On-press developing lithographic printing plate precursor, method for manufacturing lithographic printing plate, and printing method

Abstract

The present invention addresses the problem of providing an on-press developable lithographic printing plate precursor having excellent printing resistance, a method for manufacturing a lithographic printing plate, and a printing method. This on-press developing lithographic printing plate precursor has a support and an image recording layer, and is characterized in that the support has an aluminum plate and an anodized film disposed on the aluminum plate, the anodized film has a plurality of micropores, each micropore has a large-diameter pore portion and a small-diameter pore portion, and the large-diameter pore portion and the small-diameter pore portion are formed on the support. The large-diameter hole portion extends from the surface of the coating film to a position having a depth of 0.05-0.50 [mu] m, the small-diameter hole portion communicates with the bottom of the large-diameter hole portion, and the average diameter of the large-diameter hole portion at the surface of the coating film is 0.015-0.070 [mu] m. The average value of Si atomic weight calculated when a circular region having a diameter of 30 mm in the surface of the image recording layer side of the anodic oxide film is measured by fluorescence X-ray analysis is 0.008-0.14 mg.

Description

Technical Field

[0001] This invention relates to an on-machine developing type lithographic printing plate master, a method for manufacturing lithographic printing plates, and a printing method. Background Technology

[0002] Offset printing is a method that utilizes the repulsive properties of water and oil-based inks. The oil-loving image area of ​​the offset printing plate is used as the ink receiving area, and the hydrophilic non-image area is used as the dampening liquid receiving area (ink non-receiving area). This creates a difference in ink adhesion on the surface of the offset printing plate, so that the ink only adheres to the image area. Then, the ink is transferred to the substrate such as paper for printing.

[0003] To create lithographic printing plates with both an oleophilic image area and a hydrophilic non-image area, lithographic printing master plates (PS plates) are widely used, which are made by depositing an oleophilic photosensitive resin layer (image recording layer) on a hydrophilic support. Lithographic printing master plates are typically manufactured by exposing the lithographic printing master plate to a primary image such as high-contrast film (lithfilm), leaving a portion of the image recording layer remaining as the image area, and removing the unwanted image recording layer by dissolving it with an alkaline developer or organic solvent, thereby exposing the surface of the hydrophilic support to form the non-image area.

[0004] With increasing concern for the Earth's environment, issues related to waste liquids from wet processing, such as developing processes, have attracted attention.

[0005] To address the aforementioned issues, efforts are being made to simplify or eliminate the development or plate-making process. One such approach is "on-machine development." This involves exposing the original lithographic printing plate to light, then mounting it directly onto the printing press without further development, and removing unwanted portions of the image recording layer at the initial stage of the printing process.

[0006] As a lithographic printing plate original used in such machine development, the lithographic printing plate original described in Patent Document 1 can be cited as an example.

[0007] Patent document 1 describes a technique related to the following offset printing plate original: an image recording layer containing an infrared absorber, a polymerization initiator, and a polymerizable compound, which can be removed by printing ink and / or dampening solution, on an aluminum support treated with alkali metal silicates, wherein the Si element in the alkali metal silicate treatment has an adhesion amount of 1 mg / m² on the surface of the aluminum support. 2 Above and below 10 mg / m 2 .

[0008] Previous technical documents

[0009] Patent documents

[0010] Patent Document 1: Japanese Patent Application Publication No. 2005-014348 Summary of the Invention

[0011] The technical problem to be solved by the invention

[0012] The inventors studied the characteristics of the lithographic printing plate original described in Patent Document 1. As a result, they found that when using the lithographic printing plate original, it sometimes does not meet the higher level of printability required in recent years. There is still room for further improvement regarding the printability of the lithographic printing plate original.

[0013] In view of the above-mentioned circumstances, the objective of this invention is to provide an on-machine developable lithographic printing plate with excellent printability. Furthermore, the objective of this invention is to provide a method for manufacturing a lithographic printing plate and a printing method thereon.

[0014] means for solving technical problems

[0015] The inventors have discovered that the above-mentioned problems can be solved by the following structure.

[0016] [1]

[0017] An on-machine developing type lithographic printing plate master has a support and an image recording layer. The support has an aluminum plate and an anodized film disposed on the aluminum plate. The anodized film has a plurality of micropores extending along the depth direction from the surface of the image recording layer side. The micropores have large-diameter portions and small-diameter portions. The large-diameter portions extend from the surface of the anodized film to a depth of 0.05 to 0.50 μm. The small-diameter portions communicate with the bottom of the large-diameter portions and extend along the depth direction from the communication position. The average diameter of the large-diameter portions at the surface of the anodized film is 0.015 to 0.070 μm. The average Si atomic weight calculated by fluorescence X-ray analysis of a circular region with a diameter of 30 mm on the surface of the anodized film on the image recording layer side is 0.008 to 0.14 mg.

[0018] [2]

[0019] According to the machine-developable lithographic printing plate original described in [1], the density of the micropores on the surface of the anodic oxide film is 200 to 2000 per μm. 2 .

[0020] [3]

[0021] According to the machine-developable lithographic printing plate original described in [1] or [2], the ratio of the average maximum diameter inside the large-diameter hole to the average diameter of the large-diameter hole at the surface of the anodic oxide film is 1.2 to 10.0.

[0022] [4]

[0023] The on-machine developing type lithographic printing plate according to any one of [1] to [3] further comprises a base coating layer disposed between the support and the image recording layer, the base coating layer comprising a polymer having support adsorption groups and hydrophilic groups.

[0024] [5]

[0025] According to the on-machine developing type lithographic printing plate original described in [4], the polymer has a support adsorption group, a hydrophilic group and a polymerizing group.

[0026] [6]

[0027] According to the machine-developable lithographic printing plate original described in [4] or [5], wherein the above-mentioned hydrophilic groups have a zwitterionic structure.

[0028] [7]

[0029] The original plate for machine-developable lithographic printing according to any one of [1] to [6], wherein the image recording layer comprises an infrared absorber.

[0030] [8]

[0031] According to the machine-developable lithographic printing plate original described in [7], wherein the infrared absorber has substituents that are decomposed by infrared radiation or heat.

[0032] [9]

[0033] The original lithographic printing plate according to any one of [1] to [8], wherein the image recording layer comprises a borate compound.

[0034]

[10]

[0035] The original plate for machine-developable lithographic printing according to any one of [1] to [9], wherein the image recording layer comprises an acid chromophore.

[0036]

[11]

[0037] According to any one of [1] to

[10] , the average value of Si atomic weight calculated when measuring a circular region with a diameter of 30 mm on the surface of the anodic oxide film on the image recording layer side by fluorescence X-ray analysis is 0.010 to 0.080 mg.

[0038]

[12]

[0039] According to any one of [1] to

[11] , the average value of the Si atomic weight calculated when measuring the circular region with a diameter of 30 mm on the surface of the above-mentioned image recording layer side of the above-mentioned anodic oxide film by fluorescence X-ray analysis is 0.011 to 0.060 mg.

[0040]

[13]

[0041] A method for manufacturing a lithographic printing plate, the method comprising: an exposure step, wherein an image recording layer of an on-machine developing type lithographic printing plate original is exposed in an image-like manner to form an exposed portion and an unexposed portion; and an on-machine developing step, wherein at least one of printing ink and dampening solution is supplied on a printing press to remove the unexposed portion of the image recording layer after exposure in an image-like manner, thereby producing a lithographic printing plate.

[0042]

[14]

[0043] A printing method includes: an exposure step in which an image recording layer of an on-machine developing type lithographic printing plate master is exposed in an image-like manner to form an exposed portion and an unexposed portion; an on-machine developing step in which at least one of printing ink and dampening solution is supplied on a printing press to remove the unexposed portion of the image recording layer after exposure in an image-like manner, thereby producing a lithographic printing plate; and a printing step in which printing is performed using the produced lithographic printing plate.

[0044] Invention Effects

[0045] According to the present invention, an in-machine developable lithographic printing plate master with excellent printability can be provided. Furthermore, according to the present invention, a method for manufacturing a lithographic printing plate and a printing method can be provided. Attached Figure Description

[0046] Figure 1 This is a schematic cross-sectional view illustrating an example of the structure of the machine-developable lithographic printing plate original of the present invention.

[0047] Figure 2 This is a schematic cross-sectional view illustrating one embodiment of an anodized film.

[0048] Figure 3This is a schematic cross-sectional view illustrating another example of an embodiment of anodized film.

[0049] Figure 4 This is a graph illustrating an example of an alternating current waveform used in the hydrochloric acid electrolysis process during the manufacturing of the support.

[0050] Figure 5 This is a side view of an example of a radial-type cell used in the hydrochloric acid electrolysis process that employs alternating current in the manufacturing method of the support.

[0051] Figure 6 This is a schematic diagram showing the anodizing apparatus used in the anodizing process during the manufacture of the support. Detailed Implementation

[0052] The present invention will now be described in detail.

[0053] The description of the constituent elements described below is sometimes based on representative embodiments of the present invention, but the present invention is not limited to these embodiments.

[0054] In addition, in this specification, the numerical range indicated by “~” refers to the range including the values ​​recorded before and after “~” as the lower limit and upper limit values.

[0055] In this specification, "(meth)acrylic acid" is a term used to encompass both acrylic acid and methacrylic acid, and "(meth)acryloyl" is a term used to encompass both acryloyl and methacryloyl.

[0056] The term "process" in this specification includes not only independent processes, but also processes that can be clearly distinguished from other processes, as long as the intended purpose of the process can be achieved.

[0057] Unless otherwise specified, all physical properties are determined at 25°C.

[0058] Unless otherwise specified, each component in the composition or each constituent unit in the polymer may contain a single one or two or more in combination.

[0059] Regarding the amount of each component in the composition or each constituent unit in the polymer in this specification, unless otherwise specified, when there are multiple substances or constituent units corresponding to each component in the composition or each constituent unit in the polymer, it refers to the total amount of the corresponding multiple substances present in the composition or the corresponding multiple constituent units present in the polymer.

[0060] In this specification, a combination of two or more preferred methods is a more preferred method.

[0061] Unless otherwise specified, the weight-average molecular weight (Mw) and number-average molecular weight (Mn) in this specification refer to the molecular weight of the target compound in THF (tetrahydrofuran) solvent detected by differential refractometer using a gel permeation chromatography (GPC) analytical apparatus employing columns of TSKgel GMHxL, TSKgel G4000HxL, and TSKgel G2000HxL (all product names manufactured by TOSOH CORPORATION), and converted using polystyrene as a standard substance.

[0062] In this manual, the term "lithographic printing plate original" includes not only lithographic printing plate originals but also discarded originals. Furthermore, the term "lithographic printing plate" includes not only lithographic printing plates made from lithographic printing plate originals through exposure, development, and other operations as needed, but also discarded plates. In the case of discarded originals, exposure and development operations may not be required. Additionally, a discarded plate refers to, for example, a lithographic printing plate original used when a portion of a page is printed in monochrome or two-color in color newspaper printing, mounted on an unused printing cylinder.

[0063] In this manual, the term "machine-developable" refers to a lithographic printing plate that can be machine-developed.

[0064] In this specification, "excellent printability" means that the offset printing plate can print a large number of sheets.

[0065] [Original plate for in-machine developing lithography]

[0066] The original plate of the machine-developable lithographic printing plate involved in this invention has a support body and an image recording layer, and is an original plate of the machine-developable lithographic printing plate, wherein the support body has an aluminum plate and an anodized film disposed on the aluminum plate.

[0067] Furthermore, the anodic oxide film has a plurality of micropores extending along the depth direction from the surface on the image recording layer side. The micropores have: a large-diameter pore portion having a defined shape; and a small-diameter pore portion communicating with the bottom of the large-diameter pore portion and extending along the depth direction from the communication position.

[0068] Furthermore, the average Si atomic weight calculated when measuring the surface of the anodic oxide film on the image recording layer side by fluorescence X-ray analysis was 0.008–0.14 mg.

[0069] Hereinafter, the structure of the on-machine developing type lithographic printing plate (hereinafter also simply referred to as "lithographic printing plate") of the present invention will be described with reference to the accompanying drawings.

[0070] Figure 1 This is a schematic cross-sectional view illustrating an example of the structure of the original lithographic printing plate of the present invention.

[0071] Figure 1 The lithographic printing plate 10 shown has a support 11 and an image recording layer 12. The support 11 has an aluminum plate 13 and an anodized film 14 disposed on the aluminum plate 13.

[0072] Furthermore, the structure of the original lithographic printing plate is not limited to... Figure 1 As shown in the diagram. For example, as described later, an undercoat layer may be present between the support and the image recording layer, or a protective layer may be present on the surface of the image recording layer opposite to the support.

[0073] [Support body]

[0074] The original lithographic printing plate involved in this invention has a support body, the support body having an aluminum plate and an anodized film disposed on the aluminum plate.

[0075] The anodized film in the support is located on the image recording layer side. That is, the lithographic printing plate original has an aluminum plate, an anodized film, and an image recording layer in sequence.

[0076] Unless otherwise specified, the term "support" refers to a support having an aluminum plate and an anodized coating disposed on the aluminum plate.

[0077] <Aluminum Plate>

[0078] Aluminum sheets are made of a dimensionally stable metal with aluminum as the main component. Examples of such metals include aluminum and aluminum alloys.

[0079] Regarding aluminum sheets, reference can be made to the aluminum sheets described in International Publication No. 2023 / 032992, which is incorporated herein by reference.

[0080] <Anodized film>

[0081] The anodic oxide film on the support is a film made on the surface of the aluminum plate through anodizing treatment.

[0082] There is no particular limitation on the amount of anodized film, but from the viewpoint of superior scratch resistance, 2.0 g / m² is preferred. 2 More preferably 3.2g / m 2 The above is further optimized to 3.4g / m 2 That's all. There's no specific upper limit, but 5.0g / m 2 The following are more common, with 4.0 g / m² being the preferred value. 2 the following.

[0083] (micropores)

[0084] Anodized films have multiple micropores (micropores) formed on the surface of the anodized film on the image recording layer side (hereinafter also referred to as the "film surface"). The micropores extend from the film surface along the depth direction (towards the aluminum plate, in the thickness direction). Multiple micropores are formed on the film surface, and they are often evenly distributed on the film surface.

[0085] In addition, "micropore" is a term commonly used to describe the pore structure formed on an anodized film through anodizing treatment, and does not specify the size of the pores.

[0086] In this invention, the micropores formed on the anodic oxide film of the support have a large-diameter pore portion and a small-diameter pore portion. The large-diameter pore portion extends from the film surface to a depth of 0.05 to 0.5 μm, and the small-diameter pore portion communicates with the bottom of the large-diameter pore portion and extends along the depth direction from the communication position. The micropores have a pore structure with an average diameter d1 of 0.015 to 0.1 μm at the film surface of the large-diameter pore portion (hereinafter also referred to as "specific structure").

[0087] The specific structure of the micropores will now be described in more detail with reference to the accompanying drawings. Furthermore, in this invention, the specific structure of the micropores in the anodic oxide film is not limited to that shown in the drawings.

[0088] Figure 2 This is a schematic cross-sectional view illustrating one embodiment of an anodized film. Figure 2 The anodic oxide film 14A shown has micropores 20 consisting of large-diameter pores 22 and small-diameter pores 24.

[0089] The large-diameter aperture 22 is an aperture extending from the surface 21 of the film (the surface of the anodic oxide film 14A on the image recording layer side, not shown) to a depth D1, and communicates with the small-diameter aperture 24 at its bottom 22A. The small-diameter aperture 24 is an aperture communicating with the bottom 22A of the large-diameter aperture 22, and further extending from the communication position 23 to a depth D2.

[0090] The average diameter d1 (average opening diameter) of the film surface 21 of the large-diameter aperture 22 is 0.015 to 0.070 μm. When the average diameter d1 of the film surface 21 of the large-diameter aperture 22 is within the above range, the printability of the on-machine developing type lithographic printing plate is superior.

[0091] From the viewpoint of superior printability, the average diameter d1 in the film surface 21 of the large-diameter hole 22 is more preferably 0.020 to 0.050 μm, and even more preferably 0.022 to 0.040 μm.

[0092] The average diameter d1 of the large-diameter pores at the surface of the membrane is as follows: The membrane surface was observed using a field emission scanning electron microscope (FE-SEM) at 150,000x magnification. Four images were obtained from observations at four different locations, with an arbitrary selection of 400×600nm. 2 The measurement area was determined by measuring the diameter of 50 micropores present in the measurement area of ​​each image, and the arithmetic mean of the measurement values ​​of 200 measurement points obtained from 4 images was obtained.

[0093] In addition, when the shape of the opening of the large-diameter pore of the micropore on the surface of the film is not circular, the opening diameter of each micropore can be determined by measuring the distance between the two points with the largest distance between them on the outer periphery of the opening.

[0094] The depth D1 of the large-diameter hole (the distance from the film surface 21 to the bottom 22A) is 0.05 to 0.50 μm, and from the viewpoint of better printability, it is preferably 0.08 to 0.30 μm, and more preferably 0.10 to 0.30 μm.

[0095] The depths D1 of the large-diameter pore, D2 of the small-diameter pore (described later), and the depths of the micropores (described later) are as follows: The cross-section of the micropores along the depth direction of the anodic oxide film is observed using FE-SEM at a magnification of 150,000x. From the four observation images obtained by observing four different cross-sections, more than 25 micropores are randomly selected, and the depths of the selected micropores, large-diameter pores, and small-diameter pores are measured. The measured values ​​are then arithmetically averaged to obtain the final value.

[0096] The shape of the large-diameter hole is not limited to Figure 2 The generally straight tubular (generally cylindrical) shape shown can have its large-diameter orifice diameter varying continuously or discontinuously along the depth direction. Examples of shapes where the diameter of the large-diameter orifice varies along the depth direction include a frustum-shaped cone with the diameter decreasing towards the depth direction, a frustum-shaped cone with the diameter increasing towards the depth direction, and a shape formed by connecting multiple orifices of different diameters along the depth direction (see reference). Figure 3 The shape of the large-diameter orifice is preferably approximately straight.

[0097] There are no particular restrictions on the shape of the bottom of the large-diameter hole; it can be, for example... Figure 2 The curved (convex) shape shown at the bottom 22A can also be flat.

[0098] The shape of the large-diameter aperture is also preferably that of the inner maximum diameter portion located in the inner region deeper than the surface of the film, with an aperture diameter greater than the average diameter of the film surface.

[0099] As for shapes with the largest internal diameter portion, examples include those described later. Figure 3As shown in the anodic oxide film 14B, it has a shape formed by multiple holes of different diameters connected along the depth direction from the film surface, and a frustum-shaped cone with the diameter increasing towards the depth direction.

[0100] When the large-diameter bore has an internal maximum diameter portion, the average maximum diameter d1 inside the large-diameter bore is... max (refer to Figure 3 The ratio of the diameter of the large-diameter aperture to the average diameter d1 at the surface of the film (d1) max The value of / d1) is preferably 1.1 to 10.0, more preferably 1.1 to 5.0.

[0101] The average maximum diameter d1 inside the large-diameter hole part max The values ​​are as follows: The cross-section of the micropores along the depth direction of the anodic oxide film was observed using FE-SEM at a magnification of 150,000x. From the four observation images obtained by observing four different cross-sections, 25 micropores were randomly selected. The maximum diameter of the large-diameter pore portion of the selected micropores inside the anodic oxide film was measured, and the measured values ​​were arithmetically averaged to obtain the value.

[0102] The small-diameter hole 24 is a hole that communicates with the bottom 22A of the large-diameter hole 22 and extends further along the depth direction from the communication position 23. Figure 2 In the micropore 20 shown, one large-diameter pore portion 22 is connected to one small-diameter pore portion 24, but the micropore may also have two or more small-diameter pore portions connected to one large-diameter pore portion.

[0103] There is no particular limitation as long as the average diameter d2 of the small-diameter aperture 24 at the connecting position 23 is less than the average diameter d1 of the large-diameter aperture 22 at the film surface. However, from the viewpoint of better machine developability, it is preferably 15 nm or less, more preferably 13 nm or less, even more preferably 11 nm or less, and especially preferably 10 nm or less. There is no particular limitation on the lower limit, but it is preferably 5 nm or more.

[0104] The average diameter d2 at the connected position of the small-diameter orifice is as follows: The cross-section of the micropore along the depth direction of the anodic oxide film was observed using a field emission scanning electron microscope (FE-SEM) with a magnification of 150,000x. From the four images obtained by observing at four different locations, 20 points were randomly selected from the four images to measure the orifice diameter at the connected position. The arithmetic mean of all measured values ​​was then obtained.

[0105] From the viewpoint of balancing scratch resistance and productivity, the depth D2 of the small diameter hole 24 (the distance from the communication position 23 with the large diameter hole 22 to the bottom 24A of the small diameter hole 24) is preferably 0.1 to 5 μm, more preferably 0.2 to 4 μm, even more preferably 0.3 to 3 μm, and especially preferably 0.5 to 1.8 μm.

[0106] The shape of the small-diameter aperture is not limited to Figure 2 The generally straight tubular shape (generally cylindrical) shown can also be, for example, a conical shape where the diameter decreases towards the depth direction or a frustum-shaped shape where the diameter increases towards the depth direction. The shape of the small-diameter orifice is preferably generally straight tubular.

[0107] The shape of the bottom of the small-diameter hole is not particularly limited and can be, for example... Figure 2 The curved (convex) shape shown at the bottom 24A can also be flat.

[0108] The ratio (d1 / d2) of the average diameter d1 of the large-diameter hole 22 on the film surface 21 to the average diameter d2 of the small-diameter hole 24 at the communication position 23 is preferably 1.1 to 13, more preferably 1.5 to 6.5.

[0109] Furthermore, the ratio (D1 / D2) of the depth D1 of the large-diameter hole 22 to the depth D2 of the small-diameter hole 24 is preferably 0.005 to 50, more preferably 0.025 to 40.

[0110] Figure 3 This is a schematic cross-sectional view illustrating another example of an embodiment of anodized film. Figure 3 The anodic oxide film 14B shown has micropores 30 consisting of a large-diameter aperture 32 and a small-diameter aperture 34. The large-diameter aperture 32 is composed of an upper large-diameter aperture 36 and a lower large-diameter aperture 38. The upper large-diameter aperture 36, the lower large-diameter aperture 38, and the small-diameter aperture 34 are connected within the micropores 30.

[0111] The upper part 36 of the large-diameter aperture is an aperture that extends from the surface 31 of the film (the surface of the anodic oxide film 14B on the image recording layer side, not shown) to a depth D1u, and communicates with the lower part 38 of the large-diameter aperture in the bottom 36A.

[0112] The lower part 38 of the large-diameter hole is the part corresponding to the maximum internal diameter portion mentioned above, and is a hole that communicates with the bottom 36A of the upper part 36 of the large-diameter hole and extends further from the communication position 37 of the upper part 36 of the large-diameter hole to a depth D1b, and communicates with the small-diameter hole 34 in the bottom 38A.

[0113] The small-diameter hole 34 is a hole that communicates with the bottom 38A of the lower part 38 of the large-diameter hole and extends further from the communication position 39 of the lower part 38 of the large-diameter hole to the bottom 36A at a depth D2.

[0114] The average diameter of the upper part 36 of the large-diameter hole on the film surface 31 is the same as the average diameter of the large-diameter hole on the film surface, and preferably the range and measurement method of the average diameter are also the same.

[0115] The sum of the depth D1u (distance from the surface 31 of the film to the bottom 36A) of the upper part 36 of the large-diameter hole and the depth D1b (distance from the bottom 36A to the bottom 38A) of the lower part 38 of the large-diameter hole is equivalent to the depth D1 of the large-diameter hole, which is 0.05 to 0.5 μm.

[0116] From the viewpoint of balancing machine developability and printability, the depth D1u of the upper part 36 of the large-diameter hole is preferably 0.02 to 0.2 μm, more preferably 0.05 to 0.1 μm.

[0117] Furthermore, from the viewpoint of balancing machine developability and printability, the depth D1b of the lower part 38 of the large-diameter aperture is preferably 0.05 to 0.3 μm, more preferably 0.05 to 0.2 μm.

[0118] The depth D1u of the upper part 36 of the large-diameter hole and the depth D1b of the lower part 38 of the large-diameter hole can be measured according to the above-mentioned method for measuring the depth D1 of the large-diameter hole.

[0119] The shape of the upper part of the large-diameter hole is not limited to Figure 3 The generally straight tubular shape (generally cylindrical) shown can also be, for example, a conical shape where the diameter decreases towards the depth direction or a frustum-shaped shape where the diameter increases towards the depth direction. The upper part of the large-diameter hole is preferably a slightly straight tubular shape.

[0120] The lower part 38 of the large-diameter hole is a hole that communicates with the bottom 36A of the upper part 36 of the large-diameter hole and extends further along the depth direction from the communication position 37. For example... Figure 3 As shown, the maximum diameter of the lower part 38 of the large-diameter hole is equivalent to the maximum internal diameter d1 of the aforementioned large-diameter hole 32. max .

[0121] From the viewpoint of balancing machine developability and printability, the maximum diameter of the lower part 38 of the large-diameter aperture is preferably 0.02 to 0.2 μm, more preferably 0.03 to 0.1 μm, and even more preferably 0.04 to 0.08 μm.

[0122] Furthermore, from the viewpoint of balancing machine developability and printability, the ratio of the maximum diameter of the lower portion 38 of the large-diameter aperture to the average diameter in the film surface 31 of the upper portion 36 of the large-diameter aperture ((maximum diameter of the lower portion 38) / (average diameter in the film surface 31 of the upper portion 36 of the large-diameter aperture)) is preferably 1.2 to 10.0, more preferably 1.2 to 5.0.

[0123] The maximum diameter of the lower part 38 of the large-diameter hole can be determined based on the average maximum diameter d1 inside the large-diameter hole. max The determination method is used to determine it.

[0124] The shape of the lower part of the large-diameter hole is not limited to Figure 3 The generally straight tubular shape (generally cylindrical) shown can also be, for example, a conical shape where the diameter decreases towards the depth direction or a frustum-shaped shape where the diameter increases towards the depth direction. The shape of the lower part of the large-diameter hole is preferably a slightly straight tubular shape.

[0125] There are no particular restrictions on the shape of the bottom of the large-diameter hole; it can be curved (convex) or flat.

[0126] The small-diameter hole 34 is a hole that communicates with the bottom 38A of the lower part 38 of the large-diameter hole and extends further along the depth direction from the communication position 39.

[0127] The shape and dimensions of the small-diameter hole 34, including the preferred embodiment, are the same as those of the small-diameter hole 24 already described.

[0128] The microporous structure of anodized films is not limited to... Figure 2 and Figure 3 As shown in the diagram.

[0129] For example, as described above, a large-diameter hole can have a structure consisting of three or more holes of different diameters connected together along the depth direction.

[0130] There is no particular limitation on the depth of the micropores, but from the viewpoint of balancing machine developability and printability, it is preferably 0.01 to 1 μm, more preferably 0.05 to 0.6 μm, and even more preferably 0.07 to 0.25 μm. Furthermore, the depth of the micropores refers to the distance in the depth direction from the surface of the micropore film to the deepest part of the bottom of the micropore.

[0131] There is no particular limitation on the density of micropores on the surface of the film, but from the viewpoint of balancing on-machine developability and printability, a density of 200 to 2000 pores / μm is preferred. 2 More preferably, 400–1500 cells / μm 2 .

[0132] The density of micropores is as follows: Using a field emission scanning electron microscope (FE-SEM) at 150,000x magnification, the surface of the film was observed. Four images (400×600nm) were randomly selected from four different locations. 2 The measurement area is defined, and the number of micropores present in the measurement area is measured. The number of micropores per unit area of ​​the measurement area is calculated for each image, and the calculated values ​​are obtained by arithmetic average.

[0133] From the viewpoint of balancing on-machine developability and printability, the aperture ratio of the micropores on the film surface is preferably 10-90%, more preferably 30-85%.

[0134] The aforementioned aperture ratio is calculated by dividing the average radius obtained by dividing the average diameter of the large-diameter pores of the micropores on the surface of the membrane by 2, multiplying the average area of ​​the openings formed by the large-diameter pores of the micropores by the density (number density) of the micropores on the surface of the membrane, and converting the value into a percentage.

[0135] (Atomic weight of Si)

[0136] In the lithographic printing plate original involved in this invention, the average value of the Si atomic mass (hereinafter also referred to as "specific Si atomic mass") calculated by fluorescence X-ray analysis of a circular area with a diameter of 30 mm on the surface of the image recording layer side of the anodized film on the support is 0.008 to 0.14 mg.

[0137] The present invention was made by the inventors through the discovery that the micropores formed on the anodic oxide film of the support have a specific structure consisting of a large-diameter hole portion with a depth of 0.05 to 0.5 μm from the film surface and an average diameter d1 of 0.015 to 0.1 μm at the film surface, and a small-diameter hole portion communicating with the bottom of the large-diameter hole portion, and the specific Si atomic mass on the surface of the anodic oxide film is within the above range, which can further improve the printability of the lithographic printing plate original.

[0138] The detailed mechanism by which the on-machine developing type lithographic printing plate master of the present invention exhibits superior printability is not yet clear, but it is speculated to be as follows: On the surface of an anodized film with micropores having the aforementioned specific structure, not only are image recording layers stacked on the visible surface, but it is also possible that a portion of the image recording layer enters the interior of each micropore. Therefore, it is believed that in anodized films with micropores having the aforementioned specific structure on the surface, compared to anodized films without such micropores on the surface, the area of ​​substantial contact between the image recording layer and the surface of the support is different, and therefore the applicable range of Si amount is different for the visible surface.

[0139] In the lithographic printing plate original involved in this invention, it is speculated that by determining the specific Si atomic amount on the surface of the film to the range described above that corresponds to the anodized film with micropores having a specific structure formed on the surface, it is possible to provide an on-machine developable lithographic printing plate original with excellent printability (especially printability under harsh conditions).

[0140] The specific Si atomic weight is obtained by measuring the Kα ray intensity of Si element through fluorescence X-ray analysis of a circular region with a diameter of 30 mm on the surface of the film, and then quantifying the Si atomic weight present on the film surface using a calibration curve. Here, the "average value of Si atomic weight" refers to the value obtained by arithmetically averaging the Si atomic weights of three or more non-overlapping circular regions selected on the image recording layer side of the anodic oxide film surface, after obtaining the Si atomic weights for each region.

[0141] Detailed information regarding the method for determining specific Si atomic weights based on fluorescence X-ray analysis is described in the examples described later.

[0142] Patent document 1 states the following: If the amount of Si element adhering to the surface of an aluminum support treated with alkali metal silicate exceeds 10 mg / m²... 2 This reduces the adhesion between the image recording layer and the aluminum support, thus decreasing printability. The document describes how this adhesion amount is determined using fluorescence X-ray analysis; therefore, it is presumed that the measured Si amount is typically calculated by dividing the measured area by the fluorescence X-ray analysis. Here, if we consider the Si element adhesion amount of 10 mg / m² described in Patent Document 1... 2 Converted to the specific Si atomic weight within the 30mm circular region of this case, it is calculated to be approximately 0.007mg, which is not included in the range specified in this invention. As shown in Comparative Examples 2 and 3 of the embodiments described later, when the specific Si atomic weight is 0.007mg, the requirements of this invention are not met, and the technology disclosed in Patent Document 1 cannot solve the problem of this invention.

[0143] From the viewpoint of simultaneously achieving machine developability, ink removal, and printability, the specific Si atomic weight per unit diameter circular region of 30 mm on the surface of the anodized film is preferably 0.08 to 0.14 mg, more preferably 0.010 to 0.080 mg, and even more preferably 0.011 to 0.060 mg.

[0144] In the support of the lithographic printing plate, as a method to adjust the specific Si atomic mass on the surface of the anodic oxide film to the above-mentioned range, for example, the following method can be used: after forming an anodic oxide film with the above-mentioned micropores on an aluminum plate, in the silicate treatment (described later) performed on the formed anodic oxide film, any one of the concentration of silicate in the treatment solution, the temperature of the treatment solution, and the treatment time is changed to make adjustments.

[0145] (concave density)

[0146] From the viewpoint of superior printability, the density of recesses (hereinafter also referred to as "specific recesses") with a depth of 0.7 μm or more from the average surface, obtained by measuring a 400 μm × 400 μm range on the surface of the anodic oxide film side of the support using a non-contact three-dimensional roughness meter, is preferably 3000 to 10000 per mm. 2 More preferably, 3500–8000 pieces / mm 2 Further preferred is 5000-8000 pieces / mm 2 .

[0147] The density of a specific recess in the support is defined as the value measured below.

[0148] First, a non-contact 3D roughness meter (VertScan, manufactured by Ryoka Systems Inc.) was used to scan a 400μm × 400μm area on the surface of the anodic oxide film side (image recording layer side) of the support in a non-contact manner with a resolution of 1μm to obtain 3D data. Furthermore, the apparatus contents and measurement conditions of the aforementioned VertScan are as follows.

[0149] (1) Device contents

[0150] CCD camera: Sony HR-57

[0151] Objective lenses: ×10

[0152] Lens tube: ×1

[0153] Wavelength filter: 530 white

[0154] (2) Measurement conditions

[0155] Measurement mode: wave

[0156] Field of view: 400μm × 400μm

[0157] Scan range: Start +6μm, End -10μm

[0158] Next, image analysis was performed on the acquired 3D data using software (VS Viewer, manufactured by Ryoka Systems Inc.), and the number of recesses with a depth of 0.7 μm or more from the average surface was determined. The average surface refers to the surface on which the height values ​​of all measured data from the image recording layer side of the support within the measurement area (400 μm × 400 μm) were averaged.

[0159] Regarding the measurement, five locations were measured for each sample. The number of specified depressions was counted at each location, and then the average value was calculated and converted to the value per unit area (mm²). 2 The number of ) is used as the density of a specific concave portion.

[0160] (Specific surface area ΔS)

[0161] In the support, the specific surface area ΔS, calculated by the following formula (S1), is preferably 20 to 70% from the viewpoint of superior printability, and more preferably 30 to 60%, based on the actual area Sx obtained by measuring 256 × 256 points in a 25 μm × 25 μm range on the surface of the anodic oxide film using three-dimensional data obtained by measuring 256 × 256 points in a 25 μm × 25 μm range on the surface of the anodic oxide film using an atomic force microscope.

[0162] ΔS=(Sx-S0) / S0×100(%)(S1)

[0163] The specific surface area ΔS in the support body refers to the value measured below.

[0164] Specifically, a 1cm square section of the support is cut and placed on a horizontal sample stage of a piezoelectric scanner. The cantilever is brought close to the sample surface, and scanning is performed in the XY direction when the atomic force is applied. At this point, the sample's unevenness is obtained through piezoelectric displacement in the Z direction. A piezoelectric scanner capable of scanning 100μm in the XY direction and 15μm in the Z direction is used. A cantilever with a resonant frequency of 120–200kHz and a spring constant of 7–20N / m (e.g., "OMCL-AC200-TS" (manufactured by Olympus Corporation) and "SI-DF20" (manufactured by NANOPROBE) is used, and the measurement is performed in DFM mode (Dynamic Force Mode). Furthermore, the reference surface is determined by correcting for minute tilts of the sample by applying a least-squares approximation to the obtained three-dimensional data.

[0165] Furthermore, regarding the measurement, 512×512 points were measured on a 25×25μm surface. The resolution in the X direction was set to 0.05μm, the resolution in the Y direction was set to 0.05μm, the resolution in the Z direction was set to 1nm, and the scanning speed was set to 18μm / sec.

[0166] (Brightness)

[0167] From the perspective of improving the image visibility in the original of the developing lithographic printing plate, high brightness on the surface of the anodized film of the support is useful.

[0168] In the lithographic printing process, a plate inspection is typically performed to confirm whether an image has been recorded according to the intended purpose before mounting the printing plate on the printing press. In on-machine developing lithographic printing plates, image verification is required during the image exposure stage; therefore, a mechanism for generating the so-called printed image is used in the image exposure section.

[0169] As a method for quantitatively evaluating the readability (visibility) of the image area of ​​an on-machine developing lithographic printing plate original after image exposure, one method is to measure the brightness of the exposed area and the brightness of the unexposed area of ​​the image and calculate the difference between the two. Here, brightness can be measured using the CIE's L... * a * b * Lightness (L) in the color system * The value of lightness can be measured using a colorimeter (SpectroEye (registered trademark), manufactured by X-Rite). The greater the difference in lightness between the exposed and unexposed parts of the image obtained by measurement, the easier it is to see the image.

[0170] Due to the increased visibility, i.e., the greater difference in brightness between the exposed and unexposed areas of the image, the L on the surface of the anodic oxide film... * a * b * Lightness (L) in the color system * The value is preferably 60 to 100, and more preferably 70 to 90.

[0171] The support may have a back coating on the surface of the aluminum plate side, as needed, containing an organic polymer compound as described in Japanese Patent Application Publication No. 5-045885 or a silicon alkoxy compound as described in Japanese Patent Application Publication No. 6-035174.

[0172] <Manufacturing Method of Support Body>

[0173] The support used in the original offset printing plate of the present invention can be manufactured using known methods.

[0174] As a method for manufacturing the support, for example, a method having the following steps: a roughening process for roughening an aluminum plate; and an anodizing process for anodizing the roughened aluminum plate to form an anodized film of aluminum on the aluminum plate.

[0175] Preferably, the method further includes the following steps: a hole-expansion process, in which, after the above-mentioned anodizing process, an etching process is performed on the aluminum plate with the anodized film to enlarge the diameter of the micropores in the anodized film; and a second anodizing process, in which anodizing is further performed after the hole-expansion process. Furthermore, it is also preferable to include the following step: a silicate treatment process, in which the aluminum plate having the anodized film formed by the above-mentioned process is subjected to the silicate treatment described later.

[0176] The following is a detailed description of each of the above-mentioned processes and any additional treatments.

[0177] In addition, regarding the aluminum plate used to manufacture the support, including the preferred method, as already described.

[0178] (Roughening process)

[0179] The roughening process is a process of roughening the surface of an aluminum plate.

[0180] As a roughening treatment, one or a combination of two or more of the following are typically used: mechanical roughening treatment, chemical roughening treatment, and electrochemical roughening treatment.

[0181] From the viewpoint of effectively manufacturing the specified support, the roughening process preferably includes the following hydrochloric acid electrolysis process: for aluminum plates, in a hydrochloric acid treatment solution that may contain sulfuric acid, the temperature of the hydrochloric acid treatment solution is below 30°C, and the total charge participating in the anodic reaction of the aluminum plate is 500 C / dm. 2 The following is an example of an AC current waveform with a peak current value of 80 A / dm. 2 Under the following conditions, alternating electrolysis is performed to produce a roughened aluminum plate.

[0182] Furthermore, when the hydrochloric acid treatment solution contains sulfuric acid, the ratio of sulfuric acid content to hydrochloric acid content is preferably 0.1 or less.

[0183] (Mechanical roughening treatment)

[0184] The support can be manufactured by mechanical roughening treatment before the hydrochloric acid electrolysis process.

[0185] Examples of mechanical roughening methods include wire brushing, which involves scraping the surface of an aluminum plate with a metal wire; ball grinding, which involves abrading the surface of an aluminum plate with abrasive balls and abrasives; and brushing, which involves abrading the surface with a nylon brush and abrasives, as described in Japanese Patent Application Publication No. 6-135175 and Japanese Patent Publication No. 50-040047.

[0186] (Hydrochloric acid electrolysis process)

[0187] The preferred hydrochloric acid electrolysis process in the manufacturing method of the support is as follows: for aluminum plates, in a hydrochloric acid treatment solution that may contain sulfuric acid, the temperature of the hydrochloric acid treatment solution is below 30°C, and the total charge participating in the anodic reaction of the aluminum plate is 500 C / dm³. 2 The following is an example of an AC current waveform with a peak current value of 80 A / dm. 2 Under the following conditions, alternating current electrolysis is performed to produce a roughened aluminum plate. By performing this hydrochloric acid electrolysis treatment followed by the anodizing treatment described later, the aforementioned lithographic printing plate original can be manufactured efficiently.

[0188] The hydrochloric acid treatment solution contains hydrochloric acid. The concentration of hydrochloric acid in the hydrochloric acid treatment solution is preferably 5-30 g / L, more preferably 10-20 g / L.

[0189] The hydrochloric acid treatment solution may contain sulfuric acid. When the hydrochloric acid treatment solution contains sulfuric acid, the concentration of sulfuric acid in the hydrochloric acid treatment solution is preferably 2.0 g / L or less, more preferably 1.0 g / L or less, and even more preferably 0.5 g / L. When the hydrochloric acid treatment solution contains sulfuric acid, there is no particular limitation on the lower limit of the sulfuric acid concentration in the hydrochloric acid treatment solution, and examples of concentrations exceeding 0 g / L are possible.

[0190] The hydrochloric acid treatment solution may contain aluminum ions. When the hydrochloric acid treatment solution contains aluminum ions, the concentration of aluminum ions is preferably 1.0 to 30.0 g / L, more preferably 5.0 to 20.0 g / L.

[0191] When the hydrochloric acid treatment solution contains sulfuric acid, the ratio of sulfuric acid content to hydrochloric acid content is preferably 0.1 or less. There is no particular limitation on the lower limit, and examples exceeding 0 are possible.

[0192] The temperature of the hydrochloric acid treatment solution is preferably below 30°C, more preferably below 26°C, and even more preferably below 23°C. There is no particular limitation on the lower limit, but it is preferably above 10°C, and more preferably above 15°C.

[0193] In the hydrochloric acid electrolysis process, the total charge (the total charge participating in the anodic reaction of the aluminum plate at the end of the hydrochloric acid electrolysis process) is preferably 500 C / dm. 2 The following is more preferably 350C / dm 2The following applies. There is no particular limitation on the lower limit of total energy consumption, but 50C / dm is preferred. 2 The above is preferred, with 200C / dm. 2 above.

[0194] The peak current value of the alternating current waveform is preferably 80 A / dm. 2 Below, 70A / dm is preferred. 2 The peak current value is preferably 10 A / dm. 2 The above is preferred, with 20A / dm. 2 above.

[0195] The alternating current waveform used in hydrochloric acid electrolysis can be a sine wave, a rectangular wave, a trapezoidal wave, or a triangular wave. The preferred frequency is 0.1–250 Hz.

[0196] Figure 4 This is a graph representing an example of an alternating current waveform used in hydrochloric acid electrolysis.

[0197] exist Figure 4 In the diagram, ta represents the anode reaction time, tc represents the cathode reaction time, tp represents the time it takes for the current to reach its peak value from 0, Ia represents the peak current on the anode circulation side, and Ic represents the peak current on the cathode circulation side. In the trapezoidal wave, the time tp for the current to reach its peak value from 0 is preferably 1 to 10 msec.

[0198] The preferred conditions for one cycle of alternating current used in hydrochloric acid electrolysis are as follows: the ratio of the anode reaction time ta to the cathode reaction time tc of the aluminum plate is 1 to 20; the ratio of the charge Qc when the aluminum plate is the anode to the charge Qa when the aluminum plate is the anode is Qc / Qa is 0.3 to 20; and the anode reaction time ta is in the range of 5 to 1000 msec.

[0199] Regarding current density, the peak current values ​​of the trapezoidal wave on both the anode circulation side (Ia) and the cathode circulation side (Ic) are preferably within the above-mentioned range (80 A / dm²). 2 (Below)

[0200] In hydrochloric acid electrolysis using alternating current, it can be used Figure 5 The apparatus shown.

[0201] Figure 5 This is a side view showing an example of a radial electrolytic cell used in hydrochloric acid electrolysis using alternating current.

[0202] Figure 5In this configuration, 50 is the main electrolytic cell, 51 is the AC 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 channel, 58 is the auxiliary anode, 60 is the auxiliary anode tank, and W is the aluminum plate. When using two or more electrolytic cells, the electrolysis conditions can be the same or different.

[0203] An aluminum plate W is coiled onto a radial drum roller 52, which is immersed in the main electrolytic cell 50, and electrolyzes the aluminum plate W during transport via main electrodes 53a and 53b connected to an AC power supply 51. Electrolyte 55 is supplied from the electrolyte supply port 54 through a slit 56 to the electrolyte channel 57 between the radial drum roller 52 and the main electrodes 53a and 53b. The aluminum plate W, after being treated in the main electrolytic cell 50, is then electrolyzed in an auxiliary anode tank 60. In this auxiliary anode tank 60, an auxiliary anode 58 is positioned opposite the aluminum plate W, and electrolyte 55 is supplied in such a manner that it flows through the space between the auxiliary anode 58 and the aluminum plate W.

[0204] (Alkali etching treatment)

[0205] The preferred method for manufacturing the support is to perform alkaline etching after the mechanical roughening treatment described above, or before or after the hydrochloric acid electrolysis treatment process described above.

[0206] In addition, regarding the alkaline etching treatment performed before hydrochloric acid electrolysis, it is performed to remove rolling oil, contaminants, and natural oxide film from the surface of the aluminum plate (rolled aluminum) when mechanical roughening treatment has not been performed, and when mechanical roughening treatment has been performed, it is performed to dissolve the uneven edges generated by mechanical roughening treatment and change the steep unevenness into a smooth wavy surface.

[0207] Without mechanical roughening treatment prior to alkaline etching, the etching amount is preferably 0.1–10 g / m. 2 More preferably 1-5 g / m 2 If the etching amount is 1-10 g / m 2 This can effectively remove rolling oil, contaminants, and natural oxide film from the surface.

[0208] When mechanical roughening is performed before alkaline etching, the etching amount is preferably 3 to 20 g / m. 2 More preferably 5-15 g / m 2 .

[0209] The alkaline etching process, performed immediately after hydrochloric acid electrolysis, aims to dissolve the contaminants formed in the acidic electrolyte and the edges of the unevenness created by the hydrochloric acid electrolysis. The unevenness created by hydrochloric acid electrolysis varies depending on the type of electrolyte, and therefore the optimal etching amount also varies. However, the preferred etching amount for the alkaline etching process following hydrochloric acid electrolysis is 0–0.5 g / m². 2 More preferably 0–0.3 g / m 2 .

[0210] Examples of bases used in alkaline solutions include caustic sodas and alkali metal salts. In particular, aqueous solutions of sodium hydroxide are preferred.

[0211] The concentration of the alkaline solution can be determined according to the etching amount, but is preferably 1 to 50% by mass, more preferably 10 to 35% by mass. If aluminum ions are dissolved in the alkaline solution, the concentration of aluminum ions is preferably 0.01 to 10% by mass, more preferably 3 to 8% by mass. The temperature of the alkaline solution is preferably 20 to 90°C. The processing time is preferably 0 to 120 seconds.

[0212] Methods for bringing an aluminum plate into contact with an alkaline solution include, for example, passing the aluminum plate through a tank containing an alkaline solution, immersing the aluminum plate in a tank containing an alkaline solution, and spraying the alkaline solution onto the surface of the aluminum plate.

[0213] (Decontamination treatment)

[0214] In the manufacturing method of the support, it is preferable to perform acid washing (decontamination treatment) after hydrochloric acid electrolysis or alkaline etching to remove corrosive organisms remaining on the surface.

[0215] Examples of acids used for decontamination treatment include nitric acid, sulfuric acid, and hydrochloric acid, but other acids may also be used.

[0216] The above-mentioned decontamination treatment is carried out, for example, by contacting the aluminum plate with an acidic solution containing 0.01% to 5% aluminum ions at a concentration of 0.5% to 30% by mass, such as hydrochloric acid, nitric acid, or sulfuric acid.

[0217] Methods for bringing an aluminum plate into contact with an acidic solution include, for example, passing the aluminum plate through a tank containing an acidic solution, immersing the aluminum plate in a tank containing an acidic solution, and spraying the acidic solution onto the surface of the aluminum plate.

[0218] The surface condition of the aluminum plate after decontamination treatment will affect the subsequent growth of the natural oxide film. Therefore, the choice of acid, concentration, and temperature conditions should be appropriately selected according to the purpose.

[0219] (Water washing treatment)

[0220] The preferred manufacturing method for the support is to perform a water wash after the completion of the above-mentioned processing steps. In particular, the water wash performed at the end of the process will affect the subsequent natural oxide film growth, so it is necessary to use pure water, well water, tap water, etc. to carry it out thoroughly.

[0221] (Anodizing process (First anodizing process))

[0222] The anodizing process is a process of anodizing an aluminum plate that has been roughened by the above-mentioned roughening process to form an anodized film of aluminum on the aluminum plate.

[0223] The anodizing process can be performed once or multiple times.

[0224] There are no particular restrictions on the steps involved in the anodizing process; well-known methods can be cited.

[0225] In the anodizing process, aqueous solutions of sulfuric acid, phosphoric acid, and oxalic acid can be used as electrolytic baths. For example, the concentration of sulfuric acid can range from 100 to 300 g / L.

[0226] The conditions for anodizing can be appropriately set by the electrolyte used, for example, a electrolyte temperature of 5–70°C (preferably 10–60°C) and a current density of 0.5–60 A / dm³. 2 (Preferred value: 5-60 A / dm) 2 The voltage is 1-100V (preferably 5-50V), the electrolysis time is 1-100 seconds (preferably 5-60 seconds), and the film weight is 0.1-5g / m³. 2 (Preferred concentration: 0.2–3 g / m) 2 ).

[0227] In the method of manufacturing the support, from the viewpoint of further improving the adhesion between the support and the image recording layer, an aqueous solution containing sulfuric acid or phosphoric acid is preferred as the electrolytic bath used in the anodizing process.

[0228] (Bore reaming process)

[0229] The aperture enlargement process is a process that involves etching the aluminum plate with the anodic oxide film after the above-mentioned anodizing process, thereby enlarging the diameter of the micropores in the anodic oxide film (aperture enlargement process).

[0230] Hole enlargement can be performed by contacting the aluminum plate obtained through the above-described anodizing process with an acidic or alkaline aqueous solution. There are no particular limitations on the contact method; examples include immersion and spraying.

[0231] (Second anodizing treatment)

[0232] In the manufacturing method of the support, it is preferable to perform a second anodizing process after the first anodizing process and the hole enlargement process described above.

[0233] There are no particular restrictions on the steps of the second anodizing process, and well-known methods can be cited.

[0234] In the second anodizing process, aqueous solutions of sulfuric acid, phosphoric acid, and oxalic acid can be used as the electrolytic bath. For example, the concentration of sulfuric acid can be 100–300 g / L.

[0235] The conditions for the second anodic oxidation treatment can be appropriately set by the electrolyte used, for example, a electrolyte temperature of 5 to 70°C (preferably 10 to 60°C) and a current density of 0.5 to 60 A / dm³. 2 (Preferred value: 5-60 A / dm) 2 The voltage is 1-100V (preferably 5-50V), the electrolysis time is 1-100 seconds (preferably 5-60 seconds), and the film weight is 0.1-5g / m³. 2 (Preferred concentration: 0.2–3 g / m) 2 ).

[0236] The electrolytic bath used in the second anodizing process is preferably an aqueous solution containing sulfuric acid or phosphoric acid, and more preferably an aqueous solution containing sulfuric acid.

[0237] (Third anodizing process)

[0238] In the manufacturing method of the support, an anodizing process based on phosphoric acid solution can be further performed after the first anodizing process and the hole enlargement process and before the second anodizing process to form an anodized film with a larger pore size (the third anodizing process).

[0239] There are no particular restrictions on the steps of the third anodizing process; well-known methods can be cited.

[0240] In the third anodizing process, an aqueous phosphoric acid solution can be used as an electrolytic bath. For example, the concentration of phosphoric acid in the aqueous phosphoric acid solution can be 10 to 300 g / L.

[0241] The conditions for the third anodic oxidation treatment can be appropriately set by the electrolyte used, for example, a electrolyte temperature of 5 to 70°C (preferably 10 to 60°C) and a current density of 0.5 to 60 A / dm³. 2 (Preferred value: 5-60 A / dm) 2 The voltage is 1-100V (preferably 5-50V), the electrolysis time is 1-100 seconds (preferably 5-60 seconds), and the film weight is 0.1-5g / m³. 2 (Preferred concentration: 0.2–3 g / m) 2).

[0242] The preferred electrolyte bath used in the third anodizing process is an aqueous solution containing phosphoric acid.

[0243] (Silicate processing process)

[0244] The preferred method for manufacturing the support includes a silicate treatment step of performing silicate treatment on an aluminum plate that has been anodized and expanded by the above-mentioned anodizing and hole-expanding processes. This is because the silicate treatment step allows for the easy manufacture of supports with a specific Si atomic weight within a specified range.

[0245] Silicate treatment is a process in which an aqueous solution (hereinafter also referred to as "treatment solution") containing alkali metal silicates such as sodium silicate and potassium silicate is brought into contact with an anodized film formed on an aluminum plate. In silicate treatment, it is preferable to immerse the aluminum plate having the anodized film in the treatment solution.

[0246] For information on silicate treatment, please refer to the methods and procedures described in U.S. Patent No. 2,714,066 and U.S. Patent No. 3,181,461, which are incorporated herein by reference.

[0247] Examples of alkali metal silicates used in silicate treatment include sodium silicate, potassium silicate, and lithium silicate. In addition to alkali metal silicates, the treatment solution may also contain appropriate amounts of alkali metal hydroxides such as sodium hydroxide, potassium hydroxide, and lithium hydroxide.

[0248] Furthermore, the treatment solution may also contain alkaline earth metal salts or Group IVA metal salts. Examples of alkaline earth metal salts include nitrates such as calcium nitrate, strontium nitrate, magnesium nitrate, and barium nitrate; sulfates; hydrochlorides; phosphates; acetates; oxalates; and borates. Examples of Group IVA metal salts include titanium tetrachloride, titanium trichloride, potassium titanium fluoride, potassium titanium oxalate, titanium sulfate, titanium tetraiodide, zirconium oxychloride, zirconium dioxide, zirconium oxychloride, and zirconium tetrachloride. These alkaline earth metal salts and Group IVA metal salts may be used alone or in combination of two or more.

[0249] The treatment conditions and concentration of the treatment solution for silicate treatment are adjusted appropriately according to the size of the aluminum plate and anodized film being treated, as well as the structure (specific structure) and density of the micropores.

[0250] The content of alkali metal silicates in the treatment solution is, for example, 3 to 30% by mass relative to the total mass of the treatment solution, preferably 3 to 10% by mass.

[0251] The temperature of the treatment solution used in silicate treatment is, for example, 30 to 80°C, more preferably 40 to 70°C.

[0252] The processing time for silicate treatment is, for example, 1 to 15 seconds, more preferably 3 to 10 seconds.

[0253] [Image recording layer]

[0254] The original offset printing plate involved in this invention has an image recording layer.

[0255] As an image recording layer, it is preferably an image recording layer that can be removed by at least one of printing ink and dampening solution.

[0256] Furthermore, the image recording layer is preferably a negative image recording layer, and more preferably a water-soluble or water-dispersible negative image recording layer.

[0257] The following describes the contents of each component in the image recording layer.

[0258] <Infrared absorber>

[0259] The image recording layer preferably contains an infrared absorber.

[0260] There are no particular limitations on what can be used as an infrared absorber; for example, pigments and dyes can be cited.

[0261] As dyes that can be used as infrared absorbers, commercially available dyes and well-known dyes listed in publications such as "Dye Handbook" (The Society of Synthetic Organic Chemistry, Japan, 2006) can be used. Specifically, examples include azo dyes, metal complex salt azo dyes, pyrazolone azo dyes, naphthoquinone dyes, anthraquinone dyes, phthalocyanine dyes, carbonium dyes, quinone imine dyes, methylene dyes, anthocyanin dyes, squaric acid pigments, pyranium salts, and metal thiolate complexes.

[0262] Among these dyes, anthocyanin, squaric acid, pyranonium salt, nickel thiol complex, or indocyanine are preferred, anthocyanin or indocyanine are more preferred, and anthocyanin is even more preferred.

[0263] Furthermore, as an infrared absorber, a cationic polymethimide pigment having an oxygen or nitrogen atom at the meta position is preferred. Examples of cationic polymethimide pigments include anthocyanins, pyranonium pigments, thiopyranonium pigments, and azulenium pigments; from the viewpoints of availability and solvent solubility during the induction reaction, anthocyanins are more preferred.

[0264] Specific examples of anthocyanins include compounds described in paragraphs 0017-0019 of Japanese Patent Application Publication No. 2001-133969, paragraphs 0016-0021 of Japanese Patent Application Publication No. 2002-023360, paragraphs 0012-0037 of Japanese Patent Application Publication No. 2002-040638, paragraphs 0034-0041 of Japanese Patent Application Publication No. 2002-278057, paragraphs 0080-0086 of Japanese Patent Application Publication No. 2008-195018, paragraphs 0035-0043 of Japanese Patent Application Publication No. 2007-090850, and paragraphs 0105-0113 of Japanese Patent Application Publication No. 2012-206495.

[0265] Furthermore, compounds described in paragraphs 0008 to 0009 of Japanese Patent Application Publication No. 5-005005 and paragraphs 0022 to 0025 of Japanese Patent Application Publication No. 2001-222101 are also preferred.

[0266] As a pigment, the preferred compounds are those described in paragraphs 0072 to 0076 of Japanese Patent Application Publication No. 2008-195018.

[0267] The infrared absorber preferably includes an infrared absorber that decomposes upon exposure to infrared light (decomposition-type infrared absorber), and more preferably includes a decomposition-type chromogenic infrared absorber.

[0268] The hypothesis is as follows: by using a decomposable infrared absorber as an infrared absorber, the decomposable infrared absorber or its decomposition products promote polymerization, and the printability is improved by the interaction between the decomposable infrared absorber's decomposition products and the polymerizable compound.

[0269] Decomposable infrared absorbers preferably have substituents that are broken down by infrared radiation or heat. Substituents that are broken down by infrared radiation or heat refer to substituents that have bonds that are broken down by any one of the following: energy generated when returning from an excited state due to infrared absorption to a substrate state, chemical reaction occurring from the excited state, or heat generated by infrared radiation.

[0270] The decomposition-type infrared absorber preferably has the function of absorbing infrared rays based on infrared exposure and converting the absorbed infrared rays into heat.

[0271] Regarding decomposition-type infrared absorbers, it is sufficient to absorb at least a portion of the light in the infrared wavelength region (wavelength 750nm to 1mm) and decompose it. It is preferable to have an infrared absorber with a maximum absorption wavelength in the wavelength region of 750 to 1400nm, and more preferably to have an infrared absorber with a maximum absorption wavelength in the wavelength region of 760 to 900nm.

[0272] Furthermore, the decomposition-type infrared absorber is preferably a compound that decomposes upon infrared exposure and has a maximum absorption wavelength in the 500–600 nm wavelength region.

[0273] As a decomposable infrared absorber, it is preferably an infrared absorber that decomposes through thermal or electron transfer caused by infrared exposure, or both. More preferably, it is an infrared absorber that decomposes through electron transfer caused by infrared exposure. Here, "decomposition through electron transfer" means that electrons excited from the HOMO (highest occupied molecular orbital) to the LUMO (lowest unoccupied molecular orbital) of the decomposable infrared absorber by infrared exposure are transferred within the molecule to electron-accepting groups (groups with potential close to the LUMO), thereby causing decomposition.

[0274] Preferred examples of infrared absorbers (especially infrared absorbers that decompose upon exposure to infrared light) include compounds described in International Publication No. 2020 / 262692, Japanese Patent Publication No. 2008-544322, International Publication No. 2016 / 027886 and International Publication No. 2019 / 219560, which are incorporated herein by reference.

[0275] Substituents that can be decomposed by infrared radiation or heat, such as -OR, are examples of such substituents. 1 -NR a R b -NR c (SO2R) d ) and -NR e (CO2R) f The group represented by ).

[0276] Among them, R 1 Indicates that R is obtained through thermal or infrared exposure. 1 -O bond cleavage substituents, R a and R b Each independently represents an aryl group, R c R e and R f Each can be independently represented by an alkyl or aryl group, R d Indicates alkyl, aryl, or -NR d1 R d2 R d1 and R d2 Each can be represented independently as a hydrogen atom, alkyl group, or aryl group.

[0277] Regarding the above-OR 1 -NR a R b -NRc (SO2R) d ) and -NR e (CO2R) f The preferred manner of the groups represented by ) will be described later.

[0278] From the viewpoint of machine developability and chemical resistance, the compound represented by the following formula (A) is more preferred as a decomposable infrared absorber.

[0279] [Chemical Formula 1]

[0280]

[0281] In formula A, + Y A1 =Constituted by the following structure:

[0282] [Chemical Formula 2]

[0283]

[0284] One representation of,

[0285] Y A2 - Composed of the following structure:

[0286] [Chemical Formula 3]

[0287]

[0288] One representation of R, where n represents 0, 1, 2, or 3, and p and q independently represent 0, 1, or 2, respectively. A1 and R A2 Each can be independently represented by a hydrocarbon group, or R A1 R A2 R Ad and R Aa The two atoms in R that contain the atoms required to form a ring structure become one. Ad At least one of them indicates that it is converted into a form greater than the above-mentioned R through a chemical reaction induced by infrared irradiation or exposure to heat. Ad A stronger electron donor group, or R Aa At least one of them indicates that it is converted into a form greater than the above-mentioned R through a chemical reaction induced by infrared irradiation or exposure to heat. Aa Groups with stronger electron donors, other R Ad and R Aa Each can be independently represented by a hydrogen atom, a halogen atom, or -R. Ae -OR Af -SR Ag and -NR Au R Av The group consisting of RAe R Af R Ag R Au and R Av Each of the above can be independently represented by an aliphatic hydrocarbon group, an aryl group, or a heteroaryl group. The conversion described above provides an increase in light absorption in the wavelength range of 400 nm to 700 nm.

[0289] Furthermore, R A1 and R A2 The hydrocarbon group and R Ae R Af R Ag R Au and R Av The aliphatic hydrocarbon group, aryl group, or heteroaryl group in it may have substituents.

[0290] Furthermore, the aforementioned R, converted through a chemical reaction Ad Preferably, it is any of the groups shown below.

[0291] [Chemical Formula 4]

[0292]

[0293] In the above formula, Aa, Ab, Ac, and Ad independently represent 0 or 1, and -L A - indicates a bonding group, R A17 Represents a hydrogen atom, an aliphatic hydrocarbon group that may be substituted, an aryl group that may be substituted, or a heteroaryl group that may be substituted, or R. A17 and R A3 R A17 and R A5 、or R A17 and R A11 They together contain the atoms required to form the ring structure, R A4 For -OR A10 -NR A13 R A14 Or -CF3, R A10 R indicates an aryl group that can be substituted, a heteroaryl group that can be substituted, or an α-branched aliphatic hydrocarbon group, depending on the situation. A13 and R A14 Each can independently represent a hydrogen atom, an aliphatic hydrocarbon group that may be substituted, an aryl group that may be substituted, or a heteroaryl group that may be substituted, or R A13 and R A14 It contains the atoms required to form a ring structure and becomes one, R A3 It is a hydrogen atom, an aliphatic hydrocarbon group that can be substituted as appropriate, an aryl group that can be substituted as appropriate, or a heteroaryl group that can be substituted as appropriate, or R A3Includes R A10 R A13 and R A14 At least one of the atoms required to form a ring structure becomes a single entity, R A6 This indicates aliphatic hydrocarbon groups that can be substituted, aryl groups that can be substituted, heteroaryl groups that can be substituted, and -OR. A10 -NR A13 R A14 Or -CF3, where R A10 R A13 and R A14 With R A4 The meanings are the same in both cases, R A5 Represents a hydrogen atom, an aliphatic hydrocarbon group that may be substituted, an aryl group that may be substituted, or a heteroaryl group that may be substituted, or R. A5 Includes R A10 R A13 and R A14 At least one of the atoms required to form a ring structure becomes a single entity, R A11 R A15 and R A16 Each can independently represent a hydrogen atom, an aliphatic hydrocarbon group that may be substituted, an aryl group that may be substituted, or a heteroaryl group that may be substituted, or R A15 and R A16 It contains the atoms required to form a ring structure and becomes one, R A12 R indicates an aliphatic hydrocarbon group that can be substituted, an aryl group that can be substituted, or a heteroaryl group that can be substituted, depending on the situation. A7 and R A9 R represents a hydrogen atom or an aliphatic hydrocarbon group that can be substituted, respectively. A8 This indicates -COO- or -COOR A8’ , where R A8’ R represents a hydrogen atom, an alkali metal cation, an ammonium ion, or a mono-, di-, tri-, or tetraalkylammonium ion. A18 This indicates an aryl group that can be substituted, a heteroaryl group that can be substituted, or an α-branched aliphatic hydrocarbon group.

[0294] From the viewpoint of machine developability and chemical resistance, compounds having substituents that can be broken down by heat or infrared exposure are particularly preferred as compounds represented by the following formula (1).

[0295] [Chemical Formula 5]

[0296]

[0297] In equation (1), M 1 R is a substituent that is cleaved by heat or infrared exposure. 2 and R 3 Each can be independently represented by a hydrogen atom or an alkyl group, R 2 and R 3 They can be connected to form a ring, Ar 1 and Ar 2 Each group independently represents a group that forms a benzene ring or a naphthalene ring, Y 1 and Y 2 Each of the oxygen atom, sulfur atom, and -NR atom can be represented independently. 0 -or dialkylmethylene, R 4 and R 5 Each independently represents an aliphatic hydrocarbon group, R 6 ~R 9 Each can be independently represented by a hydrogen atom or an alkyl group, R 0 It represents a hydrogen atom, alkyl group, or aryl group; Za represents a counterion that neutralizes the charge.

[0298] The compound represented by the above formula (1) is preferably a compound that decomposes by exposure to heat or infrared light and generates a compound with a large absorption wavelength at 500 nm to 600 nm.

[0299] Regarding M in equation (1) 1 The preferred method will be described later.

[0300] Furthermore, R 2 ~R 9 R 0 Ar 1 and Ar 2 It may have substituents such as hydrophilic groups described later. Examples of substituents include alkoxy, aryloxy, amino, alkylthio, arylthio, halogen, carboxyl, carboxylate, sulfonyl, sulfonate, alkoxycarbonyl, aryloxycarbonyl, phosphonic acid, phosphonate ester, and groups formed by combining these. Furthermore, when the above-mentioned groups are anionic, salts can be formed, and the counter cation can be a cation with an anthocyanin structure, or a proton, metal cation, onium, etc.

[0301] R in equation (1) 2 ~R 9 and R 0 The alkyl group 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 can be straight-chain, branched, or have a cyclic structure.

[0302] Among the alkyl groups, methyl, ethyl, propyl, or butyl are preferred.

[0303] As R 0 The aryl group in the aryl group is preferably an aryl group with 6 to 30 carbon atoms, more preferably an aryl group with 6 to 20 carbon atoms, and even more preferably an aryl group with 6 to 12 carbon atoms.

[0304] Furthermore, the aforementioned aryl group may have substituents. Examples of substituents include alkyl, alkoxy, aryloxy, amino, alkylthio, arylthio, halogen, carboxyl, carboxylate, sulfonyl, sulfonate, alkoxycarbonyl, aryloxycarbonyl, and groups formed by combining them.

[0305] Specifically, examples include phenyl, p-methoxyphenyl, p-dimethylaminophenyl, and naphthyl.

[0306] Preferred R 2 and R 3 They connect to form a ring.

[0307] In R 2 and R 3 When a ring is formed by connecting elements, the number of ring elements is preferably 5 or 6, more preferably 6.

[0308] Y 1 and Y 2 Each of the oxygen atom, sulfur atom, and -NR atom can be represented independently. 0 -or dialkylmethylene, preferably -NR 0 - or dialkylmethylene, more preferably dialkylmethylene.

[0309] R 0 It represents a hydrogen atom, an alkyl group, or an aryl group, preferably an alkyl group.

[0310] R 4 and R 5 Preferably, they are the same group. And, in R 4 and R 5 In the case of having anionic groups, R 4 and R 5 Preferably, it is the same group except that it has an anionic group and has a counter cation or does not have a counter cation.

[0311] Furthermore, R 4 and R 5 Preferably, each is a straight-chain alkyl group or an alkyl group with a sulfonate group at the end, more preferably methyl, ethyl or butyl with a sulfonate group at the end.

[0312] Furthermore, the counter cation of the sulfonate group can be the quaternary ammonium group in formula (1), or it can be an alkali metal cation or an alkaline earth metal cation.

[0313] R 6 ~R9 Each can be represented independently as a hydrogen atom or an alkyl group, preferably a hydrogen atom.

[0314] Ar 1 and Ar 2 Each group independently represents a group that forms a benzene ring or a naphthalene ring. Substituents may be present on the aforementioned benzene ring and naphthalene ring. Examples of substituents include alkyl, alkoxy, aryloxy, amino, alkylthio, arylthio, halogen, carboxyl, carboxylate, sulfonyl, sulfonate, alkoxycarbonyl, aryloxycarbonyl, and groups formed by combining these groups.

[0315] Za represents the counter ion that neutralizes the charge. When an anion is present, examples include sulfonate ions, carboxylate ions, tetrafluoroborate ions, hexafluorophosphate ions, p-toluenesulfonate ions, and perchlorate ions, with hexafluorophosphate ions being particularly preferred. When a cation is present, alkali metal ions, alkaline earth metal ions, ammonium ions, pyridinium ions, or sulfonium ions are preferred, more preferably sodium ions, potassium ions, ammonium ions, pyridinium ions, or sulfonium ions, and even more preferably sodium ions, potassium ions, or ammonium ions.

[0316] R 1 ~R 9 R 0 Ar 1 Ar 2 Y 1 and Y 2 It can have anionic or cationic structures, if R 1 ~R 9 R 0 Ar 1 Ar 2 Y 1 and Y 2 If all groups are electrically neutral, then Za is a monovalent counter anion, but for example, in R... 1 ~R 9 R 0 Ar 1 Ar 2 Y 1 and Y 2 When Za has two or more anionic structures, it can also become a counter cation.

[0317] From the perspectives of edge pollution inhibition, color development, and time-dependent color development, M in the above formula (1) 1 Preferred is -NR a R b -NR c (SO2R) d ) or -NR e (CO2R) f ).

[0318] Among them, R a and R b Each independently represents an aryl group, R c R e and R f Each can be independently represented by an alkyl or aryl group, R d Indicates alkyl, aryl, or -NR d1 R d2 R d1 and R d2 Each can be represented independently as a hydrogen atom, alkyl group, or aryl group.

[0319] R c ~R f R d1 and R d2 The alkyl group is preferably an alkyl group with 1 to 20 carbon atoms.

[0320] Furthermore, R a ~R f R d1 and R d2 The aryl group is preferably an aryl group with 6 to 20 carbon atoms.

[0321] R a ~R f R d1 and R d2 The alkyl and aryl groups in the compound can have substituents. Examples of substituents include alkoxy, aryloxy, amino, alkylthio, arylthio, halogen, carboxyl, carboxylate, sulfonyl, sulfonate, alkoxycarbonyl, aryloxycarbonyl, phosphonic acid, phosphonate ester, and groups formed by combining these. Furthermore, when the above groups are anionic, salts can be formed, and the counter cation can be a cation with an anthocyanin structure, or a proton, metal cation, onium, etc.

[0322] Furthermore, M in the above equation (1) 1 Preferred option: -OR 1 .

[0323] Among them, R 1 Indicates that R is obtained through thermal or infrared exposure. 1 Substituents that break down -O bonds.

[0324] From the perspective of color development, R 1 Preferably, it is a group represented by any one of the formulas 1-1 to 1-7 below, and more preferably, it is a group represented by any one of the formulas 1-1 to 1-3 below.

[0325] [Chemical Formula 6]

[0326]

[0327] In Equations 1-1 to 1-7, ● represents the bonding site with the oxygen atom, R 20 Each can independently represent a hydrogen atom, alkyl group, alkenyl group, aryl group, or -OR group. 24 -NR 25 R 26 or -SR 27 R 21 Each of the following can be independently represented by a hydrogen atom, alkyl group, or aryl group; R 22 Indicates aryl, -OR 24 -NR 25 R 26 -SR 27 -C(=O)R 28 -OC (=O)R 28 Or halogen atoms, R 23 Indicates aryl, alkenyl, alkoxy, or onnnyl, R 24 ~R 27 Each of the following can be independently represented by a hydrogen atom, alkyl group, or aryl group; R 28 Each can be independently represented by alkyl, aryl, or -OR. 24 -NR 25 R 26 or -SR 27 Z 1 Represents counterions that neutralize charge.

[0328] Specific examples of the above compounds are shown below. In the following structural formulas, Me represents a methyl group, and TsO - This indicates the toluenesulfonic acid anion.

[0329] [Chemical Formula 7]

[0330]

[0331] [Chemical Formula 8]

[0332]

[0333] [Chemical Formula 9]

[0334]

[0335] [Chemical Formula 10]

[0336]

[0337] [Chemical Formula 11]

[0338]

[0339] [Chemical Formula 12]

[0340]

[0341] [Chemical Formula 13]

[0342]

[0343] [Chemical Formula 14]

[0344]

[0345] [Chemical Formula 15]

[0346]

[0347] [Chemical Formula 16]

[0348]

[0349] [Chemical Formula 17]

[0350]

[0351] [Chemical Formula 18]

[0352]

[0353] [Chemical Formula 19]

[0354]

[0355] [Chemical Formula 20]

[0356]

[0357] [Chemical Formula 21]

[0358]

[0359] Infrared absorbers can be used in combination with one type or in combination with two or more types. Furthermore, pigments and dyes can be used in combination as infrared absorbers.

[0360] The content of infrared absorber in the image recording layer is preferably 0.1 to 10.0% by mass relative to the total mass of the image recording layer, more preferably 0.5 to 5.0% by mass.

[0361] <Acidic colorant>

[0362] The image recording layer contains acid chromophores.

[0363] In this specification, "acid colorant" refers to a compound that has the property of producing color through electron-accepting compounds such as acids and changing the color of the image recording layer.

[0364] The preferred acid colorant is a compound that develops color by heating in a state where it has accepted an electron-accepting compound such as an acid.

[0365] Examples of acids include protic acids and Lewis acids. Furthermore, the heating temperature during the above-mentioned heating is preferably 80–200°C, more preferably 100–180°C.

[0366] Examples of acid color-forming agents include compounds with partial skeletons such as lactones, lactams, sulopentalides, spiropyrans, esters, and amides, which are colorless compounds that rapidly open or cleave upon contact with electron-accepting compounds.

[0367] From the viewpoint of color development and visibility, the acid colorant preferably contains a colorless pigment, and more preferably a colorless pigment.

[0368] From the viewpoint of colorless pigments, colorless pigments having a phthaloyl structure or a fluorane structure are preferred.

[0369] As an acid colorant, from the viewpoint of developability, color development and visibility after a period of time, the compound represented by formula (3a) or formula (3b) below is preferred, and the compound represented by formula (3a) below is more preferred.

[0370] [Chemical Formula 22]

[0371]

[0372] In formula (3a), Ar1 and Ar2 independently represent aryl groups that can have substituents or heteroaryl groups that can have substituents, respectively, and R 10 and R 11 Each can be independently represented by a hydrogen atom, an alkyl group, an aryl group that may have substituents, or a heteroaryl group that may have substituents.

[0373] In equation (3b), ERG independently represents electron-donating groups, n represents an integer from 1 to 5, X1 to X4 independently represent hydrogen atoms, halogen atoms, or monovalent organic groups, Y1 and Y2 independently represent C or N, X1 does not exist when Y1 is N, and X4 does not exist when Y2 is N, R 12 and R 13 Each can be independently represented by a hydrogen atom, an alkyl group, an aryl group that may have substituents, or a heteroaryl group that may have substituents.

[0374] The alkyl group in formula (3a) or formula (3b) can be straight-chain, branched, or cyclic. The alkyl group in formula (3a) or formula (3b) preferably has 1 to 20 carbon atoms, more preferably 1 to 8, even more preferably 1 to 4, and especially preferably 1 or 2.

[0375] The aryl group in formula (3a) or formula (3b) preferably has 6 to 20 carbon atoms, more preferably 6 to 10, and even more preferably 6 to 8. Examples of aryl groups in formula (3a) or formula (3b) that can have substituents include phenyl, naphthyl, anthracene, and phenanthrene.

[0376] Examples of heteroaryl groups in formula (3a) or formula (3b) include furanyl, pyridinyl, pyrimidinyl, pyrazolyl and thiophenyl group, which may have substituents.

[0377] Furthermore, the alkyl, aryl, and heteroaryl groups in formula (3a) or (3b) may have substituents. Examples of substituents include alkyl, aryl, heteroaryl, halogen atom, amino, alkylamino, arylamino, heteroarylamino, dialkylamino, monoalkylmonoarylamino, monoalkylmonoheteroarylamino, diarylamino, diheteroarylamino, monoarylmonoheteroarylamino, hydroxyl, alkoxy, aryloxy, heteroaryloxy, acyl, alkoxycarbonyl, aryloxycarbonyl, heteroaryloxycarbonyl, and cyano. Moreover, these substituents can be further substituted by these substituents.

[0378] The substituents mentioned above can be electron-donating groups.

[0379] From the viewpoint of colorimetry and visibility, the electron-donating group represented by ERG and the electron-donating group represented by the above-mentioned substituents are preferably amino, alkylamino, arylamino, heteroarylamino, dialkylamino, monoalkylmonoarylamino, monoalkylmonoheteroarylamino, diarylamino, diheteroarylamino, monoarylmonoheteroarylamino, alkoxy, aryloxy, heteroaryloxy or alkyl, more preferably alkoxy, aryloxy, heteroaryloxy or alkyl, and even more preferably alkoxy.

[0380] From the perspective of color development and visibility, R in equation (3a) 10 and R 11 Preferably, each is an alkyl group or an aryl group that may have an electron-donating group, more preferably a methyl group or an aryl group that has an electron-donating group, and even more preferably a phenyl group that has an electron-donating group at the para position.

[0381] From the viewpoint of color development and visibility, Ar1 and Ar2 in formula (3a) are preferably aryl groups that may have at least one substituent at the ortho position or heteroaryl groups that may have at least one substituent at the ortho position, more preferably aryl groups that may have at least one substituent at the ortho position, even more preferably phenyl groups that may have at least one substituent at the ortho position, and especially preferably phenyl groups that may have at least one substituent at the ortho position and an electron-donating group at the para position.

[0382] From the perspective of color development and visibility, R in equation (3b)12 and R 13 Preferably, it is an aryl group substituted with a hydrogen atom, alkyl group, or alkoxy group; more preferably, it is an alkyl group; and even more preferably, it is a methyl group.

[0383] In formula (3b), n is preferably an integer from 1 to 3, and more preferably 1 or 2.

[0384] From the viewpoint of color development and visibility, X1 to X4 in formula (3b) are preferably hydrogen atoms or chlorine atoms, and more preferably hydrogen atoms.

[0385] From the viewpoint of color development and visibility, Y1 and Y2 in formula (3b) are preferably at least one of C, and more preferably both Y1 and Y2 are C.

[0386] Preferred examples of acid colorants include compounds S-1 to S-20. Additionally, Me represents methyl, Et represents ethyl, and Ph represents phenyl.

[0387] [Chemical Formula 23]

[0388]

[0389] [Chemical Formula 24]

[0390]

[0391] [Chemical Formula 25]

[0392]

[0393] [Chemical Formula 26]

[0394]

[0395] [Chemical Formula 27]

[0396]

[0397] These acid colorants can be used alone or in combination of two or more.

[0398] The content of the acid colorant is preferably 0.5 to 10% by mass relative to the total mass of the image recording layer, more preferably 1 to 5% by mass.

[0399] <Polymerization Initiator>

[0400] The image recording layer preferably contains a polymerization initiator.

[0401] Polymerization initiators are compounds that generate polymerization initiators such as free radicals or cations through the energy of light, heat, or both. As polymerization initiators, compounds that generate free radicals through light, heat, or both and initiate the polymerization of compounds having polymerizable unsaturated groups are preferred (so-called free radical polymerization initiators).

[0402] Examples of polymerization initiators include electron-accepting polymerization initiators and electron-donating polymerization initiators.

[0403] The image recording layer preferably includes at least one of an electron-accepting polymerization initiator and an electron-donating polymerization initiator as a polymerization initiator, and more preferably includes both an electron-accepting polymerization initiator and an electron-donating polymerization initiator.

[0404] (Electron-receiving polymerization initiator)

[0405] Electron-accepting polymerization initiators are compounds that generate polymerization initiators such as free radicals or cations through the energy of light, heat, or both. Well-known thermal polymerization initiators, compounds with bonds having low bond dissociation energies, and photopolymerization initiators can be appropriately used as electron-accepting polymerization initiators.

[0406] As an electron-accepting polymerization initiator, a free radical polymerization initiator is preferred.

[0407] Examples of free radical polymerization initiators include (a) organohalides, (b) carbonyl compounds, (c) azo compounds, (d) organoperoxides, (e) metallocene compounds, (f) azide compounds, (g) hexaarylbisimidazole compounds, (i) disulfone compounds, (j) oxime ester compounds, and (k) onium salt compounds.

[0408] (a) As an organohalide, for example, the compounds described in paragraphs 0022 to 0023 of Japanese Patent Application Publication No. 2008-195018 can be cited.

[0409] (b) Carbonyl compounds, for example, can be described in paragraph 0024 of Japanese Patent Application Publication No. 2008-195018.

[0410] (c) As an azo compound, for example, the azo compound described in Japanese Patent Application Publication No. 8-108621 can be cited.

[0411] As an (d) organic peroxide, for example, the compound described in paragraph 0025 of Japanese Patent Application Publication No. 2008-195018 can be cited.

[0412] As for (e) metallocene compounds, examples include the compounds described in paragraph 0026 of Japanese Patent Application Publication No. 2008-195018.

[0413] Examples of (f) azide compounds include 2,6-bis(4-azidobenzylidene)-4-methylcyclohexanone.

[0414] As a (g) hexaaryl biimidazole compound, for example, the compound described in paragraph 0027 of Japanese Patent Application Publication No. 2008-195018 can be cited.

[0415] (i) As a disulfone compound, examples include the compounds described in Japanese Patent Application Publication No. 61-166544 and Japanese Patent Application Publication No. 2002-328465.

[0416] (k) As an onium salt compound, for example, the compounds described in paragraphs 0028 to 0030 of Japanese Patent Application Publication No. 2008-195018 can be cited.

[0417] Onium-based polymerization initiators are preferred as free radical polymerization initiators. Onium-based polymerization initiators are onium salt compounds that, when exposed to infrared light and the electrons of an infrared absorber are excited, generate free radicals or other polymerization initiating species by accepting an electron through intermolecular electron movement.

[0418] From the viewpoint of superior printability, iodonium salt compounds, sulfonium salt compounds, or azazine iodonium salt compounds are preferred as onium-based polymerization initiators, more preferably iodonium salt compounds or sulfonium salt compounds, and even more preferably iodonium salt compounds.

[0419] As an iodonium salt compound, a diaryl iodonium salt compound is preferred, more preferably a diphenyl iodonium salt compound substituted with an electron-donating group, such as an alkyl or alkoxy group, and even more preferably an asymmetric diphenyl iodonium salt compound.

[0420] Specific examples of iodonium salt compounds include those described in European Patent Nos. 104 and 143, U.S. Patent Nos. 339,049 and 410,201, and Japanese Patent Application Publication Nos. 2-150848 and 2-296514.

[0421] As a counter anion for iodonium salt compounds and sulfonium salt compounds, sulfonamide anion or sulfonylimide anion is preferred, more preferably sulfonylimide anion. As a sulfonamide anion, arylsulfonamide anion is preferred. As a sulfonylimide anion, bis(arylsulfonylimide) anion is preferred.

[0422] Specific examples of sulfonamide anions or sulfonamide anions include the compounds described in International Publication No. 2020 / 262692.

[0423] Electron-accepting polymerization initiators can be used alone or in combination with two or more.

[0424] The content of the electron-receiving polymerization initiator is preferably 0.1 to 50% by mass relative to the total mass of the image recording layer, more preferably 0.5 to 30% by mass, and even more preferably 0.8 to 20% by mass.

[0425] (Electron-donating polymerization initiator)

[0426] From the viewpoint of superior chemical resistance and printability in offset printing plates, polymerization initiators preferably include electron-donating polymerization initiators.

[0427] Examples of electron-donating polymerization initiators include the following compounds.

[0428] (i) Alkyl or arylate complexes: These are thought to involve the oxidative cleavage of carbon-heterobonds, generating active free radicals. Specifically, borates are an example.

[0429] (ii) Glycine compounds: It is believed that an active free radical is generated by the cleavage of the CX bond on the carbon adjacent to nitrogen due to oxidation. 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 acids (which may have substituents on the phenyl group).

[0430] (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 free radicals through the same action. Specifically, phenylthioacetic acid (which may have substituents in the phenyl group) can be cited as an example.

[0431] (iv) Tin-containing compounds: Compounds obtained by replacing the nitrogen atom of the above-mentioned glycine compound with a tin atom can generate active free radicals through the same action.

[0432] (v) Sulfites: These can generate reactive free radicals through oxidation. Sodium arylsulfite is a specific example.

[0433] As a specific example of an electron-donating polymerization initiator, one can cite the electron-donating polymerization initiator described in International Publication No. 2020 / 262692.

[0434] The image recording layer preferably contains a borate compound as an electron-donating polymerization initiator.

[0435] As a borate compound, a tetraarylborate compound or a monoalkyltriarylborate compound is preferred. From the viewpoint of compound stability, a tetraarylborate compound is more preferred, and a tetraphenylborate compound is even more preferred.

[0436] There are no particular limitations on the counter cations present in borate compounds, but alkali metal ions or tetraalkylammonium ions are preferred, and sodium ions, potassium ions or tetrabutylammonium ions are more preferred.

[0437] Sodium tetraphenylborate is preferred as a borate compound.

[0438] When the image recording layer contains a borate compound as an electron-donating polymerization initiator, from the viewpoints of visibility, printability, and stability over time, the image recording layer more preferably also contains an onium salt compound as an electron-accepting polymerization initiator.

[0439] As an example of a preferred method when the image recording layer includes both an electron-accepting polymerization initiator and an electron-donating polymerization initiator, a method in which the electron-accepting polymerization initiator and the electron-donating polymerization initiator form a salt can be cited. For example, a salt formed from an iodonium compound and a borate compound, which are ononium-based polymerization initiators, can be exemplified by an iodoborate compound.

[0440] As a specific example of the aforementioned iodine borate compounds, the compound described in International Publication No. 2020 / 262692 can be cited.

[0441] Electron-donating polymerization initiators can be used in combination with one or more.

[0442] The content of the electron-donating polymerization initiator (preferably a borate compound) relative to the total mass of the image recording layer 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.

[0443] The content of the polymerization initiator (the total content of electron-accepting polymerization initiator and electron-donating polymerization initiator) is preferably 0.1 to 50% by mass relative to the total mass of the image recording layer, more preferably 0.5 to 30% by mass, and even more preferably 0.8 to 20% by mass.

[0444] Furthermore, from the viewpoint of superior visibility, the content of the polymerization initiator (the total content of electron-accepting and electron-donating polymerization initiators) relative to the content of the acid colorant is preferably 0.5 molar equivalents or more, more preferably 1.0 molar equivalents or more, and even more preferably 3.0 molar equivalents or more. There is no particular upper limit, but relative to the content of the acid colorant, it is preferably 10.0 molar equivalents or less.

[0445] <Polymerizing compounds>

[0446] The image recording layer preferably contains a polymeric compound.

[0447] In this specification, a polymerizable compound is a compound having polymerizable groups.

[0448] There are no particular restrictions on the polymerizable group; it can be a free radical polymerizable group or a cationic polymerizable group, with a free radical polymerizable group being preferred.

[0449] Examples of free radical polymerizable groups include (meth)acryloyl, allyl, vinylphenyl, and vinyl groups, which have olefinic unsaturated groups. From a reactivity point of view, (meth)acryloyl is preferred.

[0450] The molecular weight (weight-average molecular weight in the case of a molecular weight distribution) of the polymeric compound is preferably 50 or more and less than 2500.

[0451] The polymerizable compound can be, for example, a free radical polymerizable compound or a cationic polymerizable compound, and is preferably an addition polymerizable compound (an olefinic unsaturated compound) having at least one olefinic unsaturated bond.

[0452] As an olefinically unsaturated compound, it is preferably a compound having at least one terminal olefinically unsaturated bond, and more preferably a compound having two or more terminal olefinically unsaturated bonds. The polymerizable compound may be in the chemical form of a monomer, prepolymer (i.e., dimer, trimer, or oligomer), or a mixture thereof.

[0453] Of these, from the viewpoint of printability, polymeric compounds containing 3 or more functional groups are preferred, polymeric compounds containing 7 or more functional groups are more preferred, and polymeric compounds containing 10 or more functional groups are even more preferred. Furthermore, from the viewpoint of printability of the obtained lithographic printing plate, the polymeric compounds preferably contain olefinically unsaturated compounds with 3 or more functional groups (preferably 7 or more functional groups, more preferably 10 or more functional groups), and even more preferably (meth)acrylate compounds with 3 or more functional groups (preferably 7 or more functional groups, more preferably 10 or more functional groups).

[0454] From the viewpoint of machine developability and suppression of color development defects over time, the image recording layer preferably contains a polymeric compound with two or fewer functions, more preferably contains a difunctional polymeric compound, and even more preferably contains a difunctional (meth)acrylate compound.

[0455] From the viewpoints of printability, machine developability, and suppression of color development defects over time, the content of polymeric compounds with two or fewer functions (preferably two-functional polymeric compounds) is preferably 5 to 100% by mass, more preferably 10 to 100% by mass, and even more preferably 15 to 100% by mass, relative to the total mass of the polymeric compounds in the aforementioned image recording layer.

[0456] (Oligomers)

[0457] The polymeric compound contained in the image recording layer is preferably a polymeric compound that is an oligomer.

[0458] In this specification, oligomers refer to polymeric compounds with a molecular weight (weight average molecular weight in the case of a molecular weight distribution) of 600 to 40,000 and containing at least one polymeric group.

[0459] Hereinafter, the polymeric compounds contained in the image recording layer will also be referred to as "oligomers".

[0460] From the viewpoint of excellent chemical resistance and printability, the molecular weight of the oligomer is preferably 1000 to 25000.

[0461] From the viewpoint of improving printability, the number of polymeric groups in one molecule of oligomer is preferably two or more, more preferably three or more, even more preferably six or more, and particularly preferably ten or more.

[0462] There is no particular limit to the upper limit of the number of polymerizable groups in the oligomer, but the number of polymerizable groups is preferably 20 or less.

[0463] From the viewpoint of printability and machine developability, as an oligomer, a polymeric compound having 7 or more polymeric groups and a molecular weight of 1,000 to 40,000 is preferred, and a polymeric compound having 7 or more but less than 20 polymeric groups and a molecular weight of 1,000 to 25,000 is more preferred.

[0464] In addition, the image recording layer may contain polymer components that may be generated during the manufacturing process of oligomers.

[0465] From the viewpoints of printability, visibility and machine developability, the oligomer preferably comprises at least one compound selected from the group consisting of compounds having urethane bonds, compounds having ester bonds and compounds having epoxy residues, and preferably comprises compounds having urethane bonds.

[0466] In this specification, an epoxy residue refers to a structure formed by an epoxy group, such as a structure identical to the structure obtained by reacting an acid group (carboxylic acid group, etc.) with an epoxy group.

[0467] As a compound having a carbamate bond, the compound described in International Publication No. 2020 / 262692 is preferred.

[0468] As a compound having urethane bonds, a compound that introduces polymeric groups into a polyurethane obtained by reacting a polyisocyanate compound with a polyol compound can be used.

[0469] For example, a compound having urethane bonds can be obtained by reacting a compound having epoxy and polymerizable groups with a polyurethane oligomer, which is obtained by reacting a polyol compound having acid groups with a polyisocyanate compound.

[0470] In compounds containing ester bonds, which are examples of oligomers, the number of polymerizable groups is preferably three or more, more preferably six or more. The upper limit is preferably 20 or less.

[0471] Examples of oligomers include compounds containing epoxy residues, preferably compounds containing hydroxyl groups within the compound.

[0472] The number of polymerizable groups in a compound containing epoxy residues is preferably 2 to 6, more preferably 2 or 3.

[0473] As a compound having the aforementioned epoxy residues, it can be obtained, for example, by reacting acrylic acid with a compound having an epoxy group.

[0474] Commercially available oligomers may be used, including but 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 NipponSynthetic Chemical Industry Co., Ltd.), U-15HA (manufactured by Shin-Nakamura Chemical Co., Ltd.), EBECRYL450, EBECRYL657, EBECRYL885, EBECRYL800, EBECRYL3416, and EBECRYL860 (all manufactured by DAICEL-ALLNEX LTD.).

[0475] From the viewpoint of improving chemical resistance, printability, and inhibition of machine developing residue, the content of oligomers relative to the total mass of polymeric compounds in the image recording layer is preferably 30 to 100% by mass, more preferably 50 to 100% by mass, and even more preferably 80 to 100% by mass.

[0476] (Low molecular weight polymeric compounds)

[0477] Polymerizable compounds may also contain polymerizable compounds other than the oligomers mentioned above.

[0478] From a chemical resistance point of view, low molecular weight polymers are preferred as polymeric compounds other than oligomers. Low molecular weight polymers can be in the chemical form of monomers, dimers, trimers, or mixtures thereof.

[0479] From the viewpoint of chemical resistance, the preferred polymeric compound is at least one polymeric compound selected from the group consisting of polymeric compounds having three or more olefinic unsaturated groups and polymeric compounds having an isocyanurate ring structure.

[0480] In this specification, low molecular weight polymeric compounds refer to polymeric compounds with a molecular weight (weight average molecular weight in the case of a molecular weight distribution) of 50 or more and less than 600.

[0481] From the viewpoint of excellent chemical resistance, printing resistance and inhibition of machine-developed residues, the molecular weight of the low-molecular-weight polymeric compound is preferably 100 or more and less than 600, more preferably 300 or more and less than 600, and even more preferably 400 or more and less than 600.

[0482] When the polymeric compound includes a low-molecular-weight polymeric compound as a polymeric compound other than the oligomer (the total amount of the two or more low-molecular-weight polymeric compounds), from the viewpoint of chemical resistance, printability, and inhibition of machine-developed residues, the ratio of the oligomer to the low-molecular-weight polymeric compound (oligomer / low-molecular-weight polymeric 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.

[0483] As a low-molecular-weight polymerizable compound, the polymerizable compounds described in paragraphs 0082 to 0086 of International Publication No. 2019 / 013268 are also preferred.

[0484] The details of the usage method, such as the structure of the polymeric compound, whether to use it alone or in combination, and the amount to be added, can be set arbitrarily.

[0485] From the viewpoint of printability, the image recording layer preferably contains two or more polymeric compounds.

[0486] The content of polymeric compounds (the total content of polymeric compounds when there are two or more polymeric compounds) relative to the total mass of the image recording layer is preferably 5 to 75% by mass, more preferably 10 to 70% by mass, and even more preferably 15 to 60% by mass.

[0487] <Particles>

[0488] From the viewpoint of printability, the aforementioned image recording layer preferably contains particles.

[0489] The particles can be either organic or inorganic, but from the viewpoint of printability, organic particles are preferred, and polymer particles are more preferred.

[0490] Organic particles are particles composed of organic matter, while polymer particles are particles composed of polymers. In other words, polymer particles refer to polymers with a particle shape contained in the image recording layer.

[0491] The polymer particles are preferably selected from the group consisting of thermoplastic resin particles, thermally reactive resin particles, polymer particles with polymerizable groups, microcapsules containing hydrophobic compounds, and microgels (crosslinked polymer particles). Among them, polymer particles or microgels with polymerizable groups are preferred.

[0492] The polymer particles preferably contain at least one olefinic unsaturated group to improve the printability of the exposed portion and the machine developability of the unexposed portion.

[0493] From the viewpoint of printability and machine developability, thermoplastic resin particles are preferred as polymer particles.

[0494] As a specific way in which the aforementioned polymer particles may be included in the image recording layer, examples include the polymer particles described in International Publication No. 2020 / 262692, which is incorporated herein by reference.

[0495] As inorganic particles, known inorganic particles can be used, and metal oxide particles such as silicon dioxide particles and titanium dioxide particles can be preferred.

[0496] The average particle size of the aforementioned particles is preferably 0.01–3.0 μm, more preferably 0.03–2.0 μm, and even more preferably 0.10–1.0 μm. Good resolution and long-term stability can be obtained within this range.

[0497] The average particle size of the aforementioned particles was determined using the same dynamic light scattering method as the average particle size of the aforementioned thermoplastic resin particles. Alternatively, instead of using the dynamic light scattering method, electron microscope images of the particles could be taken, the particle size of a total of 5000 particles measured on the images, and the arithmetic mean calculated as the average particle size. Furthermore, for non-spherical particles, the diameter is defined as the diameter of a circle having the same area as the particle area in the image.

[0498] Unless otherwise specified, the average particle size is the volume average particle size.

[0499] The image recording layer described above may contain only one type of particle (preferably polymer particles) or two or more types.

[0500] From the viewpoint of machine developability and printability, the content of particles (preferably polymer particles) in the image recording layer is preferably 5 to 90% by mass, more preferably 10 to 90% by mass, further preferably 20 to 90% by mass, and especially preferably 50 to 90% by mass, relative to the total mass of the image recording layer.

[0501] <Adhesive Polymers>

[0502] The image recording layer may contain an adhesive polymer.

[0503] The aforementioned polymer particles are not part of the aforementioned adhesive polymer. That is, the adhesive polymer is a polymer that is not in particle shape.

[0504] The preferred adhesive polymers are (meth)acrylic resins, polyvinyl acetal resins, or polyurethane resins.

[0505] As the adhesive polymer, known adhesive polymers used in the image recording layer of a lithographic printing plate master can be used, and adhesive polymers used in machine-developable lithographic printing plate masters (also known as machine-developable adhesive polymers) are preferred. As the machine-developable adhesive polymer, adhesive polymers having epoxy alkyl chains are preferred.

[0506] Other preferred examples of adhesive polymers include star-shaped polymers, adhesive polymers having constituent units formed from aromatic vinyl compounds, polyvinyl acetals, and resins having fluorine atoms (more preferably copolymers containing fluorinated aliphatic groups). A star-shaped polymer is defined as a polymer chain having a polyfunctional thiol with 6 or more functions and 10 or fewer functions as its core, bonded to the core via thioether bonds, and the polymer chain having polymerizable groups.

[0507] Specific examples of the adhesive polymers that may be included in the image recording layer include those described in Japanese Patent Application Publication No. 2012-148555 and International Publication No. 2020 / 262692, which are incorporated herein by reference.

[0508] The adhesive polymer can be used alone or in combination with two or more.

[0509] The adhesive polymer can be contained in the image recording layer in any amount. When the image recording layer contains an adhesive polymer, the content of the adhesive polymer relative to the total mass of the image recording layer is preferably 1 to 90% by mass, more preferably 5 to 80% by mass.

[0510] <Polymerization Inhibitor>

[0511] From the viewpoint of superior stability over time and better developability after time, the image recording layer preferably contains polymerization inhibitors. By including polymerization inhibitors in the image recording layer, unwanted thermal polymerization of polymerizable compounds, especially free radical polymerizable compounds, can be prevented during the manufacturing or storage of the image recording layer.

[0512] Examples of polymerization inhibitors include hydroquinone, p-methoxyphenol, di-tert-butyl-p-cresol, pyrogallol, tert-butylcatechol, benzoquinone, 4,4'-thiobis(3-methyl-6-tert-butylphenol), 2,2'-methylenebis(4-methyl-6-tert-butylphenol), and N-nitroso-N-phenylhydroxylamine aluminum salt.

[0513] From the viewpoint of superior stability over time and better developability after time, the compound represented by the following formula (Ph) is preferred as a polymerization inhibitor.

[0514] [Chemical Formula 28]

[0515]

[0516] In formula (Ph), X P Represents O, S, or NH, Y P Represents N or CH, R P1 R represents a hydrogen atom or an alkyl group. P2 and R P3 Each of the following groups can be independently represented: halogen atom, alkylthio group, arylthio group, alkoxy group, aryloxy group, alkyl group, aryl group, acylthio group or acyl group. mp and np can be independently represented: integers from 0 to 4.

[0517] From the perspective of stability over time and reproducibility after time, X in formula (Ph) P Preferably O or S, more preferably S.

[0518] From the perspective of stability over time and reproducibility after time, Y in formula (Ph) P N is preferred.

[0519] From the perspective of stability over time and reproducibility after time, R in formula (Ph) P1 Preferably, it is a hydrogen atom or a methyl group, more preferably a hydrogen atom.

[0520] R in formula (Ph) P2 and R P3 Preferably, each is independently a halogen atom, alkylthio group, arylthio group, alkoxy group, aryloxy group, alkyl group, or aryl group.

[0521] From the viewpoint of stability over time and developability after time, mp and np in formula (Ph) are preferably integers from 0 to 2, more preferably 0 or 1, and even more preferably 0.

[0522] Polymerization inhibitors can be used alone or in combination with two or more.

[0523] The content of the polymerization inhibitor relative to the total mass of the image recording layer is preferably 0.001 to 5% by mass, more preferably 0.01 to 1% by mass.

[0524] <Chain transfer agent>

[0525] Image recording layers may contain chain transfer agents. Chain transfer agents help improve the printability of lithographic printing plates.

[0526] As a chain transfer agent, a thiol compound is preferred. From the viewpoint of boiling point (low volatility), a thiol compound with 7 or more carbon atoms is more preferred, and a compound with 7 or more carbon atoms and a thiol group on the aromatic ring (aromatic thiol compound) is even more preferred. As the above-mentioned thiol compound, a monofunctional thiol compound is preferred.

[0527] As a specific example of a chain transfer agent, the compound described in International Publication No. 2020 / 262692 can be cited.

[0528] Chain transfer agents can be used alone or in combination with two or more.

[0529] The content of the chain transfer agent relative to the total mass of the image recording layer 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.

[0530] <Other Ingredients>

[0531] In addition to the components mentioned above, the image recording layer may contain lipophilic agents (e.g., phosphoric compounds, nitrogen-containing low-molecular-weight compounds, ammonium-containing polymers), development promoters, surfactants, higher fatty acid derivatives, plasticizers, and inorganic layered compounds. For details regarding these other components, please refer to paragraphs 0114 to 0159 of Japanese Patent Application Publication No. 2008-284817.

[0532] Furthermore, as a specific example of a development promoter, the compound described in International Publication No. 2020 / 262692 can be cited.

[0533] <Methods for forming image recording layers>

[0534] Regarding the image recording layer, as described in paragraphs 0142 to 0143 of Japanese Patent Application Publication No. 2008-195018, a coating liquid can be prepared by dispersing or dissolving the above-mentioned components in a known solvent, and the coating liquid can be applied to a support using a known method such as a bar coater, and then dried to form the image recording layer.

[0535] As a solvent, known solvents can be used. Specific examples of solvents include those described in paragraph 0142 of Japanese Patent Application Publication No. 2008-195018.

[0536] One solvent may be used alone, or two or more may be used in combination. The concentration of solid components in the coating solution is preferably 1 to 50% by mass.

[0537] The coating amount (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 properties of the image recording layer, it is preferably 0.3 to 3.0 g / m². 2 .

[0538] The thickness of the image recording layer is preferably 0.1 to 3.0 μm, more preferably 0.3 to 2.0 μm.

[0539] The thickness of each layer in the lithographic printing plate original is determined by making a section cut perpendicular to the surface of the lithographic printing plate original and observing the cross section of the section using a scanning electron microscope (SEM).

[0540] [Other layers]

[0541] The original lithographic printing plate may contain layers other than the support and image recording layer mentioned above.

[0542] For example, to improve the adhesion between the support and the image recording layer, the original offset printing plate may have an undercoat layer disposed between the support and the image recording layer as needed.

[0543] Furthermore, the original lithographic printing plate can have a protective layer (outer coating) on ​​the image recording layer as needed to prevent scratches, oxygen barriers, and ablation during high-intensity laser exposure.

[0544] <Undercoat>

[0545] The original plate for offset printing is preferably coated with a base layer.

[0546] By using a base coating on the lithographic printing plate, for example in the case of a negative image recording layer, the adhesion between the support and the image recording layer is enhanced in the exposed area, preventing the image recording layer from peeling off from the support in the unexposed area. Therefore, it is possible to suppress the decrease in printability while improving developability. Furthermore, in the case of infrared laser exposure, the base coating acts as a heat insulation layer, preventing the heat generated during exposure from diffusing to the support and reducing sensitivity.

[0547] There are no particular limitations on the composition of the base coating, but from the viewpoint of better printability, it is preferable to include a polymer (hereinafter also referred to as "polymer I") having support adsorption groups and hydrophilic groups.

[0548] The details of the mechanism by which the printability of the original offset printing plate is improved by including the aforementioned polymer I in the base coating are not yet clear, but it is speculated that by applying a base coating containing polymer I to the surface of an anodized film having micropores with the aforementioned specific structure and a specific Si atomic mass within a specified range, an attractive-like interaction occurs between the Si atoms present on the film surface and the inner walls of the micropores and the support adsorption groups of polymer I, and the hydrophilic groups of polymer I act on the image recording layer. As a result, the adhesion between the support and the image recording layer is improved, thereby improving printability.

[0549] Support adsorption groups are groups that, through interaction with the support, can remain on the support even during the developing process on the printing press.

[0550] Examples of adsorption groups that serve as support structures include oxyacid structures, oxyacid salt structures, oxyacid ester structures, and oxyacid ester salt structures of phosphorus atoms. Preferably, these groups are selected from the group consisting of phosphonic acid groups, phosphate ester groups, and their salts, and more preferably, phosphate ester groups or their salts.

[0551] Examples of hydrophilic groups include groups with zwitterionic structures (betaine structures), groups with polyalkoxy structures, sulfonic acid groups and their salts, and carboxylic acid groups and their salts. From the viewpoint of suppressing ink residue on the support and exhibiting superior resistance to staining, groups with zwitterionic structures or groups with polyalkoxy structures are preferred, and groups with zwitterionic structures are more preferably preferred.

[0552] Here, a zwitterionic structure refers to a structure having at least one cation and at least one anion. Additionally, normally the number of cations is equal to the number of anions, resulting in an overall neutral structure. However, in this specification, even when the number of cations and anions is not equal, a zwitterionic structure is also defined as having a required amount of counterions to eliminate charge.

[0553] Polymer I is preferably a copolymer having repeating units having groups selected from the group consisting of phosphonic acid groups, phosphate ester groups and their salts on the side chain, and repeating units having at least one of zwitterionic structure and polyalkoxy structure on the side chain. With the above configuration, printability and resistance to staining are superior.

[0554] In this specification, "main chain" refers to the longest bonded chain in the polymer compound that constitutes the resin, and "side chain" refers to a bonded chain that branches off from the main chain.

[0555] Furthermore, in this specification, repeating units having groups selected from the group consisting of phosphonic acid groups, phosphate ester groups and their salts are also referred to as repeating units A, and repeating units having zwitterionic structures are also referred to as repeating units B.

[0556] From the viewpoints of printability, resistance to staining and developability, the content of repeating unit A in polymer I is preferably 1 to 40% by mass relative to the total mass of polymer I, more preferably 3 to 30% by mass, and even more preferably 5 to 20% by mass.

[0557] From the viewpoint of resistance to contamination and developability, the content of repeating unit B in polymer I is preferably 30 to 95% by mass relative to the total mass of polymer I, more preferably 40 to 90% by mass, and even more preferably 50 to 85% by mass.

[0558] Polymer I preferably also has polymerizable groups. That is, polymer I is preferably a polymer having support adsorption groups, hydrophilic groups and polymerizable groups.

[0559] Polymer I more preferably has an olefinic unsaturated group as a polymerizable group, and even more preferably has a repeating unit (also called "repeating unit C") having an olefinic unsaturated group on its side chain.

[0560] When polymer I contains repeating unit C, from the viewpoint of printability and resistance to contamination, the content of repeating unit C relative to the total mass of the polymer is preferably 1 to 30% by mass, more preferably 3 to 20% by mass, and even more preferably 5 to 15% by mass.

[0561] Polymer I is preferably an acrylic resin polymerized from (meth)acrylate compounds and / or (meth)acrylamide compounds.

[0562] From the viewpoint of resistance to contamination and developability, the total content of repeating unit A and repeating unit B in polymer I is preferably 50 to 99% by mass relative to the total mass of the polymer, more preferably 70 to 97% by mass, and even more preferably 80 to 95% by mass.

[0563] The weight-average molecular weight (Mw) of polymer I can be arbitrarily set by the performance design of the lithographic printing plate. From the viewpoint of superior printability and stain resistance, the weight-average molecular weight of polymer I is preferably 20 million to 1 million, more preferably 40 million to 500,000, and even more preferably 50 million to 400,000.

[0564] Polymer I can also be synthesized by known methods. As a method for synthesizing polymer I, free radical polymerization is preferred, followed by a ureation reaction in which the amino group of the polymer side chain reacts with an isocyanate compound having a free radical polymerization reactive group, or an amidation reaction in which the amino group of the polymer side chain reacts with an acid anhydride having a free radical polymerization reactive group.

[0565] As a free radical polymerization method, it is applicable to methods described in publications such as New Experimental Polymer Science 3 (edited by the Polymer Society, published by Kyoritsu Publishing, March 28, 1996), Synthesis and Reaction of Polymers 1 (edited by the Polymer Society, published by Kyoritsu Publishing, May 1992), New Lectures on Experimental Chemistry 19, Polymer Chemistry (I) (edited by the Chemical Society of Japan, published by Maruzen, November 20, 1955), and Lectures on Polymer Synthesis Chemistry in Materials Science (published by Tokyo Denki University Press, September 1995).

[0566] The polymer I contained in the base coating can be used alone or in combination of two or more.

[0567] The content of polymer I in the base coating is preferably 50 to 100% by mass relative to the total mass of the total solids in the base coating excluding volatile components, more preferably 60 to 100% by mass, and even more preferably 70 to 100% by mass.

[0568] (Method for forming the base coating)

[0569] There are no particular limitations on the method of forming the primer layer. For example, a method can be described by applying a primer layer forming coating liquid containing components such as polymer I that constitute the primer layer onto the anodic oxide film of the support.

[0570] Preferably, the coating liquid used to form the primer layer contains a solvent. Examples of solvents include water, alcohol compounds, and organic solvents and mixtures thereof.

[0571] Various known methods can be cited as methods for applying coating liquids used to form primer layers. Examples include bar coating, spin coating, spray coating, curtain coating, dip coating, air knife coating, doctor blade coating, and roller coating.

[0572] The preferred coating weight (solid content) for the primer layer is 0.1–100 mg / m³. 2 More preferably 1–30 mg / m³ 2 .

[0573] <Protective Layer>

[0574] The lithographic printing plate master preferably has a protective layer (also called an "outer coating") on the surface of the image recording layer opposite to the support. That is, it is preferably a lithographic printing plate master having a support, an image recording layer and a protective layer in sequence.

[0575] The protective layer may have at least one of the following functions: inhibiting the image formation barrier reaction by blocking oxygen, preventing the formation of scratches in the image recording layer, and preventing ablation during high-intensity laser exposure.

[0576] Protective layers with such properties are described, for example, in U.S. Patent No. 3,458,311 and Japanese Patent Publication No. 55-049729. As the low-oxygen permeability polymer used in the protective layer, either a water-soluble polymer or a hydrophobic polymer (water-insoluble polymer) can be appropriately selected, or two or more can be mixed as needed. From the viewpoint of machine developability, a water-soluble polymer is preferred.

[0577] In this specification, a water-soluble polymer refers to a polymer whose solubility in pure water at 25°C exceeds 5% by mass.

[0578] Examples of water-soluble polymers used in the protective layer include polyvinyl alcohol, modified polyvinyl alcohol, polyvinylpyrrolidone, cellulose derivatives, polyethylene glycol, and poly(meth)acrylonitrile.

[0579] Furthermore, the water-soluble polymer preferably includes at least one selected from the group consisting of modified polyvinyl alcohol and cellulose derivatives.

[0580] As a modified polyvinyl alcohol, acid-modified polyvinyl alcohol having carboxyl or sulfonyl groups is preferred. Specifically, the modified polyvinyl alcohols described in Japanese Patent Application Publication Nos. 2005-250216 and 2006-259137 can be cited as examples.

[0581] Examples of cellulose derivatives include methylcellulose, hydroxypropyl methylcellulose, and carboxymethylcellulose.

[0582] The water-soluble polymers mentioned above preferably include polyvinyl alcohol, and more preferably include polyvinyl alcohol with a saponification degree of 50% or more.

[0583] The aforementioned 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, as long as it is below 100%.

[0584] The degree of saponification was determined according to the method described in JIS K 6726:1994.

[0585] Furthermore, as a protective layer, a preferred method is to include polyvinyl alcohol and polyethylene glycol.

[0586] 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.

[0587] The protective layer preferably comprises a hydrophobic polymer.

[0588] Hydrophobic polymers are polymers that can dissolve less than 5g or not at all in 100g of pure water at 125℃.

[0589] Examples of hydrophobic polymers include polyethylene, polystyrene, polyvinyl chloride, polyvinylidene chloride, poly(meth)acrylate (e.g., poly(meth)acrylate, poly(meth)acrylate, poly(meth)acrylate, poly(meth)acrylate, poly(meth)acrylate, etc.), and copolymers composed of the raw material monomers of these resins.

[0590] Preferably, polyvinylidene chloride resin is included as a hydrophobic polymer. Furthermore, styrene-acrylic acid copolymer (also known as styrene-acrylic resin) is preferably included as a hydrophobic polymer.

[0591] From the viewpoint of machine developability, hydrophobic polymers are preferably hydrophobic polymer particles.

[0592] Hydrophobic polymers can be used alone or in combination of two or more.

[0593] When the protective layer contains a hydrophobic polymer, the content of the hydrophobic polymer relative to the total mass of the protective layer is preferably 1 to 70% by mass, more preferably 5 to 50% by mass, and even more preferably 10 to 40% by mass.

[0594] From the viewpoint of improving the visibility of the exposed area, the protective layer preferably includes a chromophore precursor. A chromophore precursor is a compound that emits color upon stimulation by light or acids and has the property of changing the color of the image recording layer. Examples of chromophore precursors include infrared absorbers and acid chromophores.

[0595] The protective layer preferably contains an infrared absorber as a chromophore precursor, and more preferably contains a decomposable infrared absorber as a chromophore precursor.

[0596] The infrared absorbers and acid chromophores contained in the protective layer, including their preferred forms, are the same as those contained in the image recording layer.

[0597] The chromophore precursor contained in the protective layer can be used alone or in combination with two or more components.

[0598] From the viewpoint of color development, the content of the chromophore precursor in the protective layer is preferably 0.10 to 50% by mass relative to the total mass of the protective layer, more preferably 0.50 to 30% by mass, and even more preferably 1.0 to 20% by mass.

[0599] From the viewpoint of suppressing development defects, the protective layer preferably contains filler.

[0600] Examples of fillers include inorganic particles, organic resin particles, and inorganic layered compounds. Among these, inorganic layered compounds are preferred. By using inorganic layered compounds, it is possible to effectively suppress re-attachment from the roller surface to the image recording layer surface.

[0601] Inorganic layered compounds are particles with thin, flat, plate-like shapes. Examples include natural mica, synthetic mica, talc (represented by the formula 3MgO·4SiO·H2O), monzocarp, montmorillonite, saponite, lithium montmorillonite, and zirconium phosphate.

[0602] Mica compounds are preferred inorganic layered compounds. Examples of mica compounds include: A(B, C). 2-5 D4O 10 (OH, F, O)₂ [where A is any one of K, Na, or Ca; B and C are any one of Fe(II), Fe(III), Mn, Al, Mg, or V; and D is Si or Al.] represents natural mica, synthetic mica, and other mica groups.

[0603] As inorganic layered compounds, examples include the inorganic layered compounds described in International Publication No. 2020 / 262692, which is incorporated herein by reference.

[0604] Examples of inorganic particles include silicon dioxide particles and other metal oxide particles. The following inorganic layered compounds are not included among inorganic particles.

[0605] Examples of organic resin particles include cross-linked resin particles.

[0606] The content of filler (preferably an inorganic layered compound) relative to the total mass of the protective layer is preferably 1 to 60% by mass, more preferably 3 to 50% by mass. When an inorganic layered compound is included within the above range, oxygen barrier properties are improved, good sensitivity can be obtained, and the reduction in ink adhesion can be prevented.

[0607] In addition to the components mentioned above, the protective layer may also contain known additives such as plasticizers for imparting flexibility and surfactants for improving coatability. Furthermore, the protective layer may contain the lipophilic agent described in the image recording layer.

[0608] The protective layer can be formed by a known method of coating a composition containing the above-mentioned components. The coating amount (converted to solids content) of the protective layer is preferably 0.0–10 g / m². 2 More preferably, it is 0.02–3 g / m 2 More preferably, it is 0.02–1 g / m 2 .

[0609] There is no particular limitation on the thickness of the protective layer in the original offset printing plate, but it is preferably 0.1 to 5.0 μm, and more preferably 0.3 to 4.0 μm.

[0610] The lithographic printing plate may also have known layers overlaid on top of the lithographic printing plate, other than those described above. For example, if necessary, a back coating may be provided on the surface of the support opposite to the image recording layer side.

[0611] [Layered structure]

[0612] The original lithographic printing plates can be stacked to form a composite material.

[0613] The laminate consisting of multiple lithographic printing plates preferably also includes a protective material to protect the lithographic printing plates. Since the lithographic printing plate is a thin sheet with a metal support, if there are bends, scratches, or deformations at corners, edges, or inside, problems such as blurry images during photosensitive exposure or uneven ink distribution during printing can easily occur. Therefore, in the case of a laminate consisting of multiple lithographic printing plates, it is preferable to use protective material to protect the specified number of plates.

[0614] For example, by using packaging materials to encase a laminate containing multiple offset printing plates and protective materials as packaging, and then handling the goods within the package (handling and storage, etc.), deformation (bending, etc.) of the original plates is less likely to occur during handling, thus suppressing damage to the original plates. Furthermore, even if external forces are applied to the packaging, a portion of them is absorbed by the protective material, thereby suppressing deformation and scratches on the original plates.

[0615] There are no particular limitations on the placement of the protective material in the laminate; examples include the top of the laminate, between the laminated lithographic printing plates, and the bottom of the laminate. Preferably, the protective material is placed at least at the top of the laminate, and more preferably at least at the top and bottom.

[0616] There are no particular limitations on the material of the protective material; examples include thick paper, cardboard, and plastic. From the viewpoint of suppressing development defects, cardboard or plastic is preferred, and plastic is more preferred. Examples of plastics include polyester, polycarbonate, and polyolefin, with polyester being the most preferred.

[0617] There are no particular restrictions on the size (both vertical and horizontal) and thickness of the protective material; it can be appropriately selected according to the original offset printing plate being protected.

[0618] From the viewpoint of suppressing poor development defects, the moisture content of the protective material is preferably 10% by mass or less, more preferably 7% by mass or less, and even more preferably 3% by mass or less. The lower limit of the moisture content is 0% by mass. The moisture content (equilibrium moisture content) of the protective material is determined according to the method described in JIS P 8202 (1998).

[0619] Laminated bodies can have padding paper between the original lithographic printing plates.

[0620] Examples of materials that can be used as backing paper include: paper made from 100% wood pulp by mass, paper made from synthetic pulp mixed with wood pulp, and paper with a low-density or high-density polyethylene layer on its surface.

[0621] Furthermore, the laminated body can be packaged as a whole using known packaging materials.

[0622] [The manufacturing method of the original plate for lithographic printing]

[0623] As a method for manufacturing the original lithographic printing plate of the present invention, for example, a method including a step of making a support comprising an aluminum plate and an anodized film, and a step of forming an image recording layer on the surface of the anodized film side of the made support.

[0624] The process for manufacturing the support body is described in the aforementioned "Method for Manufacturing the Support Body", and the process for forming the image recording layer is described in the aforementioned "Method for Forming the Image Recording Layer".

[0625] After the process of manufacturing the support body, a process of forming a base coating on the surface of the anodic oxide film side of the obtained support body can be performed as needed, followed by a process of forming the image recording layer on the surface of the formed base coating.

[0626] Furthermore, after the process of forming the image recording layer described above, a process of forming a protective layer on the surface of the formed image recording layer can be performed.

[0627] The method for forming the primer layer and the process for forming the protective layer are as described above.

[0628] [Methods for manufacturing offset printing plates and printing methods]

[0629] The invention describes a method for manufacturing a lithographic printing plate using the lithographic printing plate master of the present invention, and a printing method using the lithographic printing plate of the present invention.

[0630] The method for manufacturing a lithographic printing plate of the present invention comprises: a step of exposing the image recording layer of a lithographic printing plate original in an image-like manner (image exposure) to form an exposed portion and an unexposed portion (exposure step); and a step of supplying at least one of printing ink and dampening solution on a printing press to remove the unexposed portion of the image recording layer after exposure in an image-like manner, thereby producing a lithographic printing plate (machine development step).

[0631] The printing method of the present invention includes, for example, a step of exposing the image recording layer of a lithographic printing plate to an image (image exposure) and forming an exposed portion and an unexposed portion (exposure step); a step of supplying at least one of printing ink and dampening solution to a printing press to remove the unexposed portion of the image recording layer, thereby producing a lithographic printing plate (machine development step); and a step of printing using the produced lithographic printing plate (printing step).

[0632] The following is a detailed description of each of the above processes.

[0633] <Exposure Process>

[0634] The method for making and printing lithographic printing plates involves an exposure process that exposes the image recording layer of the original lithographic printing plate to form an exposed portion and an unexposed portion.

[0635] Regarding image exposure, it can be performed, for example, by laser exposure through a transparent original image having a line image or a dot image, or by laser beam scanning based on digital data.

[0636] The wavelength of the light source for image exposure is preferably 750–1400 nm. When using a light source that emits light with a wavelength of 750–1400 nm, it is preferable to use an image recording layer containing an infrared absorber that has absorption in this wavelength region.

[0637] Examples of light sources that emit wavelengths of 750–1400 nm include solid-state lasers and semiconductor lasers that emit infrared radiation. For infrared lasers, the output power is preferably 100 mW or higher, the exposure time per pixel is preferably less than 20 microseconds, and the irradiation energy is preferably 10–300 mJ / cm². 2 Furthermore, multi-beam laser equipment is preferred to shorten the exposure time. The exposure mechanism can be any of the following: internal drum type, external drum type, or flat plate type.

[0638] Image exposure can be performed using conventional methods such as plate-making machines. Image exposure can be performed on the printing press after the original lithographic printing plate is mounted on it.

[0639] <On-machine developing process>

[0640] In the on-machine developing process, a lithographic printing plate is manufactured by supplying at least one of printing ink and dampening solution to a lithographic printing plate master that has been exposed to an image on a printing press, thereby removing the image recording layer of the unexposed portion.

[0641] That is, if the lithographic printing plate is directly mounted on the printing press after image exposure without any developing solution treatment, or if the lithographic printing plate is mounted on the printing press and then image exposure is performed, followed by the supply of printing ink and dampening solution and printing, then in the initial stage of printing, the unexposed portion of the image recording layer is dissolved or dispersed and removed by the supplied printing ink and / or dampening solution in the unexposed area, thereby exposing the hydrophilic surface to that portion. On the other hand, in the exposed area, the image recording layer cured by exposure forms an oily ink receiving portion with an oleophilic surface. Initially, either printing ink or dampening solution can be supplied to the plate, but from the viewpoint of preventing contamination of the image recording layer components from which dampening solution has been removed, it is preferable to supply printing ink first.

[0642] In this way, the original lithographic printing plate is produced on the printing press through on-machine development and is directly used in multiple printings.

[0643] <Printing Process>

[0644] The printing method includes a printing process that uses a lithographic printing plate manufactured through an exposure process and an on-machine development process to print on a recording medium.

[0645] As the printing ink used in the printing process, various known inks can be used as needed. Oil-based inks or ultraviolet-curing inks (UV inks) are preferred.

[0646] In the above printing process, dampening solution can be supplied as needed.

[0647] Regarding the above printing process, the above on-machine developing process can be performed continuously without stopping the printing press.

[0648] As a recording medium, it is possible to use known recording media as needed.

[0649] In the methods for making and printing lithographic printing plates, the entire surface of the lithographic printing plate or the original lithographic printing plate can be heated at any stage, including before exposure, during exposure, from exposure to development, and after development, as needed. This heating promotes the image formation reaction in the image recording layer, resulting in advantages such as improved sensitivity and printability, as well as stabilized sensitivity.

[0650] Heating the original lithographic printing plate before development can prevent problems such as curing of unexposed areas, so it is preferable to heat it under mild conditions below 150°C.

[0651] When the lithographic printing plate is heated after development, sufficient image enhancement can be obtained, and problems such as deterioration of the support and thermal decomposition of the image area can be suppressed. Therefore, it is preferable to heat under very strong conditions, such as in the range of 100 to 500°C.

[0652] Example

[0653] The present invention will now be described in detail through embodiments. However, the materials, amounts, proportions, processing contents, and processing steps shown in the following embodiments can be appropriately modified without departing from the spirit of the invention. Therefore, the scope of the present invention is not to be limited by the specific examples shown below.

[0654] Additionally, regarding polymers, molecular weight is weight-average molecular weight (Mw), and the ratio of repeating units is molar percentage. Furthermore, the expression "%" indicates "mass %", and the expression "parts" indicates "parts by mass".

[0655] [Manufacturing Example 1: Manufacturing of the Support]

[0656] The support body 1 was manufactured by performing the following treatment on an aluminum plate (aluminum alloy plate) with a thickness of 0.3 mm and a material of 1S. In addition, a water washing process was performed between all processing steps, and the liquid was drained by clamping rollers after the water washing process.

[0657] <Alkali Etching Treatment (1)>

[0658] An aqueous solution of caustic soda (26% by mass) and aluminum ions (6.5% by mass) was sprayed onto an aluminum plate at 70°C for etching. Afterwards, the plate was washed with water using a sprayer. The aluminum dissolution rate on the surface after electrochemical roughening was 5 g / m². 2 .

[0659] <Decontamination treatment using acidic aqueous solution (1)>

[0660] Next, an acidic aqueous solution was used for decontamination. Specifically, the acidic aqueous solution was sprayed onto the aluminum plate using a sprayer and the decontamination was carried out for 3 seconds. The acidic aqueous solution used in the decontamination process was a 150 g / L sulfuric acid solution at a temperature of 30°C.

[0661] <Hydrochloric acid electrolysis treatment>

[0662] Next, hydrochloric acid electrolysis was performed using an electrolyte solution with a concentration of 13 g / L hydrochloric acid, 15 g / L aluminum ions, and 1.0 g / L sulfuric acid, using alternating current. The electrolyte temperature was maintained at 25°C. Aluminum chloride was added to adjust the aluminum ion concentration.

[0663] The alternating current waveform is a symmetrical sine wave with positive and negative phases, and a frequency of 50 Hz. The ratio of the anode reaction time to the cathode reaction time in one cycle of the alternating current is 1:1. The current density, expressed as the peak current value of the alternating current waveform, is 35 A / dm³. 2 Furthermore, the charge amount, calculated as the total charge amount of the aluminum plate participating in the anode reaction, is 300 C / dm. 2 Regarding electrolytic treatment, with a 2.5-second energizing interval, at 75C / dm 2 The process was performed in four steps. A carbon electrode was used as the counter electrode for the aluminum plate. Afterwards, a water washing process was carried out.

[0664] <Alkali Etching Treatment (2)>

[0665] An aqueous solution of caustic soda (5% by mass) and aluminum ions (0.5% by mass) was sprayed onto an aluminum plate that had undergone hydrochloric acid electrolysis for etching at 45°C. The aluminum dissolution rate on the surface treated with hydrochloric acid electrolysis was 0.2 g / m². 2 After that, it was washed with water.

[0666] <Decontamination treatment using acidic aqueous solution (2)>

[0667] Next, an acidic aqueous solution was used for decontamination. Specifically, the acidic aqueous solution was sprayed onto the aluminum plate using a sprayer and the decontamination was carried out for 3 seconds. The acidic aqueous solution used in the decontamination process had a sulfuric acid concentration of 170 g / L and an aluminum ion concentration of 5 g / L. The solution temperature was 35°C.

[0668] <First Anodizing Treatment>

[0669] use Figure 6 The DC electrolysis-based anodizing apparatus shown was used for the first anodizing process. Anodizing was performed under the conditions shown in Table 1, resulting in an anodized film of a specified thickness. The concentration of sulfuric acid in the first anodizing process was 170 g / L.

[0670] exist Figure 6 In the anodizing apparatus 610 shown, the aluminum plate 616 is as follows: Figure 6 As indicated by the middle arrow, the aluminum plate 616 is conveyed. In the power supply tank 612 containing electrolyte 618, the aluminum plate 616 is charged (+) by the power supply electrode 620. The aluminum plate 616 is then conveyed upwards in the power supply tank 612 by roller 622, and after being reversed downwards by clamping roller 624, it is conveyed to the electrolytic treatment tank 614 containing electrolyte 626, and reversed horizontally by roller 628. Next, the aluminum plate 616 is charged (-) by electrolytic electrode 630, thereby forming an anodized film on its surface. The aluminum plate 616 leaving the electrolytic treatment tank 614 is then conveyed to the subsequent process. In the anodizing apparatus 610, a direction-changing mechanism is formed by rollers 622, 624, and 628. In the space between the power supply tank 612 and the electrolytic treatment tank 614, the aluminum plate 616 is conveyed in a convex and inverted U-shape via rollers 622, 624, and 628. The power supply electrode 620 and the electrolytic electrode 630 are connected to a DC power supply 634. A tank wall 632 is disposed between the power supply tank 612 and the electrolytic treatment tank 614.

[0671] <Hole Enlargement Treatment>

[0672] The aluminum plate that underwent the first anodizing treatment was immersed in a caustic soda aqueous solution at 40°C with a sodium hydroxide concentration of 5% by mass and an aluminum ion concentration of 0.5% by mass, and then subjected to a pore-expanding treatment for the processing times shown in Table 1. Afterwards, it was washed with water using a sprayer.

[0673] <Second Anodizing Treatment>

[0674] Use based on Figure 6 The DC electrolytic anodizing apparatus shown was used to perform a second anodizing treatment on an aluminum plate that had undergone the aforementioned hole-expansion treatment. More specifically, the anodizing treatment was performed under the conditions described in the "Second Anodizing Treatment" column of Table 1, forming an anodized film of a specified structure. The concentration of sulfuric acid in the second anodizing treatment was 170 g / L.

[0675] <Silicate Treatment>

[0676] The aluminum plate that underwent the second anodizing treatment was subjected to silicate treatment to obtain support 1. More specifically, the aluminum plate that underwent the second anodizing treatment was immersed in a sodium silicate aqueous solution No. 3 with a concentration of 5% by mass and a liquid temperature of 40°C for 12 seconds.

[0677] [Manufacturing Examples 2-29]

[0678] The conditions of each process performed in Manufacturing Example 1 were changed to those described in Table 1. Otherwise, the supports 2 to 29 were manufactured according to the same steps as in Manufacturing Example 1.

[0679] In the table, the "Concentration (mass %)" column for "Silicate Treatment" indicates the percentage of alkali metal silicate content relative to the total mass of the No. 3 sodium silicate aqueous solution used in the silicate treatment.

[0680] [Table 1]

[0681]

[0682] [Table 2]

[0683]

[0684] [Preparation of the base coat coating solution]

[0685] The following components were mixed to prepare primer coating solutions A to C for forming the primer layer.

[0686] (Primer coating liquid A)

[0687] • Compound for primer coating (1): 0.010 parts

[0688] Chelest (registered trademark) 400 (chelating agent, manufactured by Chelest Corporation): 0.0280 parts

[0689] • Chelest 3EAF (chelating agent, manufactured by Chelest Corporation): 0.0499 parts

[0690] • Surfactant (EMALEX (registered trademark) 710, manufactured by NIHON EMULSION Co., Ltd.): 0.00159 parts

[0691] • Preservative (Biohope (registered trademark) L, KI Chemical Industry Co.,LTD.): 0.00149 parts

[0692] Water: 2,8219 portions

[0693] [Chemical Formula 29]

[0694]

[0695] (Primer coating liquid B)

[0696] • Compound for primer coating (2): 0.010 parts

[0697] Chelest 400 (chelating agent, manufactured by Chelest Corporation): 0.0280 parts

[0698] • Chelest 3EAF (chelating agent, manufactured by Chelest Corporation): 0.0499 parts

[0699] Surfactant (EMALEX 710, manufactured by NIHON EMULSION Co., Ltd.): 0.00159 parts

[0700] • Preservative (Biohope L, KI Chemical Industry Co.,LTD.): 0.00149 parts

[0701] Water: 2,8219 portions

[0702] [Chemical Formula 30]

[0703]

[0704] • Compound for primer coating (3): 0.010 parts

[0705] Chelest 400 (chelating agent, manufactured by Chelest Corporation): 0.0280 parts

[0706] • Chelest 3EAF (chelating agent, manufactured by Chelest Corporation): 0.0499 parts

[0707] Surfactant (EMALEX 710, manufactured by NIHON EMULSION Co., Ltd.): 0.00159 parts

[0708] • Preservative (Biohope L, KI Chemical Industry Co.,LTD.): 0.00149 parts

[0709] Water: 2,8219 portions

[0710]

[0711] [Preparation of image recording layer coating solution]

[0712] <Image Recording Layer Coating Solution A>

[0713] The image recording layer coating solution A was prepared by mixing the following components.

[0714] • Infrared absorber (IR-1 below): 0.0200 parts

[0715] • Infrared absorber (IR-2 below): 0.0050 parts

[0716] • Acid colorant (S-1 below): 0.0300 parts

[0717] • Acid colorant (S-2 below): 0.0120 parts

[0718] • Onium-based polymerization initiator (I-1 below): 0.0981 parts

[0719] • Borate compound (sodium tetraphenylborate (TPB)): 0.0270 parts

[0720] • Polymerizable compound (M-4 below, 70%): 0.3536 parts

[0721] Fluorinated surfactant (1) (structure described below) 0.004 parts

[0722] • Anionic surfactant (A-1 below, 30%): 0.1620 parts

[0723] ·2-Butanone: 5.3155 parts

[0724] ·1-Methoxy-2-propanol: 2.8825 parts

[0725] Methanol: 2.3391 parts

[0726] · Microgel solution (5): 2.8779 parts

[0727] [Chemical Formula 31]

[0728]

[0729] [Chemical Formula 32]

[0730]

[0731] [Chemical Formula 33]

[0732]

[0733] [Chemical Formula 34]

[0734]

[0735] [Chemical Formula 35]

[0736]

[0737] (Synthesis of polymeric compound M-4)

[0738] A mixed solution of Takenate (registered trademark) D-160N (polyisocyanate trimethylolpropane adduct, manufactured by Mitsui Chemicals, Inc., 4.7 parts), ARONIX (registered trademark) M-403 (manufactured by TOAGOSEI CO.,LTD., with an NCO value of Takenate D-160N and a hydroxyl value of ARONIX M-403 in a 1:1 ratio), tert-butylbenzoquinone (0.02 parts), and methyl ethyl ketone (11.5 parts) was heated to 65°C. NEOSTANN (registered trademark) U-600 (bismuth-based polycondensation catalyst, manufactured by Nitto Kasei Co., Ltd., 0.11 parts) was added to the reaction solution, and the mixture was 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 50% by weight solution of urethane acrylate (polymeric compound M-4). Molecular fractionation of urethane acrylate solutions was performed using a recycle-type GPC (equipment: LC908-C60, columns: JAIGEL-1H-40 and 2H-40 (manufactured by Japan Analytical Industry)) with tetrahydrofuran (THF) as the eluent. The weight-average molecular weight of the polymeric compound M-4 was 20,000.

[0739] (Preparation of microgel solution (5))

[0740] The following components were mixed to prepare a microgel solution (5) for preparing image recording layer coating solution A.

[0741] • Microgels (4) (solid component concentration 21.8% by mass) 2.2707 parts

[0742] 0.6072 parts of 1-methoxy-2-propanol

[0743] -Preparation of microgels (4)-

[0744] The following oil and aqueous phase components 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, and then 5.20 parts of a 10% (w / w) aqueous solution of 1,8-diazabicyclo[5.4.0]undec-7-ene-octanoate (U-CAT SA102, manufactured by San-Apro Ltd.) was added. The mixture was stirred at room temperature for 30 minutes and then allowed to stand at 45°C for 24 hours. Distilled water was added to adjust the solids concentration to 21.8% (w / w), thus obtaining an aqueous dispersion of microgel (4). The volume average particle size was determined by light scattering using a dynamic light scattering particle size distribution measuring device LB-500 (manufactured by HORIBA, Ltd.), and the result was 0.28 μm.

[0745] (oil phase component)

[0746] (Component 1) 12.0 parts of ethyl acetate

[0747] (Component 2) An adduct (50% by mass ethyl acetate solution, manufactured by Mitsui Chemicals, Inc.) formed by adding trimethylolpropane (6 mol) and xylene diisocyanate (18 mol) to the adduct and then adding methyl mono-terminated polyoxyethylene (1 mol, repeat number of ethylene oxide units: 90) to the adduct.

[0749] (Component 3) Polyisocyanate compound (1) (as a 50% by mass ethyl acetate solution) 15.0 parts

[0751] (Component 4) 11.54 parts of 65% by weight ethyl acetate solution of dipentaerythritol pentaacrylate (SR-399, manufactured by Sartamomer Japan Inc.)

[0752] (Component 5) 4.42 parts of a 10% ethyl acetate solution of a sulfonate surfactant (PIONIN A-41-C, manufactured by Takemoto Oil & Fat Co., Ltd.).

[0753] (Aqueous phase composition)

[0754] 46.87 parts distilled water

[0755] -Preparation of polyisocyanate compound (1)-

[0756] In a suspension of 17.78 parts (80 molar equivalents) of isophorone diisocyanate and 7.35 parts (20 molar equivalents) of the following polyphenol compound (1) in ethyl acetate (25.31 parts), 0.043 parts of tris(2-ethylhexanoate) bismuth (NEOSTANN U-600, manufactured by NITTO KASEI CO., LTD.) was added and the mixture was stirred. The reaction temperature was set at 50°C at the point where heating was suppressed, and the mixture was stirred for 3 hours to obtain an ethyl acetate solution (50% by mass) of polyisocyanate compound (1).

[0757] [Chemical Formula 36]

[0758]

[0759] <Image Recording Layer Coating Solution B>

[0760] The image recording layer coating solution B was prepared by mixing the components shown below.

[0761] ·2-Butanone: 5.3155 parts

[0762] ·1-Methoxy-2-propanol: 2.8825 parts

[0763] Methanol: 2.3391 parts

[0764] • Polymerizable compound (M-4 above, 70%): 0.3571 parts

[0765] • Electron-accepting polymerization initiator (I-1 above): 0.025 parts

[0766] • Borate compound (sodium tetraphenylborate (TPB)): 0.030 parts

[0767] • Cleavage-prone chromogenic compound (infrared absorber) (hereinafter IR-3): 0.035 parts

[0768] Trimethylbenzene phosphate: 0.0125 parts

[0769] • Anionic surfactant (A-1 above): 0.0162 parts

[0770] · Microgel solution (5): 2.8779 parts

[0771] Fluorinated surfactant (1) (with the above structure): 0.0042 parts

[0772] [Chemical Formula 37]

[0773]

[0774] [Preparation of protective coating solution]

[0775] The following components are mixed to prepare a protective coating solution A for forming a protective layer.

[0776] Water: 1.0161 parts

[0777] • METOLOSE (registered trademark) SM04 (methylcellulose, manufactured by Shin-Etsu Chemical Co., Ltd., degree of methoxy substitution = 1.8): 0.0600 parts

[0778] •FS-102 (Styrene-acrylic resin, manufactured by Nipponpaint Industrial Coatings Co.,LTD., Tg=103℃, 17% aqueous dispersion): 0.1177 parts

[0779] • RAPISOL (registered trademark) A-80 (anionic surfactant, manufactured by NOF CORPORATION, 80% aqueous solution): 0.0063 parts

[0780] [Example 1]

[0781] On the surface of the anodic oxide film side of the support 1 manufactured in Manufacturing Example 1, a dry coating amount of 0.1 g / m is applied. 2 The primer coating liquid A is applied in a certain manner and dried at 120°C for 40 seconds to form the primer coating A.

[0782] The image recording layer coating solution A prepared by the above method is applied to the surface of the formed base coating A by bar coating, and then dried in an oven at 120°C for 40 seconds to form a dry coating weight of 1.0 g / m². 2 The image recording layer A is obtained by stacking the support 1, the base layer A and the image recording layer A.

[0783] Next, the protective coating liquid A is applied to the surface of the formed image recording layer A by a rod coating, and then dried in an oven at 120°C for 60 seconds to form a dry coating weight of 0.80 g / m². 2 The protective layer A is used to create a lithographic printing plate master composed of a stacked support, a base layer A, an image recording layer A, and a protective layer A.

[0784] [Examples 2-22, Comparative Examples 1-4]

[0785] As shown in Table 2 below, support bodies 2 to 22 and 26 to 29 were used to replace support body 1, respectively. Otherwise, a lithographic printing plate original was made by stacking support bodies, base layer A, image recording layer A and protective layer A according to the method described in Example 1.

[0786] [Example 23]

[0787] A base layer B was formed by replacing the support body 1 with a support body 23 and replacing the base layer coating liquid A with a base coating liquid B. Otherwise, a lithographic printing plate original was made by laminating the support body, the base layer B, the image recording layer A and the protective layer A according to the method described in Example 6.

[0788] [Example 24]

[0789] A base layer C was formed by replacing the support body 1 with a support body 24 and replacing the base layer coating liquid A with a base layer coating liquid C. Otherwise, a lithographic printing plate original was made by laminating the support body, the base layer C, the image recording layer A and the protective layer A according to the method described in Example 6.

[0790] [Example 25]

[0791] An image recording layer B is formed by using a support 25 instead of a support 1 and using an image recording layer coating liquid B instead of an image recording layer coating liquid A. Otherwise, a lithographic printing plate original is made by laminating a support, a base layer A, an image recording layer B and a protective layer A according to the method described in Example 6.

[0792] [Measurement]

[0793] <Density of micropores>

[0794] The density of micropores in the anodic oxide film of each support manufactured by Examples 1 to 29 was determined by using the FE-SEM method described above.

[0795] The density of micropores in the anodic oxide film measured on each support (unit: pores / μm) 2 (See Table 2 below.)

[0796] <Specific Si atomic weight on film surface>

[0797] The specific Si atomic weight in the anodic oxide film of each support manufactured by Examples 1 to 29 was determined by fluorescence X-ray analysis and calibration curve method.

[0798] As the standard sample used to prepare the calibration curve, a sample was obtained by uniformly dropping an aqueous solution containing a known amount of silicon atoms onto a 30 mm φ area of ​​an aluminum plate and then allowing it to dry. The determination conditions for fluorescence X-ray analysis are shown below.

[0799] Fluorescence X-ray analysis apparatus: RIX3000 manufactured by Rigaku Corporation; X-ray tube: Rh; Spectrometer: Si-Kα; Tube voltage: 50kV; Tube current: 50mA; Slit: Coarse (COARSE); Spectroscopic crystal: RX4; Detector: F-PC; Analysis area: 30mmφ; Peak position (2θ): 144.75deg; Background (2θ): 140.70deg and 146.85deg; Accumulation time: 80 s / sample

[0800] 〔evaluate〕

[0801] The following properties were evaluated for the lithographic printing plates manufactured in each embodiment and comparative example.

[0802] <Evaluation of printability (1)>

[0803] The original lithographic printing plate, prepared in the above manner, was exposed using an exposure machine (manufactured by Fujifilm Corporation, "LuxelPLATESETTER T-6000III") equipped with an infrared semiconductor laser, at an external drum speed of 1000 rpm, laser output of 70%, and a resolution of 2400 dpi (dots per inch, 1 inch is 2.54 cm). The exposed image includes a solid image and a 50% dot map with 20 μm dot FM (Frequency Modulation) halftone screening.

[0804] The obtained exposed lithographic printing plate was mounted on the plate cylinder of a printing press "SX-74" manufactured by Heidelberger Druckmaschinen AG without prior development. A 100L dampening solution circulation tank with a built-in nonwoven filter and temperature control device was connected to the printing press. Using a dampening solution of Ecolity-2 (manufactured by Fujifilm Corporation) / tap water = 2 / 98 (volume ratio) and Values-G(N) ink (manufactured by Dainippon Ink and Chemicals, Inc.), the dampening solution and ink were supplied via the standard automatic printing start-up method of the SX-74 printing press. After on-machine development, printing was carried out at a rate of 10,000 sheets per hour on TOKUBISHI ART paper (manufactured by MITSUBISHI PAPERMILLS LIMITED., continuous yield 76.5kg). In addition, to evaluate printability under harsh conditions, the above printing was performed with the circumferential speed difference (slip rate) between the printing plate cylinder and the dampening cylinder set to 9%.

[0805] As the number of printed sheets increases, the image recording layer gradually wears down, and the ink concentration on the printed material decreases. The number of printed sheets at which the density of the solid image begins to fade visually, compared to the start of printing, is used as the evaluation number of printed sheets.

[0806] Based on the number of evaluation prints obtained, printability under harsh conditions was evaluated according to the following evaluation criteria. A higher number of evaluation prints indicates better printability.

[0807] (Evaluation criteria for printability (1))

[0808] 10: The number of printed copies is 100,000 or more.

[0809] 9: The number of printed copies is evaluated as being between 90,000 and 100,000.

[0810] 8: The number of printed copies is evaluated as being between 80,000 and 90,000.

[0811] 7: The number of printed copies is evaluated as being between 70,000 and 80,000.

[0812] 6: The number of printed copies is evaluated as being between 60,000 and 70,000.

[0813] 5: The number of printed copies is evaluated as being between 50,000 and 60,000.

[0814] 4: The number of printed copies is evaluated as being between 40,000 and 50,000.

[0815] 3: The number of printed copies is evaluated as being between 30,000 and 40,000.

[0816] 2: The number of printed copies is evaluated as being between 20,000 and 30,000.

[0817] 1: Evaluation: The number of printed copies is less than 20,000.

[0818] <Evaluation of printability (2)>

[0819] The original lithographic printing plate, prepared in the above manner, was exposed using an exposure machine (manufactured by Fujifilm Corporation, "LuxelPLATESETTER T-6000III") equipped with an infrared semiconductor laser, at an external drum speed of 1000 rpm, laser output of 70%, and a resolution of 2400 dpi (dots per inch, 1 inch is 2.54 cm). The exposed image includes a solid image and a 50% dot map with 20 μm dot FM (Frequency Modulation) halftone screening.

[0820] The exposed lithographic printing plate was mounted on the plate cylinder of a printing press (manufactured by KOMORI Corporation, "LITHRONE 26") without prior development. After on-machine development using a dampening solution of Ecolity-2 (manufactured by Fujifilm Corporation) / tap water = 2 / 98 (volume ratio) and a water-based spot color ink (calcium carbonate content 20% by mass), the dampening solution and ink were supplied via the press's standard automatic printing start-up method. Printing was then performed at a rate of 10,000 sheets per hour on TOKUBISHI ART paper (manufactured by MITSUBISHI PAPER MILLS LIMITED., continuous yield 76.5 kg). Additionally, an ink containing 20% ​​by mass of calcium carbonate was used to evaluate printability under harsh conditions.

[0821] As the number of printed sheets increases, the image recording layer gradually wears down, resulting in a decrease in ink density on the printed material. The number of printed sheets at which the density of the solid image begins to fade visually, compared to the start of printing, is used as the evaluation number of printed sheets.

[0822] Based on the number of evaluation prints obtained, printability under harsh conditions was evaluated according to the following evaluation criteria. A higher number of evaluation prints indicates better printability.

[0823] (Evaluation criteria for printability (2))

[0824] 10: The number of printed copies is 100,000 or more.

[0825] 9: The number of printed copies is evaluated as being between 90,000 and 100,000.

[0826] 8: The number of printed copies is evaluated as being between 80,000 and 90,000.

[0827] 7: The number of printed copies is evaluated as being between 70,000 and 80,000.

[0828] 6: The number of printed copies is evaluated as being between 60,000 and 70,000.

[0829] 5: The number of printed copies is evaluated as being between 50,000 and 60,000.

[0830] 4: The number of printed copies is evaluated as being between 40,000 and 50,000.

[0831] 3: The number of printed copies is evaluated as being between 30,000 and 40,000.

[0832] 2: The number of printed copies is evaluated as being between 20,000 and 30,000.

[0833] 1: Evaluation: The number of printed copies is less than 20,000.

[0834] <Evaluation of in-machine developability>

[0835] The original lithographic printing plate was exposed using an exposure machine equipped with an infrared semiconductor laser (manufactured by Fujifilm Corporation, LuxelPLATESETTER T-6000III) at an outer drum speed of 1000 rpm, laser output power of 70%, and a resolution of 2400 dpi. The exposure was set to an image-style exposure that included a solid image and a 50% halftone dot plot with FM (Frequency Modulation) halftone.

[0836] The original lithographic printing plate, exposed to the image, was mounted on the printing cylinder of the "LITHRONE26" printing press (manufactured by KOMORI Corporation) without prior development. Using a dampening solution of Ecolity-2 (manufactured by Fujifilm Corporation) / tap water = 2 / 98 (volume ratio) and Values-G(N) black ink (manufactured by Dainippon Ink and Chemicals, Inc.), the dampening solution and ink were supplied via the press's standard automatic printing start-up method, followed by on-machine development. The printing was then performed at a rate of 10,000 sheets per hour on 100 sheets of TOKUBISHI ART paper (ream weight: 76.5 kg, manufactured by MITSUBISHI PAPER MILLS LIMITED.).

[0837] After on-machine development of the unexposed portion of the 50% dot pattern on the printing press, the number of sheets of printing paper required to reach a state where the ink no longer transfers to the non-image portion of the halftone dots (hereinafter also referred to as "waste paper number") was measured. Based on the measured waste paper number and the following criteria, on-machine developability was evaluated. As described below, it can be said that the lower the waste paper number, the better the on-machine developability.

[0838] (Evaluation criteria for in-machine developability)

[0839] 10: The number of damaged sheets of paper is 5 or less.

[0840] 9: The number of sheets of paper damaged is 6 to 10.

[0841] 8: The number of sheets of paper damaged is 11 to 15.

[0842] 7: The number of sheets of paper damaged is 16 to 19.

[0843] 6: The number of sheets of paper damaged is 20 to 25.

[0844] 5: The number of sheets of paper damaged is 26 to 29.

[0845] 4: The number of sheets of paper damaged is 30 to 34.

[0846] 3: The number of sheets of paper damaged is 35 to 39.

[0847] 2: The number of sheets of paper damaged is 40 to 50.

[0848] 1: The number of damaged sheets of paper is 51 or more.

[0849] <Evaluation of ink removal performance>

[0850] In the aforementioned evaluation test of on-machine developability, after obtaining a good print where the ink had not transferred to the non-image areas of the halftone dots, an evaluation test ink (made by adding varnish to ink (manufactured by DIC Corporation "Fushion-EZ(S)")) was applied to the non-image areas of the offset printing plate, and printing was restarted. The number of sheets of paper required (number of wasted sheets) from the restart until a good print where no visual contamination was obtained was measured.

[0851] Ink removal performance was evaluated based on the measured number of sheets of paper damaged, according to the following criteria. As described below, it can be said that the fewer sheets of paper damaged, the better the ink removal performance.

[0852] (Evaluation criteria for ink removal performance)

[0853] 10: The number of damaged sheets of paper is 5 or less.

[0854] 9: The number of sheets of paper damaged is 6 to 10.

[0855] 8: The number of sheets of paper damaged is 11 to 15.

[0856] 7: The number of sheets of paper damaged is 16 to 19.

[0857] 6: The number of sheets of paper damaged is 20 to 25.

[0858] 5: The number of sheets of paper damaged is 26 to 29.

[0859] 4: The number of sheets of paper damaged is 30 to 34.

[0860] 3: The number of sheets of paper damaged is 35 to 39.

[0861] 2: The number of sheets of paper damaged is 40 to 50.

[0862] 1: The number of damaged sheets of paper is 51 or more.

[0863] Table 2 shows the structure and evaluation results of the original lithographic printing plates for each embodiment and comparative example.

[0864] In the table, the "d1" column in the "Large Diameter Hole" section, "d1" max The “D1” column and the “D2” column respectively represent the average diameter d1 of the large-diameter aperture at the surface of the film and the average maximum diameter d1 inside the aperture. max And depth D1. Furthermore, the "d2" and "D2" columns in the "Small Diameter Hole" column represent the average diameter d2 and depth D2 at the connection point between the small diameter hole and the large diameter hole, respectively.

[0865] In the table, "*1" refers to the micropores formed on the anodized film in the original offset printing plates of Comparative Examples 1 and 2, which are cylindrical pores with an average diameter of 0.012 μm at the surface of the film and extending from the surface of the film to a depth of 1 μm.

[0866] [Table 3]

[0867]

[0868] As can be clearly seen from Table 2, the original lithographic printing plates of Examples 1 to 25 have superior printability compared to the original lithographic printing plates of Comparative Examples 1 and 2, which do not have a specific structure of micropores, and the original lithographic printing plates of Comparative Examples 3 and 4, which have a specific Si atomic weight of less than 0.008 mg or more than 0.14 mg.

[0869] The comparison of Examples 1 to 10 confirmed the following: when the specific Si atomic weight is 0.008 to 0.138 mg, the printability of the lithographic printing plate is better, and when the specific Si atomic weight is 0.012 to 0.035 mg, the printability of the lithographic printing plate is particularly better.

[0870] The comparison of Examples 1 and 11-14 confirmed that when the average diameter d1 of the large-diameter hole at the surface of the film is 0.022-0.040 μm, the printability of the lithographic printing plate original is superior.

[0871] The comparison of Examples 1 and 15-18 confirmed that when the depth D1 of the large-diameter hole from the surface of the film is 0.08-0.30 μm, the printability of the lithographic printing plate original is superior.

[0872] The comparison of Examples 6, 23, and 24 confirms that the printability of the lithographic printing plate original is superior by using a polymer with polymeric groups in the base coating.

[0873] Symbol Explanation

[0874] ta - Anode reaction time, tc - Cathode reaction time, tp - Time from 0 to peak current, Ia - Peak current on the anode circulation side, Ic - Peak current on the cathode circulation side, 10 - Original plate for offset printing, 11 - Support, 12 - Image recording layer, 13 - Aluminum plate, 14, 14A, 14B - Anodized film, 20, 30 - Micropores, 21, 31 - Film surface, 22, 32 - Large diameter orifice, 22A, 24A, 32A, 34A, 36A - Bottom, 23, 37, 39 - Connecting position, 24, 34 - Small diameter orifice, 36 - Large diameter orifice Upper part, 38-Large diameter hole, Lower part, 50-Main electrolytic cell, 51-AC power supply, 52-Radial drum roller, 53a, 53b-Main electrode, 54-Electrolyte supply port, 55-Electrolyte, 56-Slit, 57-Electrolyte channel, 58-Auxiliary anode, 60-Auxiliary anode tank, W-Aluminum plate, 610-Anodizing treatment device, 612-Power supply tank, 614-Electrolytic treatment tank, 616-Aluminum plate, 618, 626-Electrolyte, 620-Power supply electrode, 622, 628-Roller, 624-Clamping roller, 630-Electrolytic electrode, 632-Tank wall, 634-DC power supply.

Claims

1. An on-machine developing type lithographic printing plate master, comprising a support and an image recording layer, The support body has an aluminum plate and an anodized film disposed on the aluminum plate. The anodic oxide film has a plurality of micropores extending along the depth direction from the surface of the image recording layer side. The micropores have a large-diameter portion and a small-diameter portion. The large-diameter portion extends from the surface of the anodic oxide film to a depth of 0.05 μm to 0.50 μm. The small-diameter portion communicates with the bottom of the large-diameter portion and extends along the depth direction from the communication position. The average diameter of the large-diameter holes on the surface of the anodic oxide film is 0.015 μm to 0.070 μm. The average Si atomic weight calculated by fluorescence X-ray analysis of a circular region with a diameter of 30 mm on the surface of the anodic oxide film on the image recording layer side was 0.008 mg to 0.14 mg.

2. The on-machine developing type lithographic printing plate original according to claim 1, wherein, The density of micropores on the surface of the anodic oxide film is 200 per μm. 2 ~2000 / μm 2 .

3. The on-machine developing type lithographic printing plate original according to claim 1 or 2, wherein, The ratio of the average maximum diameter inside the large-diameter orifice to the average diameter of the large-diameter orifice at the surface of the anodic oxide film is 1.2 to 10.

0.

4. The on-machine developing type lithographic printing plate master according to claim 1 or 2, further comprising a base coating layer disposed between the support and the image recording layer. The base coating comprises a polymer having support adsorption groups and hydrophilic groups.

5. The on-machine developing type lithographic printing plate original according to claim 4, wherein, The polymer has support adsorption groups, hydrophilic groups, and polymerizable groups.

6. The on-machine developing type lithographic printing plate original according to claim 4, wherein, The hydrophilic group has a zwitterionic structure.

7. The on-machine developing type lithographic printing plate original according to claim 1 or 2, wherein, The image recording layer contains an infrared absorber.

8. The on-machine developing type lithographic printing plate original according to claim 7, wherein, The infrared absorber has substituents that are decomposed by infrared radiation or heat.

9. The on-machine developing type lithographic printing plate original according to claim 1 or 2, wherein, The image recording layer contains a borate compound.

10. The on-machine developing type lithographic printing plate original according to claim 1 or 2, wherein, The image recording layer contains an acid colorant.

11. The on-machine developing type lithographic printing plate original according to claim 1 or 2, wherein, The average Si atomic weight calculated by fluorescence X-ray analysis of a circular region with a diameter of 30 mm on the surface of the anodic oxide film on the image recording layer side was 0.010 mg to 0.080 mg.

12. The on-machine developing type lithographic printing plate original according to claim 1 or 2, wherein, The average Si atomic weight calculated by fluorescence X-ray analysis of a circular region with a diameter of 30 mm on the surface of the anodic oxide film on the image recording layer side was 0.011 mg to 0.060 mg.

13. A method for manufacturing a lithographic printing plate, the method comprising: The exposure process involves exposing the image recording layer of the original on-machine developing type lithographic printing plate as described in claim 1 or 2 in an image-like manner, thereby forming an exposed portion and an unexposed portion. and The on-machine developing process involves supplying at least one of printing ink and dampening solution to a printing press to remove the unexposed portions of the image recording layer after exposure in an image-like manner, thereby producing a lithographic printing plate.

14. A printing method comprising: The exposure process involves exposing the image recording layer of the original on-machine developing type lithographic printing plate as described in claim 1 or 2 in an image-like manner, thereby forming an exposed portion and an unexposed portion. The on-machine developing process involves supplying at least one of printing ink and dampening solution to a printing press to remove unexposed portions of the image recording layer after exposure in an image-like manner, thereby creating a lithographic printing plate; and The printing process involves printing using the prepared lithographic printing plate.

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