as polymer particles, those obtained by the reaction of a polyhydric isocyanate compound, which is an adduct of a polyhydric phenol compound having two or more hydroxyl groups in its molecule with isophorone diisocyanate, and a compound having active hydrogen are preferred from the viewpoint of print resistance, stain resistance, and storage stability of the resulting lithographic printing plate. As the above-mentioned polyhydric phenol compound, a compound having multiple benzene rings with phenolic hydroxyl groups is preferred. The compound having the active hydrogen described above is preferably a polyol compound or a polyamine compound, more preferably a polyol compound, and even more preferably at least one compound selected from the group consisting of propylene glycol, glycerin, and trimethylolpropane. As resin particles obtained by the reaction of a polyvalent isocyanate compound, which is an adduct of a polyvalent phenol compound having two or more hydroxyl groups in its molecule with isophorone diisocyanate, and a compound having active hydrogen, polymer particles described in paragraphs 0032 to 0095 of Japanese Patent Application Publication No. 2012-206495 are preferred.

[0294] Furthermore, from the viewpoint of print resistance and solvent resistance of the resulting lithographic printing plate, it is preferable that the polymer particles include both i) constituent units having a hydrophobic main chain and a pendant cyano group directly bonded to the hydrophobic main chain, and ii) constituent units having a pendant group containing a hydrophilic polyalkylene oxide segment. As the hydrophobic main chain mentioned above, an acrylic resin chain is preferred. Preferred examples of the pendant cyano group mentioned above include -[CH2CH(C≡N)]- or -[CH2C(CH3)(C≡N)]-. Furthermore, the constituent units having the pendant cyano group can be easily derived from ethylene-based unsaturated monomers, such as acrylonitrile or methacrylonitrile, or combinations thereof. Furthermore, as the alkylene oxide in the hydrophilic polyalkylene oxide segment described above, ethylene oxide or propylene oxide is preferred, and ethylene oxide is more preferred. The number of repeating alkylene oxide structures in the hydrophilic polyalkylene oxide segment described above is preferably 10 to 100, more preferably 25 to 75, and even more preferably 40 to 50. Particles of a resin having a hydrophobic main chain and comprising both i) a constituent unit having a pendant cyano group directly bonded to the hydrophobic main chain, and ii) a constituent unit having a pendant group containing a hydrophilic polyalkylene oxide segment, are preferably those described in paragraphs 0039 to 0068 of Japanese Patent Publication No. 2008-503365.

[0295] Furthermore, the polymer particles described above preferably have hydrophilic groups from the viewpoint of print resistance and on-press developability. The hydrophilic groups mentioned above are not particularly limited as long as they have a hydrophilic structure, but examples include acidic groups such as carboxyl groups, hydroxyl groups, amino groups, cyano groups, and polyalkylene oxide structures. In particular, from the viewpoint of on-press developability and print durability, the polyalkylene oxide structure is preferred, and the polyethylene oxide structure, polypropylene oxide structure, or polyethylene / propylene oxide structure is more preferred. Furthermore, from the viewpoint of on-pressure development and suppression of developing residue during on-pressure development, it is preferable that the polyalkylene oxide structure has a polypropylene oxide structure, and it is more preferable that it has both a polyethylene oxide structure and a polypropylene oxide structure. Furthermore, the hydrophilic group preferably includes a constituent unit having a cyano group or a group represented by the following formula Z, more preferably a constituent unit represented by the following formula (AN) or a group represented by the following formula Z, and particularly preferably a group represented by the following formula Z, from the viewpoint of print resistance, ink transfer, and on-press developability. *-QWY formula Z In formula Z, Q represents a divalent linking group, W represents a divalent group having a hydrophilic structure or a divalent group having a hydrophobic structure, Y represents a monovalent group having a hydrophilic structure or a monovalent group having a hydrophobic structure, either W or Y has a hydrophilic structure, and * represents a bonding site with another structure.

[0296] [ka]

[0297] In formula (AN), R AN represents a hydrogen atom or a methyl group.

[0298] From the viewpoint of print resistance, it is preferable that the polymer contained in the above polymer particles includes structural units formed by compounds having cyano groups. The cyano group is usually introduced into the resin as a constituent unit containing a cyano group, using a compound (monomer) that has a cyano group. Examples of compounds having a cyano group include acrylonitrile compounds, with (meth)acrylonitrile being a preferred example. The constituent unit having a cyano group is preferably a constituent unit formed by an acrylonitrile compound, and more preferably a constituent unit formed by (meth)acrylonitrile, i.e., a constituent unit represented by the above formula (AN). If the above polymer includes a polymer having a cyano group, the content of the cyano group in the polymer having a cyano group, preferably the component represented by the above formula (AN), is preferably 5% to 90% by mass, more preferably 20% to 80% by mass, and particularly preferably 30% to 60% by mass, based on the total mass of the polymer having a cyano group, from the viewpoint of print resistance.

[0299] Furthermore, from the viewpoint of print resistance, ink transfer properties, and on-press developability, it is preferable that the polymer particles include polymer particles having a group represented by the above formula Z.

[0300] In the above formula Z, Q is preferably a divalent linking group having 1 to 20 carbon atoms, and more preferably a divalent linking group having 1 to 10 carbon atoms. Furthermore, Q in the above formula Z is preferably an alkylene group, an arylene group, an ester bond, an amide bond, or a group formed by combining two or more of these, and more preferably a phenylene group, an ester bond, or an amide bond.

[0301] The hydrophilic divalent group in W of the above formula Z is a polyalkylene oxy group, or a polyalkylene oxy group with -CH2CH2NR at one end. W It is preferable that the group is bonded to -. Note that R W represents a hydrogen atom or an alkyl group. The divalent group having a hydrophobic structure in W of the above formula Z is -R WA-, -OR WA -O-, -R W NR WA -NR W -, -OC(=O)-R WA -O-, or -OC(=O)-R WA It is preferable that it be -O-. WA Each of these independently represents a linear, branched, or cyclic alkylene group having 6 to 120 carbon atoms, a haloalkylene group having 6 to 120 carbon atoms, an arylene group having 6 to 120 carbon atoms, an alkalinelene group having 6 to 120 carbon atoms (a divalent group obtained by removing one hydrogen atom from an alkylaryl group), or an aralkylene group having 6 to 120 carbon atoms.

[0302] The monovalent group having a hydrophilic structure in Y of the above formula Z is -OH, -C(=O)OH, a polyalkylene oxy group having a hydrogen atom or alkyl group at one end, or -CH2CH2NR at the other end of a polyalkylene oxy group having a hydrogen atom or alkyl group at one end. W It is preferable that the group is bonded to a - group. The monovalent group having a hydrophobic structure in Y of the above formula Z is a linear, branched, or cyclic alkyl group having 6 to 120 carbon atoms, a haloalkyl group having 6 to 120 carbon atoms, an aryl group having 6 to 120 carbon atoms, an alcaryl group (alkylaryl group) having 7 to 120 carbon atoms, an aralkyl group having 7 to 120 carbon atoms, or -OR WB , -C(=O)OR WB , or -OC(=O)R WB It is preferable that this is the case. WB This represents an alkyl group having 6 to 20 carbon atoms.

[0303] In polymer particles having the group represented by the above formula Z, it is more preferable that W is a divalent group having a hydrophilic structure, Q is a phenylene group, an ester bond, or an amide bond, W is a polyalkylene oxy group, and Y is a polyalkylene oxy group whose terminal end is a hydrogen atom or an alkyl group, from the viewpoint of print resistance, ink transfer, and on-press developability.

[0304] Furthermore, from the viewpoint of print resistance and on-press developability, the above polymer particles preferably include polymer particles having polymerizable groups, and more preferably include polymer particles having polymerizable groups on the particle surface. Furthermore, from the viewpoint of print resistance, the above polymer particles preferably include polymer particles having hydrophilic groups and polymerizable groups. The polymerizable group described above may be a cationic polymerizable group or a radical polymerizable group, but from the viewpoint of reactivity, a radical polymerizable group is preferable. The polymerizable group is not particularly limited as long as it is polymerizable, but from the viewpoint of reactivity, an ethylenically unsaturated group is preferred, a vinylphenyl group (styryl group), a (meth)acryloxy group, or a (meth)acrylamide group is more preferred, and a (meth)acryloxy group is particularly preferred. Furthermore, it is preferable that the polymer in polymer particles having polymerizable groups has constituent units having polymerizable groups. Furthermore, polymerizable groups may be introduced to the surface of polymer particles by polymer reaction.

[0305] Furthermore, from the viewpoint of print resistance and on-press developability, the image recording layer preferably contains addition polymerization resin particles having a dispersible group as the polymer particles, and more preferably the dispersible group contains a group represented by the formula Z.

[0306] Furthermore, the polymer particles preferably contain a resin having urea bonds, from the viewpoint of print resistance, ink transfer properties, on-press developability, and suppression of developing residue during on-press development. Suitable resins having the above-mentioned urea bond include those described in International Publication No. 2020 / 262692.

[0307] Furthermore, the image recording layer preferably contains thermoplastic resin particles from the viewpoint of print resistance and on-press developability. The thermoplastic resin contained in the thermoplastic resin particles is not particularly limited and includes, for example, polyethylene, polystyrene, polyvinyl chloride, polyvinylidene chloride, methyl poly(meth)acrylate, ethyl poly(meth)acrylate, butyl poly(meth)acrylate, polyacrylonitrile, polyvinyl acetate, and copolymers thereof. The thermoplastic resin may also be in latex form. The thermoplastic resin according to the present invention is preferably a resin that melts or softens due to the heat generated in the exposure process described later, thereby forming part or all of the hydrophobic film that forms the recording layer.

[0308] From the viewpoint of ink adhesion and print resistance, the above thermoplastic resin preferably includes a resin having structural units formed by aromatic vinyl compounds and structural units having cyano groups. Suitable examples of resins having structural units formed from aromatic vinyl compounds and structural units having cyano groups include those described in International Publication No. 2020 / 262692.

[0309] The thermoplastic resin contained in the above-mentioned thermoplastic resin particles preferably has hydrophilic groups from the viewpoint of print resistance and on-press developability. There are no particular restrictions on hydrophilic groups as long as they have a hydrophilic structure, but examples include acidic groups such as carboxyl groups, hydroxyl groups, amino groups, cyano groups, and polyalkylene oxide structures. The hydrophilic group is preferably a group having a polyalkylene oxide structure, a group having a polyester structure, or a sulfonic acid group, from the viewpoint of print resistance and on-press developability, more preferably a group having a polyalkylene oxide structure or a sulfonic acid group, and even more preferably a group having a polyalkylene oxide structure.

[0310] From the viewpoint of on-air developability, the above polyalkylene oxide structure is preferably a polyethylene oxide structure, a polypropylene oxide structure, or a poly(ethylene oxide / propylene oxide) structure. Furthermore, from the viewpoint of on-air developability, among the hydrophilic groups mentioned above, it is preferable that the polyalkylene oxide structure has a polypropylene oxide structure, and it is more preferable that it has both a polyethylene oxide structure and a polypropylene oxide structure. From the viewpoint of on-preparability, the number of alkylene oxide structures in the above polyalkylene oxide structure is preferably 2 or more, more preferably 5 or more, even more preferably 5 to 200, and particularly preferably 8 to 150.

[0311] Furthermore, from the viewpoint of on-pressure development, the hydrophilic group is preferably the group represented by the formula Z.

[0312] The glass transition temperature (Tg) of the thermoplastic resin is preferably 60°C to 150°C, more preferably 80°C to 140°C, and even more preferably 90°C to 130°C, from the viewpoint of print resistance and ink adhesion. When thermoplastic resin particles contain two or more types of thermoplastic resins, the value obtained by the FOX formula described later is called the glass transition temperature of the thermoplastic resin.

[0313] In this invention, the glass transition temperature of the resin can be measured using differential scanning calorimetry (DSC). The specific measurement method shall be carried out in accordance with the methods described in JIS K 7121 (1987) or JIS K 6240 (2011). In this specification, the glass transition temperature used is the extrapolation glass transition onset temperature (hereinafter sometimes referred to as Tig). The method for measuring the glass transition temperature will be explained in more detail. To determine the glass transition temperature, the apparatus is held at a temperature approximately 50°C lower than the expected Tg of the resin until it stabilizes. Then, the temperature is heated at a heating rate of 20°C / min to a temperature approximately 30°C higher than the temperature at which the glass transition is completed, and a differential thermal analysis (DTA) curve or digital sensor cell (DSC) curve is created. The extrapolation glass transition onset temperature (Tig), i.e., the glass transition temperature Tg as defined herein, is determined as the temperature at the intersection of a straight line drawn by extending the low-temperature baseline of the DTA curve or DSC curve toward the high-temperature side, and a tangent line drawn at the point where the slope of the curve representing the stepwise transition portion of the glass transition is maximum.

[0314] When thermoplastic resin particles contain two or more types of thermoplastic resins, the Tg of the thermoplastic resins contained in the thermoplastic resin particles can be determined as follows. When the Tg of the first thermoplastic resin is denoted as Tg1(K), and the mass fraction of the first thermoplastic resin relative to the total mass of thermoplastic resin components in the thermoplastic resin particle is denoted as W1, and the Tg of the second resin is denoted as Tg2(K), and the mass fraction of the second resin relative to the total mass of thermoplastic resin components in the thermoplastic resin particle is denoted as W2, the Tg0(K) of the thermoplastic resin particle can be estimated according to the following FOX formula. FOX formula: 1 / Tg0=(W1 / Tg1)+(W2 / Tg2) Furthermore, if the thermoplastic resin particles contain three types of resin, or if the pretreatment solution contains three types of thermoplastic resin particles with different types of thermoplastic resin, the Tg of the thermoplastic resin particles can be estimated according to the following formula, as described above, where Tgn(K) is the Tg of the nth resin and Wn is the mass fraction of the nth resin relative to the total mass of the resin components in the thermoplastic resin particles. FOX formula: 1 / Tg0=(W1 / Tg1)+(W2 / Tg2)+(W3 / Tg3)...+(Wn / Tgn)

[0315] For example, the EXSTAR6220 from SII Nanotechnology can be used as a differential scanning calorimeter (DSC).

[0316] From the viewpoint of print resistance, the arithmetic mean particle size of the thermoplastic resin particles is preferably 1 nm or more and 200 nm or less, more preferably 3 nm or more and less than 80 nm, and even more preferably 10 nm or more and 49 nm or less.

[0317] In this invention, the arithmetic mean particle size of thermoplastic resin particles refers to the value measured by dynamic light scattering (DLS), unless otherwise specified. The measurement of the arithmetic mean particle size of thermoplastic resin particles by DLS is performed using a Brookhaven BI-90 (manufactured by Brookhaven Instrument Company) in accordance with the manual for the above-mentioned instrument.

[0318] The weight-average molecular weight of the thermoplastic resin contained in the thermoplastic resin particles is preferably 3,000 to 300,000, and more preferably 5,000 to 100,000.

[0319] The method for producing the thermoplastic resin contained in the thermoplastic resin particles is not particularly limited and can be produced by known methods. For example, it can be obtained by polymerizing a styrene compound, an acrylonitrile compound, and, if necessary, at least one compound selected from the group consisting of the above N-vinyl heterocyclic compound, a compound used to form a structural unit having an ethylenically unsaturated group, a compound used to form a structural unit having an acidic group, a compound used to form a structural unit having a hydrophobic group, and a compound used to form other structural units, by a known method.

[0320] Specific examples of thermoplastic resins contained in thermoplastic resin particles include those described in International Publication No. 2020 / 262692.

[0321] The average particle size of the above particles is preferably 0.01 μm to 3.0 μm, more preferably 0.03 μm to 2.0 μm, and even more preferably 0.10 μm to 1.0 μm. Good resolution and stability over time can be obtained within this range. In this invention, the average primary particle size of the above particles shall be measured by light scattering, or by taking electron microscope images of the particles, measuring the particle size of a total of 5,000 particles on the image, and calculating the average value. For non-spherical particles, the particle size shall be the particle size of a spherical particle having the same particle area as the particle on the image. Furthermore, unless otherwise specified, the average particle size in this invention shall be the volume-average particle size.

[0322] The image recording layer described above may contain one type of particle, particularly polymer particles, or two or more types. Furthermore, from the viewpoint of on-press developability and print durability, the content of particles, particularly polymer particles, in the image recording layer is preferably 5% to 90% by mass, more preferably 10% to 90% by mass, even more preferably 20% to 90% by mass, and particularly preferably 50% to 90% by mass, relative to the total solid content of the image recording layer. Furthermore, from the viewpoint of on-press developability and print durability, the polymer particle content in the image recording layer is preferably 20% to 100% by mass, more preferably 35% to 100% by mass, even more preferably 50% to 100% by mass, and particularly preferably 80% to 100% by mass, based on the total mass of the components with a molecular weight of 3,000 or more in the image recording layer.

[0323] [Binder polymer] The image recording layer may contain a binder polymer. The polymer particles described above do not fall under the category of the binder polymer. In other words, the binder polymer is a polymer that is not in the form of particles. As the binder polymer, (meth)acrylic resin, polyvinyl acetal resin, or polyurethane resin is preferred.

[0324] In particular, known binder polymers used in the image recording layer of lithographic printing plates can be suitably used as the binder polymer. As an example, a binder polymer used in press-developed lithographic printing plates (hereinafter also referred to as press-developed binder polymer) will be described in detail. For binder polymers used in on-pressure development, binder polymers having alkylene oxide chains are preferred. Binder polymers having alkylene oxide chains may have poly(alkylene oxide) moieties in the main chain or in the side chains. Alternatively, they may be graft polymers having poly(alkylene oxide) in the side chains, or block copolymers composed of blocks of poly(alkylene oxide)-containing repeating units and blocks of (alkylene oxide)-free repeating units. When the main chain contains a poly(alkylene oxide) moiety, polyurethane resin is preferred. When the side chain contains a poly(alkylene oxide) moiety, examples of main chain polymers include (meth)acrylic resin, polyvinyl acetal resin, polyurethane resin, polyurea resin, polyimide resin, polyamide resin, epoxy resin, polystyrene resin, novolac-type phenolic resin, polyester resin, synthetic rubber, and natural rubber, with (meth)acrylic resin being particularly preferred.

[0325] Another preferred example of a binder polymer is a polymer compound (hereinafter also referred to as a star-shaped polymer compound) having a polyfunctional thiol with 6 to 10 functionalities as a core, to which polymer chains are bonded by sulfide bonds, and in which the polymer chains have polymerizable groups. From the viewpoint of curability, star-shaped polymer compounds are preferably those having polymerizable groups such as ethylenically unsaturated groups in the main chain or side chains, more preferably in the side chains. Examples of star-shaped polymer compounds include those described in Japanese Patent Publication No. 2012-148555 or International Publication No. 2020 / 262692.

[0326] The molecular weight of the binder polymer, as calculated by the GPC method in terms of polystyrene, is preferably 2,000 or more, more preferably 5,000 or more, and even more preferably 10,000 to 300,000 in weight-average molecular weight (Mw).

[0327] If necessary, hydrophilic polymers such as polyacrylic acid and polyvinyl alcohol described in Japanese Patent Publication No. 2008-195018 can be used in combination. Furthermore, lipophilic polymers and hydrophilic polymers can also be used in combination.

[0328] Furthermore, the image recording layer preferably contains a polymer having structural units formed from aromatic vinyl compounds, and more preferably contains a polymer having structural units formed from aromatic vinyl compounds and an infrared absorbent that decomposes upon infrared exposure, from the viewpoint of print resistance and on-press developability.

[0329] Furthermore, the binder polymer used in the present invention preferably has a glass transition temperature (Tg) of 50°C or higher, more preferably 70°C or higher, even more preferably 80°C or higher, and particularly preferably 90°C or higher, from the viewpoint of suppressing a decrease in on-pressure developability over time. Furthermore, regarding the upper limit of the glass transition temperature of the binder polymer, from the viewpoint of how easily water penetrates into the image recording layer, 200°C is preferred, and 120°C or lower is more preferred.

[0330] As the binder polymer having the above-mentioned glass transition temperature, polyvinyl acetal is preferred from the viewpoint of further suppressing the decrease in on-pressure developability over time. Polyvinyl acetal is a resin obtained by acetalizing the hydroxyl groups of polyvinyl alcohol with an aldehyde. In particular, polyvinyl butyral obtained by acetalizing (i.e., butyralizing) the hydroxyl group of polyvinyl alcohol with butyraldehyde is preferred. Furthermore, polyvinyl acetal is preferably made of ethylenically unsaturated groups from the viewpoint of improving print resistance. Suitable examples of polyvinyl acetal include those described in International Publication No. 2020 / 262692.

[0331] The image recording layer in the present invention preferably contains a resin having fluorine atoms, and more preferably contains a copolymer containing fluoroaliphatic groups. By using a resin containing fluorine atoms, particularly a copolymer containing fluoroaliphatic groups, surface abnormalities caused by foaming during the formation of the image recording layer can be suppressed, improving the texture of the coated surface, and further enhancing the ink adhesion of the formed image recording layer. Furthermore, an image recording layer containing a fluoroaliphatic group-containing copolymer results in higher gradation, high sensitivity to laser light, good fogging due to scattered and reflected light, and excellent print durability, making it possible to obtain a lithographic printing plate.

[0332] As the fluoroaliphatic group-containing copolymer mentioned above, those described in International Publication No. 2020 / 262692 can be suitably used.

[0333] In the image recording layer used in the present invention, one type of binder polymer may be used alone, or two or more types may be used in combination. The binder polymer can be included in the image recording layer in any amount, but the binder polymer content is preferably 1% to 90% by mass, and more preferably 5% to 80% by mass, relative to the total solid content of the image recording layer.

[0334] [Chain transfer agent] The image recording layer used in the present invention may contain a chain transfer agent. The chain transfer agent contributes to improving the print durability of the lithographic printing plate. As the chain transfer agent, thiol compounds are preferred, thiol compounds with 7 or more carbon atoms are more preferred from the viewpoint of boiling point (low volatility), and compounds having a mercapto group on the aromatic ring (aromatic thiol compounds) are even more preferred. The above thiol compounds are preferably monofunctional thiol compounds. Specific examples of chain transfer agents include those described in International Publication No. 2020 / 262692.

[0335] Chain transfer agents may be added individually or in combination of two or more types. The content of the chain transfer agent is preferably 0.01% to 50% by mass, more preferably 0.05% to 40% by mass, and even more preferably 0.1% to 30% by mass, relative to the total solid content of the image recording layer.

[0336] [Lipid-reducing agent] The image recording layer preferably further contains an oil-sensitive agent to improve ink adhesion. Examples of the above-mentioned lipid-reducing agents include onium compounds, nitrogen-containing low molecular weight compounds, and ammonium compounds such as ammonium group-containing polymers. In particular, when the protective layer contains inorganic layered compounds, these compounds function as surface coating agents for the inorganic layered compounds, thereby suppressing the reduction in ink adhesion during printing caused by the inorganic layered compounds.

[0337] Furthermore, from the viewpoint of fat-retaining properties, the fat-retaining agent is preferably an onium compound. Examples of onium compounds include phosphonium compounds, ammonium compounds, and sulfonium compounds. From the above viewpoint, at least one onium compound selected from the group consisting of phosphonium compounds and ammonium compounds is preferred. Preferred ammonium compounds include nitrogen-containing low molecular weight compounds and ammonium group-containing polymers. Specific examples of lipid-reducing agents include those described in International Publication No. 2020 / 262692.

[0338] The content of the lipid-sensitive agent is preferably 1% to 40.0% by mass, more preferably 2% to 25.0% by mass, and even more preferably 3% to 20.0% by mass, relative to the total solid content of the image recording layer.

[0339] The image recording layer may contain one type of lipid-sensitive agent alone, or two or more types in combination. One preferred embodiment of the image recording layer used in the present invention is one which contains two or more compounds as an oil-sensitive agent. Specifically, in the present invention, the image recording layer used preferably contains a phosphonium compound, a nitrogen-containing low molecular weight compound, and an ammonium group-containing polymer as the grease-sensitive agent, from the viewpoint of achieving both on-pressure developability and grease-retention properties, and more preferably a phosphonium compound, a quaternary ammonium salt, and an ammonium group-containing polymer as the grease-sensitive agent.

[0340] [Developing accelerator] The image recording layer used in the present invention preferably further contains a development accelerator. The development accelerator preferably has a polarity term value of SP of 6.0 to 26.0, more preferably 6.2 to 24.0, even more preferably 6.3 to 23.5, and particularly preferably 6.4 to 22.0.

[0341] SP value (solubility parameter, unit: (cal / cm)) in this invention 3 ) 1 / 2 The value of the polarity term in ) shall be the value of the polarity term δp in the Hansen solubility parameter. The Hansen solubility parameter is a representation in three dimensions of the solubility parameter introduced by Hildebrand, divided into three components: dispersion term δd, polarity term δp, and hydrogen bonding term δh. In this invention, the above polarity term δp is used. δp[cal / cm 3 ] is the Hansen solubility parameter, dipole force term, V [cal / cm 3 ] is the molar volume, and μ[D] is the dipole moment. For δp, the following simplified formula by Hansen and Beerbower is generally used.

[0342]

number

[0343] The development accelerator is preferably a hydrophilic polymer compound or a hydrophilic low-molecular-weight compound. In this invention, hydrophilicity means that the polarity term of the SP value is between 6.0 and 26.0, a hydrophilic polymer compound means a compound with a molecular weight (or weight-average molecular weight if it has a molecular weight distribution) of 3,000 or more, and a hydrophilic low molecular weight compound means a compound with a molecular weight (or weight-average molecular weight if it has a molecular weight distribution) of less than 3,000.

[0344] Examples of hydrophilic polymer compounds include cellulose compounds, with cellulose compounds being preferred. Examples of cellulose compounds include cellulose, or compounds in which at least a portion of cellulose has been modified (modified cellulose compounds), with modified cellulose compounds being preferred. Preferred modified cellulose compounds include compounds in which at least a portion of the hydroxyl groups of cellulose are substituted with at least one group selected from the group consisting of alkyl groups and hydroxyalkyl groups. The degree of substitution in a compound in which at least a portion of the hydroxyl groups of the cellulose described above is substituted with at least one group selected from the group consisting of alkyl groups and hydroxyalkyl groups is preferably 0.1 to 6.0, and more preferably 1 to 4. As the modified cellulose compound, alkylcellulose compounds or hydroxyalkylcellulose compounds are preferred, and hydroxyalkylcellulose compounds are more preferred. Methylcellulose is a preferred example of an alkylcellulose compound. Hydroxypropylcellulose is a preferred example of a hydroxyalkylcellulose compound.

[0345] The molecular weight (or weight-average molecular weight if it has a molecular weight distribution) of the hydrophilic polymer compound is preferably 3,000 to 5,000,000, and more preferably 5,000 to 200,000.

[0346] Examples of hydrophilic low molecular weight compounds include glycol compounds, polyol compounds, organic amine compounds, organic sulfonic acid compounds, organic sulfamine compounds, organic sulfuric acid compounds, organic phosphonic acid compounds, organic carboxylic acid compounds, and betaine compounds, with polyol compounds, organic sulfonic acid compounds, or betaine compounds being preferred.

[0347] Examples of glycol compounds include glycols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, and tripropylene glycol, as well as ether or ester derivatives of these compounds. Examples of polyol compounds include glycerin, pentaerythritol, and tris(2-hydroxyethyl) isocyanurate. Examples of organic amine compounds include triethanolamine, diethanolamine, monoethanolamine, and their salts. Examples of organic sulfonic acid compounds include alkyl sulfonic acid, toluene sulfonic acid, benzene sulfonic acid, and their salts, with alkyl sulfonic acid having 1 to 10 carbon atoms in the alkyl group being preferred. Examples of organic sulfamine compounds include alkyl sulfamic acids and their salts. Examples of organic sulfuric acid compounds include alkyl sulfuric acid, alkyl ether sulfuric acid, and their salts. Examples of organic phosphonic acid compounds include phenylphosphonic acid and its salts. Examples of organic carboxylic acid compounds include tartaric acid, oxalic acid, citric acid, malic acid, lactic acid, gluconic acid, and their salts. Examples of betaine compounds include phosphobetaine compounds, sulfobetaine compounds, and carboxybetaine compounds, with trimethylglycine being a preferred example.

[0348] The molecular weight (or weight-average molecular weight if a molecular weight distribution exists) of the hydrophilic low molecular weight compound is preferably 100 or more and less than 3,000, and more preferably 300 to 2,500.

[0349] The development accelerator is preferably a compound having a cyclic structure. The cyclic structure is not particularly limited, but examples include glucose rings, isocyanuric rings, aromatic rings, and aliphatic rings, in which at least some of the hydroxyl groups may be substituted, with glucose rings or isocyanuric rings being preferred. Examples of compounds containing a glucose ring include the cellulose compounds mentioned above. Examples of compounds having an isocyanuric ring include the aforementioned tris(2-hydroxyethyl)isocyanurate. Examples of compounds having an aromatic ring include the aforementioned toluenesulfonic acid and benzenesulfonic acid. Examples of compounds having an aliphatic ring include the alkyl sulfates mentioned above, in which the alkyl group has a ring structure.

[0350] Furthermore, the compound having the above cyclic structure preferably has a hydroxyl group. Preferred examples of compounds having a hydroxyl group and a cyclic structure include the cellulose compounds mentioned above and the tris(2-hydroxyethyl) isocyanurate mentioned above.

[0351] Furthermore, the development accelerator is preferably an onium compound. Examples of onium compounds include ammonium compounds and sulfonium compounds, with ammonium compounds being preferred. Examples of onium compounds used as development accelerators include trimethylglycine. Furthermore, the onium compounds in the above-mentioned electron-accepting polymerization initiators are compounds whose SP value polarity term is not between 6.0 and 26.0, and are therefore not included in the development accelerators.

[0352] The image recording layer may contain one type of development accelerator alone, or two or more types in combination. One preferred embodiment of the image recording layer used in the present invention is one which contains two or more compounds as a development accelerator. Specifically, the image recording layer used in the present invention preferably contains, from the viewpoint of on-pressure developability and ink transfer, the above polyol compound and the above betaine compound, the above betaine compound and the above organic sulfonic acid compound, or the above polyol compound and the above organic sulfonic acid compound as a development accelerator.

[0353] The content of the development accelerator relative to the total solid content of the image recording layer is preferably 0.1% by mass or more and 20% by mass or less, more preferably 0.5% by mass or more and 15% by mass or less, and even more preferably 1% by mass or more and 10% by mass or less.

[0354] [Other ingredients] The image recording layer may contain other components such as surfactants, polymerization inhibitors, higher fatty acid derivatives, plasticizers, and inorganic layered compounds. Specifically, refer to paragraphs 0114 to 0159 of Japanese Patent Application Publication No. 2008-284817. As a polymerization inhibitor, known polymerization inhibitors such as phenothiazines can be used.

[0355] [Formation of the image recording layer] The image recording layer in the lithographic printing plate of the present invention can be formed, for example, by dispersing or dissolving the necessary components in a known solvent to prepare a coating solution, applying the coating solution onto a support by a known method such as bar coating, and drying it, as described in paragraphs 0142 to 0143 of Japanese Patent Application Publication No. 2008-195018. Any known solvent can be used as the solvent. Specifically, examples include water, acetone, methyl ethyl ketone (2-butanone), cyclohexane, ethyl acetate, ethylene dichloride, tetrahydrofuran, toluene, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol dimethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, acetylacetone, cyclohexanone, diacetone alcohol, ethylene glycol monomethyl ether acetate, ethylene glycol ethyl ether acetate, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether acetate, 1-methoxy-2-propanol, 3-methoxy-1-propanol, methoxymethoxyethanol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, 3-methoxypropyl acetate, N,N-dimethylformamide, dimethyl sulfoxide, γ-butyrolactone, methyl lactate, ethyl lactate, etc. The solvent may be used alone or in combination of two or more types. The solid content concentration in the coating solution is preferably 1% to 50% by mass. The amount of coating (solid content) of the image recording layer after coating and drying varies depending on the application, but from the viewpoint of obtaining good sensitivity and good film characteristics of the image recording layer, 0.3 g / m² is recommended. 2 ~3.0g / m 2 It is preferable. Furthermore, the thickness of the image recording layer is preferably 0.1 μm to 3.0 μm, and more preferably 0.3 μm to 2.0 μm. In the present invention, the thickness of each layer in the lithographic printing plate is determined by preparing a section cut perpendicular to the surface of the lithographic printing plate and observing the cross-section of the section using a scanning microscope (SEM).

[0356] The image recording layer is preferably water-soluble or water-dispersible from the viewpoint of providing developability on board. Here, "water-soluble" means that 0.1 g or more dissolves in 100 g of water at 20°C, and "water-dispersible" means that it is uniformly dispersed in water at 20°C.

[0357] <Undercoat layer> The lithographic printing plate of the present invention may have an undercoat layer (sometimes called an intermediate layer) between the image recording layer and the support. The undercoat layer strengthens the adhesion between the support and the image recording layer in the exposed areas and makes it easier for the image recording layer to peel off from the support in the unexposed areas, thereby contributing to improved developability while suppressing a decrease in print durability. In addition, in the case of infrared laser exposure, the undercoat layer functions as a heat insulating layer, which has the effect of preventing the heat generated by exposure from diffusing to the support and reducing sensitivity.

[0358] Examples of compounds used in the undercoat layer include polymers having adsorbent groups and hydrophilic groups that can be adsorbed onto the support surface. Polymers having adsorbent groups and hydrophilic groups, and further having crosslinkable groups, are preferred to improve adhesion with the image recording layer. The compounds used in the undercoat layer may be low-molecular-weight compounds or polymers. Two or more compounds may be mixed and used as needed.

[0359] When the compound used in the undercoat layer is a polymer, copolymers of monomers having adsorbent groups, monomers having hydrophilic groups, and monomers having crosslinkable groups are preferred. Preferred adsorbent groups that can be adsorbed onto the support surface are phenolic hydroxyl groups, carboxyl groups, -PO3H2, -OPO3H2, -CONHSO2-, -SO2NHSO2-, and -COCH2COCH3. Preferred hydrophilic groups are sulfo groups or their salts, and carboxyl groups. Preferred crosslinking groups are acrylic groups, methacrylic groups, acrylamide groups, methacrylamide groups, and allyl groups. The polymer may have crosslinkable groups introduced by salt formation between the polar substituent of the polymer and a compound having a substituent oppositely charged to the polar substituent and an ethylenically unsaturated bond, or it may be further copolymerized with other monomers, preferably hydrophilic monomers.

[0360] Specifically, suitable examples include silane coupling agents having an ethylenically double bond reactive group that can be added and polymerized as described in Japanese Patent Publication No. 10-282679, and phosphorus compounds having an ethylenically double bond reactive group as described in Japanese Patent Publication No. 2-304441. Low molecular weight or high molecular weight compounds having a crosslinkable group (preferably an ethylenically unsaturated group), a functional group that interacts with the support surface, and a hydrophilic group as described in Japanese Patent Publication Nos. 2005-238816, 2005-125749, 2006-239867, and 2006-215263 are also preferably used. More preferable examples include polymers having adsorbent groups, hydrophilic groups, and crosslinkable groups that can be adsorbed onto the surface of a support, as described in Japanese Patent Publication No. 2005-125749 and Japanese Patent Publication No. 2006-188038.

[0361] The content of ethylenically unsaturated groups in the polymer used for the undercoat layer is preferably 0.1 mmol to 10.0 mmol, more preferably 0.2 mmol to 5.5 mmol per gram of polymer. The weight-average molecular weight (Mw) of the polymer used in the undercoat layer is preferably 5,000 or more, and more preferably between 10,000 and 300,000.

[0362] In addition to the above-mentioned undercoat compound, the undercoat layer may also contain, to prevent soiling over time, a chelating agent, a secondary or tertiary amine, a polymerization inhibitor, or a compound having an amino group or a functional group having polymerization-inhibiting ability that interacts with the support surface (for example, 1,4-diazabicyclo[2.2.2]octane (DABCO), 2,3,5,6-tetrahydroxy-p-quinone, chloranil, sulfophthalic acid, hydroxyethylethylenediaminetriacetic acid, dihydroxyethylethylenediaminediacetic acid, hydroxyethyliminodiacetic acid, etc.).

[0363] The primer layer is applied by a known method. The amount of primer layer applied (solid content) is 0.1 mg / m². 2 ~100mg / m 2 Preferably, 1 mg / m² 2 ~30mg / m 2 This is preferable.

[0364] <Protective layer> The lithographic printing plate of the present invention may have a protective layer (sometimes called an "overcoat layer") on top of the image recording layer. In a preferred embodiment, the lithographic printing plate of the present invention preferably comprises a support, an image recording layer, and a protective layer in this order. In another preferred embodiment, the lithographic printing plate of the present invention preferably comprises a support, an undercoat layer, an image recording layer, and a protective layer in this order.

[0365] The thickness of the protective layer is preferably greater than the thickness of the image recording layer. In addition to suppressing image formation inhibition reactions by blocking oxygen, the protective layer may also have functions to prevent scratches in the image recording layer and to prevent ablation during high-intensity laser exposure.

[0366] Protective layers with such properties are described, for example, in U.S. Patent No. 3,458,311 and Japanese Patent Publication No. 55-49729. As for the oxygen-low permeability polymer that can be used in the protective layer, water-soluble polymers and water-insoluble polymers can be appropriately selected and used, and two or more types can be mixed and used as needed; however, from the viewpoint of on-machine developability, it is preferable to include a water-soluble polymer. In this invention, a water-soluble polymer means a polymer whose solubility in water at 25°C exceeds 5% by mass. Examples of water-soluble polymers that can be used in the protective layer include polyvinyl alcohol, modified polyvinyl alcohol, polyvinylpyrrolidone, cellulose derivatives, polyethylene glycol, and poly(meth)acrylonitrile. Furthermore, it is preferable that the hydrophilic polymer includes at least one selected from the group consisting of modified polyvinyl alcohol and cellulose derivatives. As the modified polyvinyl alcohol, acid-modified polyvinyl alcohol having a carboxyl group or a sulfo group is preferably used. Specifically, examples include the modified polyvinyl alcohols described in Japanese Patent Publication No. 2005-250216 and Japanese Patent Publication No. 2006-259137. Examples of cellulose derivatives include methylcellulose, hydroxypropylmethylcellulose, and carboxymethylcellulose.

[0367] Among the water-soluble polymers mentioned above, it is preferable that the polymer contains polyvinyl alcohol, and it is even more preferable that it contains polyvinyl alcohol with a degree of saponification of 50% or more. The degree of saponification is preferably 60% or higher, more preferably 70% or higher, and even more preferably 85% or higher. There is no particular upper limit to the degree of saponification; it should be 100% or less. The degree of saponification described above is measured according to the method described in JIS K 6726:1994. Furthermore, one preferred embodiment of the protective layer is one that includes polyvinyl alcohol and polyethylene glycol.

[0368] In the present invention, when the protective layer contains a water-soluble polymer, the content of the water-soluble polymer relative to the total mass of the protective layer is preferably 1% to 99% by mass, more preferably 3% to 97% by mass, and even more preferably 5% to 95% by mass.

[0369] The protective layer preferably contains a hydrophobic polymer. A hydrophobic polymer is a polymer that dissolves in less than 5g of pure water at 125°C or does not dissolve at all in 100g of pure water. Examples of hydrophobic polymers include polyethylene, polystyrene, polyvinyl chloride, polyvinylidene chloride, alkyl poly(meth)acrylates (e.g., methyl poly(meth)acrylate, ethyl poly(meth)acrylate, butyl poly(meth)acrylate, etc.), and copolymers of these resin raw material monomers. Furthermore, it is preferable that the hydrophobic polymer includes polyvinylidene chloride resin. Furthermore, it is preferable that the hydrophobic polymer includes a styrene-acrylic copolymer (also known as styrene-acrylic resin). Furthermore, from the viewpoint of on-air developability, the hydrophobic polymer is preferably in the form of hydrophobic polymer particles.

[0370] Hydrophobic polymers may be used individually or in combination of two or more types.

[0371] If the protective layer contains a hydrophobic polymer, the hydrophobic polymer content is preferably 1% to 70% by mass, more preferably 5% to 50% by mass, and even more preferably 10% to 40% by mass, relative to the total solid content of the protective layer.

[0372] In the present invention, it is preferable that the area occupancy rate of the hydrophobic polymer on the surface of the protective layer is 30 area % or more, more preferably 40 area % or more, and even more preferably 50 area % or more. An example of the upper limit for the area occupancy rate of the hydrophobic polymer on the surface of the protective layer is 90 area. The area occupancy rate on the surface of the hydrophobic polymer protective layer can be measured as follows. Using an ULVAC-PHI nano TOFII time-of-flight secondary ion mass spectrometer (TOF-SIMS), the protective layer surface is irradiated with a Bi ion beam (primary ions) at an accelerating voltage of 30 kV. By measuring the peaks of ions (secondary ions) corresponding to the hydrophobic regions (i.e., regions due to hydrophobic polymers) emitted from the surface, hydrophobic regions are mapped to a 100 μm area. 2The area occupied by the hydrophobic portion is measured, and the area ratio of the hydrophobic portion is determined. This is defined as the "area ratio of the hydrophobic polymer on the protective layer surface." For example, if the hydrophobic polymer is an acrylic resin, then C6H 13 O - Measurement is performed based on the peak. Furthermore, if the hydrophobic polymer is polyvinylidene chloride, C2H2Cl + Measurement is performed based on the peak. The above-mentioned area occupancy ratio can be adjusted by the amount of hydrophobic polymer added, etc.

[0373] The protective layer may contain an inorganic layered compound to enhance oxygen barrier properties. The inorganic layered compound is a thin, flat particle and includes, for example, mica group such as natural mica and synthetic mica, talc represented by the formula: 3MgO·4SiO·H2O, teniolite, montmorillonite, saponite, hectorite, zirconium phosphate, and the like. The inorganic layered compound that is preferably used is a mica compound. For example, a mica compound of formula A(B,C) 2-5 D4O 10 Examples of mica groups include natural mica and synthetic mica represented by (OH,F,O)2 [where A is one of K, Na, or Ca; B and C are one of Fe(II), Fe(III), Mn, Al, Mg, or V; and D is Si or Al].

[0374] In the mica group, natural micas include muscovite, soda mica, phlogopite, biotite, and scallop mica. Synthetic micas include fluorinated phlogopite (KMg3(AlSi3O)). 10 ) F2, Potassium tetrasilicon mica KMg 2.5 Si4O 10 ) Non-swelling mica such as F2, and Na tetrasilyl mica NaMg 2.5 (Si4O 10 )F2, Na or Li teniolite (Na,Li)Mg2Li(Si4O 10 )F2, montmorillonite-based Na or Li hectorite (Na,Li) 1 / 8 Mg 2 / 5 Li 1 / 8 (Si4O10 Examples include swelling mica such as F2. Furthermore, synthetic smectite is also useful.

[0375] Among the mica compounds mentioned above, fluorine-based swelling mica is particularly useful. Specifically, swelling synthetic mica has a layered structure consisting of unit crystal lattice layers with a thickness of about 10 Å to 15 Å (1 Å = 0.1 nm), and the intralattice metal atom substitution is significantly greater than in other clay minerals. As a result, the lattice layers suffer from a deficiency of positive charge, and Li is present between the layers to compensate for this. + na + Ca 2+ Mg 2+ It adsorbs cations such as Li. The cations interposed between these layers are called exchangeable cations and can exchange with various cations. In particular, the cations between the layers are Li + na + In this case, the small ionic radius results in weak bonds between the layered crystal lattices, causing significant swelling in water. When sheared in this state, it easily cleaves and forms a stable sol in water. Swellable synthetic mica exhibits this tendency strongly and is therefore particularly preferred for use.

[0376] Regarding the shape of the mica compound, from the viewpoint of diffusion control, the thinner the thickness, the better, and the larger the planar size, as long as it does not hinder the smoothness of the coated surface or the transmission of active light, the better. Therefore, the aspect ratio is preferably 20 or more, more preferably 100 or more, and particularly preferably 200 or more. The aspect ratio is the ratio of the major axis to the thickness of the particle, and can be measured, for example, from a projection image obtained from a microscopic photograph of the particle. The larger the aspect ratio, the greater the effect obtained.

[0377] The particle size of the mica compound is preferably 0.3 μm to 20 μm, more preferably 0.5 μm to 10 μm, and particularly preferably 1 μm to 5 μm in average major axis. The average thickness of the particles is preferably 0.1 μm or less, more preferably 0.05 μm or less, and particularly preferably 0.01 μm or less. Specifically, for example, in the case of swelling synthetic mica, which is a representative compound, a preferred embodiment is a thickness of about 1 nm to 50 nm and a surface size (major axis) of about 1 μm to 20 μm.

[0378] The content of the inorganic layered compound is preferably 1% to 60% by mass, and more preferably 3% to 50% by mass, relative to the total solid content of the protective layer. Even when multiple types of inorganic layered compounds are used in combination, it is preferable that the total amount of inorganic layered compounds is within the above content range. Within this range, oxygen barrier properties are improved and good sensitivity is obtained. In addition, a decrease in paint adhesion can be prevented.

[0379] The protective layer may contain known additives such as plasticizers for imparting flexibility, surfactants for improving applicability, and inorganic particles for controlling surface slipperiness. Furthermore, the protective layer may contain the oil-sensitive agents described for the image recording layer.

[0380] The protective layer is applied by a known method. The amount of protective layer applied (solid content) is 0.01 g / m². 2 ~10g / m 2 Preferably, 0.02 g / m 2 ~3g / m 2 More preferably, 0.02 g / m 2 ~1g / m 2 That is particularly preferable. The thickness of the protective layer in the lithographic printing plate used in the present invention is preferably 0.1 μm to 5.0 μm, and more preferably 0.3 μm to 4.0 μm. The thickness of the protective layer in the lithographic printing plate used in the present invention is preferably 1.1 to 5.0 times, and more preferably 1.5 to 3.0 times, the thickness of the image recording layer.

[0381] The lithographic printing plate of the present invention may have other layers besides those described above. Other layers are not particularly limited and may include known layers. For example, a backcoat layer may be provided on the side of the support opposite to the image recording layer, if necessary.

[0382] The lithographic printing plate of the present invention has a sag shape at its edges. Specifically, these edges are at least two opposing edges of the lithographic printing plate of the present invention. Preferably, the sag shape described above has a sag amount X of 25 to 150 μm and a sag width Y of 70 to 300 μm.

[0383] Figure 3 schematically shows the cross-sectional shape of the edge of a lithographic printing plate. In Figure 3, the lithographic printing plate 1 has a sag 2 at its edge. The distance X between the upper end of the end face 1c of the lithographic printing plate 1 (the boundary point between the sag 2 and the end face 1c) and the extension of the image recording layer surface (or protective layer surface if a protective layer is formed) 1a is called the "sag amount X," and the distance Y between the point where the image recording layer surface 1a of the lithographic printing plate 1 begins to sag and the extension of the end face 1c is called the "sag width Y."

[0384] Regarding the edge sag shape, the sag amount X is preferably 25 μm or more, more preferably 35 μm or more, and even more preferably 40 μm or more. The upper limit of the sag amount X is preferably 150 μm from the viewpoint of preventing deterioration of on-press developability due to deterioration of the edge surface condition. If on-press developability deteriorates, ink may adhere to the remaining image recording layer, which may cause edge staining. If the sag amount X is too small, the ink adhering to the edge may be easily transferred to the blanket, which may cause edge staining. When the sag amount X is in the range of 25 to 150 μm, if the sag width Y is small, the occurrence of cracks at the edge increases, and printing ink may accumulate there, which may cause edge staining. From this viewpoint, the sag width Y is preferably in the range of 70 to 300 μm, and more preferably in the range of 80 to 250 μm. Note that the above ranges of sag amount and sag width are not related to the edge shape of the support surface 1b of the lithographic printing plate original 1. Typically, at the edges of the lithographic printing plate 1, sagging occurs at the boundary B between the image recording layer and the support, and also at the support surface 1b, similar to the image recording layer surface 1a.

[0385] The formation of the end portion having the aforementioned sagging shape can be achieved, for example, by adjusting the cutting conditions of the lithographic printing plate. Specifically, this can be done by adjusting the gap between the upper and lower cutting blades, the amount of cutting action, and the blade angle in a slitter device used for cutting lithographic printing plates. Figure 4 is a conceptual diagram showing an example of the cutting section of a slitter device. The slitter device has a pair of upper and lower cutting blades 10 and 20 arranged vertically. The cutting blades 10 and 20 are circular blades on a disc, and the upper cutting blades 10a and 10b are supported coaxially on a rotation axis 11, and the lower cutting blades 20a and 20b are supported coaxially on a rotation axis 21. The upper cutting blades 10a and 10b and the lower cutting blades 20a and 20b rotate in opposite directions. The lithographic printing plate 30 is passed between the upper cutting blades 10a and 10b and the lower cutting blades 20a and 20b and cut to a predetermined width. By adjusting the gap between the upper cutting blade 10a and the lower cutting blade 20a and the gap between the upper cutting blade 10b and the lower cutting blade 20b in the cutting section of the slitter device, it is possible to form an end with a sagging shape.

[0386] Specifically, the above-mentioned ends are at least two opposing sides of the lithographic printing plate original of the present invention. In the lithographic printing plate original according to the present invention, from the viewpoint of further suppressing edge staining, it is preferable that the area ratio of cracks present on the surface of the anodic oxide film in the region corresponding to the sag width Y is 10% or less. Here, the region corresponding to the sag width Y refers to the region from the intersection of the extension line of the image recording layer surface (or protective layer surface, if a protective layer is formed) 1a and the extension line of the end face 1c in Figure 3 above, until the extension line of 1a touches the image recording layer surface (or protective layer surface, if a protective layer is formed).

[0387] The area ratio of cracks present on the surface of the anodized film is calculated using the following method. The constituent layers (undercoat layer, image recording layer, protective layer) of the lithographic printing plate are removed using a PlasmaReactorPR300 manufactured by Yamato Scientific Co., Ltd. The surface of the exposed aluminum support with anodized coating is treated with a 3nm Pt-Pd film to create a conductive sample. This sample is observed using a Hitachi High-Technologies Corporation S-4800 field emission scanning electron microscope (FE-SEM) at an acceleration voltage of 30kV, and a series of images are acquired from the edges towards the center at an observation magnification of 1,500x to obtain a 150×50μm image. Using the image processing software "ImageJ", the crack shape is extracted from this image by utilizing the brightness difference between the crack area and the surface of the anodized coating layer, binarization is performed, and the percentage of cracks in the 150×50μm area is calculated as the crack area ratio.

[0388] From the viewpoint of preventing edge staining, the area ratio of cracks is more preferably 8% or less, and even more preferably 7% or less.

[0389] In order to adjust the area ratio of cracks present on the surface of the anodic oxide film in the region corresponding to the sag width Y to 10% or less, although not particularly limited, the amount of anodic oxide film in the above anodic oxide film should be 0.5 to 3.0 g / m². 2 It is preferable to control it within the range.

[0390] [Method for preparing lithographic printing plates, and lithographic printing method] The method for producing a lithographic printing plate using a lithographic printing plate master in the present invention is not particularly limited, but it is preferable to include a step of image exposure of the lithographic printing plate master (exposure step) and a step of removing the image recording layer in the non-image areas by supplying at least one selected from the group consisting of printing ink and dampening water to the exposed lithographic printing plate master on a printing press (on-press development step). The lithographic printing method using a lithographic printing plate according to the present invention comprises the steps of: exposing the lithographic printing plate to image (exposure step); supplying at least one selected from the group consisting of printing ink and dampening water on a printing press to remove the image recording layer in the non-image areas and produce a lithographic printing plate (on-press development step); and printing using the obtained lithographic printing plate (hereinafter also referred to as the "printing step"). It is preferable that it includes ) and .

[0391] <Exposure process> The method for producing a lithographic printing plate using the lithographic printing plate of the present invention preferably includes an exposure step in which the lithographic printing plate is image-exposed to form exposed and unexposed areas. The lithographic printing plate of the present invention is preferably image-exposed by laser exposure through a transparent original image having a line image, a halftone image, etc., or by laser light scanning using digital data. The wavelength of the light source is preferably 750 nm to 1,400 nm. Suitable light sources with a wavelength of 750 nm to 1,400 nm include solid-state lasers and semiconductor lasers that emit infrared light. For infrared lasers, the output is preferably 100 mW or more, the exposure time per pixel is preferably 20 microseconds or less, and the irradiation energy is preferably 10 mJ / cm². 2 ~300 mJ / cm 2 It is preferable that this be the case. Furthermore, it is preferable to use a multi-beam laser device in order to shorten the exposure time. The exposure mechanism may be any of the following: an internal drum system, an external drum system, or a flatbed system. Image exposure can be performed using conventional methods, such as with a platesetter. In the case of on-press development, the lithographic printing plate can be mounted on the printing press, and then the image exposure may be performed on the press.

[0392] <On-press development process> The method for producing a lithographic printing plate using a lithographic printing plate master in the present invention preferably includes an on-press development step in which at least one selected from the group consisting of printing ink and dampening water is supplied on the printing press to remove the image recording layer in the non-image areas. The onboard film processing method is described below.

[0393] [On-press development method] In the on-press development method, it is preferable that the exposed lithographic printing plate is supplied with oil-based ink and water-based components on the printing press, and the image recording layer in the non-image areas is removed to produce the lithographic printing plate. In other words, if a lithographic printing plate is exposed to image light and then mounted directly onto a printing press without any development process, or if the lithographic printing plate is mounted onto a printing press, exposed to image light on the press, and then printed using oil-based ink and water-based components, in the early stages of printing, the uncured image recording layer in the non-image areas is dissolved or dispersed and removed by either or both of the supplied oil-based ink and water-based components, exposing a hydrophilic surface in those areas. On the other hand, in the exposed area, the image recording layer hardened by exposure forms an oil-based ink receiving area having a lipophilic surface. The first substance supplied to the plate surface may be an oil-based ink or an aqueous component, but it is preferable to supply the oil-based ink first in order to prevent contamination of the aqueous component by the components of the image recording layer from which the aqueous component has been removed. In this way, the lithographic printing plate is developed on the printing press and used as is for printing many copies. As the oil-based ink and aqueous component, ordinary lithographic printing ink and dampening solution are preferably used.

[0394] <Printing process> The lithographic printing method using a lithographic printing plate according to the present invention includes a printing step of supplying printing ink to the lithographic printing plate and printing on a recording medium. There are no particular restrictions on the printing ink, and various known inks can be used as desired. Oil-based inks or UV-curing inks are preferred as printing inks. Furthermore, dampening solution may be supplied during the printing process as needed. Furthermore, the above printing process may be carried out continuously with the above-mentioned on-press development process or the above-mentioned developer solution development process without stopping the printing press. There are no particular restrictions on the recording medium; any known recording medium can be used as desired.

[0395] In the method for producing a lithographic printing plate and the lithographic printing method using a lithographic printing plate according to the present invention, the entire surface of the lithographic printing plate may be heated before exposure, during exposure, and between exposure and development, if necessary. Such heating promotes the image formation reaction in the image recording layer, which can result in advantages such as improved sensitivity and print durability, and stabilized sensitivity. Pre-development heating is preferably performed under mild conditions of 150°C or less. This configuration prevents problems such as hardening of non-image areas. For post-development heating, very strong conditions are preferable, preferably in the range of 100°C to 500°C. This range provides sufficient image enhancement and suppresses problems such as deterioration of the support and thermal decomposition of the image area. [Examples]

[0396] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. In these examples, unless otherwise specified, "%" and "parts" refer to "mass%" and "parts by mass," respectively. In polymer compounds, unless otherwise specified, molecular weight is the weight-average molecular weight (Mw), and the ratio of constituent repeating units is expressed as mole percentage. Furthermore, the weight-average molecular weight (Mw) is the value measured as a polystyrene equivalent by gel permeation chromatography (GPC).

[0397] [Examples 1-47 and Comparative Examples 1-2]

[0398] <Preparation of support 1> A support 1 was fabricated by subjecting a 0.3 mm thick aluminum plate (aluminum alloy plate) of material 1S to the following treatments (Fa) to (Fg). Water washing was performed between all treatment steps, and after the water washing, the liquid was removed using a nip roller.

[0399] (Fa) Alkaline etching treatment An aluminum plate was etched by spraying it with an aqueous solution of caustic soda containing 26% by mass of caustic soda and 6.5% by mass of aluminum ions at a temperature of 70°C. The amount of aluminum dissolved in the surface to be subsequently subjected to electrochemical roughening treatment was 5 g / m². 2 That was the case.

[0400] (Fb) Desmatt treatment using acidic aqueous solution As an acidic aqueous solution, a sulfuric acid solution with a concentration of 150 g / L at a liquid temperature of 30°C was sprayed onto an aluminum plate for 3 seconds to perform the desmatt treatment.

[0401] (Fc) Electrochemical roughening treatment Electrochemical surface roughening treatment was performed using an electrolyte solution with a hydrochloric acid concentration of 14 g / L, an aluminum ion concentration of 13 g / L, and a sulfuric acid concentration of 3 g / L, with alternating current. The electrolyte solution temperature was 30°C. The aluminum ion concentration was adjusted by adding aluminum chloride. The waveform of an alternating current is a sine wave with symmetrical positive and negative waveforms, with a frequency of 50 Hz, anode reaction time and cathode reaction time in one cycle of the alternating current at a ratio of 1:1, and current density at the peak current value of the alternating current waveform is 75 A / dm². 2 The amount of electric charge was 450 C / dm², which is the sum of the electric charges that the aluminum plate participates in the anode reaction. 2 The electrolytic treatment is 112.5C / dm 2 The procedure was performed in four separate steps, with a 4-second interval between applications. A carbon electrode was used as the counter electrode to the aluminum plate.

[0402] (Fd) Alkaline etching treatment An aluminum plate was etched by spraying it with an aqueous solution of caustic soda containing 5% by mass of caustic soda and 0.5% by mass of aluminum ions at a temperature of 45°C. The amount of aluminum dissolved on the electrochemically roughened surface was 0.2 g / m². 2 That was the case.

[0403] Desmatt treatment using (Fe) acidic aqueous solution As an acidic aqueous solution, a solution with a sulfuric acid concentration of 170 g / L and an aluminum ion concentration of 5 g / L at a liquid temperature of 35°C was sprayed onto an aluminum plate for 3 seconds to perform the desmatt treatment.

[0404] (Ff) First stage anodizing treatment The first stage of anodic oxidation was performed using a DC electrolytic anodic oxidation apparatus with the structure shown in Figure 6. A 150 g / L aqueous phosphoric acid solution was used as the electrolyte, with a liquid temperature of 35°C and a current density of 4.5 A / dm². 2 Anodizing treatment was performed under the following conditions, resulting in a film thickness of 1 g / m². 2 An anodic oxide film was formed. In the anodic oxidation treatment apparatus 410 shown in Figure 6, the aluminum plate 416 is transported as indicated by the arrows in Figure 6. In the power supply tank 412 where the electrolyte 418 is stored, the aluminum plate 416 is charged positively by the power supply electrode 420. Then, in the power supply tank 412, the aluminum plate 416 is transported upward by the roller 422, its direction is changed downward by the nip roller 424, and then it is transported toward the electrolytic treatment tank 414 where the electrolyte 426 is stored, and its direction is changed horizontally by the roller 428. Next, the aluminum plate 416 is charged negatively by the electrolytic electrode 430, forming an anodic oxide film on its surface, and the aluminum plate 416 that has left the electrolytic treatment tank 414 is transported to the next process. In the above-described anodizing apparatus 410, a direction changing mechanism is formed by rollers 422, nip roller 424, and roller 428, and the aluminum plate 416 is conveyed in a mountain shape and an inverted U shape by the rollers 422, 424, and 428 in the space between the power supply tank 412 and the electrolytic treatment tank 414. The power supply electrode 420 and the electrolytic electrode 430 are connected to a DC power supply 434.

[0405] (Fg) Second stage anodic oxidation treatment The second stage of anodic oxidation was performed using a DC electrolytic anodic oxidation apparatus with the structure shown in Figure 6. A 170 g / L sulfuric acid aqueous solution was used as the electrolyte, with a liquid temperature of 50°C and a current density of 13 A / dm². 2 Anodizing treatment was performed under the following conditions, resulting in a film thickness of 2.6 g / m². 2An anodic oxide film was formed. Afterward, it was washed with water using a spray. The average diameter of the micropores in support 1 was 40 nm. The value of lightness L* in the L*a*b* color system for the anodic oxide film surface of support 1 was 83.7. The amount of anodic oxidation coating on support 1 is 2.6 g / m². 2 That was the case.

[0406] <Preparation of support 1-2> The amount of film in (Fg) above is 2.2 g / m². 2 Except for the change, support 1-2 was obtained in the same manner as support 1. The amount of anodic oxidation coating on support 1-2 is 2.2 g / m². 2 That was the case.

[0407] <Preparation of supports 1-3> The amount of film in (Fg) above is 1.8 g / m² 2 Except for the change, supports 1-3 were obtained in the same manner as support 1. The amount of anodic oxidation coating on supports 1-3 is 1.8 g / m². 2 That was the case.

[0408] <Preparation of support 2> Support 2 was fabricated according to the method for manufacturing the support in Example 5 of International Publication No. 2021 / 67054. The amount of anodic oxidation coating on support 2 is 2.6 g / m². 2 That was the case.

[0409] <Fabrication of support 3> A support 3 was manufactured by subjecting a 0.3 mm thick aluminum plate (aluminum alloy plate) of material 1S to the following treatments (Ja) to (Jm). Water washing was performed between all treatment steps, and after the water washing, liquid was removed using a nip roller.

[0410] (Ja) Mechanical surface roughening treatment (brush grain method) Using the apparatus shown in Figure 5, a pumice suspension (specific gravity 1.1 g / cm³) was prepared. 3While supplying the polishing slurry liquid to the surface of the aluminum plate, mechanical surface roughening treatment was performed using a rotating bundled brush. In Figure 5, 31 is the aluminum plate, 32 and 34 are roller-shaped brushes (bundled brushes in this embodiment), 33 is the polishing slurry liquid, and 35, 36, 37 and 38 are support rollers. In the mechanical surface roughening treatment, the median diameter (μm) of the abrasive material was set to 30 μm, the number of brushes to 4, and the brush rotation speed (rpm) to 250 rpm. The material of the bundled brush was 6-10 nylon, with a bristle diameter of 0.3 mm and a bristle length of 50 mm. The brushes were densely planted in a φ300 mm stainless steel cylinder with holes drilled in it. The distance between the two support rollers (φ200 mm) at the bottom of the bundled brush was 300 mm. The bundled brush was pressed against the aluminum plate until the load on the drive motor that rotated the brush was 10 kW more than the load before the bundled brush was pressed against the aluminum plate. The direction of brush rotation was the same as the direction of movement of the aluminum plate.

[0411] (Jb) Alkaline etching treatment An aluminum plate was etched by spraying it with an aqueous solution of caustic soda containing 26% by mass of caustic soda and 6.5% by mass of aluminum ions at a temperature of 70°C. The amount of aluminum dissolved in the surface to be subsequently subjected to electrochemical roughening treatment was 10 g / m². 2 That was the case.

[0412] (Jc) Desmatt treatment using acidic aqueous solution As an acidic aqueous solution, waste nitric acid used in the subsequent electrochemical surface roughening treatment was sprayed onto an aluminum plate for 3 seconds at a liquid temperature of 35°C to perform the desmatt treatment.

[0413] (Jd) Electrochemical roughening treatment using aqueous nitric acid solution A continuous electrochemical surface roughening treatment was performed using a 60 Hz AC voltage. The electrolyte used was an aqueous solution of 10.4 g / L nitric acid to which aluminum nitrate was added to adjust the aluminum ion concentration to 4.5 g / L, at a liquid temperature of 35°C. The AC power waveform is shown in Figure 1, with a current value travel time tp of 0.8 msec, a duty cycle of 1:1, and a trapezoidal rectangular wave AC. Electrochemical surface roughening was performed using a carbon electrode as the counter electrode. A ferrite anode was used as the auxiliary anode. The electrolytic cell shown in Figure 2 was used. The current density was 30 A / dm² at the peak current value. 2 5% of the current flowing from the power supply was diverted to the auxiliary anode. Electrical quantity (C / dm 2 ) is the total amount of electric charge when the aluminum plate is at anode, which is 185 C / dm 2 That was the case.

[0414] (Je) Alkali etching treatment An aluminum plate was etched by spraying it with an aqueous solution of caustic soda containing 27% by mass of caustic soda and 2.5% by mass of aluminum ions at a temperature of 50°C. The amount of aluminum dissolved was 3.5 g / m². 2 That was the case.

[0415] (Jf) Desmatt treatment using acidic aqueous solution As an acidic aqueous solution, a solution with a sulfuric acid concentration of 170 g / L and an aluminum ion concentration of 5 g / L at a liquid temperature of 30°C was sprayed onto an aluminum plate for 3 seconds to perform the desmatt treatment.

[0416] (Jg) Electrochemical roughening treatment using hydrochloric acid aqueous solution A continuous electrochemical surface roughening treatment was performed using a 60 Hz AC voltage. The electrolyte used was a 6.2 g / L aqueous solution of hydrochloric acid to which aluminum chloride was added to adjust the aluminum ion concentration to 4.5 g / L, at a liquid temperature of 35°C. The AC power waveform is shown in Figure 1, with a current value travel time tp of 0.8 msec, a duty cycle of 1:1, and a trapezoidal rectangular wave AC. Electrochemical surface roughening was performed using a carbon electrode as the counter electrode. A ferrite anode was used as the auxiliary anode. The electrolytic cell shown in Figure 2 was used. The current density was 25 A / dm² at the peak current value. 2 Therefore, the amount of electricity in hydrochloric acid electrolysis (C / dm 2 ) is the total amount of electricity when the aluminum plate is at anode, which is 63C / dm 2 That was the case.

[0417] (Jh) Alkali etching treatment An aluminum plate was etched by spraying it with an aqueous solution of caustic soda containing 5% by mass of caustic soda and 0.5% by mass of aluminum ions at a temperature of 60°C. The amount of aluminum dissolved was 0.2 g / m². 2 That was the case.

[0418] (Ji) Desmatt treatment using acidic aqueous solution As an acidic aqueous solution, a solution of waste liquid (sulfuric acid concentration 170 g / L and aluminum ion concentration 5 g / L) generated in an anodizing process at a liquid temperature of 35°C was sprayed onto an aluminum plate for 4 seconds to perform the desmatt treatment.

[0419] (Jj) First stage anodizing treatment The first stage of anodic oxidation was performed using a DC electrolytic anodic oxidation apparatus with the structure shown in Figure 6. A 170 g / L sulfuric acid aqueous solution was used as the electrolyte, with a liquid temperature of 50°C and a current density of 30 A / dm². 2 Anodizing treatment was performed under the following conditions, resulting in a film thickness of 0.3 g / m². 2 An anodic oxide film was formed.

[0420] (Jk) Pore-wide processing An anodized aluminum plate was immersed in a caustic soda aqueous solution with a caustic soda concentration of 5% by mass and an aluminum ion concentration of 0.5% by mass for 3 seconds at 40°C to perform a pore widening treatment.

[0421] (Jl) Second stage anodizing treatment The second stage of anodic oxidation was performed using a DC electrolytic anodic oxidation apparatus with the structure shown in Figure 6. A 170 g / L sulfuric acid aqueous solution was used as the electrolyte, with a liquid temperature of 50°C and a current density of 13 A / dm². 2 Anodizing treatment was performed under the following conditions, resulting in a film thickness of 2.6 g / m². 2 An anodic oxide film was formed.

[0422] (Jm) Hydrophilization treatment To ensure hydrophilicity in the non-image areas, the aluminum plate was silicate-treated by immersing it in a 2.5% by mass sodium silicate aqueous solution at 50°C for 7 seconds. The amount of Si deposited was 8.5 mg / m². 2 The average diameter of the micropores was 30 nm. The value of lightness L* in the L*a*b* color system for the anodic oxide film surface of support 3 was 72.3. The amount of anodic oxidation coating on support 3 is 2.6 g / m². 2 That was the case.

[0423] <Preparation of support 4> -Alkaline etching treatment- An aluminum plate was etched by spraying it with a caustic soda aqueous solution containing 26% by mass of caustic soda and 6.5% by mass of aluminum ions at a temperature of 55°C. Afterward, it was rinsed with water by spraying. The amount of aluminum dissolved in the surface to be subsequently subjected to electrochemical roughening treatment was 3 g / m². 2 That was the case.

[0424] -Desmat treatment using acidic aqueous solution (first desmat treatment)- Next, a desmatt treatment was performed using an acidic aqueous solution. The acidic aqueous solution used for the desmatt treatment was a 170 g / L sulfuric acid solution. The solution temperature was 30°C. The acidic aqueous solution was sprayed onto the aluminum plate and desmatt treatment was performed for 3 seconds. After that, it was rinsed with water.

[0425] -Electrochemical surface roughening treatment- Next, electrochemical surface roughening treatment was performed using an electrolytic solution of hydrochloric acid and alternating current. The electrolyte temperature was 40°C. The waveform of the alternating current was a sine wave with symmetrical positive and negative waveforms, and the frequency was 50 Hz. The amount of electric charge was the sum of the electric charges that the aluminum plate participated in the anode reaction, which was 300 C / dm². 2 The procedure was carried out using a carbon electrode as the counter electrode to the aluminum plate. Afterwards, a water washing treatment was performed.

[0426] -Alkaline etching treatment- An aqueous solution of caustic soda, containing 5% by mass of caustic soda and 0.5% by mass of aluminum ions, was sprayed onto an aluminum plate that had undergone electrochemical roughening treatment at a temperature of 35°C, resulting in an etching amount of 0.1 g / m². 2 The following etching process was performed. Afterward, a water washing process was carried out.

[0427] -Desmat treatment using acidic aqueous solution- Next, a desmatt treatment was performed using an acidic aqueous solution. The acidic aqueous solution used for the desmatt treatment was a 170 g / L sulfuric acid solution. The solution temperature was 30°C. The acidic aqueous solution was sprayed onto the aluminum plate and desmatt treatment was performed for 3 seconds. After that, it was rinsed with water.

[0428] -Anodizing treatment- Using a sulfuric acid solution of 170 g / L at a temperature of 40°C, a direct current was used to determine the amount of anodic oxide film coating at 2.6 g / m². 2 Anodizing treatment was performed to obtain the support 4. The amount of anodic oxidation coating on support 4 is 2.6 g / m². 2 That was the case.

[0429] <Formation of undercoat layer 1> On the support, apply a primer coating liquid (1) with the following composition, with a dry coating amount of 26 mg / m². 2 The coat was applied in such a manner to form the first undercoat layer.

[0430] (Primer coating liquid (1)) • Undercoat compound (2) (structure shown below) 0.013 parts Hydroxyethyliminodiacetic acid 0.005 parts • Ethylenediaminetetraacetate tetrasodium 0.005 parts • Polyoxyethylene lauryl ether 0.0003 parts ·Wednesday 3.15 parts

[0431] [ka]

[0432] In the above-mentioned undercoat compound (2), the number in the lower right corner of the parentheses for each constituent unit represents the mass ratio, and the number in the lower right corner of the parentheses for the ethylene oxy unit represents the number of repetitions.

[0433] <Formation of undercoat layer 2> Undercoat layer 2 was formed on the support in the same manner as undercoat layer 1, except that undercoat layer coating liquid (2) was used, which was an undercoat layer coating liquid (1) of the above composition to which the following compounds were added. Amount of monosodium phosphate that corresponds to the dry coating amount shown in Table 1

[0434] <Formation of undercoat layer 3> On the support, apply the primer coating liquid (3) with the following composition, with a dry coating amount of 0.03 g / m². 2 The coat was applied in such a way that it formed the base coat layer 3.

[0435] (Primer coating liquid (3)) • Polyacrylic acid aqueous solution (40% by mass) Jurymer AC-10S (manufactured by Toagosei Co., Ltd.) 3.0 unit ·Wednesday 27.0 parts

[0436] <Formation of undercoat layer 4> A primer layer 4 was formed on the support in the same manner as primer layer 3, except that a primer layer coating solution (4) was used, which was made by adding the following compounds to the primer layer coating solution (3) of the above composition. Amount of monosodium phosphate that corresponds to the dry coating amount shown in Table 1

[0437] <Formation of image recording layers 1-11 and 20> Each of the image recording layer coating solutions (image recording layer coating solutions (1) to (11), (20)) with the following composition was applied in a bar, and then oven-dried at 100°C for 60 seconds to form image recording layers 1 to 10 and 19, respectively, with a thickness of 1.2 μm. Each image recording layer coating solution was obtained by mixing and stirring the following photosensitive solutions (photosensitive solutions (1) to (11), (20)) and microgel solution (1) immediately before coating.

[0438] (Photosensitive liquid) • Acid colorants listed in Table 1 Amount of dry coating amount listed in Table 1 • Oxo salts listed in Table 1. Amount of dry application as listed in Table 1. • Binder polymer (6) 23% by mass 1-methoxy-2-propanol solution (structure shown below) 0.2891 copies • Binder polymer (7) 23% by mass 1-methoxy-2-propanol solution (structure shown below) 0.4574 copies • 0.0278 parts of the infrared absorber listed in Table 1 • Borate compound (1) (sodium tetraphenylborate) 0.015 parts • Polymerization initiator (1) (structure shown below) 0.2348 parts • Polymerizable compound (1) (Tris(acryloyloxyethyl) isocyanurate, NK ester A-9300 40% 2-butanone solution, manufactured by Shin-Nakamura Chemical Industry Co., Ltd.) 0.2875 copies • Low molecular weight hydrophilic compound (1) (tris(2-hydroxyethyl) isocyanurate) 0.0287 parts • Low molecular weight hydrophilic compound (2) (trimethylglycine) 0.0147 parts • 0.25 parts of anionic surfactant 1 30% by mass aqueous solution (structure shown below) • UV absorber (1) (TINUVIN405, manufactured by BASF Ltd.) (structure shown below) 0.04 parts • Fluorine-based surfactant (1) (structure shown below) 0.004 parts • Phosphonium compound (1) (structure shown below) 0.020 parts 2-Butanone 5,346 parts 1-Methoxy-2-propanol 3.128 parts • Methanol 0.964 parts ·Pure water 0.036 part

[0439] (Microgel solution (1)) ·Microgel (1) (solid content 21.8% by mass) 2.243 parts 1-Methoxy-2-propanol 0.600 parts

[0440] (Preparation of microgel (1)) The method for preparing the microgel (1) used in the above microgel solution is shown below.

[0441] <Preparation of polyhydric isocyanate compound (1)> To a suspension of 17.78 parts (80 molar equivalents) of isophorone diisocyanate and 7.35 parts (20 molar equivalents) of the following polyhydric phenol compound (1) in ethyl acetate (25.31 parts), 0.043 parts of bismastris (2-ethylhexanoate) (Neostan U-600, manufactured by Nitto Kasei Co., Ltd.) was added and the mixture was stirred. Once the exothermic reaction subsided, the reaction temperature was set to 50°C and the mixture was stirred for 3 hours to obtain an ethyl acetate solution (50% by mass) of polyhydric isocyanate compound (1).

[0442] [ka]

[0443] <Preparation of Microgel (1)> The oil phase and aqueous phase components listed below were mixed and emulsified using a homogenizer at 12,000 rpm for 10 minutes. The resulting emulsion was stirred at 45°C for 4 hours, then 5.20 parts of a 10% by mass aqueous solution of 1,8-diazabicyclo[5.4.0]undec-7-en-octylate (U-CAT SA102, manufactured by Sunapro Co., Ltd.) were added, stirred at room temperature for 30 minutes, and allowed to stand at 45°C for 24 hours. The solid content concentration was adjusted to 21.8% by mass with distilled water to obtain an aqueous dispersion of microgel (4). The volume-average particle size was measured by light scattering using a dynamic light scattering particle size distribution analyzer LB-500 (manufactured by Horiba, Ltd.), and was found to be 0.28 μm.

[0444] (Oil phase components) (Component 1) Ethyl acetate 12.0 parts (Component 2) An adduct obtained by adding trimethylolpropane (6 moles) and xylene diisocyanate (18 moles), to which methyl-terminated polyoxyethylene (1 mole, number of oxyethylene units repeated: 90) is added (50% by mass ethyl acetate solution, manufactured by Mitsui Chemicals, Inc.) 3.76 copies (Component 3) Polyhydric isocyanate compound (1) (as a 50% by mass ethyl acetate solution) 15.0 copies (Component 4) 11.54 parts of a 65% by mass ethyl acetate solution of dipentaerythritol pentaacrylate (SR-399, manufactured by Sartomer) (Component 5) 4.42 parts of a 10% ethyl acetate solution of a sulfonate-type surfactant (Pionin A-41-C, manufactured by Takemoto Oil Co., Ltd.)

[0445] (Aqueous phase component) Distilled water 46.87 parts

[0446] <Synthesis of binder polymer (6)> 78.0 g of 1-methoxy-2-propanol was weighed into a three-necked flask and heated to 70°C under a nitrogen stream. A mixed solution consisting of 52.1 g of Bremmer PME-100 (methoxydiethylene glycol monomethacrylate, manufactured by Nippon Oil & Fats Co., Ltd.), 21.8 g of methyl methacrylate, 14.2 g of methacrylic acid, 2.15 g of hexakis(3-mercaptopropionic acid)dipentaerythritol, 0.38 g of V-601 (2,2'-azobis(isobutyrate)dimethyl, manufactured by Wako Pure Chemical Industries, Ltd.), and 54 g of 1-methoxy-2-propanol was added dropwise to this reaction vessel over 2 hours and 30 minutes. After the addition was complete, the temperature was raised to 80°C and the reaction was continued for another 2 hours. A mixed solution consisting of 0.04 g of V-601 and 4 g of 1-methoxy-2-propanol was added, and the reaction was continued at 90°C for 2.5 hours. After the reaction was complete, the reaction solution was cooled to room temperature. To the above reaction solution, 137.2g of 1-methoxy-2-propanol, 0.24g of 4-hydroxytetramethylpiperidine-N-oxide, 26.0g of glycidyl methacrylate, and 3.0g of tetraethylammonium bromide were added and the mixture was thoroughly stirred, then heated at 90°C. After 18 hours, the reaction solution was cooled to room temperature (25°C) and then diluted with 99.4 g of 1-methoxy-2-propanol. The binder polymer (6) thus obtained had a solid content concentration of 23% by mass, and a polystyrene-equivalent mass-average molecular weight measured by GPC was 35,000.

[0447] [ka]

[0448] <Synthesis of binder polymer (7)> 78.00 g of 1-methoxy-2-propanol was weighed into a three-necked flask and heated to 70°C under a nitrogen stream. A mixed solution consisting of 52.8 g of Bremmer PME-100 (methoxydiethylene glycol monomethacrylate, manufactured by Nippon Oil & Fats Co., Ltd.), 2.8 g of methyl methacrylate, 25.0 g of methacrylic acid, 6.4 g of hexakis(3-mercaptopropionic acid) dipentaerythritol, 1.1 g of V-601 (2,2'-azobis(isobutyrate)dimethyl, manufactured by Wako Pure Chemical Industries, Ltd.), and 55 g of 1-methoxy-2-propanol was added dropwise to this reaction vessel over 2 hours and 30 minutes. After the addition was complete, the temperature was raised to 80°C and the reaction was continued for another 2 hours. After 2 hours, a mixed solution consisting of V-601:0.11g and 1-methoxy-2-propanol:1g was added, and the temperature was raised to 90°C and the reaction was continued for 2.5 hours. After the reaction was complete, the reaction solution was cooled to room temperature. To the above reaction solution, 177.2g of 1-methoxy-2-propanol, 0.28g of 4-hydroxytetramethylpiperidine-N-oxide, 46.0g of glycidyl methacrylate, and 3.4g of tetrabutylammonium bromide were added and the mixture was thoroughly stirred, then heated at 90°C. After 18 hours, the reaction solution was cooled to room temperature (25°C), and then diluted with 0.06 g of 4-methoxyphenol and 114.5 g of 1-methoxy-2-propanol. The binder polymer (7) obtained in this way had a solid content concentration of 23% by mass, and a polystyrene-equivalent weight-average molecular weight of 15,000 as measured by GPC.

[0449] [ka]

[0450] [ka]

[0451] [ka]

[0452] <Formation of image recording layer 12> The image recording layer coating solution (12) with the following composition was applied in a bar, and then oven-dried at 110°C for 40 seconds, resulting in a dry weight of 0.9 g / m². 2 An image recording layer 12 was formed.

[0453] (Image recording layer coating solution (12)) • Acid colorants listed in Table 1 Amount of dry coating amount listed in Table 1 • 0.0278 parts of the infrared absorber listed in Table 1 • Electron-accepting polymerization initiator (I-3) (see below): 0.0981 parts • Borate compound (1) (see below): 0.0270 parts ·Polymerizable compound (M-1): 0.3536 parts • Tricresil phosphate: 0.0125 parts • Anionic surfactant 1 (see below): 0.0162 parts • Paionin A-41-C (manufactured by Takemoto Oil Co., Ltd., 70% methanol solution): 0.0081 copies • Fluorine-based surfactant (1) (see below): 0.0042 parts 2-Butanone: 5,3155 parts • 1-Methoxy-2-propanol: 2.8825 parts Methanol: 2,3391 parts • Microgel solution: 2.8779 parts • Tinuvin 928 (manufactured by BASF Ltd.) 0.0300 units

[0454] [ka]

[0455] [ka]

[0456] M-1: A polymerizable compound obtained by reacting DESMODUR® N100 with hydroxyethyl acrylate and pentatriitol acrylate in a molar ratio of 1:1.5:1.5, at a concentration of 80% by mass in a 2-butanone solution. (Weight average molecular weight: 1650)

[0457] (Microgel solution) The method for preparing the microgel used in the above microgel solution is shown below. -Preparation of polyvalent isocyanate compounds- To a suspension of 17.78 parts (80 molar equivalents) of isophorone diisocyanate and 7.35 parts (20 molar equivalents) of the following polyhydric phenol compound (1) in ethyl acetate (25.31 parts), 0.043 parts of bismastris (2-ethylhexanoate) (Neostan U-600, manufactured by Nitto Kasei Co., Ltd.) was added and the mixture was stirred. Once the exothermic reaction subsided, the reaction temperature was set to 50°C and the mixture was stirred for 3 hours to obtain an ethyl acetate solution (50% by mass) of polyhydric isocyanate compound (1).

[0458] [ka]

[0459] -Preparation of microgels- The oil phase and aqueous phase components listed below were mixed and emulsified using a homogenizer at 12,000 rpm for 10 minutes. The resulting emulsion was stirred at 45°C for 4 hours, then 5.20 g of a 10% by mass aqueous solution of 1,8-diazabicyclo[5.4.0]undec-7-en-octylate (U-CAT SA102, manufactured by Sunapro Co., Ltd.) was added, stirred at room temperature for 30 minutes, and allowed to stand at 45°C for 24 hours. The solid content concentration was adjusted to 20% by mass with distilled water to obtain an aqueous dispersion of microgel (1). The average particle size was measured by light scattering and found to be 0.28 μm.

[0460] ~Oil phase components~ (Component 1) Ethyl acetate: 12.0 parts (Component 2) An adduct prepared by adding trimethylolpropane (6 molar equivalents) and xylene diisocyanate (18 molar equivalents), to which terminally methylated polyoxyethylene (1 molar equivalent, number of oxyethylene units repeated: 90) is added (50% by mass ethyl acetate solution, manufactured by Mitsui Chemicals, Inc.): 3.76 parts (Component 3) Polyhydric isocyanate compound (1) (as a 50% by mass ethyl acetate solution): 15.0 parts (Component 4) 65% by mass ethyl acetate solution of dipentaerythritol pentaacrylate (SR-399, manufactured by Sartomer): 11.54 parts (Component 5) 10% ethyl acetate solution of sulfonate-type surfactant (Pionin A-41-C, manufactured by Takemoto Oil Co., Ltd.): 4.42 parts

[0461] ~Aqueous phase components~ Distilled water: 46.87 parts

[0462] -Preparation of polyvalent isocyanate compounds- To a suspension of 17.78 parts (80 molar equivalents) of isophorone diisocyanate and 7.35 parts (20 molar equivalents) of the following polyhydric phenol compound (1) in ethyl acetate (25.31 parts), 0.043 parts of bismastris (2-ethylhexanoate) (Neostan U-600, manufactured by Nitto Kasei Co., Ltd.) was added and the mixture was stirred. Once the exothermic reaction subsided, the reaction temperature was set to 50°C and the mixture was stirred for 3 hours to obtain an ethyl acetate solution (50% by mass) of polyhydric isocyanate compound (1).

[0463] [ka]

[0464] <Formation of image recording layer 13> The image recording layer coating solution (13) with the following composition was applied in a bar, and then oven-dried at 120°C for 40 seconds, resulting in a dry coating amount of 1.0 g / m². 2 An image recording layer 13 was formed.

[0465] (Image recording layer coating solution (13)) • Acid colorants listed in Table 1: Amount corresponding to the dry application amount listed in Table 1. • Infrared absorber listed in Table 1: 0.0400 parts Electron-accepting polymerization initiator (Int-1): 0.1090 parts Electron-donating polymerization initiator (TPB): 0.0250 parts Polymerizable compound (see M-4 below): 0.4714 parts Anionic surfactant (A-1): 0.0400 parts Fluorine-based surfactant (W-1): 0.0042 parts 2-Butanone: 4.3551 parts 1-Methoxy-2-propanol: 3.9260 parts Methanol: 2.6947 parts Polymer particles R: 2.3256 parts

[0466] Int-1: The following compounds

[0467] [ka]

[0468] TPB: The following compounds

[0469] [ka]

[0470] A-1: The following compounds

[0471] [ka]

[0472] W-1: The following compounds

[0473] [ka]

[0474] <Method for synthesizing polymerizable compounds (M-4)> A mixed solution of Takenate D-160N (polyisocyanate trimethylolpropane adduct, manufactured by Mitsui Chemicals, Inc., 4.7 parts), Arronix M-403 (manufactured by Toagosei Co., Ltd., in an amount that results in a 1:1 ratio between the NCO value of Takenate D-160N and the hydroxyl value of Arronix M-403), t-butylbenzoquinone (0.02 parts), and methyl ethyl ketone (11.5 parts) was heated to 65°C. Neostan U-600 (bismuth-based polycondensation catalyst, manufactured by Nitto Kasei Co., Ltd., 0.11 parts) was added to the reaction solution and heated at 65°C for 4 hours. The reaction solution was cooled to room temperature (25°C), and methyl ethyl ketone was added to synthesize a urethane acrylate (M-4) solution with a solid content of 50% by mass.

[0475] <Preparation of polymer particles R> -Preparation of oil phase components- 6.66 g of WANNATE® PM-200 (polyfunctional isocyanate compound: manufactured by Manka Chemical Co., Ltd.), 5.46 g of Takenate® D-116N (a 50% by mass ethyl acetate solution of an adduct of trimethylolpropane (TMP), m-xylylene diisocyanate (XDI), and polyethylene glycol monomethyl ether (EO90) (structure shown below): manufactured by Mitsui Chemicals, Inc.), 11.24 g of a 65% by mass ethyl acetate solution of SR399 (dipentaerythritol pentaacrylate: manufactured by Sartomer Co., Ltd.), 14.47 g of ethyl acetate, and 0.45 g of Pionin® A-41-C (manufactured by Takemoto Oil & Fat Co., Ltd.) were mixed and stirred at room temperature (25°C) for 15 minutes to obtain the oil phase component.

[0476] [ka]

[0477] -Preparation of aqueous phase components- 47.2g of distilled water was prepared as the aqueous phase component.

[0478] -Microcapsule Formation Process- The oil phase component was added to the aqueous phase component and mixed. The resulting mixture was then emulsified using a homogenizer at 12,000 rpm for 16 minutes to obtain an emulsion. 16.8 g of distilled water was added to the resulting emulsion, and the resulting liquid was stirred at room temperature for 180 minutes. Next, the stirred liquid was heated to 45°C and stirred for 5 hours while maintaining the liquid temperature at 45°C to remove ethyl acetate from the liquid. The solid content concentration was adjusted to 20% by mass with distilled water to obtain an aqueous dispersion of polymer particles R. The volume-average particle size of R was measured to be 165 nm using a laser diffraction / scattering particle size distribution analyzer LA-920 (manufactured by Horiba, Ltd.).

[0479] <Formation of image recording layers 14-15> Each of the image recording layer coating solutions (image recording layer coating solutions (14) to (15)) with the following composition was applied in a bar, and then oven-dried at 110°C for 40 seconds, resulting in a dry weight of 0.9 g / m². 2 Image recording layers 14 and 15 were formed, respectively.

[0480] (Image recording layer coating solution) 1-Propanol 39.75 parts 2-Butanone 39.85 parts • γ-butyllactone 0.88 parts Polymer Emulsion A *1 6.95 copies ·KLUCEL E *2 0.25 parts Iodonium salt A *3 (I-1) 0.15 parts Iodonium salt B *4 (I-2) 0.15 parts 3-Mercapto-1,2,4-triazole 0.05 part BYK 336 *5 0.18 parts Techpolymer SSX-105 *6 0.47 parts ·Polymerizable compound M-1 1.65 parts ·Polymerizable compound M-3 0.77 part • Acid colorants listed in Table 1: Amount corresponding to the dry application amount listed in Table 1. • Oxo salts listed in Table 1. Amount of dry application as listed in Table 1. • Infrared absorber listed in Table 1: 0.15 parts

[0481] *1: Polymer emulsion A is a dispersion containing polymer particles of a graft copolymer of poly(ethylene glycol) methyl ether methacrylate / styrene / acrylonitrile = 10:9:81 in a solvent with an n-propanol / water mass ratio of 80 / 20, at a concentration of 24% by mass. Its volume-average particle size is 193 nm. *2: Klucel E refers to hydroxypropylcellulose available from Hercules. *3: Compound represented by the following formula 1 *4: Compound represented by the following formula 2

[0482] [ka]

[0483] *5: Xylene / methoxypropyl acetate solution containing modified polydimethylsiloxane copolymer at a concentration of 25% by mass (manufactured by BYK Chemie) *6: Cross-linked acrylic beads, average particle size 5.0 μm (Sekisui Chemical Co., Ltd.)

[0484] M-1: A polymerizable compound obtained by reacting DESMODUR® N100 with hydroxyethyl acrylate and pentatriitol acrylate in a molar ratio of 1:1.5:1.5, at a concentration of 80% by mass in a 2-butanone solution. (Weight average molecular weight: 1650) M-3: Dipentaerythritol pentaacrylate "Sartmer SR399" (manufactured by Sartomer Company)

[0485] <Formation of image recording layers 16-17> Each of the image recording layer coating solutions (image recording layer coating solutions (16) to (17)) with the following composition was applied in a bar, and then oven-dried at 50°C for 60 seconds, resulting in a dry coating amount of 0.9 g / m². 2Image recording layers 16 and 17 were formed, respectively.

[0486] (Image recording layer coating solution) • Acid colorants listed in Table 1: Amount corresponding to the dry application amount listed in Table 1. • Oxo salts listed in Table 1. Amount of dry application as listed in Table 1. • Infrared absorber listed in Table 1: 0.15 parts Polymer dispersion: 0.675 parts Hydroxypropyl methylcellulose: 0.400 parts Monomer 1:0.036 parts Monomer 2:0.115 parts Monomer 3:0.087 parts Surfactant 1:0.045 parts Iodonium salt 1:0.073 parts Iodonium salt 2:0.053 parts Phenothiazine: 0.005 parts 1-Propanol: 2.6 parts 2-Butanone: 3.5 parts 1-Methoxy-2-propanol: 0.92 parts δ-Butyrolactone: 0.10 parts Wednesday: 1.16 parts

[0487] Polymer dispersion: The polymer dispersion was prepared according to Example 10 of European Patent Application Publication No. 1,765,593 and used as a 23.5 wt% n-propanol / water dispersion in an 80:20 weight ratio. Hydroxypropyl methylcellulose: 5% aqueous solution. 30% is methoxylated and 10% is hydroxypropoxylated. At 20°C, the viscosity of a 2% by mass aqueous solution is 5 mPa·s. Monomer 1: The following compound

[0488] [ka]

[0489] Monomer 2: The following compound

[0490] [ka]

[0491] Monomer 3: The following compound

[0492] [ka]

[0493] Surfactant 1: BYK302 manufactured by Byk Chemie was used as a 25% by mass solution in 1-methoxy-2-propanol. Iodonium salt 1: The following compounds

[0494] [ka]

[0495] Iodonium salt 2: The following compounds

[0496] [ka]

[0497] Phenothiazine:: The following compounds

[0498] [ka]

[0499] <Formation of image recording layers 18 and 19> Each of the image recording layer coating solutions (image recording layer coating solutions (18) to (19)) with the following composition was applied in a bar, and then oven-dried at 120°C for 40 seconds, with a dry weight of 1.0 g / m². 2 Image recording layers 18 and 19 were formed, respectively.

[0500] Each image recording layer coating solution contained the components listed below and was prepared with a mixed solvent of 1-methoxy-2-propanol (MFG):methyl ethyl ketone (MEK):methanol = 4:4:1 (mass ratio) to achieve a solid content of 6% by mass. • Acid colorants listed in Table 1: Amount corresponding to the dry application amount listed in Table 1. • Oxo salts listed in Table 1. Amount of dry application as listed in Table 1. • Infrared absorber listed in Table 1: 0.020 parts • Electron-accepting polymerization initiator (I-4) 0.06 parts • Borate compound (1) 0.050 parts ·Polymerizable compound M-1 0.50 part • Binder polymer P-2 0.15 parts ·Tinuvin928 0.03 part ·Hydrophilic compound T-2 0.01 part

[0501] P-2: Polyvinyl acetal, manufactured by Sekisui Chemical Co., Ltd. (S-Rec BL10)

[0502] [ka]

[0503] M-1: A polymerizable compound obtained by reacting DESMODUR® N100 with hydroxyethyl acrylate and pentatriitol acrylate in a molar ratio of 1:1.5:1.5, at a concentration of 80% by mass in a 2-butanone solution. (Weight average molecular weight: 1650)

[0504] Image recording layers 1 to 20 are uniformly dispersed in water at 20°C. Image recording layers 1 to 20 are water-dispersible.

[0505] <Formation of protective layers 1-20 and 23> After applying each protective layer coating solution (protective layer coating solutions (1) to (20), (23)) with the following composition onto the image recording layer using a bar coating method, the mixture is oven-dried at 120°C for 60 seconds, resulting in a dry coating amount of 0.15 g / m². 2Protective layers 1-20 and 23 were formed, respectively.

[0506] (Protective coating liquid) • Oxo salts listed in Table 1. Amount of dry application as listed in Table 1. • Inorganic layered compound dispersion (1) (see below): 1.5 parts • Hydrophilic polymer (1) (structure shown below, Mw: 30,000) (solids content): 0.03 parts • Polyvinyl alcohol (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., CKS50, sulfonic acid modified, degree of saponification 99 mol% or more, degree of polymerization 300) 6% by mass aqueous solution: 0.10 parts • Polyvinyl alcohol (manufactured by Kuraray Co., Ltd., PVA-405, degree of saponification 81.5 mol%, degree of polymerization 500) 6% by mass aqueous solution: 0.03 parts • Surfactant (Emarex 710, manufactured by Nippon Emulsion Co., Ltd., structure shown below): 1% by mass aqueous solution: 0.86 parts • Ion-exchanged water: 6.0 parts

[0507] [ka]

[0508] (Preparation of inorganic layered compound dispersion (1)) 193.6 parts of deionized water were mixed with 6.4 parts of synthetic mica Somasif ME-100 (manufactured by Coop Chemical Co., Ltd.), and the mixture was dispersed using a homogenizer until the volume-average particle size (laser scattering method) reached 3 μm. The aspect ratio of the resulting dispersed particles was 100 or greater.

[0509] <Formation of protective layers 21 and 22> Each protective coating solution (protective coating solutions (21) to (22)) with the following composition was applied using a bar coating method, and then oven-dried at 120°C for 60 seconds, resulting in a dry coating amount of 0.15 g / m². 2 Protective layers 21 and 22 were formed, respectively. Each protective coating solution contained the components listed below and was prepared with deionized water to a solid content of 6% by mass. • Oxo salts listed in Table 1. Amount of dry application as listed in Table 1. • Hydrophilic polymer WP-1 0.70 parts • Hydrophilic polymer WP-2 0.20 parts • Hydrophilic polymer WP-3 0.20 parts • Surfactant 0.002 parts

[0510] WP-1: Polyvinyl alcohol, Sigma-Aldrich Mowiol 4-88 WP-2: Polyvinyl alcohol, Sigma-Aldrich Mowiol 8-88 WP-3: The following resin (Mw52,000) Surfactant: Anionic surfactant, Rapisol A-80, manufactured by NOF Corporation.

[0511] [ka]

[0512] [Preparation of lithographic printing plates] The above-mentioned support, undercoat layer, image recording layer, and protective layer were combined as shown in Table 1 to prepare the lithographic printing plates for Examples 1 to 47 and Comparative Examples 1 to 2.

[0513] The resulting lithographic printing plate was 50 cm in diameter. 2 The pH of the solution obtained by immersing the sample in 5 mL of water is shown in Table 1. The above pH was measured by the following method. The resulting lithographic printing plate was 50 cm in diameter. 2 1cm 2 The original printing plate was cut into 50 small pieces and placed in a glass bottle. 5.0 mL of pure water was added, and the glass bottle was treated in an ultrasonic cleaner for 1 hour. After that, the pH of the water in which the lithographic printing plate was immersed was measured using a pH meter (Nikko Hansen Co., Ltd. Lacomstar Handy Type Combined Meter PC450). The water temperature at this time was 25°C. Ultrapure water was used as the pure water.

[0514] [Table 1]

[0515] [Table 2]

[0516] [Table 3]

[0517] [Table 4]

[0518] Note that although the phosphate in protective layer 23 is not an oxoate, it is listed in the oxoate column for convenience.

[0519] The details of each component used in Table 1 are as follows. Ph represents the phenyl group.

[0520] <Acid coloring agent>

[0521] [ka]

[0522] <Infrared absorbent>

[0523] [ka] TIFF0007830125000075.tif3976 TIFF0007830125000076.tif6483TIFF0007830125000077.tif5179

[0524] <Print durability evaluation> The resulting lithographic printing plate was subjected to an infrared semiconductor laser with a wavelength of 830 nm, using a Fujifilm Luxel PLATESETTER T-6000III, at a rate of 110 mJ / cm². 2The exposure was adjusted to achieve the specified exposure level. The exposed image included a solid image, a 50% halftone chart of the AM screen, and non-image areas. The exposed lithographic printing plate was mounted on an offset rotary printing press manufactured by Tokyo Kikai Seisakusho Co., Ltd., and 150,000 copies were printed on newsprint at a speed of 100,000 copies / hour using Soybee KKST-S (red) manufactured by Inktec Co., Ltd. as the printing ink for newspapers and Toyo ALKY manufactured by Toyo Ink Co., Ltd. as the dampening solution. As the number of printed sheets increased, the image recording layer gradually wore down, reducing its ink-receiving capacity, which led to a decrease in ink density on the printing paper. This was visually confirmed. 5: Almost no change compared to when there were 10,000 sheets. 4: Approximately 70% of the images remain compared to when there were 10,000 images. 3: Approximately 50% of the images remain compared to when there were 10,000 images. 2: Approximately 20% of the images remain compared to when there were 10,000 images. 1: Items with almost no ink left.

[0525] <Visibility (Color Development) Evaluation> The obtained lithographic printing plates were left in a 60% RH environment for 1 hour, then packaged in aluminum kraft paper and stored at 60°C for 2 days. Using the aged lithographic printing plates, an infrared semiconductor laser with a wavelength of 830 nm was used to measure 110 mJ / cm² using a Fujifilm Luxel PLATESETTER T-6000III. 2 The exposure was adjusted to achieve the specified exposure level. The exposed image included both solid areas and non-image areas. Exposure was performed at 25°C and 50% RH. The color development of lithographic printing plates was measured immediately after exposure. The measurements were performed using a Konica Minolta CM2600d spectrophotometer and CM-S100W operation software, employing the SCE (Specular Reflectance Rejection) method. Color development was evaluated using the L* value (lightness) of the L*a*b* color system, specifically the difference ΔL between the L* value of the exposed area and the L* value of the unexposed area. A larger ΔL value indicates better color development.

[0526] <Cutting of lithographic printing plates> The lithographic printing plate was cut using a rotary blade as shown in Figure 4, adjusting the gap between the upper and lower cutting blades, the amount of cutting action, and the blade tip angle to create a rounded shape at the edges. Table 1 shows the amount of sagging X and the width of sagging Y in the sagging shape. Table 1 shows the area ratio of cracks present on the surface of the anodic oxide film in the portion corresponding to the sag width Y. The crack area ratio was calculated according to the method described above. The edge stain resistance was evaluated as follows:

[0527] <Edge stain resistance> A lithographic printing plate was exposed using a Fujifilm Luxcel PLATESETTER T-6000III equipped with an infrared semiconductor laser, under the following conditions: external drum rotation speed of 1,000 rpm, laser output of 70%, and resolution of 24,000 dpi. The exposed images included solid images, 50% halftone images, and charts containing non-image areas. The exposed lithographic printing plate was mounted on an offset rotary printing press manufactured by Tokyo Kikai Seisakusho Co., Ltd., and printed on newspaper paper at a speed of 100,000 sheets / hour using Soybee KKST-S manufactured by Inktec Co., Ltd. (and Toyo ALKY manufactured by Toyo Ink Co., Ltd. as the dampening solution). The 1,000th printed sheet was sampled using 1.5 times the water level mark above the base stain removal mark, and the degree of linear staining caused by the edges of the lithographic printing plate was evaluated according to the following criteria. 5: Not dirty at all A level between 4:5 and 3 3: Slightly dirty, but acceptable. An intermediate level between 2:3 and 1 (acceptable level) 1: Clearly soiled and unacceptable level

[0528] The results shown in Table 1 indicate that the lithographic printing plate according to the present invention provides good visibility and suppresses edge smudging. Furthermore, it can be seen that the lithographic printing plate according to the present invention has good visibility, suppresses edge smudging, and also exhibits excellent print durability. Examples 20 and 21 should be interpreted as Reference Examples 20 and 21, respectively. [Explanation of Symbols]

[0529] 1 Planographic printing plate original plate 1a Image recording layer surface 1b Support surface 1c end face 2 Dare 10 Cutting blades 10a Upper cutting blade 10b Upper cutting blade 11 Rotation axis 20 cutting blades 20a Lower cutting blade 20b Lower cutting blade 21 Rotation axis 30 Planographic printing plate original plate 31 Aluminum plate 32, 34 Roller-shaped brush 33 Polishing slurry liquid 35, 36, 37, 38 Support rollers 50 Main electrolyzer 51 AC power supply 52 Radial Drum Roller 53a, 53b Main pole 54 Electrolyte supply port 55 Electrolyte 56 slits 57 Electrolyte passage 58 Auxiliary anode 60 Auxiliary anode tank 410 Anodizing treatment apparatus 412 Power tank 414 Electrolytic treatment tank 416 Aluminum plate 418, 426 Electrolyte 420 Power supply electrode 422,428 Laura 424 Nipple Roller 430 Electrolytic electrode 432 Tank wall 434 DC power supply B. Boundary between the image recording layer and the support. W Aluminum plate X Amount of sauce Y width

Claims

1. An aluminum support having an anodized film has one or more layers including an image recording layer, A lithographic printing plate original comprising at least one of the one or more layers containing an oxoate with a molecular weight of 1000 or less, The image recording layer contains an acid colorant, The content of the oxo salt is substantially the same in at least one plane of the one or more layers, The oxo salt comprises at least one selected from the group consisting of phosphates, phosphonates, phosphinates, sulfates, sulfites, sulfonates, sulfinates, nitrates, nitrites, and silicates. The aforementioned lithographic printing plate is a lithographic printing plate having a drooping shape at its edges.

2. The lithographic printing plate according to claim 1, wherein the oxo salt comprises at least one selected from the group consisting of phosphates, phosphonates, phosphinates, sulfates, sulfites, sulfinates, nitrates, and nitrites.

3. The lithographic printing plate according to claim 1 or 2, wherein the oxo salt comprises at least one selected from the group consisting of phosphates, phosphonates, and phosphinates.

4. A lithographic printing plate according to any one of claims 1 to 3, comprising a protective layer on the image recording layer, wherein the protective layer contains the oxoate salt.

5. The oxo salt content is 5 mg / m² ２ ~100 mg / m² ２ A lithographic printing plate according to any one of claims 1 to 4.

6. An aluminum support having an anodized film has one or more layers including an image recording layer, A lithographic printing plate original comprising at least one of the one or more layers containing an oxoate with a molecular weight of 1000 or less, The image recording layer contains an acid colorant, The content of the oxo salt is substantially the same in at least one plane of the one or more layers, The oxo salt comprises at least one selected from the group consisting of phosphates, phosphonates, phosphinates, sulfates, sulfites, sulfonates, sulfinates, nitrates, nitrites, and silicates. The aforementioned lithographic printing plate has a drooping shape at its edges. The lithographic printing plate original plate 50cm ２ A lithographic printing plate master in which the pH of the solution obtained by immersing the plate in 5 mL of water is between 6.5 and 9.

0.

7. The lithographic printing plate according to any one of claims 1 to 6, wherein the acid colorant has a structure that undergoes ring opening or a leaving group is removed by the decomposition of a decomposable group, and the structure that undergoes ring opening or a leaving group is removed by the decomposition of the decomposable group is a structure represented by any one of the following formulas 1a to 1d. 【Chemistry 1】 In formulas 1a to 1d, R １ and R ２ This represents the portion that connects to the parent structure of the acid colorant. R ３ and R ４ Each of these independently represents either an aryl group or a heteroaryl group. R ５ This represents a hydrocarbon group. X represents the leaving group.

8. The lithographic printing plate according to claim 7, wherein the acid colorant has a parent structure represented by any of the following formulas 2a to 2f. 【Chemistry 2】 In Formulae 2a to 2f, Structure b represents a structure that undergoes ring opening by decomposition of the decomposable group, and R １ -R ９ each independently represents a hydrogen atom, an alkyl group, or an alkoxy group. The structures represented by formulas 2a to 2f have one or more of the aforementioned decomposable groups on the aromatic ring in formulas 2a to 2f.

9. The lithographic printing plate according to any one of claims 1 to 6, wherein the acid coloring agent is a compound represented by either of the following formulas 3a or 3b. 【Transformation 3】 In formula (3a), Ar １ Ar ２ Each of these independently represents either an aryl group or a heteroaryl group. R １０ , R １１ These independently represent a hydrogen atom, an alkyl group, an aryl group, and a heteroaryl group, respectively. In formula (3b), ERG each independently represents an electron-donating group, n represents an integer from 1 to 5, and X １ ~X ４ Each of these independently represents a hydrogen atom, a halogen atom, or a monovalent organic group, Y １ and Y ２ Each of these independently represents either C or N, and Y １ If it is N, then X １ Y does not exist. ２ If it is N, then X ４ It does not exist, R １２ and R １３ Each of these independently represents a hydrogen atom, an alkyl group, an aryl group, or a heteroaryl group.

10. The content of the acid colorant is 5 mg / m² ２ ~50 mg / m² ２ A lithographic printing plate according to any one of claims 1 to 9.

11. The lithographic printing plate according to any one of claims 1 to 10, wherein the image recording layer comprises a polymerizable compound, a polymerization initiator, and an infrared absorber.

12. The lithographic printing plate according to claim 11, wherein the infrared absorbent comprises a compound represented by the following formula 4. 【Chemistry 4】 In formula 4, R １４ and R １５ Each of these independently represents a hydrogen atom or an alkyl group, and R １４ and R １５ They may be connected to each other to form a ring, R １６ ~R １９ Each of these independently represents a hydrogen atom or an alkyl group, and R ２０ and R ２１ Each of these independently represents an alkyl group or an aryl group, Y ３ and Y ４ These are, independently, an oxygen atom, a sulfur atom, and -NR ０ - or represents a dialkylmethylene group, R ０ Ar represents a hydrogen atom, alkyl group, or aryl group. ３ and Ar ４ Each of these independently represents a group that forms a benzene ring or naphthalene ring which may have a group represented by formula 5 described later, and A １ -NR ２２ R ２３ , -X ５ -L １ Or it represents a halogen atom, R ２２ and R ２３ Each of these independently represents an alkyl group, an aryl group, an alkoxycarbonyl group, or an arylsulfonyl group, X ５ represents an oxygen atom or a sulfur atom, L １ represents a hydrocarbon group or a heteroaryl group, and Za represents a counterion that neutralizes the charge. -X ６ Formula 5 In formula 5, X ６ This is a halogen atom, -C(=O)-X ７ -R ２４ , -C(=O)-NR ２５ R ２６ , -OC(=O)-R ２７ -CN, -SO ２ NR ２８ R ２９ , or represents a perfluoroalkyl group, X ７ R represents a single bond or an oxygen atom. ２４ and R ２７ Each of these independently represents an alkyl group or an aryl group, R ２５ , R ２６ , R ２８ and R ２９ Each of these independently represents a hydrogen atom, an alkyl group, or an aryl group.

13. The lithographic printing plate according to any one of claims 1 to 12, wherein the image recording layer contains an electron-donating polymerization initiator.

14. The lithographic printing plate according to claim 13, wherein the electron-donating polymerization initiator is a borate compound.

15. The amount of anodic oxide in the aforementioned anodic oxide coating is 3.0 g / m². ２ The following is a lithographic printing plate according to any one of claims 1 to 14.

16. The sag shape is a sag shape with a sag amount X of 25 to 150 μm and a sag width Y of 70 to 300 μm, according to any one of claims 1 to 15.

17. The lithographic printing plate according to claim 16, wherein the crack area ratio present on the surface of the anodic oxide film in the region corresponding to the sag width Y is 10% or less.

18. A method for producing a printing plate, comprising the steps of: exposing a lithographic printing plate according to any one of claims 1 to 17 to an image; and supplying at least one of printing ink and dampening water to remove unexposed portions of the image recording layer in the lithographic printing plate.

Images