On-press developing type lithographic printing plate precursor, method for producing lithographic printing plate, lithographic printing method, and color developing agent

Abstract

Provided is an on-press development type lithographic printing plate precursor, a method for producing a lithographic printing plate using the on-press development type lithographic printing plate precursor, a lithographic printing method, and a color former represented by Formula 1 or Formula 2. The on-press development type lithographic printing plate precursor has a support and an image recording layer on the support, and the image recording layer contains a compound represented by Formula 1 or Formula 2 and an organic compound having a Group 13 element. In Formula 1 and Formula 2, R 1 ~R 7 independently represent a hydrogen atom or a monovalent organic group, L 1 and L 2 represent a divalent organic group.

Description

TECHNICAL FIELD

[0001] The present application relates to an on-press development type lithographic printing plate precursor, a method for producing a lithographic printing plate, a lithographic printing method, and a color developing agent. BACKGROUND

[0002] Generally, a lithographic printing plate is composed of an oleophilic image portion that accepts ink in a printing process and a hydrophilic non-image portion that accepts dampening water. Lithographic printing is a method in which, by utilizing the property that water and oily ink repel each other, the oleophilic image portion of a lithographic printing plate is made as an ink-accepting portion, the hydrophilic non-image portion is made as a dampening water-accepting portion (non-ink-accepting portion), a difference in the adhesiveness of ink is created on the surface of the lithographic printing plate, and the ink is caused to be attached only to the image portion, after which the ink is transferred to a printed matter such as paper to perform printing.

[0003] In order to produce this lithographic printing plate, conventionally, a lithographic printing plate precursor (PS plate) in which an oleophilic photosensitive resin layer (image-recording layer) is provided on a hydrophilic support body has been widely used. Generally, a lithographic printing plate is obtained by producing a plate by the following method: after the lithographic printing plate precursor is exposed to light through an original image such as a high-contrast film, the portion of the image-recording layer that becomes the image portion is left remaining, and the unnecessary image-recording layer other than this is dissolved and removed by an alkali developer or an organic solvent, thereby exposing the surface of the hydrophilic support body and forming the non-image portion.

[0004] Furthermore, as the concern for the global environment has been increasing, environmental problems related to waste liquid accompanying wet processing such as development processing have become apparent.

[0005] In view of the above environmental problems, simplification and processing-free of development or plate production are being directed. As one of the simple production methods, a method called "on-press development" is performed. That is, on-press development is a method in which, after a lithographic printing plate precursor is exposed to light, the lithographic printing plate precursor is directly mounted to a printing machine without being subjected to the conventional development, and the removal of the unnecessary portion of the image-recording layer is performed at the initial stage of the usual printing process.

[0006] In the present application, a lithographic printing plate precursor that can be used for such on-press development is referred to as an "on-press development type lithographic printing plate precursor".

[0007] As a conventional photosensitive composition, for example, the composition described in Patent Document 1 can be given.

[0008] In Patent Document 1, a photosensitive composition containing 0.01 mass% to 5 mass% of curcumin is described.

[0009] Patent Document 1: U.S. Patent Application Publication No. 2005 / 0130064 SUMMARY

[0010] Technical problem to be solved by the invention

[0011] An embodiment of the present invention aims to provide an on-press development type lithographic printing plate precursor excellent in ink turbidity inhibition and visual recognition over time.

[0012] Another embodiment of the present invention aims to provide a method for producing a lithographic printing plate or a lithographic printing method using the above-described on-press development type lithographic printing plate precursor.

[0013] Still another embodiment of the present invention aims to provide a color developer excellent in color development of an organic compound having a Group 13 element.

[0014] Means for solving the technical problem

[0015] Among the means for solving the above-described problem, the following means are included.

[0016] <1> An on-press development type lithographic printing plate precursor having: a support; and an image recording layer on the support, the image recording layer containing a compound represented by Formula 1 or Formula 2 described below and an organic compound having a Group 13 element.

[0017] [Chemical Formula 1]

[0018]

[0019] In Formula 1 and Formula 2, R 1 to R 7 independently represent a hydrogen atom or a monovalent organic group, L 1 and L 2 represent a divalent organic group, L 1 , R 2 , and R 3 , 2 or more groups of L 2 , R 4 , and R 6 , and 2 or more groups of L 2 , R 5 , and R 7 may be linked to form a ring structure.

[0020] <2> The on-press development type lithographic printing plate precursor according to <1>, wherein

[0021] The above-described organic compound having a Group 13 element is an electron-donating polymerization initiator.

[0022] <3> The on-press development type lithographic printing plate precursor according to <2>, wherein

[0023] The above electron-donating polymerization initiator has an electron-withdrawing group.

[0024] <4> The on-press development type lithographic printing plate precursor according to any one of <1> to <3>, wherein

[0025] The compound represented by the above formula 1 or formula 2 has a proportion of the keto form or imine form at 25°C of 10 mol% or more.

[0026] <5> The on-press development type lithographic printing plate precursor according to any one of <1> to <4>, wherein

[0027] The compound represented by the above formula 1 or formula 2 includes a compound having a ring structure.

[0028] <6> The on-press development type lithographic printing plate precursor according to any one of <1> to <5>, wherein

[0029] The compound represented by the above formula 1 or formula 2 includes a compound having two or more ring structures.

[0030] <7> The on-press development type lithographic printing plate precursor according to any one of <1> to <6>, wherein

[0031] The compound represented by the above formula 1 or formula 2 includes a compound having an electron-donating group on an aromatic ring.

[0032] <8> The on-press development type lithographic printing plate precursor according to any one of <1> to <7>, wherein

[0033] The content of the compound represented by the above formula 1 or formula 2 is 0.05 mass% to 2.5 mass% with respect to the total mass of the above image recording layer.

[0034] <9> The on-press development type lithographic printing plate precursor according to any one of <1> to <8>, wherein

[0035] The above image recording layer further includes an electron-accepting polymerization initiator.

[0036] <10> The on-press development type lithographic printing plate precursor according to <9>, wherein

[0037] The above electron-accepting polymerization initiator includes a compound represented by the following formula (II).

[0038] [Chemical Formula 2]

[0039]

[0040] In formula (II), X A represents a halogen atom, R A represents an aryl group.

[0041] <11> The on-press development type lithographic printing plate precursor according to any one of <1> to <10>, wherein

[0042] The above-mentioned organic compound having a Group 13 element includes a compound formed of a cation having an electron-accepting polymerization initiator structure and an anion having an electron-donating polymerization initiator structure to form a counter salt.

[0043] <12> The on-press development type lithographic printing plate precursor according to any one of <1> to <11>, wherein

[0044] The above-mentioned image recording layer further contains a polar organic solvent.

[0045] <13> The on-press development type lithographic printing plate precursor according to <12>, wherein

[0046] The above-mentioned polar organic solvent is at least one solvent selected from the group consisting of dimethyl sulfoxide and N-methylpyrrolidone.

[0047] <14> A method for producing a lithographic printing plate, comprising: a step of exposing the on-press development type lithographic printing plate precursor according to any one of <1> to <13> to an image shape; and a step of supplying at least one selected from the group consisting of a printing ink and a dampening solution on a printing press to remove the image recording layer of a non-image portion.

[0048] <15> A lithographic printing method, comprising: a step of exposing the on-press development type lithographic printing plate precursor according to any one of <1> to <13> to an image shape; a step of supplying at least one selected from the group consisting of a printing ink and a dampening solution to remove the image recording layer of a non-image portion on a printing press to produce a lithographic printing plate; and a step of performing printing using the obtained lithographic printing plate.

[0049] <16> A color developing agent represented by the following Formula 1 or Formula 2.

[0050] [Chemical Formula 3]

[0051]

[0052] In Formula 1 and Formula 2, R 1 ~R 7 each independently represent a hydrogen atom or a monovalent organic group, L 1 and L 2 represent a divalent organic group, L 1 , R 2 and R 3 , 2 or more groups of L 2 , R 4 and R 6 , and 2 or more groups of L 2 , R5 and two or more groups in R 7 two or more groups in R

[0053] <17> The color developing agent according to <16>, wherein

[0054] The color developing agent represented by the above formula 1 or formula 2 has a proportion of a keto form or an imine form of 10 mol% or more at 25°C.

[0055] <18> The color developing agent according to <16> or <17>, wherein

[0056] The color developing agent represented by the above formula 1 or formula 2 contains a compound having a ring structure.

[0057] <19> The color developing agent according to any one of <16> to <18>, wherein

[0058] The color developing agent represented by the above formula 1 or formula 2 contains a compound having two or more ring structures.

[0059] <20> The color developing agent according to any one of <16> to <19>, wherein

[0060] The color developing agent represented by the above formula 1 or formula 2 is a compound having an electron-donating group on an aromatic ring.

[0061] Effects of the Invention

[0062] According to an embodiment of the present invention, it is possible to provide an on-press development type lithographic printing plate precursor excellent in ink turbidity suppression and visual recognition over time.

[0063] Further, according to another embodiment of the present invention, it is possible to provide a method for producing a lithographic printing plate using the above-described on-press development type lithographic printing plate precursor or a lithographic printing method.

[0064] According to still another embodiment of the present invention, it is possible to provide a color developing agent excellent in color development of an organic compound having a Group 13 element. BRIEF DESCRIPTION OF DRAWINGS

[0065] Figure 1 is a schematic cross-sectional view of an embodiment of an aluminum support body preferably used in the present invention.

[0066] Figure 2 is a schematic cross-sectional view of an embodiment of an aluminum support body having an anodized film.

[0067] Figure 3 is a schematic view of an anodizing treatment device used in an anodizing treatment in a method for producing an aluminum support body having an anodized film. DETAILED DESCRIPTION

[0068] Hereinafter, the contents of the present application will be described in detail. The description of the constitutional elements described below is based on representative embodiments of the present application, but the present application is not limited to such embodiments.

[0069] In addition, in the present specification, "~" indicating a numerical range is used in the meaning that the numerical values recited before and after it are included as lower limit values and upper limit values.

[0070] Also, in the notation of groups (radicals) in the present specification, the notation of substituted and unsubstituted includes not only groups having no substituent (unsubstituted groups), but also groups having a substituent (substituted groups). For example, "alkyl" includes not only alkyl groups having no substituent (unsubstituted alkyl groups), but also alkyl groups having a substituent (substituted alkyl groups).

[0071] In the present specification, "(meth)acrylic acid" is a term used as a meaning including both acrylic acid and methacrylic acid, and "(meth)acryloyl" is a term used as a meaning including both acryloyl and methacryloyl.

[0072] Also, the term "step" in the present specification includes not only a single step, but also, even in a case where it cannot be clearly distinguished from other steps, as long as the intended purpose of the step can be achieved, it is included in the term. Also, in the present application, the definition of "mass%" is the same as that of "weight%", and the definition of "mass parts" is the same as that of "weight parts".

[0073] As long as there is no particular limitation, in the present application, each component in the composition or each constitutional unit in the polymer can be contained singly as one kind, or two or more kinds can be used in combination.

[0074] Also, in the present application, as for the amount of each component in the composition or each constitutional unit in the polymer, in a case where a plurality of substances or constitutional units corresponding to each component in the composition or each constitutional unit in the polymer is present, as long as there is no particular description, it means the total amount of the corresponding plurality of substances present in the composition or the corresponding plurality of each constitutional unit present in the polymer.

[0075] Also, in the present application, a combination of two or more preferred modes is more preferred.

[0076] Further, unless otherwise specified, the weight average molecular weight (Mw) and the number average molecular weight (Mn) in the present application are molecular weights calculated as polystyrene by using a gel permeation chromatography (GPC) analysis device using a column of TSKgel GMHxL, TSKgel G4000HxL, TSKgel G2000HxL (all are trade names manufactured by TOSOH CORPORATION), and by solvent THF (tetrahydrofuran), differential refractometer detection, and using polystyrene as a standard substance.

[0077] In the present application, the term "lithographic printing plate precursor" includes not only a lithographic printing plate precursor but also a waste plate precursor. Further, the term "lithographic printing plate" includes not only a lithographic printing plate produced by performing an operation such as exposure and development on a lithographic printing plate precursor as needed but also a waste plate. In the case of a waste plate precursor, an operation such as exposure and development is not necessarily required. In addition, a waste plate refers to a lithographic printing plate precursor used for mounting on an unused printing plate cylinder in the case where a part of a page is printed in monochrome or in two colors, for example, in color newspaper printing.

[0078] In the present application, "excellent printing durability" means that the number of printable sheets of a lithographic printing plate is large. Hereinafter, the printing durability when a UV-curable ink (UV ink) is used as an ink at the time of printing will be referred to as "UV printing durability".

[0079] Hereinafter, the present application will be described in detail.

[0080] (On-press developing type lithographic printing plate precursor)

[0081] The on-press developing type lithographic printing plate precursor according to the present application has: a support; and an image recording layer on the support, the image recording layer containing a compound represented by the following Formula 1 or Formula 2 and an organic compound having a Group 13 element.

[0082] [Chemical Formula 4]

[0083]

[0084] In Formula 1 and Formula 2, R 1 ~R 7 respectively independently represent a hydrogen atom or a monovalent organic group, L 1 and L 2 represent a divalent organic group, L 1 , R 2 and R 3 of two or more groups, L 2 , R 4 and R 6 of two or more groups, and L 2 , R5 two or more groups in R 7 two or more groups in R

[0085] Further, the on-press development type lithographic printing plate precursor according to the present application can be either a negative type or a positive type, but is preferably a negative type.

[0086] The present inventors have found that the color of ink in a printed image is sometimes turbid in the conventional on-press development type lithographic printing plate precursor.

[0087] As a result of intensive studies by the present inventors, it has been found that the on-press development type lithographic printing plate precursor having the above structure can provide excellent ink turbidity inhibition.

[0088] The detailed mechanism by which the above effects are obtained is not clear, but is presumed as follows.

[0089] It is presumed that the compound represented by the above Formula 1 or Formula 2 functions as a color developer, but the compound represented by Formula 1 or Formula 2 is a non-conjugated ketone type compound, and thus the compound itself has little coloring. Therefore, it is presumed that even if the compound represented by the above Formula 1 or Formula 2 contained in the above image recording layer dissolves out into the ink, the effect on the color tone of the ink is small, and ink turbidity can be inhibited.

[0090] Further, it is presumed that the on-press development type lithographic printing plate precursor according to the present application, by virtue of the above image recording layer containing the compound represented by the above Formula 1 or Formula 2 and the organic compound having a Group 13 element, the compound represented by the above Formula 1 or Formula 2 captures the organic compound having a Group 13 element as such or a decomposition product produced by the organic compound having a Group 13 element by exposure, and develops color by modification to an enol type, and the degree of color development or color change in the exposed portion becomes higher, and thus the visual recognition of the exposed portion over time is also excellent.

[0091] Hereinafter, the details of each of the components in the lithographic printing plate precursor according to the present application will be described.

[0092] <IMAGE RECORDING LAYER>

[0093] The on-press development type lithographic printing plate precursor according to the present application has an image recording layer, and the above image recording layer contains the compound represented by the above Formula 1 or Formula 2 and the organic compound having a Group 13 element.

[0094] The image recording layer used in the present application is preferably a negative type, and more preferably a water-soluble or water-dispersible negative type.

[0095] As for the lithographic printing plate precursor according to the present application, from the viewpoint of on-press developability, it is preferred that the unexposed portion of the image-recording layer be removable by at least either of a fountain solution or a printing ink.

[0096] [compound represented by formula 1 or formula 2]

[0097] The above-mentioned image-recording layer contains a compound represented by the above-mentioned formula 1 or formula 2.

[0098] Further, the compound represented by the above-mentioned formula 1 or formula 2 is preferably a color developing agent, and more preferably a compound which undergoes a color developing reaction with the above-mentioned organic compound having a Group 13 element or a decomposition product produced by exposure to the above-mentioned organic compound having a Group 13 element.

[0099] The "color developing reaction" in the present application refers to a chemical reaction accompanying a color development or a color change phenomenon.

[0100] Further, as the decomposition product produced by the above-mentioned exposure, not only a decomposition product produced by the above-mentioned exposure, but also a compound produced by further decomposition or modification of the above-mentioned decomposition product is included.

[0101] Further, from the viewpoint of visual recognition of the exposed portion, the above-mentioned color developing reaction is preferably a complex formation reaction, and more preferably a boron complex formation reaction.

[0102] An example of the above-mentioned color developing reaction is shown below. An example is shown below in which C-1 is used as the compound represented by the above-mentioned formula 1 or formula 2, sodium tetraphenylborate is used as the decomposition product produced by exposure to the image-recording layer, and sodium tetraphenylborate is decomposed and boronic acid is produced via triphenylboron (BPh3) as the compound having a Group 13 element. Due to keto-enol tautomerism, C-1 produces an enol form as an equilibrium. By reacting the above-mentioned enol form with boronic acid, the following boron complex (Complex) is produced, and a color developing reaction from C-1 (colorless to light yellow) to the following boron complex (orange to red) is produced.

[0103] Further, the following shows an example of hydrolysis to boronic acid, but for example, diphenyl monohydroxyboron, monophenyl dihydroxyboron, or the like can form a complex with C-1, and triphenylboron can coordinate with the enol form C-1 as a ligand of zero valence, and form a complex.

[0104] [Chemical Formula 5]

[0105]

[0106] As the compound represented by the above formula 1 or formula 2, from the viewpoints of ink turbidity inhibitory property, visual recognition degree of the exposed portion, and visual recognition degree of the exposed portion over time, a compound having one or more 1,3-diimine structures, a ketone structure having a heteroaromatic group having a nitrogen atom at an ortho position at a β position, or a methine structure having two or more heteroaromatic groups having a nitrogen atom at an ortho position is preferred, a compound having one or more 1,3-diimine structures or a ketone structure having a heteroaromatic group having a nitrogen atom at an ortho position at a β position is more preferred, and a compound having one or more ketone structures having a heteroaromatic group having a nitrogen atom at an ortho position at a β position is particularly preferred.

[0107] Further, as the compound represented by the above formula 1 or formula 2, a compound having one or more enamine structures having a heteroaromatic group having a nitrogen atom at an ortho position or imine structures having a heteroaromatic group having a nitrogen atom at an ortho position at a β position can also be given.

[0108] Further, as the above heteroaromatic group having a nitrogen atom at an ortho position, from the viewpoints of ink turbidity inhibitory property, visual recognition degree of the exposed portion, and visual recognition degree of the exposed portion over time, a 2-pyrazinyl group, 5-methyl-2-pyrazinyl group, 2-pyrimidinyl group, 2-pyridyl group, 4-trifluoromethyl-2-pyridyl group, 4-trifluoromethyl-6-chloro-2-pyridyl group, 4,6-bistrifluoromethyl-2-pyridyl group, 2-benzothiazolyl group, 2-naphthothiazolyl group, 2-quinoxalinyl group, or 3-methyl-2-quinoxalinyl group is preferred, a 2-pyrazinyl group, 5-methyl-2-pyrazinyl group, 2-pyrimidinyl group, 2-pyridyl group, 4-trifluoromethyl-2-pyridyl group, 4-trifluoromethyl-6-chloro-2-pyridyl group, or 4,6-bistrifluoromethyl-2-pyridyl group is more preferred, and a 2-pyrazinyl group, 5-methyl-2-pyrazinyl group, or 2-pyrimidinyl group is particularly preferred.

[0109] Further, the compound represented by the above formula 1 or formula 2 can be a salt or a hydrate.

[0110] Further, as the compound represented by the above formula 1 or formula 2, in the case where a complex is formed by reacting with a decomposition product generated by exposure of the above image recording layer, in the above complex, it can be a monodentate ligand or a polydentate ligand, but from the viewpoints of complex formation property, ink turbidity inhibitory property, visual recognition degree of the exposed portion, and visual recognition degree of the exposed portion over time, a polydentate ligand is preferred, a bidentate to hexadentate ligand is more preferred, a bidentate to tetradentate ligand is further preferred, and a bidentate or tridentate ligand is particularly preferred, with a bidentate ligand being most preferred.

[0111] Further, in the on-press development type lithographic printing plate precursor according to the present application, it is preferred that, after exposure, the compound represented by the above formula 1 or formula 2 reacts with a decomposition product generated by exposure of the above-mentioned organic compound having a Group 13 element, to form a complex having a compound represented by the above formula 1 or formula 2 as a ligand of zero valence or having an anion obtained by removing one hydrogen atom from a compound represented by the above formula 1 or formula 2 as a ligand of one valence, and it is more preferred that the compound represented by the above formula 1 or formula 2 reacts with a decomposition product generated by exposure of the above-mentioned image-recording layer, to form a complex having an anion obtained by removing one hydrogen atom from a compound represented by the above formula 1 or formula 2 as a ligand of one valence.

[0112] From the viewpoints of ink turbidity inhibitory property, visual recognition degree of the exposed portion, and visual recognition degree of the exposed portion over time, the compound represented by the above formula 1 or formula 2 preferably contains a compound having a ring structure.

[0113] Further, from the viewpoints of ink turbidity inhibitory property, visual recognition degree of the exposed portion, and visual recognition degree of the exposed portion over time, the compound represented by the above formula 1 or formula 2 more preferably contains a compound having two or more ring structures.

[0114] Furthermore, from the viewpoints of ink turbidity inhibitory property, visual recognition degree of the exposed portion, and visual recognition degree of the exposed portion over time, the compound represented by the above formula 1 or formula 2 more preferably contains a compound having an electron-donating group on an aromatic ring.

[0115] In formula 1, L 1 , R 2 , and R 3 may be bonded to form a ring structure.

[0116] In formula 2, L 2 , R 4 , and R 6 may be bonded to form a ring structure, and L 2 , R 5 , and R 7 may be bonded to form a ring structure.

[0117] Further, the above-mentioned ring structure is preferably an aromatic ring structure or a heteroaromatic ring structure.

[0118] From the viewpoints of ink turbidity inhibitory property, visual recognition degree of the exposed portion, and visual recognition degree of the exposed portion over time, R 1 in formula 1 is preferably a monovalent organic group having an aromatic ring, more preferably an aryl group, and particularly preferably a phenyl group, a 4-dialkylaminophenyl group, or a 4-diarylamino phenyl group.

[0119] Furthermore, from the perspectives of ink turbidity suppression, visual recognition of the exposed area, and visual recognition of the exposed area over time, R in Equation 1... 1 Preferably, it is an aryl group having an electron-donating group.

[0120] Moreover, R in Equation 1 1 The number of carbon atoms is preferably 6 to 50, more preferably 6 to 20, and especially preferably 8 to 20.

[0121] In Equation 1, from the viewpoints of ink turbidity suppression, visual recognizability of the exposed area, and visual recognizability of the exposed area over time, R is preferred. 2 and R 3 They bond together to form a ring structure.

[0122] As R 2 and R 3 From the viewpoints of ink turbidity suppression, visual recognition of the exposed area, and visual recognition of the exposed area over time, the bonded ring structure is preferably a pyridine ring structure, a pyrazine ring structure, a pyrimidine ring structure, a benzothiazole structure, or a naphthothiazole structure; more preferably a pyridine ring structure, a pyrazine ring structure, or a pyrimidine ring structure; even more preferably a pyrazine ring structure or a pyrimidine ring structure; and especially preferably a pyrazine ring structure.

[0123] Furthermore, the aforementioned ring structure may have substituents, such as halogen atoms, alkyl groups, amino groups, alkylamino groups, dialkylamino groups, alkylarylamino groups, diarylamino groups, alkoxy groups, cyano groups, alkoxycarbonyl groups, acyl groups, and acyloxy groups. Moreover, the aforementioned substituents may be further substituted by other substituents.

[0124] R in Equation 1 2 and R 3 When bonding does not form a ring structure, the following method is preferred.

[0125] From the perspective of visual recognizability of the exposure area, R in Equation 1 2 Preferably, it is a monovalent organic group, more preferably an alkyl or aryl group, and especially preferably an aryl group.

[0126] From the perspective of visual recognizability of the exposure area, R in Equation 1 3 Preferably, it contains hydrogen atoms, alkyl groups, or aryl groups.

[0127] R in Equation 1 2 The number of carbon atoms is preferably 1 to 50, more preferably 6 to 20.

[0128] Furthermore, R in Equation 1 3 The number of carbon atoms is preferably 0 to 50, more preferably 0 to 20.

[0129] From the viewpoints of ink turbidity inhibitory property, visual recognition degree of the exposed portion, and visual recognition degree of the exposed portion over time, L in Formula 1 1 is preferably an alkylene group or an alkylene group having an acyloxy group, more preferably a methylene group or a methylene group having an acyloxy group, and particularly preferably a methylene group.

[0130] Further, from the viewpoints of visual recognition degree of the exposed portion and visual recognition degree of the exposed portion over time, the acyloxy group is preferably an acyloxy group having 1 to 10 carbon atoms, more preferably an acyloxy group having 1 to 4 carbon atoms, and particularly preferably an acetyloxy group.

[0131] From the viewpoints of ink turbidity inhibitory property, visual recognition degree of the exposed portion, and visual recognition degree of the exposed portion over time, R 4 and R 5 in Formula 2 are each independently preferably a monovalent organic group having an aromatic ring, more preferably an aryl group, and particularly preferably a phenyl group, a 4-dialkylaminophenyl group, or a 4-trifluoromethylphenyl group.

[0132] Further, from the viewpoints of ink turbidity inhibitory property, visual recognition degree of the exposed portion, and visual recognition degree of the exposed portion over time, the aryl group is preferably an aryl group having an electron-donating group.

[0133] Further, the number of carbon atoms of R 4 and R 5 in Formula 2 is each independently preferably 6 to 50, more preferably 6 to 20, and particularly preferably 8 to 20.

[0134] In Formula 2, from the viewpoints of ink turbidity inhibitory property, visual recognition degree of the exposed portion, and visual recognition degree of the exposed portion over time, it is preferable that R 4 and R 6 be bonded to form a ring structure, and that R 5 and R 7 be bonded to form a ring structure.

[0135] As the ring structure formed by the bonding of R 4 and R 6 or R 5 and R 7 , from the viewpoints of ink turbidity inhibitory property, visual recognition degree of the exposed portion, and visual recognition degree of the exposed portion over time, it is preferable that the ring structure be a pyridine ring structure, a pyrazine ring structure, a pyrimidine ring structure, a benzothiazole structure, or a naphthothiazole structure, more preferably a pyridine ring structure, a pyrazine ring structure, or a pyrimidine ring structure, and particularly preferably a pyridine ring structure.

[0136] Further, the ring structure can have the substituent described above.

[0137] In Formula 2, from the viewpoints of ink turbidity inhibitory property, visual recognition degree of the exposed portion, and visual recognition degree of the exposed portion over time, it is preferable that R 4 and R 6 , or R5 and R 7 When bonding does not form a ring structure, the following method is preferred.

[0138] R in Equation 2 4 and R 5 Each organic group is preferably a monovalent organic group, more preferably an alkyl or aryl group, and especially preferably an aryl group.

[0139] From the perspective of visual recognizability of the exposure area, R in Equation 2 6 and R 7 Each of the following is preferably a hydrogen atom, an alkyl group, or an aryl group.

[0140] R in Equation 2 4 and R 5 The number of carbon atoms in each is preferably 1 to 50, more preferably 6 to 20.

[0141] Furthermore, R in Equation 2 6 and R 7 The number of carbon atoms in each is preferably 0 to 50, more preferably 0 to 20.

[0142] From the perspectives of ink turbidity suppression, visual recognizability of the exposed area, and visual recognizability of the exposed area over time, L in Equation 2 2 Preferably, it is an alkylene group or an alkylene group having a cyano group, more preferably a methylene group or a methylene group having a cyano group.

[0143] The compound represented by Formula 1 can be a polymer, in which case R in the compound represented by Formula 1 2 Preferably, the linker group is -C (=NR). 3 )-L 1 -C(=O)-R 1 Furthermore, in the case of forming a polymer, preferably a dimer, two R groups are preferred. 2 and 2 Rs 3 They bond together to form a heteroaromatic ring having two or more nitrogen atoms, more preferably a pyrazine ring.

[0144] Furthermore, the compound represented by Formula 2 can be a polymer, in which case R in the compound represented by Formula 2 5 Preferably, the linker group is -C (=NR). 7 )-L 2 -C (=NR) 6 -R 4 Furthermore, in the case of forming a polymer, preferably a dimer, two R groups are preferred. 5 and 2 Rs 7 They bond together to form a heteroaromatic ring having two or more nitrogen atoms, more preferably a pyrazine ring.

[0145] From the viewpoints of the ink turbidity inhibitory property, the visual recognition degree of the exposed portion, and the visual recognition degree of the exposed portion over time, the proportion of the keto form or the imine form of the compound represented by the above formula 1 or formula 2 at 25°C is preferably 1 mol% or more, more preferably 10 mol% or more, further preferably 20 mol% or more, and particularly preferably 50 mol% or more and 100 mol% or less.

[0146] The method for measuring the proportion of the keto form or the imine form in the present application is as follows.

[0147] The sample 1.0 mg was dissolved in 0.5 mL of deuterated chloroform CDCl3 (manufactured by FUJIFILM Wako Pure Chemical Corporation), and NMR (manufactured by Bruker) measurement was performed at 25°C. The peak values of the CH2 group or the CHR group (R represents an arbitrary group corresponding to the compound contained in the sample to be measured) of the keto form and the CH group of the enol form are different, and therefore the proportion (mol%) of the keto form was calculated from the respective integral ratios. The imine form was also calculated by the same method.

[0148] From the viewpoints of the complex formation property, the ink turbidity inhibitory property, the visual recognition degree of the exposed portion, and the visual recognition degree of the exposed portion over time, the molecular weight of the compound represented by the above formula 1 or formula 2 is preferably 200 to 1,500, more preferably 200 to 800, further preferably 200 to 600, and particularly preferably 250 to 600.

[0149] As the compound represented by the above formula 1 or formula 2, specifically, the following C-1 to C-17 can be preferably selected. In addition, Me represents a methyl group, Ph represents a phenyl group, and t-Bu represents a tert-butyl group.

[0150] [Chemical Formula 6]

[0151]

[0152] [Chemical Formula 7]

[0153]

[0154] [Chemical Formula 8]

[0155]

[0156] The compound represented by the above formula 1 or formula 2 can be used only one kind, or two or more kinds can be used at the same time.

[0157] Furthermore, the above complex can be formed only one kind, or two or more kinds can be formed.

[0158] From the viewpoints of complex formation property, ink turbidity inhibitory property, visual recognition degree of the exposed portion, and visual recognition degree of the exposed portion over time, the content of the compound represented by the above Formula 1 or Formula 2 with respect to the total mass of the above image recording layer is preferably 0.001 mass% to 5 mass%, more preferably 0.01 mass% to 3 mass%, further preferably 0.05 mass% to 2.5 mass%, and particularly preferably 0.05 mass% to 1.0 mass%.

[0159] From the viewpoints of complex formation property, ink turbidity inhibitory property, visual recognition degree of the exposed portion, and visual recognition degree of the exposed portion over time, the content M of the compound represented by the above Formula 1 or Formula 2 in the above image recording layer is preferably 0.001 to 1.5, more preferably 0.01 to 1, further preferably 0.05 to 0.8. C The molar ratio of the content M of the above-mentioned organic compound having a Group 13 element to the content M of the above-mentioned organic compound having a Group 13 element described later is preferably M DI = 0.001 to 1.5, more preferably M C = 0.01 to 1, further preferably M DI = 0.05 to 0.8. C DI C DI

[0160] [Organic compound having a Group 13 element]

[0161] The image recording layer in the lithographic printing plate precursor according to the present application contains an organic compound having a Group 13 element, and as the organic compound having a Group 13 element, an electron-donating polymerization initiator (also referred to as "polymerization aid") is preferably contained.

[0162] The electron-donating polymerization initiator is a compound that generates a polymerization initiator species such as a radical when one electron is supplied to the orbital from which one electron of the infrared absorber is detached through intermolecular electron movement when the electron of the infrared absorber is excited or moves within the molecule by infrared exposure.

[0163] As the electron-donating polymerization initiator, an electron-donating radical polymerization initiator is preferably used.

[0164] From the viewpoints of ink turbidity inhibitory property, visual recognition degree of the exposed portion, and visual recognition degree of the exposed portion over time, the organic compound having a Group 13 element, and the electron-donating polymerization initiator are preferably a boron compound, more preferably a borate compound, further preferably a tetraaryl borate compound, and particularly preferably a tetraphenyl borate compound.

[0165] From the viewpoints of ink turbidity inhibitory property, visual recognition degree of the exposed portion, and visual recognition degree of the exposed portion over time, the above electron-donating polymerization initiator preferably has an electron-withdrawing group.

[0166] ​​​​As the borate compound, from the viewpoints of print durability and visual recognition, a tetraarylborate compound or a monoalkyltriaarylborate compound is preferred, and a tetraarylborate compound is more preferred.

[0167] As the borate compound, from the viewpoints of print durability and visual recognition, a tetraarylborate compound or a monoalkyltriaarylborate compound is preferred, and a tetraarylborate compound is more preferred.

[0168] As the above-mentioned electron-withdrawing group, from the viewpoints of decomposability and visual recognition, a halogen atom, a halogenated alkyl group, an acyl group, a carboxyl group, and the like can be mentioned.

[0169] As the counter cation of the borate compound, there is no particular limitation, but an alkali metal ion or a tetraalkylammonium ion is preferred, and a sodium ion, a potassium ion, or a tetrabutylammonium ion is more preferred.

[0170] As the counter cation of the borate compound, among the infrared absorbers described in the present specification, a cationic polyformazan dye can be mentioned. For example, as the counter cation of a cyanine dye, the above-mentioned borate compound can be used.

[0171] As the borate compound, specifically, sodium tetraphenylborate is preferred.

[0172] The following shows B-1 to B-9 as preferred specific examples of the electron-donating polymerization initiator, and of course, is not limited to these. In the following chemical formulas, Ph represents a phenyl group, and Bu represents an n-butyl group.

[0173] [Chemical Formula 9]

[0174]

[0175] Further, from the viewpoint of improving sensitivity, the highest occupied orbital (HOMO) of the electron-donating polymerization initiator is preferably -6.00 eV or higher, more preferably -5.95 eV or higher, further preferably -5.93 eV or higher, and particularly preferably greater than -5.90 eV.

[0176] Further, as the upper limit, -5.00 eV or lower is preferred, and -5.40 eV or lower is more preferred.

[0177] The organic compound having a Group 13 element can be used alone or two or more kinds can be used at the same time.

[0178] The content of the organic compound having a Group 13 element, preferably the above-mentioned electron-donating polymerization initiator, is preferably 0.01 to 30 mass%, more preferably 0.05 to 25 mass%, and further preferably 0.1 to 20 mass%, relative to the total mass of the image-recording layer, from the viewpoints of ink turbidity inhibition, visual recognition of the exposed portion, and visual recognition of the exposed portion over time.

[0179] Also, from the viewpoint of UV printing durability, the content of the organic compound having a Group 13 element, preferably the above-mentioned electron-donating polymerization initiator, in the image-recording layer is preferably more than the content of the infrared absorber, more preferably 1.05 to 5 times the content of the infrared absorber, and particularly preferably 1.1 to 3 times the content of the infrared absorber.

[0180] In the present application, the organic compound having a Group 13 element can be a compound in which an electron-donating polymerization initiator and a later-described electron-accepting polymerization initiator form a counter salt.

[0181] For example, in the present application, a compound in which the anion in the electron-donating polymerization initiator and the cation in the electron-accepting polymerization initiator form a counter salt is preferred, a compound in which an onium cation and a borate anion form a counter salt is more preferred, a compound in which an iodonium cation or a sulfonium cation and a borate anion form a counter salt is further preferred, and a compound in which a diaryliodonium cation or a triarylsulfonium cation and a tetraarylborate anion form a counter salt is particularly preferred.

[0182] The preferred modes of the anion in the electron-donating polymerization initiator and the cation in the electron-accepting polymerization initiator are the same as the preferred modes of the anion in the electron-donating polymerization initiator and the cation in the electron-accepting polymerization initiator described above.

[0183] In the case where the image-recording layer contains the anion of the electron-donating polymerization initiator and the cation of the electron-accepting polymerization initiator (i.e., in the case where a compound forming the above-mentioned counter salt is contained), the image-recording layer contains the electron-accepting polymerization initiator and the above-mentioned electron-donating polymerization initiator.

[0184] Also, the compound in which the electron-donating polymerization initiator and the electron-accepting polymerization initiator form a counter salt can be used as the electron-donating polymerization initiator and can be used as the electron-accepting polymerization initiator.

[0185] Also, the compound in which the electron-donating polymerization initiator and the electron-accepting polymerization initiator form a counter salt can be used in combination with the above-mentioned electron-donating polymerization initiator and can be used in combination with the above-mentioned electron-accepting polymerization initiator.

[0186] The image recording layer in the present application also contains an infrared absorber and an electron-donating polymerization initiator, and from the viewpoint of improving sensitivity and print durability, the value of HOMO of the above-mentioned infrared absorber - HOMO of the above-mentioned electron-donating polymerization initiator is preferably 0.70 eV or less, more preferably 0.60 eV or less, further preferably 0.50 eV or less, and particularly preferably 0.50 eV to -0.10 eV.

[0187] In addition, the negative value means that the HOMO of the above-mentioned electron-donating polymerization initiator is higher than the HOMO of the above-mentioned infrared absorber.

[0188] In the present application, the MO (molecular orbital) energy calculation of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) is calculated by the following method.

[0189] First, free counter ions in the compound as the calculation object are excluded from the calculation object. For example, in the case of a cationic one-electron-donating polymerization initiator and a cationic infrared absorber, the counter anion is excluded from the calculation object, and in the case of an anionic one-electron-donating polymerization initiator, the counter cation is excluded from the calculation object. The free here means that the compound as the object is not linked to the counter ion by a covalent bond.

[0190] The quantum chemical calculation software Gaussian16 is used to perform structure optimization under DFT (B3LYP / 6-31G (d)).

[0191] Regarding the MO energy calculation, the quantum chemical calculation software Gaussian16 is used to perform under DFT (B3LYP / 6-31+G (d, p) / PCM (solvent = methanol)) using the optimal structure obtained by the above-mentioned structure optimization. In addition, for the compound containing iodine, the calculation is performed under DFT (B3LYP / DGDZVP / PCM (solvent = methanol)).

[0192] The optimal structure here means the structure with the most stable total energy obtained by DFT calculation. The structure optimization is repeated as needed, and thus the most stable structure is found.

[0193] The MO energy Ebare (unit: Hartree) obtained by the above-mentioned MO energy calculation is converted to Escaled (unit: eV) which is the value used as HOMO and LUMO in the present application according to the following formula.

[0194] [Calculation formula of HOMO] Escaled = 0.823168 x 27.2114 x Ebare - 1.07634

[0195] 〔Calculation formula of LUMO〕 Escaled=0.820139 x 27.2114 x Ebare-1.086039

[0196] Further, 27.2114 is a coefficient for converting Hartree to eV only, 0.823168 and -1.07634 used when calculating HOMO, and 0.820139 and -1.086039 used when calculating LUMO are adjustment coefficients, and are determined in a manner that the calculated values of HOMO and LUMO of the compound become matched with the measured values.

[0197] 〔Electron-accepting polymerization initiator〕

[0198] The image recording layer in the present application preferably further contains a polymerization initiator, and more preferably further contains an electron-accepting polymerization initiator as the polymerization initiator.

[0199] The electron-accepting polymerization initiator is a compound that generates a polymerization initiator species such as a radical by accepting one electron through intermolecular electron movement when the electron of the infrared absorber is excited by infrared exposure.

[0200] The electron-accepting polymerization initiator is a compound that generates a polymerization initiator species such as a radical or a cation by the energy of light, heat, or both, and a publicly known thermal polymerization initiator, a compound having a bond with a small bond dissociation energy, a photopolymerization initiator, or the like can be appropriately selected and used.

[0201] As the electron-accepting polymerization initiator, a radical polymerization initiator is preferred, and an onium salt compound is more preferred.

[0202] Further, as the electron-accepting polymerization initiator, an infrared photosensitive polymerization initiator is preferred.

[0203] Furthermore, as the electron-accepting polymerization initiator, from the viewpoint of improving sensitivity and UV print durability, an iodonium salt compound or a compound having a halogenated alkyl group is preferred, and a compound having a halogenated alkyl group is more preferred.

[0204] Further, as the compound having a halogenated alkyl group, from the viewpoint of improving sensitivity and UV print durability, a compound having a perhalogenated alkyl sulfonyl group is preferred, a compound having a trihalomethyl sulfonyl group is more preferred, and a compound having a tribromomethyl sulfonyl group is particularly preferred.

[0205] Among the above-mentioned electron-accepting polymerization initiators, as the preferred electron-accepting polymerization initiator, from the viewpoint of curability, an oxime ester compound and an onium salt compound can be given. Among them, from the viewpoint of print durability, an iodonium salt compound, a sulfonium salt compound, or an azinium salt compound is preferred, an iodonium salt compound or a sulfonium salt compound is more preferred, and an iodonium salt compound is particularly preferred.

[0206] The following shows specific examples of these compounds, but the present application is not limited thereto.

[0207] As examples of the iodonium salt compound, a diaryliodonium salt compound is preferable, and more preferably a diphenyl iodonium salt compound substituted with an electron-donating group such as an alkyl group or an alkoxy group, and an unsymmetrical diphenyl iodonium salt compound is preferable. As specific examples, diphenyl iodonium hexafluorophosphate, 4-methoxyphenyl-4-(2-methylpropyl)phenyl iodonium hexafluorophosphate, 4-(2-methylpropyl)phenyl-p-tolyl iodonium hexafluorophosphate, 4-hexyloxyphenyl-2,4,6-trimethoxyphenyl iodonium hexafluorophosphate, 4-hexyloxyphenyl-2,4-diethoxyphenyl iodonium tetrafluoroborate, 4-octyloxyphenyl-2,4,6-trimethoxyphenyl iodonium 1-perfluorobutanesulfonate, 4-octyloxyphenyl-2,4,6-trimethoxyphenyl iodonium hexafluorophosphate, and bis(4-tert-butylphenyl) iodonium tetraphenylborate can be given.

[0208] Further, as examples of the counter anion of the iodonium salt compound and the sulfonium salt compound, a sulfonic acid anion, a carboxylic acid anion, a tetrafluoroboric acid anion, a hexafluorophosphoric acid anion, a p-toluenesulfonic acid anion, a p-toluenesulfonic acid anion, a sulfonamide anion, or a sulfimide anion can be given.

[0209] Among them, a sulfonamide anion or a sulfimide anion is preferable, and a sulfimide anion is more preferable.

[0210] As the sulfonamide anion, an arylsulfonamide anion is preferable.

[0211] Further, as the sulfimide anion, a diarylsulfimide anion is preferable.

[0212] As specific examples of the sulfonamide anion or the sulfimide anion, the compounds described in International Publication No. 2019 / 013268 can be given.

[0213] Further, as the above electron-accepting type polymerization initiator, from the viewpoints of the visual recognition after exposure, the developability, and the UV printing durability in the obtained lithographic printing plate, a compound represented by the following formula (II) or formula (III) is preferable, and a compound represented by formula (II) is particularly preferable.

[0214] [Chemical Formula 10]

[0215]

[0216] In formula (II) and formula (III), X A represents a halogen atom, R A , R A1and R A2 each independently represents a monovalent hydrocarbon group having 1 to 20 carbon atoms.

[0217] R in formula (II) A is preferably an aryl group.

[0218] X in formula (II) and formula (III) A may be exemplified by a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. Among these, with respect to a chlorine atom or a bromine atom, since the sensitivity is excellent, it is preferred, and particularly a bromine atom is preferred.

[0219] and, in formula (II) and formula (III), R A , R A1 , and R A2 each independently is preferably an aryl group, and more preferably an aryl group substituted with an amido group from the viewpoint that the balance between sensitivity and storage stability is excellent.

[0220] and, as the above-mentioned electron-accepting polymerization initiator, particularly preferably contains a compound represented by formula (IV).

[0221] [Chemical Formula 11]

[0222]

[0223] In formula (IV), X A represents a halogen atom, R A3 , and R A4 each independently represents a hydrogen atom or a monovalent hydrocarbon group having 1 to 20 carbon atoms, and pA and qA each independently represents an integer of 1 to 5. Among these, pA + qA = 2 to 6.

[0224] As specific examples of the electron-accepting polymerization initiator, compounds shown in the following, and the like can be exemplified, but the present application is not limited to these.

[0225] [Chemical Formula 12]

[0226]

[0227] [Chemical Formula 13]

[0228]

[0229] [Chemical Formula 14]

[0230]

[0231] [Chemical Formula 15]

[0232]

[0233] [Chemical Formula 16]

[0234]

[0235] [Chemical Formula 17]

[0236]

[0237] [Chemical Formula 18]

[0238]

[0239] From the viewpoint of improving sensitivity, the lowest unoccupied molecular orbital (LUMO) of the electron-accepting polymerization initiator is preferably -3.00 eV or less, more preferably -3.02 eV or less.

[0240] Furthermore, the lower limit is preferably -3.80 eV or more, more preferably -3.50 eV or more.

[0241] The electron-accepting polymerization initiator can be used alone or in combination of two or more.

[0242] The content of the electron-accepting polymerization initiator is preferably 0.1 to 50% by mass, more preferably 0.5 to 30% by mass, and particularly preferably 0.8 to 20% by mass, relative to the total mass of the image-recording layer.

[0243] The image-recording layer in the present application further contains an infrared absorber and an electron-accepting polymerization initiator. From the viewpoint of improving sensitivity and print durability, the value of LUMO of the electron-accepting polymerization initiator - LUMO of the infrared absorber is preferably 1.00 eV or less, more preferably 0.80 eV or less, further preferably 0.70 eV or less, particularly preferably 0.70 to -0.10 eV, and most preferably 0.70 to 0.30 eV.

[0244] In addition, the negative value means that the LUMO of the infrared absorber is higher than the LUMO of the electron-accepting polymerization initiator.

[0245] [Infrared absorber]

[0246] The image-recording layer in the present application preferably further contains an infrared absorber.

[0247] There is no particular limitation on the infrared absorber, and pigments and dyes, for example, can be given.

[0248] As the dye which can be used as the infrared absorber, commercially available dyes and well-known dyes described in documents such as "Dye Handbook" (The Society of Synthetic Organic Chemistry, Japan. Editor, published in 45th year of Showa) can be used. Specifically, dyes such as azo dyes, metal complex salt azo dyes, pyrazolone azo dyes, naphthoquinone dyes, anthraquinone dyes, phthalocyanine dyes, carbonium dyes, quinonimine dyes, methine dyes, cyanine dyes, squarylium dyes, pyrylium salts, metal thiol complexes, and the like can be mentioned.

[0249] As the dye which is preferred among these dyes, cyanine dyes, squarylium dyes, pyrylium salts, nickel thiol complexes, indocyanine dyes can be mentioned. More preferably, cyanine dyes, indocyanine dyes are mentioned. Among these, cyanine dyes are particularly preferred.

[0250] As the above-mentioned infrared absorber, a cationic poly-methine dye having an oxygen atom, a nitrogen atom or a halogen atom at the meta position is preferred. As the cationic poly-methine dye, cyanine dyes, pyrylium dyes, thiopyrylium dyes, azulene dyes and the like are mentioned, and from the viewpoint of easiness of obtaining, solvent solubility at the time of introduction reaction and the like, cyanine dyes are preferred.

[0251] As specific examples of the cyanine dye, the compounds described in paragraphs 0017 to 0019 of Japanese Patent Application Publication No. 2001-133969, paragraphs 0016 to 0021 of Japanese Patent Application Publication No. 2002-023360, and paragraphs 0012 to 0037 of Japanese Patent Application Publication No. 2002-040638 are mentioned, and the compounds described in paragraphs 0034 to 0041 of Japanese Patent Application Publication No. 2002-278057, paragraphs 0080 to 0086 of Japanese Patent Application Publication No. 2008-195018 are preferred, and particularly preferred are the compounds described in paragraphs 0035 to 0043 of Japanese Patent Application Publication No. 2007-90850 and paragraphs 0105 to 0113 of Japanese Patent Application Publication No. 2012-206495.

[0252] Further, the compounds described in paragraphs 0008 to 0009 of Japanese Patent Application Publication No. 5-5005 and paragraphs 0022 to 0025 of Japanese Patent Application Publication No. 2001-222101 can also be preferably used. As the pigment, the compounds described in paragraphs 0072 to 0076 of Japanese Patent Application Publication No. 2008-195018 are preferred.

[0253] Further, as the above-mentioned infrared absorber, a decomposable compound which is described later as a color-changing compound of the outermost layer and which is decomposed by infrared exposure can also be preferably used.

[0254] From the viewpoint of print durability and visual recognition, the highest occupied molecular orbital (HOMO) of the above-mentioned infrared absorber is preferably -5.250 eV or less, more preferably -5.30 eV or less, further preferably -5.80 eV or more and -5.35 eV or less, and particularly preferably -5.65 eV or more and -5.40 eV or less.

[0255] From the viewpoint of stability over time, improved sensitivity, and UV print durability, the lowest unoccupied molecular orbital (LUMO) of the above-mentioned infrared absorber is preferably less than -3.70 eV, more preferably less than -3.80 eV, further preferably -4.20 eV or more and less than -3.80 eV, and particularly preferably -4.00 eV or more and less than -3.80 eV.

[0256] The infrared absorber can be used alone or in combination with two or more.

[0257] Also, as the infrared absorber, a pigment and a dye can be used in combination.

[0258] The content of the infrared absorber is preferably 0.1 to 10.0 mass%, more preferably 0.5 to 5.0 mass%, with respect to the total mass of the image recording layer.

[0259] [Polymerizable Compound]

[0260] The image recording layer in the present application preferably further contains a polymerizable compound.

[0261] In the present application, the polymerizable compound refers to a compound having a polymerizable group.

[0262] There is no particular limitation on the polymerizable group, and it can be any known polymerizable group, but it is preferably an ethylenically unsaturated group. Also, the polymerizable group can be a radical polymerizable group or a cationic polymerizable group, but it is preferably a radical polymerizable group.

[0263] As the radical polymerizable group, a (meth)acryloyl group, an allyl group, a vinylphenyl group, a vinyl group, or the like can be given, and from the viewpoint of reactivity, a (meth)acryloyl group is preferred.

[0264] The molecular weight (weight average molecular weight in the case of having a molecular weight distribution) of the polymerizable compound is preferably 50 or more and less than 2,500.

[0265] The polymerizable compound used in the present application can be a radical polymerizable compound or a cationic polymerizable compound, and it is preferably an addition polymerizable compound (ethylenically unsaturated compound) having at least one ethylenically unsaturated bond.

[0266] As the ethylenically unsaturated compound, a compound having at least one terminal ethylenically unsaturated bond is preferable, and a compound having two or more terminal ethylenically unsaturated bonds is more preferable. The polymerizable compound has, for example, a chemical form of a monomer, a prepolymer (dimer, trimer, or oligomer), or a mixture thereof.

[0267] As the above polymerizable compound, from the viewpoint of UV printing durability, a polymerizable compound containing 3 or more functional groups is preferable, a polymerizable compound containing 7 or more functional groups is more preferable, and a polymerizable compound containing 10 or more functional groups is further preferable. Also, from the viewpoint of UV printing durability in the obtained lithographic printing plate, the above polymerizable compound preferably contains 3 or more (preferably 7 or more, and more preferably 10 or more) ethylenically unsaturated compounds, and further preferably contains 3 or more (preferably 7 or more, and more preferably 10 or more) (meth)acrylate compounds.

[0268] Also, as the above polymerizable compound, from the viewpoint of on-press developability and contamination inhibition, a polymerizable compound containing 2 or less functional groups is preferable, a polymerizable compound containing 2 functional groups is more preferable, and a (meth)acrylate compound containing 2 functional groups is particularly preferable.

[0269] From the viewpoints of printing durability, on-press developability, and contamination inhibition, the content of a polymerizable compound containing 2 or less functional groups (preferably a polymerizable compound containing 2 functional groups) is preferably 5 to 100 mass%, more preferably 10 to 100 mass%, and particularly preferably 50 to 100 mass%, relative to the total mass of the polymerizable compound in the above image recording layer.

[0270] < Oligomer >

[0271] As the polymerizable compound contained in the image recording layer, a polymerizable compound containing an oligomer (hereinafter, also referred to simply as "oligomer") is preferable.

[0272] In the present application, the oligomer means a polymerizable compound having a molecular weight (weight average molecular weight in the case of having a molecular weight distribution) of 600 or more and 10,000 or less, and containing at least one polymerizable group.

[0273] From the viewpoint of excellent chemical resistance and UV printing durability, the molecular weight of the oligomer is preferably 1,000 or more and 5,000 or less.

[0274] Also, from the viewpoint of improving UV printing durability, the number of polymerizable groups in one molecule of the oligomer is preferably 2 or more, more preferably 3 or more, further preferably 6 or more, and particularly preferably 10 or more.

[0275] Further, the upper limit of the number of polymerizable groups in the oligomer is not particularly limited, but the number of polymerizable groups is preferably 20 or less.

[0276] From the viewpoints of UV printing durability and on-press developability, the number of polymerizable groups in the oligomer is preferably 7 or more, and the molecular weight is preferably 1,000 or more and 10,000 or less, and more preferably the number of polymerizable groups is 7 or more and 20 or less, and the molecular weight is 1,000 or more and 5,000 or less.

[0277] In addition, a polymer component that can be generated during the production of the oligomer can be contained.

[0278] From the viewpoints of UV printing durability, visual recognition, and on-press developability, the oligomer preferably has at least one selected from the group consisting of a compound having a urethane bond, a compound having an ester bond, and a compound having an epoxy residue, and preferably has a compound having a urethane bond.

[0279] In the present application, the epoxy residue refers to a structure formed from an epoxy group, and for example, indicates the same structure as that obtained by the reaction of an acid group (carboxylic acid group, etc.) with an epoxy group.

[0280] As the compound having a urethane bond as an example of the oligomer, for example, a compound having at least a group represented by the following formula (Ac-1) or formula (Ac-2) is preferable, and a compound having at least a group represented by the following formula (Ac-1) is more preferable.

[0281] [Chemical Formula 19]

[0282]

[0283] In formula (Ac-1) and formula (Ac-2), L 1 ~L 4 Each independently represents a divalent hydrocarbon group having 2 to 20 carbon atoms, and the wavy line portion indicates a bonding position to other structures.

[0284] As L 1 ~L 4 Each independently is preferably an alkylene group having 2 to 20 carbon atoms, more preferably an alkylene group having 2 to 10 carbon atoms, and further preferably an alkylene group having 4 to 8 carbon atoms. Further, the above alkylene group can have a branched chain or a ring structure, but is preferably a linear alkylene group.

[0285] The wavy line portion in formula (Ac-1) or formula (Ac-2) is preferably directly bonded to the wavy line portion in a group represented by the following formula (Ae-1) or formula (Ae-2), respectively.

[0286] [Chemical Formula 20]

[0287]

[0288] In formula (Ae-1) and formula (Ae-2), R independently represents acryloyloxy group or methacryloyloxy group, and the wavy line portion represents the bonding position with the wavy line portion in formula (Ac-1) and formula (Ac-2).

[0289] Further, as the compound having a urethane bond, a compound obtained by introducing a polymerizable group to a polyurethane obtained by the reaction of a polyisocyanate compound and a polyol compound through a high molecular reaction can be used.

[0290] For example, the compound having a urethane bond can be obtained by reacting a compound having an epoxy group and a polymerizable group with a polyurethane oligomer obtained by reacting a polyol compound having an acid group and a polyisocyanate compound.

[0291] The number of the polymerizable groups in the compound having an ester bond exemplified as the oligomer is preferably 3 or more, and further preferably 6 or more.

[0292] The compound having an epoxy residue exemplified as the oligomer is preferably a compound containing a hydroxyl group within the compound.

[0293] Further, the number of the polymerizable groups in the compound having an epoxy residue is preferably 2 to 6, and more preferably 2 to 3.

[0294] As the compound having an epoxy residue described above, for example, a compound can be obtained by reacting acrylic acid and a compound having an epoxy group.

[0295] Specific examples of the oligomer are exemplified below, but the oligomer used in the present application is not limited thereto.

[0296] As the oligomer, commercially available products can be used, and examples thereof include UA-510H, UA-306H, UA-306I, UA-306T (all manufactured by KYOEISHA CHEMICAL CO., LTD.), UV-1700B, UV-6300B, UV7620EA (all manufactured by Nippon Synthetic Chemical Industry Co., Ltd.), U-15HA (manufactured by Shin-Nakamura Chemical Co., Ltd.), EBECRYL 450, EBECRYL 657, EBECRYL 885, EBECRYL 800, EBECRYL 3416, EBECRYL 860 (all manufactured by DAICEL-ALLNEX LTD.), and the like, but is not limited thereto.

[0297] From the viewpoint of improving chemical resistance, UV print durability, and inhibition of on-press development residue, the content of the oligomer is preferably 30% by mass or more to 100% by mass or less, more preferably 50% by mass or more to 100% by mass or less, and further preferably 80% by mass or more to 100% by mass or less, with respect to the total mass of the polymerizable compound in the image-recording layer.

[0298] <Low-molecular polymerizable compound>

[0299] The polymerizable compound can also include a polymerizable compound other than the above-described oligomer.

[0300] As the polymerizable compound other than the oligomer, from the viewpoint of chemical resistance, a low-molecular polymerizable compound is preferable. As the low-molecular polymerizable compound, a chemical form such as a monomer, a dimer, a trimer, or a mixture thereof can be used.

[0301] Further, as the low-molecular polymerizable compound, from the viewpoint of chemical resistance, at least one polymerizable compound selected from a polymerizable compound having three or more ethylenically unsaturated groups and a polymerizable compound having an isocyanurine ring structure is preferable.

[0302] In the present application, a low-molecular polymerizable compound refers to a polymerizable compound having a molecular weight (weight average molecular weight in the case of having a molecular weight distribution) of 50 or more and less than 600.

[0303] As the molecular weight of the low-molecular polymerizable compound, from the viewpoint of excellent chemical resistance, UV print durability, and inhibition of on-press development residue, 100 or more and less than 600 is preferable, 300 or more and less than 600 is more preferable, and 400 or more and less than 600 is further preferable.

[0304] In the case where the polymerizable compound includes a low-molecular polymerizable compound as the polymerizable compound other than the oligomer (in the case where two or more low-molecular polymerizable compounds are included, the total amount thereof), from the viewpoint of chemical resistance, UV print durability, and inhibition of on-press development residue, the ratio of the above-described oligomer to the low-molecular polymerizable compound (oligomer / low-molecular polymerizable compound) is preferably 10 / 1 to 1 / 10 on a mass basis, more preferably 10 / 1 to 3 / 7, and further preferably 10 / 1 to 7 / 3.

[0305] Further, as the low-molecular polymerizable compound, the polymerizable compound described in paragraphs 0082 to 0086 of International Publication No. 2019 / 013268 can also be preferably used.

[0306] The structure of the polymerizable compound, the use method of the individual use or combination, the amount of addition, and the like can be arbitrarily set.

[0307] Among them, from the viewpoint of UV printing durability, the image recording layer preferably contains two or more kinds of polymerizable compounds.

[0308] The content of the polymerizable compound (the total content of the polymerizable compounds in the case of containing two or more kinds of polymerizable compounds) is preferably 5 to 75 mass%, more preferably 10 to 70 mass%, and further preferably 15 to 60 mass% with respect to the total mass of the image recording layer.

[0309] 〔Polar organic solvent〕

[0310] From the viewpoints of ink turbidity inhibition, visual recognition of the exposed portion, and visual recognition of the exposed portion over time, the image recording layer in the present application preferably further contains a polar organic solvent.

[0311] Also, as the polar organic solvent, a non-protic polar organic solvent is preferable.

[0312] As the non-protic polar organic solvent, at least one solvent selected from the group consisting of N-methylpyrrolidone, N-ethylpyrrolidone, γ-butyrolactone, dimethyl sulfoxide, dimethylacetamide, dimethylformamide, dichloromethane, tetrahydrofuran, dioxane, and 1,3-dioxolane is preferable, at least one solvent selected from the group consisting of N-methylpyrrolidone, N-ethylpyrrolidone, γ-butyrolactone, dimethyl sulfoxide, dimethylacetamide, dimethylformamide, tetrahydrofuran, dioxane, and 1,3-dioxolane is more preferable, and at least one solvent selected from the group consisting of dimethyl sulfoxide and N-methylpyrrolidone is particularly preferable.

[0313] The polar organic solvent can be used singly or in combination with two or more kinds.

[0314] From the viewpoints of ink turbidity inhibition, visual recognition of the exposed portion, and visual recognition of the exposed portion over time, the content of the polar organic solvent is preferably 0.001 to 5.0 mass%, more preferably 0.005 to 2.0 mass%, and particularly preferably 0.01 to 1.0 mass% with respect to the total mass of the image recording layer.

[0315] 〔Particles〕

[0316] From the viewpoints of development and UV printing durability, the image recording layer in the present application preferably further contains particles. The particles can be inorganic particles or organic particles.

[0317] Among them, as the particles, organic particles are preferable, and resin particles are more preferable.

[0318] As the inorganic particles, publicly known inorganic particles can be used, and metal oxide particles such as silica particles and titanium dioxide particles can be preferably used.

[0319] <Resin particles>

[0320] As the resin particles, for example, particles containing an addition polymerization type resin (i.e., addition polymerization type resin particles), particles containing a polyaddition type resin (i.e., polyaddition type resin particles), particles containing a polycondensation type resin (i.e., polycondensation type resin particles), and the like can be mentioned, but among them, addition polymerization type resin particles or polyaddition type resin particles are preferable.

[0321] Further, as the resin particles, from the viewpoint of being able to be heat-fused, particles containing a thermoplastic resin (i.e., thermoplastic resin particles) can be used.

[0322] Further, the resin particles can be in the form of microcapsules, microgels (i.e., crosslinked resin particles), and the like.

[0323] As the resin particles, it is preferable to select from among thermoplastic resin particles, thermally reactive resin particles, resin particles having a polymerizable group, microcapsules and microgels (crosslinked resin particles) containing a hydrophobic compound. Among them, resin particles having a polymerizable group are preferable.

[0324] In a particularly preferable embodiment, the resin particles contain at least one olefinic unsaturated group. By the presence of such resin particles, it is possible to obtain the effect of improving the print durability of the exposed portions and the on-press developability of the unexposed portions.

[0325] As the thermoplastic resin particles, it is preferable to use the thermoplastic resin particles described in Research Disclosure No. 33303, January 1992, Japanese Patent Application Laid-Open No. 9-123387, Japanese Patent Application Laid-Open No. 9-131850, Japanese Patent Application Laid-Open No. 9-171249, Japanese Patent Application Laid-Open No. 9-171250, and European Patent No. 931647, and the like.

[0326] As specific examples of the resin constituting the thermoplastic resin particles, homopolymers or copolymers of monomers such as ethylene, styrene, vinyl chloride, methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate, vinylidene chloride, acrylonitrile, vinylcarbazole, acrylate or methacrylate having a polyalkylene structure, or mixtures thereof can be mentioned.

[0327] As the thermoplastic resin particles, from the viewpoints of ink adhesion and UV print durability, it is preferable to use a resin containing a constitutional unit formed of an aromatic vinyl compound and a constitutional unit having a nitrile group.

[0328] As the aromatic vinyl compound, only a compound having a structure in which a vinyl group is bonded to an aromatic ring can be mentioned, but a styrene compound, a vinyl naphthalene compound, or the like can be mentioned, and a styrene compound is preferred, and styrene is more preferred.

[0329] As the styrene compound, styrene, p-methylstyrene, p-methoxystyrene, β-methylstyrene, p-methyl-β-methylstyrene, α-methylstyrene, and p-methoxy-β-methylstyrene, or the like can be mentioned, and styrene is preferred.

[0330] From the viewpoint of ink adhesion, the content of the constitutional unit formed from the aromatic vinyl compound is preferably more than the content of the constitutional unit having a nitrile group described later, and more preferably 15 to 85% by mass, and further preferably 30 to 70% by mass, relative to the total mass of the resin.

[0331] The constitutional unit having a nitrile group is preferably introduced using a monomer having a nitrile group.

[0332] As the monomer having a nitrile group, an acrylonitrile compound can be mentioned, and a (meth)acrylonitrile is preferred.

[0333] As the constitutional unit having a nitrile group, a constitutional unit formed from a (meth)acrylonitrile is preferred.

[0334] From the viewpoint of ink adhesion, the content of the constitutional unit having a nitrile group is preferably less than the content of the constitutional unit formed from the aromatic vinyl compound described above, and more preferably 55 to 90% by mass, and more preferably 60 to 85% by mass, relative to the total mass of the resin.

[0335] Further, in the case where the resin contained in the thermoplastic resin particles contains a constitutional unit formed from an aromatic vinyl compound and a constitutional unit having a nitrile group, the content ratio (constitutional unit formed from an aromatic vinyl compound: constitutional unit having a nitrile group) of the constitutional unit formed from an aromatic vinyl compound and the constitutional unit having a nitrile group is preferably 5:5 to 9:1, and more preferably 6:4 to 8:2, on a mass basis.

[0336] From the viewpoint of UV printing durability and chemical resistance, the resin contained in the thermoplastic resin particles preferably further has a constitutional unit formed from an N-vinyl heterocyclic compound.

[0337] As the N-vinyl heterocyclic compound, for example, N-vinylpyrrolidone, N-vinylcarbazole, N-vinylpyrrole, N-vinylphenothiazine, N-vinylsuccinimide, N-vinylphthalimide, N-vinylcaprolactam, and N-vinylimidazole can be mentioned, and N-vinylpyrrolidone is preferred.

[0338] The content of the constitutional unit formed from the N-vinyl heterocyclic compound is preferably 5 to 50% by mass, more preferably 10 to 40% by mass, relative to the total mass of the thermoplastic resin.

[0339] The resin contained in the thermoplastic resin particles can contain a constitutional unit having an acidic group, but from the viewpoints of on-press developability and ink adhesion, it is preferable that the constitutional unit not contain an acidic group.

[0340] Specifically, the content of the constitutional unit having an acidic group in the thermoplastic resin is preferably 20% by mass or less, more preferably 10% by mass or less, and further preferably 5% by mass or less. The lower limit of the above content is not particularly limited and can be 0% by mass.

[0341] Also, the acid value of the thermoplastic resin is preferably 160 mgKOH / g or less, more preferably 80 mgKOH / g or less, and further preferably 40 mgKOH / g or less. The lower limit of the above acid value is not particularly limited and can be 0 mgKOH / g.

[0342] In the present application, the acid value is found by a measurement method in accordance with JIS K0070:1992.

[0343] From the viewpoint of ink adhesion, the resin contained in the thermoplastic resin particles can contain a constitutional unit containing a hydrophobic group.

[0344] As the above hydrophobic group, an alkyl group, an aryl group, an aralkyl group, and the like can be given.

[0345] As the constitutional unit containing a hydrophobic group, a constitutional unit formed from an alkyl (meth)acrylate compound, an aryl (meth)acrylate compound, or an aralkyl (meth)acrylate compound is preferable, and a constitutional unit formed from an alkyl (meth)acrylate compound is more preferable.

[0346] The content of the constitutional unit having a hydrophobic group in the resin contained in the thermoplastic resin particles is preferably 5 to 50% by mass, more preferably 10 to 30% by mass, relative to the total mass of the resin.

[0347] From the viewpoints of UV printing durability and on-press developability, the thermoplastic resin contained in the thermoplastic resin particles preferably has a hydrophilic group.

[0348] As the hydrophilic group, if it is a structure having a hydrophilic property, there is no particular limitation, but an acid group such as a carboxyl group, a hydroxyl group, an amino group, a nitrile group, a polyalkylene oxide structure, and the like can be given.

[0349] As the above hydrophilic group, from the viewpoints of UV printing durability and on-press developability, a group having a polyalkylene oxide structure, a group having a polyester structure, or a sulfonic acid group is preferred, a group having a polyalkylene oxide structure or a sulfonic acid group is more preferred, and a group having a polyalkylene oxide structure is further preferred.

[0350] As the above polyalkylene oxide structure, from the viewpoint of on-press developability, a polyethylene oxide structure, a polypropylene oxide structure, or a poly(ethylene oxide / propylene oxide) structure is preferred.

[0351] Also, from the viewpoint of on-press developability, among the above hydrophilic groups, as the polyalkylene oxide structure, a polypropylene oxide structure is preferred, and a polyethylene oxide structure and a polypropylene oxide structure are more preferred.

[0352] From the viewpoint of on-press developability, the number of alkylene oxide structures in the above polyalkylene oxide structure is preferably 2 or more, more preferably 5 or more, further preferably 5 to 200, and particularly preferably 8 to 150.

[0353] Also, from the viewpoint of on-press developability, as the above hydrophilic group, a group represented by Formula Z described below is preferred.

[0354] Among the hydrophilic groups possessed by the thermoplastic resin, a group represented by the following Formula PO is preferred.

[0355] [Chemical Formula 21]

[0356]

[0357] In Formula PO, L P Each independently represents an alkylene group, R P represents a hydrogen atom or an alkyl group, and n represents an integer of 1 to 100.

[0358] In Formula PO, L P Each independently is preferably an ethylene group, a 1-methylethylene group, or a 2-methylethylene group, and more preferably an ethylene group.

[0359] In Formula PO, R P is preferably a hydrogen atom or an alkyl group having 1 to 18 carbon atoms, more preferably a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, further preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and particularly preferably a hydrogen atom or a methyl group.

[0360] In Formula PO, n is preferably an integer of 1 to 10, and more preferably an integer of 1 to 4.

[0361] The content of the constitutional unit having the hydrophilic group is preferably 5 mass% to 60 mass%, and more preferably 10 mass% to 30 mass%, with respect to the total mass of the resin.

[0362] The resin contained in the thermoplastic resin particles can further contain other constitutional units. As the other constitutional units, constitutional units formed of acrylamide compounds, vinyl ether compounds, and the like can be cited, without particular limitation, in addition to the above-described constitutional units.

[0363] The content of the other constitutional units in the resin contained in the thermoplastic resin particles is preferably 5 to 50% by mass, and more preferably 10 to 30% by mass, relative to the total mass of the resin.

[0364] As the thermally reactive resin particles, resin particles having a thermally reactive group can be cited. The thermally reactive resin particles form a hydrophobized region by crosslinking based on thermal reaction and a change in functional group at the time of crosslinking.

[0365] As the thermally reactive group in the resin particles having a thermally reactive group, a functional group that can form a chemical bond can be cited, without particular limitation, but a polymerizable group is preferred, and as examples thereof, an ethylenically unsaturated group (e.g., acryloyl group, methacryloyl group, vinyl group, allyl group, and the like) that undergoes radical polymerization, a cationically polymerizable group (e.g., vinyl group, vinyloxy group, epoxy group, oxetanyl group, and the like) that undergoes cationic polymerization, an isocyanate group or a block thereof that undergoes addition reaction, an epoxy group, a vinyloxy group, and a functional group having an active hydrogen atom as a reaction target thereof (e.g., amino group, hydroxyl group, carboxyl group, and the like), a carboxyl group that undergoes condensation reaction and a hydroxyl group or an amino group as a reaction target thereof, an anhydride that undergoes ring-opening addition reaction and an amino group or a hydroxyl group as a reaction target thereof, and the like are preferred.

[0366] As the resin having the above-described thermally reactive group, an addition polymerization type resin, a polycondensation type resin, or a polyaddition type resin can be cited, and a thermoplastic resin can also be cited.

[0367] As the microcapsule, for example, a microcapsule that contains at least a part of the components (preferably, a hydrophobic compound) constituting the image recording layer in the interior thereof, as described in Japanese Patent Application Publication No. 2001-277740 and Japanese Patent Application Publication No. 2001-277742, is preferred. A preferred form of the image recording layer containing the microcapsule as the resin particles is a structure in which the hydrophobic component (i.e., a hydrophobic compound) of the components constituting the image recording layer is contained in the interior of the microcapsule, and the hydrophilic component (i.e., a hydrophilic compound) is contained outside the microcapsule.

[0368] The microgel (crosslinked resin particles) can contain a part of the components constituting the image recording layer in at least one of the surface or the interior thereof. In particular, from the viewpoint of the sensitivity of the lithographic printing plate precursor and the printing durability of the obtained lithographic printing plate, a reactive microgel having a polymerizable group on the surface thereof is preferred.

[0369] In order to obtain the microcapsule containing the constituent component of the image recording layer, a publicly known synthesis method can be applied.

[0370] The microgel (crosslinked resin particle) can contain a part of the constituent component of the image recording layer at least one of the surface or the inside thereof. In particular, from the viewpoint of the sensitivity of the lithographic printing plate precursor and the printing durability of the obtained lithographic printing plate, a reactive microgel having a polymerizable group on the surface thereof is preferred.

[0371] In order to obtain the microcapsule containing the constituent component of the image recording layer, a publicly known synthesis method can be applied

[0372] As the resin particle, from the viewpoint of the printing durability, the stain resistance, and the storage stability of the obtained lithographic printing plate, an addition polymerization type resin particle having a hydrophobic main chain and containing both i) a constituent unit having a nitrile group directly bonded to the above hydrophobic main chain and ii) a constituent unit having a side group containing a hydrophilic polyalkylene oxide segment is preferred. Specifically, the particle described in paragraph 0156 of Japanese Patent Application Publication No. 2019-64269 is preferred.

[0373] As the above polyhydric phenol compound, a compound having a plurality of benzene rings having a phenolic hydroxyl group is preferred.

[0374] As the compound having the above active hydrogen, a polyhydric alcohol compound or a polyamine compound is preferred, and a polyhydric alcohol compound is more preferred, and further, at least one compound selected from the group consisting of propylene glycol, glycerol, and trimethylolpropane is preferred. Also, as the above active hydrogen compound, water can be used. In the case of using water, an amine generated by the reaction of an isocyanate group with water can form a urea bond, and thus a particle can be formed.

[0375] As the particle of the resin obtained by the reaction of the polyisocyanate compound which is an adduct of a polyhydric phenol compound having 2 or more hydroxyl groups in a molecule and isophorone diisocyanate and the compound having an active hydrogen, the resin particle described in paragraphs 0230 to 0234 of International Publication No. 2018043259 is preferred.

[0376] Also, as the resin particle, from the viewpoint of the printing durability and the solvent resistance of the obtained lithographic printing plate, an addition polymerization type resin particle having a hydrophobic main chain and containing both i) a constituent unit having a nitrile group directly bonded to the above hydrophobic main chain and ii) a constituent unit having a side group containing a hydrophilic polyalkylene oxide segment is preferred. Specifically, the particle described in paragraph 0156 of Japanese Patent Application Publication No. 2019-64269 is preferred.

[0377] <<Group represented by Formula Z>>

[0378] The resin particle in the present application preferably has a group represented by the following Formula Z as a hydrophilic group.

[0379] * - Q - W - Y Formula Z

[0380] In Formula Z, Q represents a divalent linking group, W represents a divalent group having a hydrophilic structure or a divalent group having a hydrophobic structure, Y represents a monovalent group having a hydrophilic structure or a monovalent group having a hydrophobic structure, either of W and Y has a hydrophilic structure, and * represents a bonding site with other structures.

[0381] Also, it is preferable that the hydrophilic structures included in Formula Z each include a polyalkylene oxide structure.

[0382] Q in the above Formula Z is preferably a divalent linking group having 1 to 20 carbon atoms, and more preferably a divalent linking group having 1 to 10 carbon atoms.

[0383] Also, Q in the above Formula Z is preferably an alkylene group, an arylene group, an ester bond, an amide bond, or a group in which two or more of these are combined, and more preferably a phenylene group, an ester bond, or an amide bond.

[0384] The divalent group having a hydrophilic structure in W in the above Formula Z is preferably a group including a polyalkylene oxide structure, and preferably a polyalkyleneoxy group or a group in which -CH2CH2NR W - is bonded to one terminal of a polyalkyleneoxy group. Also, R W represents a hydrogen atom or an alkyl group.

[0385] The divalent group having a hydrophobic structure in W in the above Formula Z is preferably -R WA -, -O-R WA -O-, -R W N-R WA -NR W -, -OC(=O)-R WA -O-, or -OC(=O)-R WA -O-. Also, R WA each independently represents a linear, branched, or cyclic alkylene group having 6 to 120 carbon atoms, a haloalkylene group having 6 to 120 carbon atoms, an arylene group having 6 to 120 carbon atoms, an alkarylene group (a divalent group obtained by removing one hydrogen atom from an alkylaryl group) having 6 to 120 carbon atoms, or an aralkylene group having 6 to 120 carbon atoms.

[0386] The monovalent group having a hydrophilic structure in Y in the above Formula Z is preferably -OH, -C(=O)OH, a polyalkyleneoxy group in which one terminal is a hydrogen atom or an alkyl group or in which the other terminal is bonded to -CH2CH2N(R W) - group. Among them, as the monovalent group having a hydrophilic structure, a group containing a polyalkylene oxide structure, preferably a polyalkylene oxide group having a hydrogen atom or an alkyl group at the terminal or a polyalkylene oxide group having a hydrogen atom or an alkyl group at the other terminal bonded to -CH2CH2N(R W ) - group.

[0387] The monovalent group having a hydrophobic structure in Y of the above formula Z is preferably a linear, branched or cyclic alkyl group having 6 to 120 carbon atoms, a halogenated alkyl group having 6 to 120 carbon atoms, an aryl group having 6 to 120 carbon atoms, an alkylaryl (alkylaryl) group having 6 to 120 carbon atoms, an aralkyl group having 6 to 120 carbon atoms, -OR WB , -C(=O)OR WB or -OC(=O)R WB . R WB represents an alkyl group having 6 to 20 carbon atoms.

[0388] In the resin particle having a group represented by the above formula Z, from the viewpoint of print durability, ink receptivity and on-press developability, it is more preferable that W be a divalent group having a hydrophilic structure, it is more preferable that Q be a phenylene group, an ester bond or an amide bond, W be a polyalkylene oxide group, and Y be a polyalkylene oxide group having a hydrogen atom or an alkyl group at the terminal.

[0389] In addition, the group represented by formula Z can function as a dispersibility group for improving the dispersibility of the resin particle.

[0390] From the viewpoint of print durability and on-press developability, the resin particle in the present application preferably has a polymerizable group (preferably an ethylenically unsaturated group), and it is more preferable to contain a resin particle having a polymerizable group particularly on the surface. By using a resin particle having a polymerizable group, print durability (preferably UV print durability) can be improved.

[0391] From the viewpoint of print durability, the resin particle in the present application is preferably a resin particle having a hydrophilic group and a polymerizable group.

[0392] The above polymerizable group can be a cationic polymerizable group or a free radical polymerizable group, but from the viewpoint of reactivity, it is preferable to be a free radical polymerizable group.

[0393] As the above polymerizable group, there is no particular limitation as long as it is a group that can be polymerized, but from the viewpoint of reactivity, an ethylenically unsaturated group is preferable, a vinylphenyl group (styryl group), a (meth)acryloxy group or a (meth)acrylamido group is more preferable, and a (meth)acryloxy group is particularly preferable.

[0394] Further, the resin constituting the resin particles having a polymerizable group preferably has a constituting unit having a polymerizable group.

[0395] Further, the polymerizable group can be introduced to the surface of the resin particles by a polymer reaction.

[0396] Further, from the viewpoint of print durability, ink receptivity, on-press developability, and development residue inhibitory properties during on-press development, the resin particles preferably contain an addition polymerization type resin having a urea bond, more preferably contain an addition polymerization type resin having a structure obtained by at least reacting an isocyanate compound represented by the following formula (Iso) with water, and particularly preferably contain an addition polymerization type resin having a structure obtained by at least reacting an isocyanate compound represented by the following formula (Iso) with water and having a polyethylene oxide structure and a polypropylene oxide structure as a polyoxyalkylene structure. Further, the particles containing the addition polymerization type resin having the above-described urea bond are preferably microgels.

[0397] [Chemical Formula 22]

[0398]

[0399] In formula (Iso), n represents an integer of 0 to 10.

[0400] As an example of the reaction of the isocyanate compound represented by the above-described formula (Iso) with water, the following reaction can be given. Further, the following example is for the case where n = 0 and 4,4-isomer is used.

[0401] As shown below, if the isocyanate compound represented by the above-described formula (Iso) is reacted with water, amino groups are generated by partial hydrolysis of water isocyanate groups, the generated amino groups react with isocyanate groups, urea bonds are generated, and dimers are formed. Further, the following reaction is repeated, and an addition polymerization type resin having a urea bond is formed.

[0402] Further, in the following reaction, a compound (a compound having active hydrogen) reactive with isocyanate groups such as an alcohol compound, an amine compound, or the like is added, whereby the structure of the alcohol compound, the amine compound, or the like can also be introduced into the addition polymerization type resin having a urea bond.

[0403] As the compound having the above-described active hydrogen, a compound having the above-described active hydrogen is preferably selected.

[0404] [Chemical Formula 23]

[0405]

[0406] Further, the addition polymerization type resin having the above-described urea bond preferably has an ethylenic unsaturated group, and more preferably has a group represented by the following formula (PETA).

[0407] [Chemical Formula 24]

[0408]

[0409] In formula (PETA), the wavy line portion indicates a bonding position with other structures.

[0410] < Synthesis of resin particles >

[0411] The method of synthesizing the resin particles is not particularly limited, and any method that can synthesize the particles using the various resins described above can be used. As the method of synthesizing the resin particles, for example, publicly known methods such as emulsion polymerization, suspension polymerization, dispersion polymerization, soap-free polymerization, and microemulsion polymerization can be used.

[0412] In addition, publicly known methods of synthesizing microcapsules, methods of synthesizing microgels (crosslinked resin particles), and the like can be used in the synthesis of the resin particles.

[0413] < Average particle diameter of particles >

[0414] The average particle diameter of the particles is preferably from 0.01 μm to 3.0 μm, more preferably from 0.03 μm to 2.0 μm, and further preferably from 0.10 μm to 1.0 μm. Within this range, good resolution and stability over time can be obtained.

[0415] The average particle diameter of the particles is measured by a light scattering method, or an electron micrograph of the particles is taken, the diameters of a total of 5,000 particles on the photograph are measured, and the average value is calculated. In addition, in the case of non-spherical particles, the circular equivalent diameter of the particles on the photograph is used.

[0416] In addition, the average particle diameter of the particles in the present application is the volume average particle diameter unless otherwise specified.

[0417] The particles (preferably resin particles) can be used singly or in combination of two or more.

[0418] From the viewpoint of development properties and print durability, the content of the particles (preferably resin particles) is preferably from 5 mass% to 90 mass%, more preferably from 10 mass% to 90 mass%, further preferably from 20 mass% to 90 mass%, and particularly preferably from 50 mass% to 90 mass%, relative to the total mass of the image recording layer.

[0419] [Other components]

[0420] The image recording layer in the present application can contain other components in addition to the components described above.

[0421] As other components, there can be mentioned a binder polymer, an oil agent, a color developer, a chain transfer agent, a low-molecular hydrophilic compound, a sensitizing agent, a surfactant, other additives, and the like.

[0422] As other components, there can be mentioned the surfactants, colorants, printing agents, polymerization inhibitors, higher fatty acid derivatives, plasticizers, inorganic particles, low-molecular hydrophilic compounds, and the like disclosed in paragraphs 0174 to 0190 of Japanese Patent Application Publication No. 2009-255434.

[0423] Further, as other compounds, there can be mentioned the hydrophobizing precursors (microparticles capable of converting the image recording layer into hydrophobic upon application of heat), low-molecular hydrophilic compounds, sensitizing agents (for example, phosphonium compounds, nitrogen-containing low-molecular compounds, ammonium group-containing polymers), and chain transfer agents disclosed in paragraphs 0191 to 0217 of Japanese Patent Application Publication No. 2012-187907.

[0424] Further, as the surfactant, an anionic surfactant and a fluorine-based surfactant are preferable.

[0425] Binder Polymer

[0426] The image recording layer can contain a binder polymer as necessary.

[0427] Here, the binder polymer refers to a polymer other than the resin particles, that is, a polymer that is not in the form of particles.

[0428] Further, as the binder polymer, the ammonium salt-containing polymers in the sensitizing agent and the polymers used as the surfactant are excluded.

[0429] The binder polymer can preferably use a known binder polymer (for example, a (meth)acrylic acid resin, a polyvinyl acetal, a polyurethane resin, and the like) used in the image recording layer of a lithographic printing plate precursor.

[0430] As an example, the binder polymer used in an on-press development type lithographic printing plate precursor (hereinafter, also referred to as an on-press development binder polymer) is described in detail.

[0431] As the on-press development binder polymer, a binder polymer having an alkylene oxide chain is preferable. The binder polymer having an alkylene oxide chain can have a poly(alkylene oxide) site in the main chain or in the side chain. Further, it can be a graft polymer having a poly(alkylene oxide) in the side chain or a block copolymer of a block composed of a repeating unit containing a poly(alkylene oxide) and a block composed of a repeating unit not containing an alkylene oxide.

[0432] In the case of having a poly(alkylene oxide) site in the main chain, a polyurethane resin is preferable.

[0433] As the polymer that is the main chain when having a poly(alkylene oxide) moiety in the side chain, a (meth)acrylic resin, a polyvinyl acetal resin, a polyurethane resin, a polyurea resin, a polyimide resin, a polyamide resin, an epoxy resin, a polystyrene resin, a novolak phenol resin, a polyester resin, a synthetic rubber, a natural rubber, and the like can be given, and a (meth)acrylic resin is particularly preferable.

[0434] Further, as other preferable examples of the binder polymer, a high molecular compound having a core moiety of a polyfunctional mercaptan of 6 or more and 10 or less functions, and having polymer chains bonded to the core moiety via a thioether bond, and the polymer chains having a polymerizable group (hereinafter, also referred to as a star-shaped high molecular compound) can be given.

[0435] As the star-shaped high molecular compound, for example, a compound described in Japanese Patent Application Publication No. 2012-148555 can be preferably used.

[0436] As the star-shaped high molecular compound, a compound having a polymerizable group such as an olefinically unsaturated bond for improving the film strength of the image portion described in Japanese Patent Application Publication No. 2008-195018 on the main chain or the side chain, preferably the side chain can be given. Crosslinking is formed between the molecules of the star-shaped high molecular compound by the polymerizable group possessed by the star-shaped high molecular compound, and the curing is promoted.

[0437] As the polymerizable group, an olefinically unsaturated group such as a (meth)acrylic group, a vinyl group, an allyl group, a vinylphenyl group (styryl group), an epoxy group, and the like is preferable, and from the viewpoint of polymerizability, a (meth)acrylic group, a vinyl group, a vinylphenyl group (styryl group) is more preferable, and a (meth)acrylic group is particularly preferable. These groups can be introduced to the polymer by a high molecular reaction or copolymerization. Specifically, for example, a reaction of a polymer having a carboxyl group on the side chain with glycidyl methacrylate, or a reaction of a polymer having an epoxy group with a carboxylic acid containing an olefinically unsaturated group such as methacrylic acid can be utilized.

[0438] As the molecular weight of the binder polymer, the weight average molecular weight (Mw) based on the polystyrene conversion value by the GPC method is preferably 2,000 or more, more preferably 5,000 or more, and further preferably 10,000 to 300,000.

[0439] As the binder polymer, a hydrophilic polymer such as a polyacrylic acid, a polyvinyl alcohol, a polyvinyl acetal, and the like described in Japanese Patent Application Publication No. 2008-195018 can be used as needed in combination. Further, a lipophilic polymer and a hydrophilic polymer can also be used in combination.

[0440] Among them, from the viewpoint of on-press developability, the image recording layer preferably contains a polyvinyl acetal. As the polyvinyl acetal, for example, polyvinyl butyral or the like is preferably selected.

[0441] The binder polymer can be used singly or in combination of two or more.

[0442] The binder polymer can be contained in the image recording layer in any amount, but the content of the binder polymer is preferably 1 to 90 mass%, more preferably 5 to 80 mass%, relative to the total mass of the image recording layer.

[0443] - Oil agent -

[0444] The above image recording layer preferably further contains an oil agent.

[0445] The oil agent in the present application means a hydrophobic compound which is in a liquid state at 80°C and which does not mix but separates when mixed with the same mass of water.

[0446] In addition, in the case where two or more oil agents are used, even if a compound having a melting point of 80°C or higher is contained, as long as it is in a liquid state at 80°C in a state where two or more oil agents are mixed.

[0447] Further, from the viewpoint of on-press developability and fountain solution turbidity inhibitory property, the above oil agent is preferably a compound having a molecular weight of less than 1,000, more preferably a compound having a molecular weight of 200 to 800, and particularly preferably a compound having a molecular weight of 300 to 500.

[0448] Further, from the viewpoint of on-press developability and fountain solution turbidity inhibitory property, the above oil agent is preferably a compound having a boiling point of 200°C or higher at 1 atm, more preferably a compound having a boiling point of 250°C or higher at 1 atm, further preferably a compound having a boiling point of 300°C or higher at 1 atm, and particularly preferably a compound having a boiling point of 400°C or higher and 500°C or lower at 1 atm.

[0449] In addition, in the present application, unless otherwise specified, in the case where "boiling point" is referred to, it is the boiling point at 1 atm.

[0450] Further, from the viewpoint of on-press developability and fountain solution turbidity inhibitory property, the above oil agent preferably has a melting point of 50°C or lower at 1 atm, more preferably 30°C or lower at 1 atm, and particularly preferably -200°C or higher and 25°C or lower at 1 atm.

[0451] In addition, in the present application, unless otherwise specified, in the case where "melting point" is referred to, it is the melting point at 1 atm.

[0452] As the above-mentioned oil agent, a phosphoric acid ester compound, an aromatic hydrocarbon compound, a glycerin ester compound, a fatty acid compound, an aromatic ester compound, or the like can be given.

[0453] Among them, from the viewpoints of UV printing durability, ink receptivity, on-press development property, and dampening solution turbidity suppression property, at least one compound selected from the group consisting of a phosphoric acid ester compound, an aromatic hydrocarbon compound, a glycerin ester compound, and an aromatic ester compound is preferred, at least one compound selected from the group consisting of a phosphoric acid ester compound, an aromatic hydrocarbon compound, and a glycerin ester compound is more preferred, at least one compound selected from the group consisting of a phosphoric acid ester compound and an aromatic hydrocarbon compound is further preferred, and a phosphoric acid ester compound is particularly preferred.

[0454] As the phosphoric acid ester compound, from the viewpoints of UV printing durability, ink receptivity, on-press development property, and dampening solution turbidity suppression property, a phosphoric acid triester compound is preferred, a phosphoric acid triaryl ester compound is more preferred, and a mixture of two or more of ortho-, meta-, and para-positions of a trimethylphenyl phosphate is further preferred.

[0455] As the aromatic hydrocarbon compound, from the viewpoints of on-press development property and dampening solution turbidity suppression property, a compound having two or more aromatic rings is preferred, and a compound having two or more non-fused benzene rings is more preferred.

[0456] As the glycerin ester compound, from the viewpoints of on-press development property and dampening solution turbidity suppression property, a triglyceride compound is preferred, and a fatty oil is more preferred, and a fatty oil which is liquid at 25°C such as castor oil is particularly preferred.

[0457] As the fatty acid compound, from the viewpoints of on-press development property and dampening solution turbidity suppression property, an unsaturated fatty acid is preferred, an unsaturated fatty acid having 8 to 30 carbon atoms is more preferred, and an unsaturated fatty acid having 12 to 24 carbon atoms is particularly preferred.

[0458] As the aromatic ester compound, from the viewpoints of on-press development property and dampening solution turbidity suppression property, an aromatic diester compound is preferred, and an aromatic diester compound having an aliphatic ring is more preferred.

[0459] As the aliphatic ester compound, from the viewpoints of on-press development property and dampening solution turbidity suppression property, an aliphatic ester compound having a branched alkyl group is preferred, and an aliphatic ester compound having a branched alkyl group and having 10 to 24 carbon atoms is more preferred.

[0460] As the above-mentioned oil agent, from the viewpoints of UV printing durability, ink receptivity, on-press development property, and dampening solution turbidity suppression property, an oil agent having a phosphorus atom is preferred, and an oil agent having a phosphorus atom is more preferred.

[0461] Further, as the above-mentioned oil agent, from the viewpoints of on-press developability and fountain solution turbidity inhibitory property, it is preferable to contain an oil agent having an aromatic ring, more preferable to contain an oil agent having two or more aromatic rings, and particularly preferable to contain an oil agent having two or more unconjugated benzene rings.

[0462] From the viewpoints of UV printing durability, ink receptivity, on-press developability, and fountain solution turbidity inhibitory property, the clogP value of the above-mentioned oil agent is preferably 5.0 or more, more preferably 5.50 or more, further preferably 5.50 or more and 10.0 or less, and particularly preferably 5.60 or more and 7.00 or less.

[0463] The clogP value refers to a value obtained by calculating the common logarithm logP of the partition coefficient P of 1-octanol and water. As to the method and software for calculating the clogP value, a publicly known method and software can be used, but unless otherwise specified, the ClogP program incorporated in ChemBioDraw Ultra 12.0 of Cambridge soft Co. is used in the present application.

[0464] As the above-mentioned oil agent, specifically, for example, trimethylphenyl phosphate, dimethyl(l-phenylethyl)benzene, 2,4-diphenyl-4-methyl-l-pentene, dicyclohexyl phthalate, castor oil, a-linolenic acid, tris(2-ethylhexyl)phosphate, and the like can be mentioned.

[0465] The above-mentioned oil agent can be used alone or in combination of two or more, but from the viewpoints of on-press developability and fountain solution turbidity inhibitory property, the above-mentioned image recording layer preferably contains two or more oil agents having different structures.

[0466] The content of the above-mentioned oil agent is preferably 0.0001 mass% to 10.0 mass%, more preferably 0.0002 mass% to 1.0 mass%, further preferably 0.0005 mass% to 0.5 mass%, and particularly preferably 0.001 mass% to 0.05 mass%, with respect to the total mass of the image recording layer.

[0467] - Color developer -

[0468] The image recording layer in the present application preferably further contains a color developer, and more preferably further contains an acid color developer. Further, as the color developer, it is preferable to contain a leuco compound.

[0469] The "color developer" used in the present application refers to a compound having a property of developing color or decoloring and changing the color of an image recording layer by stimulation of light, acid, or the like, and the "acid color developer" refers to a compound having a property of developing color or decoloring and changing the color of an image recording layer by heating in a state of accepting an electron-accepting compound (for example, a proton such as acid). As the acid color developer, a colorless compound having a partial skeleton of lactone, lactam, sultone, spiropyran, ester, amide, or the like, and rapidly ring-opening or cleaving at the time of contact with an electron-accepting compound is particularly preferable.

[0470] As an example of such an acid color developer, the compounds described in paragraphs 0184 to 0191 of Japanese Patent Application Publication No. 2019-18412 can be given.

[0471] Among them, from the viewpoint of visual recognition, the color developer used in the present application is preferably at least one compound selected from the group consisting of a spiropyran compound, a spirooxazine compound, a spironolactone compound, and a spiroamide compound.

[0472] As the hue of the colorant after color development, from the viewpoint of visibility, it is preferable to have an absorption wavelength maximum in the range of 450 to 650 nm. As the color tone, it is preferable to be red, purple, blue, or dark green.

[0473] Also, from the viewpoints of visual recognition and visual recognition of the exposed portion, the above acid color developer is preferably a colorless colorant.

[0474] As the above colorless colorant, there is no particular limitation as long as it is a colorant having a colorless structure, but it is preferable to have a helical structure, and more preferable to have a spironolactone ring structure.

[0475] Also, as the above colorless colorant, from the viewpoints of visual recognition and visual recognition of the exposed portion, it is preferable to be a colorless colorant having a phthaloperine structure or a fluoran parent structure.

[0476] Furthermore, from the viewpoints of visual recognition and visual recognition of the exposed portion, the above colorless colorant having a phthaloperine structure or a fluoran parent structure is preferably a compound represented by any one of the following Formulae (Le-1) to (Le-3), and more preferably a compound represented by the following Formula (Le-2).

[0477] [Chemical Formula 25]

[0478]

[0479] In Formulae (Le-1) to (Le-3), ERG independently represents an electron-donating group, X1to X4independently represent a hydrogen atom, a halogen atom, or a dialkylanilino group, X5to X 10respectively, independently represent a hydrogen atom, a halogen atom or a monovalent organic group, Y1and Y2respectively independently represent C or N, X1is not present in the case where Y1is N, X4is not present in the case where Y2is N, Ra1represents a hydrogen atom, an alkyl group or an alkoxy group, and Rb1to Rb4respectively independently represent a hydrogen atom, an alkyl group, an aryl group or a heteroaryl group.

[0480] As the electron-donating group in the ERG of formula (Le-1) to formula (Le-3), from the viewpoints of color developability and visual recognition of the exposed portion, an amino group, an alkylamino group, an arylamino group, a heteroarylamino group, a dialkylamino group, a monoalkylmonoaryl amino group, a monoalkylmonoheteroaryl amino group, a diarylamino group, a diheteroarylamino group, a monoarylm onoheteroarylamino group, an alkoxy group, an aryloxy group, a heteroaryloxy group or an alkyl group is preferred, an alkoxy group, an aryloxy group, a heteroaryloxy group or an alkyl group is more preferred, and an alkoxy group is particularly preferred.

[0481] Further, as the electron-donating group in the ERG, from the viewpoints of color developability and visual recognition of the exposed portion, a disubstituted amino group having an aryl group having a substituent at at least one ortho position or a heteroaryl group having a substituent at at least one ortho position is preferred, a disubstituted amino group having a phenyl group having a substituent at at least one ortho position and an electron-donating group at a para position is more preferred, a disubstituted amino group having a phenyl group having a substituent at at least one ortho position and an aryl group or a heteroaryl group having an electron-donating group at a para position is further preferred, and a disubstituted amino group having a phenyl group having a substituent at at least one ortho position and an aryl group or a heteroaryl group having an electron-donating group at a para position is particularly preferred.

[0482] In addition, in the present application, the ortho position in an aryl group or a heteroaryl group other than a phenyl group means a bonding position adjacent to the above-mentioned 1-position when the bonding position of the aryl group or the heteroaryl group to other structures is the 1-position (for example, the 2-position, etc.).

[0483] Further, as the electron-donating group possessed by the above-mentioned aryl group or heteroaryl group, from the viewpoints of color developability and visual recognition of the exposed portion, an amino group, an alkylamino group, an arylamino group, a heteroarylamino group, a dialkylamino group, a monoalkylmonoaryl amino group, a monoalkylmonoheteroaryl amino group, a diarylamino group, a diheteroarylamino group, a monoarylm onoheteroarylamino group, an alkoxy group, an aryloxy group, a heteroaryloxy group or an alkyl group is preferred, an alkoxy group, an aryloxy group, a heteroaryloxy group or an alkyl group is more preferred, and an alkoxy group is particularly preferred.

[0484] From the viewpoints of color developability and visual recognition of the exposed portions, X1to X4in Formula (Le-1) to Formula (Le-3) are each independently preferably a hydrogen atom or a chlorine atom, more preferably a hydrogen atom.

[0485] From the viewpoints of color developability and visual recognition of the exposed portions, X5to X8in Formula (Le-2) or Formula (Le-3) are each independently preferably a hydrogen atom, a halogen atom, an alkyl group, an aryl group, an amino group, an alkylamino group, an arylamino group, a heteroaryl amino group, a dialkylamino group, a monoalkyl monoaryl amino group, a monoalkyl monoheteroaryl amino group, a diarylamino group, a diheteroaryl amino group, a monoaryl monoheteroaryl amino group, a hydroxyl group, an alkoxy group, an aryloxy group, a heteroaryloxy group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, a heteroaryloxycarbonyl group, or a cyano group, more preferably a hydrogen atom, a halogen atom, an alkyl group, an aryl group, an alkoxy group, or an aryloxy group, further preferably a hydrogen atom, a halogen atom, an alkyl group, or an aryl group, particularly preferably a hydrogen atom. 10 are each independently preferably a hydrogen atom, a halogen atom, an alkyl group, an aryl group, an amino group, an alkylamino group, an arylamino group, a heteroaryl amino group, a dialkylamino group, a monoalkyl monoaryl amino group, a monoalkyl monoheteroaryl amino group, a diarylamino group, a diheteroaryl amino group, a monoaryl monoheteroaryl amino group, a hydroxyl group, an alkoxy group, an aryloxy group, a heteroaryloxy group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, a heteroaryloxycarbonyl group, or a cyano group, more preferably a hydrogen atom, a halogen atom, an alkyl group, an aryl group, an alkoxy group, or an aryloxy group, further preferably a hydrogen atom, a halogen atom, an alkyl group, or an aryl group, particularly preferably a hydrogen atom.

[0486] From the viewpoints of color developability and visual recognition of the exposed portions, Y1and Y2in Formula (Le-1) to Formula (Le-3) are preferably at least one of C, more preferably both of Y1and Y2are C.

[0487] From the viewpoints of color developability and visual recognition of the exposed portions, Ra1in Formula (Le-1) to Formula (Le-3) is preferably an alkyl group or an alkoxy group, more preferably an alkoxy group, particularly preferably a methoxy group.

[0488] From the viewpoints of color developability and visual recognition of the exposed portions, Rb1to Rb4in Formula (Le-1) to Formula (Le-3) are each independently preferably a hydrogen atom or an alkyl group, more preferably an alkyl group, particularly preferably a methyl group.

[0489] Further, from the viewpoints of color developability and visual recognition of the exposed portions, the leuco colorant having the above phthalide structure or fluoran parent structure is more preferably a compound represented by any one of the following Formulae (Le-4) to (Le-6), further preferably a compound represented by the following Formula (Le-5).

[0490] [Chemical Formula 26]

[0491]

[0492] In Formula (Le-4) to Formula (Le-6), ERG represents an electron-donating group, X1to X4represent each independently a hydrogen atom, a halogen atom, or a dialkylanilino group, Y1and Y2represent each independently C or N, X1is not present in the case where Y1is N, X4is not present in the case where Y2is N, Ra1represents a hydrogen atom, an alkyl group, or an alkoxy group, and Rb1to Rb4represent each independently a hydrogen atom, an alkyl group, an aryl group, or a heteroaryl group.

[0493] ERG, X1to X4, Y1, Y2, Ra1, and Rb1to Rb4in formula (Le-4) to formula (Le-6) are the same as those in formula (Le-1) to formula (Le-3), and the preferable modes are also the same.

[0494] Furthermore, from the viewpoints of color development and visual recognition of the exposed portion, the above-mentioned leuco dye having a phthalide structure or a fluoran parent structure is further preferably a compound represented by any one of the following formula (Le-7) to formula (Le-9), and is particularly preferably a compound represented by the following formula (Le-8).

[0495] [Chemical Formula 27]

[0496]

[0497] In formula (Le-7) to formula (Le-9), X1to X4independently represent a hydrogen atom, a halogen atom, or a dialkylanilino group, Y1and Y2independently represent C or N, X1is not present in the case where Y1is N, X4is not present in the case where Y2is N, Ra1to Ra4independently represent a hydrogen atom, an alkyl group, or an alkoxy group, Rb1to Rb4independently represent a hydrogen atom, an alkyl group, an aryl group, or a heteroaryl group, and Rc1and Rc2independently represent an aryl group or a heteroaryl group.

[0498] X1to X4, Y1, and Y2in formula (Le-7) to formula (Le-9) are the same as those in formula (Le-1) to formula (Le-3), and the preferable modes are also the same.

[0499] From the viewpoints of color development and visual recognition of the exposed portion, Ra1to Ra4in formula (Le-7) or formula (Le-9) are each independently preferably an alkyl group or an alkoxy group, more preferably an alkoxy group, and particularly preferably a methoxy group.

[0500] From the viewpoints of color development and visual recognition of the exposed portion, Rb1to Rb4in formula (Le-7) to formula (Le-9) are each independently preferably a hydrogen atom or an aryl group substituted with an alkyl group or an alkoxy group, more preferably an alkyl group, and particularly preferably a methyl group.

[0501] From the viewpoints of color development and visual recognition of the exposed portion, Rc1and Rc2in formula (Le-8) are each independently preferably a phenyl group or an alkylphenyl group, and more preferably a phenyl group.

[0502] Further, in the formula (Le-8), from the viewpoints of color development and visual recognition of the exposed portion, Rc1and Rc2independently are preferably an aryl group having a substituent at at least one ortho position or a heteroaryl group having a substituent at at least one ortho position, more preferably an aryl group having a substituent at at least one ortho position, further preferably a phenyl group having a substituent at at least one ortho position, and particularly preferably a phenyl group having a substituent at at least one ortho position and an electron-donating group at a para position. As the above-mentioned substituent in Rc1and Rc2, the substituent described later can be mentioned.

[0503] Further, in the formula (Le-8), from the viewpoints of color development and visual recognition of the exposed portion, X1to X4are preferably hydrogen atoms, and Y1and Y2are preferably C.

[0504] Further, in the formula (Le-8), from the viewpoints of color development and visual recognition of the exposed portion, Rb1and Rb2independently are preferably an aryl group substituted with an alkyl group or an alkoxy group.

[0505] Further, in the formula (Le-8), from the viewpoints of color development and visual recognition of the exposed portion, Rb1and Rb2independently are preferably an aryl group or a heteroaryl group, more preferably an aryl group, further preferably an aryl group having an electron-donating group, and particularly preferably a phenyl group having an electron-donating group at a para position.

[0506] Further, as the above-mentioned electron-donating group in Rb1, Rb2, Rc1and Rc2, from the viewpoints of color development and visual recognition of the exposed portion, an amino group, an alkylamino group, an arylamino group, a heteroarylamino group, a dialkylamino group, a monoalkylmonoaryl amino group, a monoalkylmonoheteroaryl amino group, a diarylamino group, a diheteroarylamino group, a monoarylm onoheteroarylamino group, an alkoxy group, an aryloxy group, a heteroaryloxy group or an alkyl group is preferred, an alkoxy group, an aryloxy group, a heteroaryloxy group or an alkyl group is more preferred, and an alkoxy group is particularly preferred.

[0507] Further, as the acid color developer, from the viewpoints of color development and visual recognition of the exposed portion, a compound represented by the following formula (Le-10) is preferred.

[0508] [Chemical Formula 28]

[0509]

[0510] In the formula (Le-10), Ar1independently represents an aryl group or a heteroaryl group, and Ar2independently represents an aryl group having a substituent at at least one ortho position or a heteroaryl group having a substituent at at least one ortho position.

[0511] Ar1in the formula (Le-10) has the same meaning as Rb1and Rb2in the formulae (Le-7) to (Le-9), and the preferred modes are also the same.

[0512] Ar2in formula (Le-10) has the same meaning as Rc1and Rc2in formula (Le-7) to formula (Le-9), and the preferable modes are also the same.

[0513] The alkyl group in formula (Le-1) to formula (Le-9) can be linear, can have a branched chain, and can have a ring structure.

[0514] The number of carbon atoms of the alkyl group in formula (Le-1) to formula (Le-9) is preferably from 1 to 20, more preferably from 1 to 8, further preferably from 1 to 4, and particularly preferably 1 or 2.

[0515] The number of carbon atoms of the aryl group in formula (Le-1) to formula (Le-10) is preferably from 6 to 20, more preferably from 6 to 10, and particularly preferably from 6 to 8.

[0516] As the aryl group in formula (Le-1) to formula (Le-10), specifically, a phenyl group, a naphthyl group, an anthryl group, a phenanthryl group, and the like, which can have a substituent, can be given.

[0517] As the heteroaryl group in formula (Le-1) to formula (Le-10), specifically, a furyl group, a pyridyl group, a pyrimidyl group, a pyrazolyl group, a thiophenyl group, and the like, which can have a substituent, can be given.

[0518] Further, the monovalent organic group, the alkyl group, the aryl group, the heteroaryl group, the dialkylanilino group, the alkylamino group, the alkoxy group, and the like in formula (Le-1) to formula (Le-10) can have a substituent. As the substituent, an alkyl group, an aryl group, a heteroaryl group, a halogen atom, an amino group, an alkylamino group, an arylamino group, a heteroarylamino group, a dialkylamino group, a monoalkylmonoarylaminogroup, a monoalkylmonoheteroarylamino group, a diarylamino group, a diheteroarylamino group, a monoarylmonoheteroarylamino group, a hydroxyl group, an alkoxy group, an aryloxy group, a heteroaryloxy group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, a heteroaryloxycarbonyl group, a cyano group, and the like can be given. Further, these substituents can be further substituted with these substituents.

[0519] As the above-mentioned colorless pigments having a phthalide structure or a fluoran parent structure which can be preferably used, the following compounds can be given.

[0520] [Chemical Formula 29]

[0521]

[0522] [Chemical Formula 30]

[0523]

[0524] [Chemical Formula 31]

[0525]

[0526] [Chemical Formula 32]

[0527]

[0528] [Chemical Formula 33]

[0529]

[0530] [Chemical Formula 34]

[0531]

[0532] [Chemical Formula 35]

[0533]

[0534] [Chemical Formula 36]

[0535]

[0536] As the acid color developing agent, marketed products can also be used, and ETAC, RED500, RED520, CVL, S-205, BLACK305, BLACK400, BLACK100, BLACK500, H-7001, GREEN300, NIRBLACK78, BLUE220, H-3035, BLUE203, ATP, H-1046, H-2114 (manufactured by Fukui Yamada Chemical Co., Ltd.), ORANGE-DCF, Vermilion-DCF, PINK-DCF, RED-DCF, BLMB, CVL, GREEN-DCF, TH-107 (manufactured by HODOGAYA CHEMICAL CO., LTD.), ODB, ODB-2, ODB-4, ODB-250, ODB-Black XV, Blue-63, Blue-502, GN-169, GN-2, Green-118, Red-40, Red-8 (manufactured by YAMAMOTO CHEMICALS INC.), crystal violet lactone (manufactured by Tokyo Chemical Industry Co., Ltd.), and the like can be mentioned. Among these marketed products, ETAC, S-205, BLACK305, BLACK400, BLACK100, BLACK500, H-7001, GREEN300, NIRBLACK78, H-3035, ATP, H-1046, H-2114, GREEN-DCF, Blue-63, GN-169, crystal violet lactone are preferable because the visible light absorbance of the film formed is good.

[0537] As the colorless pigment which can be preferably used, the following compounds can be mentioned from the viewpoint of visual recognition and visual recognition of the exposed portion.

[0538] [Chemical Formula 37]

[0539]

[0540] These color developers can be used singly or in combination of two or more kinds.

[0541] The content of the color developer is preferably 0.5 to 10 mass% and more preferably 1 to 5 mass% with respect to the total mass of the image recording layer.

[0542] [Formation of the image recording layer]

[0543] The image recording layer in the lithographic printing plate precursor according to the present application can be formed, for example, by dispersing or dissolving the necessary components described above in a known solvent to prepare a coating solution, and applying the coating solution on a support by a known method such as bar coater application and drying, as described in paragraphs 0142 to 0143 of Japanese Patent Application Publication No. 2008-195018. The coating amount (solid content) of the image recording layer after the application and drying varies depending on the use, but is preferably 0.3 g / m 2 to 3.0 g / m 2 In this range, good sensitivity and good film properties of the image recording layer can be obtained.

[0544] As the solvent, a known solvent can be used. Specifically, for example, water, acetone, methyl ethyl ketone (2-butanone), cyclohexane, ethyl acetate, dichloroethane, tetrahydrofuran, toluene, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol dimethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, acetylacetone, cyclohexanone, diacetone alcohol, ethylene glycol monomethyl ether acetate, ethylene glycol ethyl ether acetate, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether acetate, 1-methoxy-2-propanol, 3-methoxy-1-propanol, methoxymethoxyethanol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, 3-methoxypropyl acetate, N,N-dimethylformamide, dimethyl sulfoxide, γ-butyrolactone, methyl lactate, ethyl lactate, and the like can be mentioned. The solvent can be used singly or in combination of two or more kinds. The solid content concentration in the coating solution is preferably 1 to 50 mass%.

[0545] The coating amount (solid content) of the image recording layer after the application and drying varies depending on the use, but is preferably 0.3 g / m2 ~ 3.0 g / m 2 .

[0546] Further, the image recording layer of the lithographic printing plate precursor according to the present application preferably has a film thickness of 0.1 μm to 3.0 μm, more preferably 0.3 μm to 2.0 μm.

[0547] In the present application, the film thickness of each layer in the lithographic printing plate precursor is confirmed by preparing a section cut along a direction perpendicular to the surface of the lithographic printing plate precursor, and observing the cross section of the section by a scanning electron microscope (SEM).

[0548] <Outermost layer>

[0549] The on-press development type lithographic printing plate precursor according to the present application preferably has an outermost layer on the image recording layer.

[0550] Further, the outermost layer preferably contains a color changeable compound from the viewpoint of visual recognition.

[0551] Further, the outermost layer is the outermost layer on the image recording layer side of the support in the on-press development type lithographic printing plate precursor.

[0552] The outermost layer can have a function of preventing scratches in the image recording layer, preventing ablation at the time of high-intensity laser exposure, and the like, in addition to a function of inhibiting an image formation hindering reaction by oxygen blocking.

[0553] - Color changeable compound -

[0554] Further, the outermost layer preferably contains a color changeable compound.

[0555] The outermost layer can contain other components such as a water-soluble polymer, a hydrophobic polymer, a sensitizing agent, an acid generator, an infrared absorber, in addition to the color changeable compound, preferably contains a color changeable compound and a water-soluble polymer, more preferably contains a color changeable compound, a water-soluble polymer, and a hydrophobic polymer.

[0556] In the present application, the "color changeable compound" refers to a compound in which the absorption in the visible light region (wavelength: 400 nm or more and less than 750 nm) changes due to infrared exposure. That is, in the present application, "color change" refers to a change in the absorption in the visible light region (wavelength: 400 nm or more and less than 750 nm) due to infrared exposure.

[0557] Specifically, as the color changeable compound in the present application, there can be mentioned (1) a compound in which the absorption in the visible light region increases due to infrared exposure compared to before the infrared exposure, (2) a compound which has the absorption in the visible light region due to infrared exposure, and (3) a compound which does not have the absorption in the visible light region due to infrared exposure.

[0558] In addition, the infrared rays in the present application are light rays having a wavelength of 750 nm to 1 mm, and preferably light rays having a wavelength of 750 nm to 1,400 nm.

[0559] As the color changeable compound, a compound that develops color due to infrared exposure is preferable.

[0560] Further, as the color changeable compound, a decomposable compound that decomposes due to infrared exposure is preferable, and a decomposable compound that decomposes by heat, electron transfer, or both, caused by infrared exposure is preferable.

[0561] More specifically, the color changeable compound in the present application is preferably a compound that decomposes (more preferably decomposes by heat, electron transfer, or both, caused by infrared exposure) due to infrared exposure, and a compound in which absorption in the visible region increases or absorption is shortened in wavelength and has absorption in the visible region compared to before infrared exposure.

[0562] Here, "decomposes by electron transfer" means that an electron excited from the HOMO (highest occupied molecular orbital) to the LUMO (lowest unoccupied molecular orbital) of the color changeable compound by infrared exposure is transferred to an electron-accepting group (a group having a potential close to the LUMO) within the molecule, and decomposition occurs as a result.

[0563] Hereinafter, a decomposable compound, which is an example of the color changeable compound, will be described.

[0564] As the decomposable compound, a compound that absorbs at least a part of light in the infrared wavelength region (wavelength region of 750 nm to 1 mm, and preferably wavelength region of 750 nm to 1,400 nm) and decomposes is acceptable, but a compound having a large absorption wavelength in the wavelength region of 750 nm to 1,400 nm is preferable.

[0565] More specifically, the decomposable compound is preferably a compound that decomposes due to infrared exposure and generates a compound having a large absorption wavelength in the wavelength region of 500 nm to 600 nm.

[0566] From the viewpoint of improving the visual recognition of the exposed portion, the decomposable compound is preferably a cyanine dye having a group (specifically, R 1 ) that decomposes by infrared exposure.

[0567] As the decomposable compound, from the viewpoint of improving the visual recognition of the exposed portion, a compound represented by the following Formula 1-1 is more preferable.

[0568] [Chemical Formula 38]

[0569]

[0570] In Formula 1-1, R 1 represents a group represented by any one of Formulas 2-1 to 4-1 below, R 11 to R 18 each independently represents a hydrogen atom, a halogen atom, -R a , -OR b , -SR c , or -NR d R e , R a to R e each independently represents a hydrocarbon group, A1, A2, and a plurality of R 11 to R 18 may be linked to form a monocyclic or polycyclic ring, A1and A2each independently represents an oxygen atom, a sulfur atom, or a nitrogen atom, n 11 and n 12 each independently represents an integer of 0 to 5, wherein the total of n 11 and n 12 is 2 or more, n 13 and n 14 each independently represents 0 or 1, and L represents an oxygen atom, a sulfur atom, or -NR 10 , R 10 represents a hydrogen atom, an alkyl group, or an aryl group, and Za represents a counter ion that neutralizes a charge.

[0571] [Chemical Formula 39]

[0572]

[0573] In Formulas 2-1 to 4-1, R 20 , R 30 , R 41 , and R 42 each independently represents an alkyl group or an aryl group, Zb represents a counter ion that neutralizes a charge, and the wavy line represents a bonding site with the group represented by L in Formula 1-1 above.

[0574] If the compound represented by Formula 1-1 is exposed to infrared light, R 1 -L bond is broken, and L becomes =O, =S, or =NR 10 , thereby changing color.

[0575] In Formula 1-1, R 1 represents a group represented by any one of Formulas 2-1 to 4-1 above.

[0576] Hereinafter, the group represented by Formula 2-1, the group represented by Formula 3-1, and the group represented by Formula 4-1 will be described.

[0577] In Formula 2-1, R 20 represents an alkyl group or an aryl group, and the wavy line portion represents a bonding site with the group represented by L in Formula 1-1.

[0578] As the alkyl group represented by R R20 , an alkyl group having 1 to 30 carbon atoms is preferred, an alkyl group having 1 to 15 carbon atoms is more preferred, and an alkyl group having 1 to 10 carbon atoms is further preferred.

[0579] The above alkyl group can be linear, can have a branched chain, or can have a ring structure.

[0580] As the aryl group represented by R 20 , an aryl group having 6 to 30 carbon atoms is preferred, an aryl group having 6 to 20 carbon atoms is more preferred, and an aryl group having 6 to 12 carbon atoms is further preferred.

[0581] As R 20 , an alkyl group is preferred from the viewpoint of visual recognition.

[0582] Also, from the viewpoints of decomposability and visual recognition, as the alkyl group represented by R 20 , a secondary alkyl group or a tertiary alkyl group is preferred, and a tertiary alkyl group is more preferred.

[0583] Also, from the viewpoints of decomposability and visual recognition, as the alkyl group represented by R 20 , an alkyl group having 1 to 8 carbon atoms is preferred, an alkyl group having 3 to 10 carbon atoms is more preferred, an alkyl group having 3 to 6 carbon atoms is further preferred, isopropyl or tert-butyl is particularly preferred, and tert-butyl is most preferred.

[0584] Hereinafter, specific examples of the group represented by the above Formula 2-1 will be shown, but the present application is not limited to these. In the following structural formulas, • represents a bonding site with the group represented by L in Formula 1-1.

[0585] [Chemical Formula 40]

[0586]

[0587] In Formula 3-1, R 30 represents an alkyl group or an aryl group, and the wavy line portion represents a bonding site with the group represented by L in Formula 1-1.

[0588] As the alkyl group and aryl group represented by R 30 , the same alkyl group and aryl group as represented by R 20 in Formula 2-1, and the same preferred mode is also preferred.

[0589] From the viewpoints of decomposability and visual recognition, as the alkyl group represented by R 30The alkyl group indicated is preferably a secondary alkyl group or a tertiary alkyl group, with a preference for a tertiary alkyl group.

[0590] Furthermore, from the perspective of decomposition and visual recognition, as a result of R 30 The alkyl group represented is preferably an alkyl group having 1 to 8 carbon atoms, more preferably a branched alkyl group having 3 to 10 carbon atoms, even more preferably a branched alkyl group having 3 to 6 carbon atoms, particularly preferably isopropyl or tert-butyl, and most preferably tert-butyl.

[0591] Moreover, from the perspective of decomposition and visual recognition, R 30 The alkyl group represented is preferably a substituted alkyl group, more preferably a fluorinated substituted alkyl group, even more preferably a perfluoroalkyl group, and especially preferably a trifluoromethyl group.

[0592] From the perspective of decomposition and visual recognition, by R 30 The aryl group represented is preferably a substituted aryl group. Examples of substituents include alkyl groups (preferably alkyl groups with 1 to 4 carbon atoms) and alkoxy groups (preferably alkoxy groups with 1 to 4 carbon atoms).

[0593] Hereinafter, specific examples of groups represented by Formula 3-1 above will be given, but the present invention is not limited to these. In the following structural formulas, ● indicates the bonding site with the group represented by L in Formula 1-1.

[0594] [Chemical Formula 41]

[0595]

[0596] In Equation 4-1, R 41 and R 42 Each group independently represents an alkyl or aryl group, Zb represents a counterion that neutralizes the charge, and the wavy line represents the bonding site with the group represented by L in Formula 1-1.

[0597] As a result of R 41 or R 42 The alkyl and aryl groups represented are related to R in Formula 2. 20 The alkyl and aryl groups are represented by the same terms, and the preferred methods are also the same.

[0598] As R 41 From the viewpoints of decomposability and visual recognizability, alkyl groups are preferred.

[0599] As R 42 From the viewpoints of decomposability and visual recognizability, alkyl groups are preferred.

[0600] From the perspective of decomposition and visual recognition, as a result of R 41 The alkyl group indicated is preferably an alkyl group having 1 to 8 carbon atoms, more preferably an alkyl group having 1 to 4 carbon atoms, and particularly preferably methyl.

[0601] From the viewpoints of the decomposability and the visual recognition, the alkyl group represented by R 42 is preferably a secondary alkyl group or a tertiary alkyl group, and is preferably a tertiary alkyl group.

[0602] From the viewpoints of the decomposability and the visual recognition, the alkyl group represented by R 42 is preferably an alkyl group having 1 to 8 carbon atoms, more preferably a branched alkyl group having 3 to 10 carbon atoms, further preferably a branched alkyl group having 3 to 6 carbon atoms, and particularly preferably isopropyl or tert-butyl, and most preferably is tert-butyl.

[0603] As for Zb in Formula 4-1, it is only required to be a counter ion for neutralizing a charge, and can also be included in Za in Formula 1-1 as a whole of the compound.

[0604] Zb is preferably a sulfonate ion, a carboxylate ion, a tetrafluoroborate ion, a hexafluorophosphate ion, a p-toluenesulfonate ion, or a perchlorate ion, and more preferably a tetrafluoroborate ion.

[0605] Hereinafter, specific examples of the group represented by the above Formula 4-1 will be shown, but the present application is not limited to these. In the following structural formulae, • indicates a bonding site with the group represented by L in Formula 1-1.

[0606] [Chemical Formula 42]

[0607]

[0608] In Formula 1-1, L is preferably an oxygen atom or -NR 10 , and particularly preferably an oxygen atom.

[0609] Further, R 10 in -NR 10 is preferably an alkyl group. As the alkyl group represented by R 10 , an alkyl group having 1 to 10 carbon atoms is preferred. Further, the alkyl group represented by R 10 may be linear, branched, or cyclic.

[0610] In the alkyl group, a methyl group or a cyclohexyl group is preferred.

[0611] In the case where R 10 in -NR 10 is an aryl group, an aryl group having 6 to 30 carbon atoms is preferred, an aryl group having 6 to 20 carbon atoms is more preferred, and an aryl group having 6 to 12 carbon atoms is further preferred. Further, these aryl groups can have a substituent.

[0612] In Formula 1-1, R 11 to R 18each independently is preferably a hydrogen atom, -R a , -OR b , -SR c , or -NR d R e .

[0613] R a to R e preferably represent a hydrocarbon group having 1 to 30 carbon atoms, more preferably a hydrocarbon group having 1 to 15 carbon atoms, and further preferably a hydrocarbon group having 1 to 10 carbon atoms.

[0614] The above hydrocarbon group can be linear, can have a branched chain, or can have a ring structure.

[0615] As the above hydrocarbon group, an alkyl group is particularly preferable.

[0616] As the above alkyl group, an alkyl group having 1 to 30 carbon atoms is preferable, an alkyl group having 1 to 15 carbon atoms is more preferable, and an alkyl group having 1 to 10 carbon atoms is further preferable.

[0617] The above alkyl group can be linear, can have a branched chain, or can have a ring structure.

[0618] Specific examples include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group, an undecyl group, a dodecyl group, a tridecyl group, a hexadecyl group, an octadecyl group, an eicosyl group, an isopropyl group, an isobutyl group, a sec-butyl group, a t-butyl group, an isopentyl group, a neopentyl group, a 1-methylbutyl group, an isohexyl group, a 2-ethylhexyl group, a 2-methylhexyl group, a cyclohexyl group, a cyclopentyl group, and a 2-norbornyl group.

[0619] Among the alkyl groups, a methyl group, an ethyl group, a propyl group, or a butyl group is preferable.

[0620] The above alkyl group can have a substituent.

[0621] Examples of the substituent include an alkoxy group, an aryloxy group, an amino group, an alkylthio group, an arylthio group, a halogen atom, a carboxyl group, a carboxylate group, a sulfo group, a sulfonate group, an alkoxycarbonyl group, an aryloxycarbonyl group, and a group formed by combining them.

[0622] R 11 to R 14 each independently is preferably a hydrogen atom or -R a (i.e., a hydrocarbon group), more preferably a hydrogen atom or an alkyl group, and further preferably a hydrogen atom except for the following cases.

[0623] wherein R 11 and R 13Alkyl groups are preferred, and the two are more preferably linked to form a ring. The ring formed can be a monocyclic or polycyclic ring. Specifically, examples of the formed ring include monocyclic rings such as cyclopentene ring, cyclopentadiene ring, cyclohexene ring, and cyclohexadiene ring, as well as polycyclic rings such as indene ring and indole ring.

[0624] Furthermore, in A1 + R bonded to the bonded carbon atom 12 Preferred and R 15 or R 16 (Preferred to be R) 16 The links form a ring, with R bonded to the carbon atom bonded to A2. 14 Preferred and R 17 or R 18 (Preferred to be R) 18 They are connected to form a ring.

[0625] In Equation 1-1, n is preferred. 13 R is 1. 16 -R a (i.e., hydrocarbon group).

[0626] Furthermore, R 16 Preferred and in A1 + R bonded to the bonded carbon atom 12 The rings are linked together to form a ring. Preferably, the ring is an indole ring, a pyranonium ring, a thiopyridinium ring, a benzoxazoline ring, or a benzimidazolinium ring; from the viewpoint of improving the visual recognizability of the exposed portion, an indole ring is more preferred. These rings may also have substituents.

[0627] In Equation 1-1, n is preferred. 14 R is 1 18 -R a (i.e., hydrocarbon group).

[0628] Furthermore, R 18 Preferably, R is bonded to the carbon atom bonded to A2. 14 The rings are linked together to form a ring. Preferably, the ring is an indole ring, a pyran ring, a thiopyran ring, a benzoxazole ring, or a benzimidazole ring; from the viewpoint of improving the visual recognizability of the exposed portion, an indole ring is more preferred. These rings may also have substituents.

[0629] R in Equation 1-1 16 and R 18 Preferably, the same groups are formed, and if each forms a ring, it is preferable to form a ring other than A1. + All rings except A2 have the same structure.

[0630] R in Equation 1-1 15 and R 17 Preferably, they are the same group. And, R15 and R 17 is preferably -R a (i.e., a hydrocarbon group), more preferably an alkyl group, further preferably a substituted alkyl group.

[0631] In the compound represented by formula 1-1, R 15 and R 17 is preferably a substituted alkyl group.

[0632] As the substituted alkyl group represented by R 15 or R 17 , a group represented by any one of the following formulas (al) to (a4) can be given.

[0633] [Chemical Formula 43]

[0634]

[0635] In formulas (al) to (a4), R W0 represents an alkylene group having 2 to 6 carbon atoms, W represents a single bond or an oxygen atom, n W1 represents an integer of 1 to 45, R W1 represents an alkyl group having 1 to 12 carbon atoms or -C(=0)-R W5 , R W5 represents an alkyl group having 1 to 12 carbon atoms, R W2 to R W4 each independently represent a single bond or an alkylene group having 1 to 12 carbon atoms, and M represents a hydrogen atom, a sodium atom, a potassium atom, or an onium group.

[0636] In formula (al), as the alkylene group represented by R W0 , ethylene, n-propylene, i-propylene, n-butylene, i-butylene, n-pentylene, i-pentylene, n-hexylene, i-hexylene, and the like can be given, preferably ethylene, n-propylene, i-propylene, or n-butylene, and particularly preferably n-propylene.

[0637] n W1 is preferably 1 to 10, more preferably 1 to 5, and particularly preferably 1 to 3.

[0638] As the alkyl group represented by R W1 , methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, t-butyl, n-pentyl, i-pentyl, neopentyl, n-hexyl, n-octyl, n-dodecyl, and the like can be given, preferably methyl, ethyl, n-propyl, i-propyl, or n-butyl, t-butyl, further preferably methyl or ethyl, and particularly preferably methyl.

[0639] The alkyl group represented by R W5 is the same as the alkyl group represented by R W1 , and the preferable modes are also the same as the alkyl group represented by RW1 The preferred method for representing alkyl groups is the same.

[0640] The following are specific examples of groups represented by formula (a1), but the invention is not limited to these. In the following structural formulas, Me represents methyl, Et represents ethyl, and * represents a bonding site.

[0641] [Chemical Formula 44]

[0642]

[0643] In equations (a2) to (a4), as R W2 ~R W4 Specific examples of the alkylene group include methylene, ethylene, n-propylene, isopropylene, n-butylene, isobutylene, n-pentylene, isopentylene, n-hexylene, isohexylene, n-octylene, n-dodecylene, etc., preferably ethylene, n-propylene, isopropylene or n-butylene, and especially preferably ethylene or n-propylene.

[0644] In equation (a3), there are two M values ​​that can be the same or different.

[0645] In formulas (a2) to (a4), examples of ononium groups represented by M include ammonium, iodonium, phosphonium, and sulfonium groups.

[0646] CO2M in formula (a2), PO3M2 in formula (a2), and SO3M in formula (a4) can all have anionic structures with M dissociation. The counter cation of the anionic structure can be A1. + It can also be R in Equation 1-1 1 -L can contain cations.

[0647] Among the groups represented by formulas (a1) to (a4), groups represented by formulas (a1), (a2), or (a4) are preferred.

[0648] n in Equation 1-1 11 and n 12 Preferably, they are the same, and all are preferably integers from 1 to 5, more preferably integers from 1 to 3, even more preferably 1 or 2, and especially preferably 2.

[0649] In Formula 1-1, A1 and A2 independently represent oxygen, sulfur, or nitrogen atoms, with nitrogen atoms being preferred.

[0650] In Formula 1-1, A1 and A2 are preferably the same atoms.

[0651] In Equation 1-1, Za represents the counter ion that neutralizes the charge.

[0652] If R 11 ~R 18and R 1 -L is an electrically neutral group, Za becomes a monovalent counter anion. However, R 11 ~R 18 and R 1 -L can have an anionic structure or a cationic structure, for example, in the case where R 11 ~R 18 and R 1 -L has two or more anionic structures, Za can also become a counter cation.

[0653] In addition, if the cyanine dye represented by Formula 1-1 is an electrically neutral structure in the entirety of the compound other than Za, Za is not required.

[0654] In the case where Za is a counter anion, sulfonate ions, carboxylate ions, tetrafluoroborate ions, hexafluorophosphate ions, p-toluenesulfonate ions, perchlorate ions, and the like can be given, and tetrafluoroborate ions are preferred.

[0655] In the case where Za is a counter cation, alkali metal ions, alkaline earth metal ions, ammonium ions, pyridinium ions, sulfonium ions, and the like can be given, and sodium ions, potassium ions, ammonium ions, pyridinium ions, or sulfonium ions are preferred, and sodium ions, potassium ions, or ammonium ions are more preferred.

[0656] As the decomposable compound, from the viewpoint of improving the visual recognition of the exposed portion, a compound represented by the following Formula 1-2 (i.e., a cyanine dye) is more preferred.

[0657] [Chemical Formula 45]

[0658]

[0659] In Formula 1-2, R 1 represents a group represented by any one of the above Formulae 2-1 to 4-1, R 19 ~R 22 each independently represent a hydrogen atom, a halogen atom, -R a , -OR b , -CN, -SR c , or -NR d R e , R 23 , and R 24 each independently represent a hydrogen atom or -R a , R a ~R e each independently represent a hydrocarbon group, R 19 and R 20 , R 21 and R 22 , or R 23 and R24 They can be linked to form single or multiple rings, where L represents an oxygen atom, a sulfur atom, or -NR. 10 -, R 10 R represents a hydrogen atom, alkyl group, or aryl group. d1 ~R d4 W 1 and W 2 Each of these can independently represent an alkyl group that may have substituents, and Za represents a counterion that neutralizes the charge.

[0660] R in Equation 1-2 1 R in Equation 1-1 1 The meanings are the same, and the preferred selection methods are also the same.

[0661] In equation 1-2, R 19 ~R 22 Each is independently preferred to be a hydrogen atom, a halogen atom, or -R. a -OR b Or -CN.

[0662] More specifically, R 19 and R 21 Preferably hydrogen atoms or -R a .

[0663] Furthermore, R 20 and R 22 Preferably hydrogen atoms, -R a -OR b Or -CN.

[0664] As a result of R 19 ~R 22 -R indicates a Preferably alkyl or alkenyl groups.

[0665] In R 19 ~R 22 All are -R a In the case of R, it is preferred 19 With R 20 and R 21 With R 22 They can be linked together to form single or multiple rings.

[0666] As R 19 With R 20 or R 21 With R 22 Examples of rings formed by linkages include benzene rings and naphthalene rings.

[0667] In Equation 1-2, R is preferred. 23 With R 24 They can be linked together to form single or multiple rings.

[0668] As R23 R 24 linked to form a ring, and the ring can be a monocyclic ring or a polycyclic ring. As the ring formed, specifically, a monocyclic ring such as a cyclopentene ring, a cyclopentadiene ring, a cyclohexene ring, a cyclohexadiene ring, and the like, and a polycyclic ring such as an indene ring and the like can be given.

[0669] In Formula 1-2, R d1 ~R d4 is preferably an unsubstituted alkyl group. Also, R d1 ~R d4 are preferably the same group.

[0670] As the unsubstituted alkyl group, an unsubstituted alkyl group having 1 to 4 carbon atoms can be given, and a methyl group is preferable.

[0671] In Formula 1-2, from the viewpoint of improving the water solubility of the compound represented by Formula 1-2, W 1 and W 2 are each independently preferably a substituted alkyl group.

[0672] As the substituted alkyl group represented by W 1 and W 2 , a group represented by any one of Formula (al) to Formula (a4) in Formula 1-1 can be given, and the preferable modes are the same.

[0673] Also, from the viewpoint of on-press developability, W 1 and W 2 are each independently preferably an alkyl group having a substituent, and are a group having at least -OCH2CH2-, a sulfo group, a salt of a sulfo group, a carboxyl group, or a salt of a carboxyl group as the substituent.

[0674] Za represents a counter ion that neutralizes the charge within the molecule.

[0675] If R 19 ~R 22 , R 23 ~R 24 , R d1 ~R d4 , W 1 , W 2 , and R 1 -L are all electrically neutral groups, Za becomes a monovalent counter anion. However, R 19 ~R 22 , R 23 ~R 24 , R d1 ~R d4 , W 1 , W 2 , and R 1 -L can have an anionic structure or a cationic structure, for example, in R19 ~R 22 R 23 ~R 24 R d1 ~R d4 W 1 W 2 and R 1 When -L has more than two anionic structures, Za can also become a counter cation.

[0676] Furthermore, if the compound represented by Formula 1-2 has an electrically neutral structure in the whole of the compound except for Za, then Za is not required.

[0677] The examples of Za as a counter anion are the same as those of Za in Formula 1-1, and the preferred methods are also the same. Furthermore, the examples of Za as a counter cation are also the same as those of Za in Formula 1-1, and the preferred methods are also the same.

[0678] From the viewpoint of decomposability and visual recognition, anthocyanins, as decomposable compounds, are further preferably compounds represented by any one of the following formulas 1-3 to 1-7.

[0679] In particular, from the viewpoint of decomposability and visual recognizability, compounds represented by any one of Formulas 1-3, 1-5 and 1-6 are preferred.

[0680] [Chemical Formula 46]

[0681]

[0682] In equations 1-3 to 1-7, R 1 R represents any one of the groups represented by formulas 2-1 to 4-1 above. 19 ~R 22 Each of the following can be used independently to represent a hydrogen atom, a halogen atom, and -R. a -OR b -CN, -SR c or -NR d R e R 25 and R 26 Each can be used independently to represent a hydrogen atom, a halogen atom, or -R. a R a ~R e Each independently represents a hydrocarbon group, R 19 With R 20 R 21 With R 22 Or R 25 With R 26 They can be linked to form single or multiple rings, where L represents an oxygen atom, a sulfur atom, or -NR. 10 -, R10 R represents a hydrogen atom, alkyl group, or aryl group. d1 ~R d4 W 1 and W 2 Each of these can independently represent an alkyl group that may have substituents, and Za represents a counterion that neutralizes the charge.

[0683] R in Equations 1-3 to 1-7 1 R 19 ~R 22 R d1 ~R d4 W 1 W 2 and L and R in Equation 1-2 1 R 19 ~R 22 R d1 ~R d4 W 1 W 2 The meanings of L and L are the same, and the preferred selection methods are also the same.

[0684] R in Equation 1-7 25 and R 26 Each atom is preferably a hydrogen atom or an alkyl group, more preferably an alkyl group, and especially preferably a methyl group.

[0685] The following are specific examples of anthocyanins that are decomposable compounds, but the present invention is not limited to these.

[0686] [Chemical Formula 47]

[0687]

[0688] Furthermore, as a decomposable compound, anthocyanin is preferably an infrared-absorbing compound as described in International Publication No. 2019 / 219560.

[0689] Furthermore, the aforementioned color-changing compounds may contain acid color-developing agents.

[0690] As an acid developer, an acid developer that is recorded as an acid developer in an image recording layer can be used, and the preferred method is also the same.

[0691] Color-changing compounds can be used alone or in combination with two or more components.

[0692] As a chromogenic compound, it can be used in combination with the decomposition compounds already described and the acid-producing agents described later.

[0693] From the viewpoint of visual recognition, the content of the color changeable compound in the outermost layer is preferably 0.10 to 50 mass%, more preferably 0.50 to 30 mass%, and further preferably 1.0 to 20 mass%, relative to the total mass of the outermost layer.

[0694] From the viewpoint of visual recognition, the content M of the color changeable compound in the outermost layer described above X to the content M of the infrared absorber in the image recording layer described above Y is preferably 0.1 or more, more preferably 0.2 or more, and particularly preferably 0.3 or more and 3.0 or less. X / M Y is preferably 0.1 or more, more preferably 0.2 or more, and particularly preferably 0.3 or more and 3.0 or less.

[0695] -Water-soluble polymer-

[0696] From the viewpoint of development removability (more preferably on-press development), the outermost layer preferably contains a water-soluble polymer.

[0697] In the present application, the water-soluble polymer refers to a polymer that dissolves 1 g or more in 100 g of pure water at 70°C, and a polymer that does not precipitate even when a solution obtained by dissolving 1 g of the polymer in 100 g of pure water at 70°C is cooled to 25°C.

[0698] As the water-soluble polymer used in the outermost layer, for example, polyvinyl alcohol, modified polyvinyl alcohol, polyvinylpyrrolidone, water-soluble cellulose derivative, polyethylene glycol, poly(meth)acrylonitrile, and the like can be given.

[0699] As the modified polyvinyl alcohol, an acid-modified polyvinyl alcohol having a carboxyl group or a sulfo group can be preferably used. Specifically, the modified polyvinyl alcohol described in Japanese Patent Application Publication No. 2005-250216 and Japanese Patent Application Publication No. 2006-259137 can be given.

[0700] As the water-soluble polymer, polyvinyl alcohol can be given as a preferable example. Among them, a polyvinyl alcohol having a saponification degree of 50% or more is further preferably used as the water-soluble polymer.

[0701] The saponification degree is preferably 60% or more, more preferably 70% or more, and further preferably 85% or more. The upper limit of the saponification degree is not particularly limited, and can be 100% or less.

[0702] The saponification degree can be measured according to the method described in JIS K 6726: 1994.

[0703] As the water-soluble polymer, polyvinylpyrrolidone can be given as a preferable example.

[0704] As the water-soluble polymer, polyvinyl alcohol and polyvinylpyrrolidone are also preferably used in combination.

[0705] The water-soluble polymer can be used singly or in combination of two or more.

[0706] In the case where the water-soluble polymer is contained in the outermost layer, the content of the water-soluble polymer is preferably 1 to 99 mass%, more preferably 3 to 97 mass%, and further preferably 5 to 95 mass%, relative to the total mass of the outermost layer.

[0707] - Other Components -

[0708] The above-mentioned outermost layer can contain, in addition to the discoloration compound and the water-soluble polymer described above, other components such as a hydrophobic polymer, a sensitizing agent, an acid generator, and an infrared absorber.

[0709] Hereinafter, the other components will be described.

[0710] << Hydrophobic Polymer >>

[0711] The above-mentioned outermost layer preferably contains a hydrophobic polymer.

[0712] The hydrophobic polymer refers to a polymer that is dissolved in less than 1 g or not dissolved in 100 g of pure water at 70°C.

[0713] As the hydrophobic polymer, for example, polyethylene, polystyrene, polyvinyl chloride, polyvinylidene chloride, poly (alkyl) (meth) acrylate (e.g., polymethyl (meth) acrylate, polyethyl (meth) acrylate, polybutyl (meth) acrylate, etc.), a copolymer obtained by combining raw material monomers of these polymers, and the like can be given.

[0714] Further, as the hydrophobic polymer, a polyvinylidene chloride resin is preferably contained.

[0715] Further, as the hydrophobic polymer, a styrene-acrylic acid copolymer is preferably contained.

[0716] Further, from the viewpoint of on-press developability, the hydrophobic polymer is preferably a hydrophobic polymer particle.

[0717] The hydrophobic polymer can be used singly or in combination of two or more.

[0718] In the case where the hydrophobic polymer is contained in the outermost layer, the content of the hydrophobic polymer is preferably 1 to 80 mass%, and more preferably 5 to 50 mass%, relative to the total mass of the outermost layer.

[0719] << Acid Generator >>

[0720] In the case where the acid color developing agent is used as the color changing compound in the outermost layer described above, an acid generator is preferably contained.

[0721] The "acid generator" in the present application is a compound that generates an acid by light or heat, and specifically refers to a compound that generates an acid by decomposition through infrared exposure.

[0722] As the generated acid, a strong acid having a pKa of 2 or less, such as a sulfonic acid or hydrochloric acid, is preferred. The acid developing agent described above can be color changed by the acid generated from the acid generator.

[0723] Specifically, as the acid generator, an onium salt compound is preferred from the viewpoint of sensitivity and stability.

[0724] As a specific example of the onium salt preferred as the acid generator, the compounds described in paragraphs 0121 to 0124 of International Publication No. 2016 / 047392 can be given.

[0725] Among them, a sulfonate, a carboxylate, BPh4 - , BF4 - , PF6 - , CIO4 - , or the like of triarylsulfonium or diaryliodonium is preferred. Here, Ph represents a phenyl group.

[0726] The acid generator can be used alone or in combination with two or more kinds.

[0727] In the case where the acid generator is contained in the outermost layer, the content of the acid generator is preferably 0.5% by mass to 30% by mass, and more preferably 1% by mass to 20% by mass, with respect to the total mass of the outermost layer.

[0728] The outermost layer described above can contain, in addition to the components described above, a sensitizer, an inorganic layered compound, a surfactant, and the like, which are well known additives.

[0729] The outermost layer is formed by coating and drying using a well-known method.

[0730] The coating amount (solid content) of the outermost layer is preferably 0.01 g / m 2 to 10 g / m 2 , more preferably 0.02 g / m 2 to 3 g / m 2 , and particularly preferably 0.1 g / m 2 to 2.0 g / m 2 .

[0731] The film thickness of the outermost layer is preferably 0.1 μm to 5.0 μm, and more preferably 0.3 μm to 4.0 μm.

[0732] The thickness of the outermost layer is preferably 0.1 to 5.0 times, more preferably 0.2 to 3.0 times, the thickness of the image recording layer.

[0733] The outermost layer can contain a plasticizer for imparting flexibility, a surfactant for improving coatability, inorganic particles for controlling surface slip, and the like.

[0734] <Supporting Body>

[0735] The lithographic printing plate precursor according to the present application has a supporting body.

[0736] As the supporting body, a known supporting body for a lithographic printing plate precursor can be appropriately selected and used.

[0737] As the supporting body, a supporting body having a hydrophilic surface (hereinafter, also referred to as "hydrophilic supporting body") is preferred.

[0738] As the supporting body in the present application, an aluminum plate subjected to roughening treatment and anodization treatment by a known method is preferred. That is, the supporting body in the present application preferably has an aluminum plate and an anodized film of aluminum provided on the aluminum plate.

[0739] Further, the supporting body preferably has an aluminum plate and an anodized film of aluminum provided on the aluminum plate, the anodized film being located on the image recording layer side from the aluminum plate, the anodized film having micropores extending in the depth direction from the surface on the image recording layer side, the average diameter of the micropores at the surface of the anodized film being more than 10 nm and 100 nm or less.

[0740] Further, the micropores are preferably composed of a large-diameter pore portion extending from the surface of the anodized film to a position at a depth of 10 nm to 1,000 nm and a small-diameter pore portion communicating with the bottom of the large-diameter pore portion and extending from the communication position to a position at a depth of 20 nm to 2,000 nm, the average diameter of the large-diameter pore portion at the surface of the anodized film being 15 nm to 100 nm, and the average diameter of the small-diameter pore portion at the communication position being 13 nm or less.

[0741] Figure 1 is a schematic cross-sectional view of one embodiment of the aluminum supporting body 12a.

[0742] The aluminum support 12a has a laminated structure in which the aluminum plate 18 and the anodized film 20a (hereinafter, also simply referred to as "anodized film 20a") are laminated in this order. Further, the anodized film 20a in the aluminum support 12a is located on the image recording layer side more than the aluminum plate 18. That is, the lithographic printing plate precursor according to the present application preferably has at least the anodized film, the image recording layer, and the water-soluble resin layer in this order on the aluminum plate.

[0743] - Anodized Film -

[0744] Next, a preferred mode of the anodized film 20a will be described.

[0745] The anodized film 20a is a film produced on the surface of the aluminum plate 18 by anodizing treatment, and has ultrafine micropores 22a that are distributed uniformly and substantially perpendicularly to the surface of the film. The micropores 22a extend from the surface of the anodized film 20a on the image recording layer side (the surface of the anodized film 20a on the side opposite to the aluminum plate 18 side) in the thickness direction (aluminum plate 18 side).

[0746] The average diameter (average opening diameter) of the micropores 22a at the surface of the anodized film 20a is preferably more than 10 nm and 100 nm or less. Of these, from the viewpoint of the balance of print durability, stain resistance, and image visual recognition, more preferably 15 nm to 60 nm, further preferably 20 nm to 50 nm, and particularly preferably 25 nm to 40 nm. The diameter inside the pores can be wider than the surface layer or narrower than the surface layer.

[0747] In the case where the average diameter is more than 10 nm, the print durability and the image visual recognition are excellent. Further, in the case where the average diameter is 100 nm or less, the print durability is excellent.

[0748] The average diameter of the micropores 22a is a value obtained by using a field emission scanning electron microscope (FE-SEM) with a magnification of 150,000 times to observe the surface of the anodized film 20a at N = 4, measuring the diameter of the micropores present in a range of 400 nm x 600 nm at 50 places in the four obtained images, and averaging the values.

[0749] Further, in the case where the shape of the micropores 22a is not circular, the circular equivalent diameter is used. The "circular equivalent diameter" refers to the diameter of a circle when the shape of the opening portion is assumed to be a circle having the same projected area as the projected area of the opening portion.

[0750] The shape of the micropores 22a is not particularly limited, and Figure 1The micro-holes 22a are substantially straight pipe-shaped (substantially cylindrical), but can be conical with a diameter that decreases toward the depth direction (thickness direction). Also, the shape of the bottom of the micro-holes 22a is not particularly limited, and can be curved (convex) or flat.

[0751] In the support body, the above-described micro-holes can be composed of a large-diameter hole portion extending from the surface of the anodized film to a position at a certain depth, and a small-diameter hole portion communicating with the bottom of the large-diameter hole portion and extending from the communication position to a position at a certain depth.

[0752] For example, as shown in FIG. 2B, the aluminum support body 12b can be in a form including an aluminum plate 18 and an anodized film 20b having micro-holes 22b composed of a large-diameter hole portion 24 and a small-diameter hole portion 26. Figure 2

[0753] For example, the micro-holes 22b in the anodized film 20b are composed of a large-diameter hole portion 24 extending from the surface of the anodized film to a position at a depth of 10 nm to 1,000 nm (depth D: refer to FIG. 2B), and a small-diameter hole portion 26 communicating with the bottom of the large-diameter hole portion 24 and further extending from the communication position to a position at a depth of 20 nm to 2,000 nm. Specifically, for example, the method described in paragraphs 0107 to 0114 of Japanese Patent Application Publication No. 2019-162855 can be used. Figure 2

[0754] -Method for Manufacturing Support Body-

[0755] As the method for manufacturing the support body used in the present application, for example, a manufacturing method in which the following processes are sequentially performed is preferable.

[0756] • Roughening treatment process: a process of performing roughening treatment on an aluminum plate

[0757] • Anodizing treatment process: a process of anodizing the aluminum plate subjected to the roughening treatment

[0758] • Enlargement treatment process: a process of bringing the aluminum plate having an anodized film obtained in the anodizing treatment process into contact with an acid aqueous solution or an alkaline aqueous solution, and enlarging the diameter of the micro-holes in the anodized film

[0759] Hereinafter, the steps of each process will be described in detail.

[0760] << Roughening treatment process >>

[0761] ​​The roughening treatment step is a step of subjecting the surface of the aluminum plate to roughening treatment including electrochemical roughening treatment. This step is preferably performed before the anodizing treatment step described later, but if the surface of the aluminum plate already has a preferable surface shape, this step need not be performed in particular. It can be performed by the method described in paragraphs 0086 to 0101 of Japanese Patent Application Publication No. 2019-162855.

[0762] <<Anodizing treatment step>>

[0763] As for the steps of the anodizing treatment step, there is no particular limitation as long as the above-described micropores can be obtained, and known methods can be cited.

[0764] In the anodizing treatment step, an aqueous solution of sulfuric acid, phosphoric acid, oxalic acid, or the like can be used as an electrolyte. For example, the concentration of sulfuric acid can be cited as 100 g / L to 300 g / L.

[0765] The conditions of the anodizing treatment can be appropriately set according to the electrolyte used, but for example, the liquid temperature can be cited as 5°C to 70°C (preferably 10°C to 60°C), the current density can be cited as 0.5 A / dm 2 ~ 60 A / dm 2 (preferably 1 A / dm 2 ~ 60 A / dm 2 ), the voltage can be cited as 1 V to 100 V (preferably 5 V to 50 V), the electrolysis time can be cited as 1 second to 100 seconds (preferably 5 seconds to 60 seconds), and the film amount can be cited as 0.1 g / m 2 ~ 5 g / m 2 (preferably 0.2 g / m 2 ~ 3 g / m 2 ).

[0766] <<Pore expanding treatment>>

[0767] The pore expanding treatment is a treatment (pore diameter expanding treatment) of expanding the diameter (pore diameter) of the micropores present in the anodized film formed by the anodizing treatment step described above.

[0768] The pore expanding treatment can be performed by bringing the aluminum plate obtained by the anodizing treatment step described above into contact with an acid aqueous solution or an alkali aqueous solution. The method of contact is not particularly limited, and for example, immersion and spraying can be cited.

[0769] The support body can have a back coating layer containing an organic high molecular compound described in Japanese Patent Application Publication No. 5-45885 or an alkyl compound of silicon described in Japanese Patent Application Publication No. 6-35174, or the like on the side opposite to the image recording layer, as needed.

[0770] <Undercoat layer>

[0771] The lithographic printing plate precursor according to the present application preferably has a primer layer (sometimes also referred to as an intermediate layer) between the image-recording layer and the support. The primer layer enhances the adhesion of the support and the image-recording layer in the exposed portions, and makes the image-recording layer easy to be peeled from the support in the unexposed portions, and thus the primer layer contributes to the improvement of the developability without impairing the printing durability. Also, in the case of exposure with infrared laser, the primer layer functions as a heat insulating layer, and thus also has the effect of preventing the heat generated by exposure from diffusing to the support, resulting in the reduction of sensitivity.

[0772] As the compound used in the primer layer, a polymer having an adsorptive group capable of adsorbing to the surface of the support and a hydrophilic group can be mentioned. In order to improve the adhesion to the image-recording layer, a polymer having an adsorptive group and a hydrophilic group, and further a cross-linkable group is preferable. The compound used in the primer layer can be either a low molecular compound or a polymer. The compound used in the primer layer can be used by mixing two or more kinds as needed.

[0773] In the case where the compound used in the primer layer is a polymer, a copolymer of a monomer having an adsorptive group, a monomer having a hydrophilic group, and a monomer having a cross-linkable group is preferable.

[0774] As the adsorptive group capable of adsorbing to the surface of the support, a phenolic hydroxyl group, a carboxyl group, -PO3H2, -OPO3H2, -CONHSO2-, -SO2NHSO2-, -COCH2COCH3 are preferable. As the hydrophilic group, a sulfo group or a salt thereof, a salt of a carboxyl group are preferable. As the cross-linkable group, an acryloyl group, a methacryloyl group, an acrylamide group, a methacrylamide group, an allyl group, and the like are preferable.

[0775] The polymer can have a cross-linkable group introduced by the salt formation of a polar substituent of the polymer and a compound having a substituent having a charge opposite to the above-mentioned polar substituent and an olefinic unsaturated bond, and can further be copolymerized with a monomer other than the above-mentioned, preferably a hydrophilic monomer.

[0776] Specifically, a silane coupling agent having an olefinic double bond reactive group capable of addition polymerization described in Japanese Patent Application Laid-Open No. 10-282679, a phosphorus compound having an olefinic double bond reactive group described in Japanese Patent Application Laid-Open No. 2-304441 are preferable. Also, a low molecular or high molecular compound having a cross-linkable group (preferably an olefinic unsaturated bond group), a functional group interacting with the surface of the support, and a hydrophilic group described in Japanese Patent Application Laid-Open Nos. 2005-238816, 2005-125749, 2006-239867, 2006-215263 can also be preferably used.

[0777] As more preferable compounds, there can be mentioned the adsorptive group adsorbable to the surface of the support body, the high-molecular polymer having a hydrophilic group and a cross-linking group described in Japanese Patent Application Publication No. 2005-125749 and Japanese Patent Application Publication No. 2006-188038.

[0778] The content of the ethylenically unsaturated bond group in the polymer used in the undercoat layer is preferably 0.1 mmol to 10.0 mmol per 1 g of the polymer, and more preferably 0.2 mmol to 5.5 mmol.

[0779] The weight average molecular weight (Mw) of the polymer used in the undercoat layer is preferably 5,000 or more, and more preferably 10,000 to 300,000.

[0780] -Hydrophilic compound-

[0781] The undercoat layer preferably contains a hydrophilic compound from the viewpoint of development.

[0782] There is no particular limitation on the hydrophilic compound, and a publicly known hydrophilic compound used in the undercoat layer can be used.

[0783] As the hydrophilic compound, carboxymethyl cellulose, phosphonic acid having an amino group such as dextrin, organic phosphonic acid, organic phosphoric acid, organic phosphinic acid, amino acid, and hydroxyl group-containing amine hydrochloride are preferably selected.

[0784] Further, as the hydrophilic compound, a compound having an amino group or a functional group having a polymerization inhibiting ability and a group interacting with the surface of the support body (for example, 1,4-diazabicyclo[2.2.2]octane (DABCO), 2,3,5,6-tetrahydroxy-p-benzoquinone, chloranil, sulfophthalic acid, ethylenediaminetetraacetic acid (EDTA) or a salt thereof, hydroxyethylethylenediaminetriacetic acid or a salt thereof, dihydroxyethylenediaminediacetic acid or a salt thereof, hydroxyethyliminodiacetic acid or a salt thereof, and the like) is preferably selected.

[0785] As the hydrophilic compound, a hydroxycarboxylic acid or a salt thereof is preferably contained from the viewpoint of scratch contamination inhibition.

[0786] Further, from the viewpoint of scratch contamination inhibition, the hydrophilic compound, preferably a hydroxycarboxylic acid or a salt thereof, is preferably contained in the layer on the above-mentioned aluminum support body. Further, the layer on the above-mentioned aluminum support body is preferably a layer on the side on which the image recording layer is formed, and preferably a layer in contact with the above-mentioned aluminum support body.

[0787] As the layer on the above-mentioned aluminum support body, as the layer in contact with the above-mentioned aluminum support body, an undercoat layer or an image recording layer is preferably selected. Further, the hydrophilic compound, preferably a hydroxycarboxylic acid or a salt thereof, can be contained in a layer other than the layer in contact with the above-mentioned aluminum support body, for example, an outermost layer or an image recording layer.

[0788] In the lithographic printing plate precursor according to the present application, the image-recording layer preferably contains a hydroxycarboxylic acid or a salt thereof from the viewpoint of scratch contamination inhibition.

[0789] Also, in the lithographic printing plate precursor according to the present application, it is also preferable to adopt a method in which the surface of the image-recording layer side of the aluminum support is surface-treated with a composition (e.g., an aqueous solution or the like) containing at least a hydroxycarboxylic acid or a salt thereof. In the case of the above-described method, the treated hydroxycarboxylic acid or salt thereof can be detected in at least a part in a state of being contained in a layer on the image-recording layer side (e.g., the image-recording layer or the subbing layer) that contacts the aluminum support.

[0790] By containing a hydroxycarboxylic acid or a salt thereof in a layer on the image-recording layer side that contacts the aluminum support such as the subbing layer, the surface of the image-recording layer side of the aluminum support can be hydrophilized, and the contact angle with water based on the air bubble drop method on the surface of the image-recording layer side of the aluminum support can be easily set to 110° or less, and the scratch contamination inhibition is excellent.

[0791] A hydroxycarboxylic acid is a general term for an organic compound having one or more carboxyl groups and one or more hydroxyl groups in one molecule, and is also referred to as a hydroxy acid, an oxo acid, a hydroxycarboxylic acid, or an alcoholic acid (see Iwanami Shoten, "Rikagaku Jiten (5th edition)", published in 1998).

[0792] The above-described hydroxycarboxylic acid or salt thereof is preferably represented by the following formula (HC).

[0793] R HC (OH) mhc (COOM HC ) nhc Formula (HC)

[0794] In formula (HC), R HC represents an organic group having mhc+nhc valence, M HC each independently represents a hydrogen atom, an alkali metal, or onium, mhc and nhc each independently represents an integer of 1 or more, and in the case where n is 2 or more, M HC may be the same or different.

[0795] In formula (HC), as the organic group having mhc+nhc valence represented by R HC , a hydrocarbon group having mhc+nhc valence or the like can be given. The hydrocarbon group can have a substituent and / or a linking group.

[0796] As the hydrocarbon group, there can be mentioned mhc+nhc-valent groups derived from aliphatic hydrocarbons such as alkylene, alkane triyl, alkane tetrayl, alkane pentayl, alkenylene, alkene triyl, alkene tetrayl, alkene pentayl, alkynylene, alkyn triyl, alkyn tetrayl, alkyn pentayl, etc., and mhc+nhc-valent groups derived from aromatic hydrocarbons such as arylene, aralkane triyl, aralkane tetrayl, aralkane pentayl, etc. As the substituent, there can be mentioned alkyl, alkenyl, alkynyl, aralkyl, aryl, etc. As specific examples of the substituent, there can be mentioned methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, hexadecyl, octadecyl, eicosyl, isopropyl, isobutyl, sec-butyl, t-butyl, isopentyl, neopentyl, 1-methylbutyl, isohexyl, 2-ethylhexyl, 2-methylhexyl, cyclohexyl, cyclopentyl, 2-norbornyl, methoxymethyl, methoxyethoxymethyl, allyloxymethyl, phenoxymethyl, acetyloxymethyl, benzoyloxymethyl, benzyl, phenethyl, α-methylbenzyl, 1-methyl-l-phenylethyl, p-methylbenzyl, cinnamyl, allyl, 1-propenylmethyl, 2-butenyl, 2-methylallyl, 2-methylpropenylmethyl, 2-propynyl, 2-butynyl, 3-butynyl, phenyl, biphenyl, naphthyl, tolyl, xylyl, mesityl, cuminyl, methoxyphenyl, ethoxyphenyl, phenoxyphenyl, acetoxyphenyl, benzoyloxyphenyl, methoxycarbonylphenyl, ethoxycarbonylphenyl, phenoxycarbonylphenyl, etc. Furthermore, the linking group is composed of at least one atom selected from the group consisting of hydrogen atom, carbon atom, oxygen atom, nitrogen atom, sulfur atom and halogen atom, and the number of atoms is preferably 1 to 50. Specifically, there can be mentioned alkylene, substituted alkylene, arylene, substituted arylene, etc., and it can have a structure in which a plurality of these divalent groups are linked by any one of amide bond, ether bond, urethane bond, urea bond and ester bond.

[0797] As the alkali metal represented by M HC As the alkali metal represented by M HC Preferably, it is an alkali metal or onium, more preferably an alkali metal.

[0798] Furthermore, from the viewpoint of scratch contamination inhibitory property, M HC Preferably, it is an alkali metal or onium, more preferably an alkali metal.

[0799] The total number of mhc and nhc is preferably 3 or more, more preferably 3 to 8, and further preferably 4 to 6.

[0800] The molecular weight of the above hydroxycarboxylic acid or salt thereof is preferably 600 or less, more preferably 500 or less, and particularly preferably 300 or less. Furthermore, the above molecular weight is preferably 76 or more.

[0801] As the hydroxycarboxylic acid or the hydroxycarboxylic acid constituting the salt of the hydroxycarboxylic acid, specifically, there can be mentioned gluconic acid, glycolic acid, lactic acid, tartronic acid, hydroxybutyric acid (2-hydroxybutyric acid, 3-hydroxybutyric acid, γ-hydroxybutyric acid, etc.), malic acid, tartaric acid, citramalic acid, citric acid, isocitric acid, leucic acid, mevalonic acid, pantothenic acid, ricinolic acid, erucic acid, cerebric acid, quinic acid, shikimic acid, monohydroxybenzoic acid derivatives (salicylic acid, pyroligneous acid (homosalicylic acid, hydroxy(methyl)benzoic acid), vanillic acid, eugenol acid, etc.), dihydroxybenzoic acid derivatives (pyrogallol, dihydroxybenzoic acid, protocatechuic acid, gentisic acid, orsellinic acid, etc.), trihydroxybenzoic acid derivatives (gallic acid, etc.), phenylacetic acid derivatives (mandelic acid, benzoinic acid, atrolactic acid, etc.), hydrogenated cinnamic acid derivatives (o-hydroxyphenylpropionic acid, phloretic acid, coumaric acid, umbellic acid, caffeic acid, ferulic acid, sinapic acid, cerebric acid, kermesic acid, etc.), and the like.

[0802] Among these, as the hydroxycarboxylic acid or the hydroxycarboxylic acid constituting the salt of the hydroxycarboxylic acid, from the viewpoint of scratch contamination inhibition, a compound having two or more hydroxyl groups is preferable, a compound having three or more hydroxyl groups is more preferable, a compound having five or more hydroxyl groups is further preferable, and a compound having five to eight hydroxyl groups is particularly preferable.

[0803] Further, as the compound having one carboxyl group and two or more hydroxyl groups, gluconic acid or shikimic acid is preferable.

[0804] As the compound having two or more carboxyl groups and one hydroxyl group, citric acid or malic acid is preferable.

[0805] As the compound having two or more carboxyl groups and one hydroxyl group, citric acid or malic acid is preferable.

[0806] Among these, as the hydroxycarboxylic acid, gluconic acid is particularly preferable.

[0807] The hydrophilic compound can be used singly or in combination of two or more.

[0808] In the case where the base coat layer contains the hydrophilic compound, preferably the hydroxycarboxylic acid or the salt thereof, the content of the hydrophilic compound, preferably the hydroxycarboxylic acid and the salt thereof, is preferably 0.01 to 50 mass%, more preferably 0.1 to 40 mass%, and particularly preferably 1.0 to 30 mass%, relative to the total mass of the base coat layer.

[0809] In the base coat layer, in addition to the above-mentioned base coat layer compound, a chelating agent, a secondary or tertiary amine, a polymerization inhibitor, or the like can be further contained for the purpose of preventing contamination over time.

[0810] The base coat layer can be applied by a publicly known method.

[0811] The coating amount (solid content) of the primer layer is preferably 0.1 mg / m 2 ~ 300 mg / m 2 , more preferably 5 mg / m 2 ~ 200 mg / m 2 .

[0812] The lithographic printing plate precursor according to the present application can have other layers in addition to the above.

[0813] There is no particular limitation on the other layers, and publicly known layers can be used. For example, a back coating layer can be provided on the side of the support opposite to the image-recording layer side, as needed.

[0814] (Method for producing lithographic printing plate and lithographic printing method)

[0815] The method for producing a lithographic printing plate according to the present application preferably includes a step of exposing the lithographic printing plate precursor according to the present application to light in an image shape (exposure step) and a step of supplying at least one selected from a printing ink and a dampening solution on a printing machine to remove the image-recording layer of the non-image area from the exposed lithographic printing plate precursor (on-press developing step).

[0816] The method for producing a lithographic printing plate according to the present application preferably includes a step of exposing the lithographic printing plate precursor according to the present application to light in an image shape (exposure step) and a step of supplying at least one selected from a printing ink and a dampening solution on a printing machine to remove the image-recording layer of the non-image area from the exposed lithographic printing plate precursor (on-press developing step).

[0817] <Exposure step>

[0818] The method for producing a lithographic printing plate according to the present application preferably includes an exposure step of exposing the lithographic printing plate precursor according to the present application to light in an image shape and forming exposed areas and unexposed areas. The lithographic printing plate precursor according to the present application is preferably exposed to light in an image shape by laser exposure using a transparent original image having a line image, a dot image, or the like or by laser beam scanning based on digital data.

[0819] A light source having a wavelength of 750 nm to 1,400 nm is preferably used. As the light source having a wavelength of 750 nm to 1,400 nm, a solid laser and a semiconductor laser that radiate infrared rays are preferable. As for the infrared laser, the output power is preferably 100 mW or more, the exposure time per 1 pixel is preferably within 20 microseconds, and the irradiation energy is preferably 10 mJ / cm 2 ~ 300 mJ / cm 2Further, in order to shorten the exposure time, a multi-beam laser device is preferably used. The exposure mechanism can be any one of an inside drum system, an outside drum system, a flat plate system, and the like.

[0820] As for the image exposure, a conventional method can be used by using a plate making machine or the like. In the case of on-press development, the image exposure can be performed on a press after the lithographic printing plate precursor is mounted on the press.

[0821] <On-press development step>

[0822] The method for producing a lithographic printing plate according to the present application preferably includes an on-press development step of supplying at least one selected from a printing ink and a dampening solution to the press to remove the image recording layer from the non-image area.

[0823] Next, the on-press development method will be described.

[0824] [On-press development method]

[0825] In the on-press development method, the image-exposed lithographic printing plate precursor is preferably developed into a lithographic printing plate by supplying an oily ink and an aqueous component to the press and removing the image recording layer from the non-image area.

[0826] That is, if the image exposure is performed on the lithographic printing plate precursor, and then the lithographic printing plate precursor is mounted on the press without any development treatment, or if the image exposure is performed on the press after the lithographic printing plate precursor is mounted on the press, and then an oily ink and an aqueous component are supplied and printing is performed, at the initial stage of the printing, in the non-image area, the image recording layer that is not cured by either or both of the supplied oily ink and aqueous component is dissolved or dispersed and removed, and thus a hydrophilic surface is exposed in the portion. On the other hand, in the exposed area, the image recording layer that is cured by the exposure forms an oily ink-accepting portion having an oleophilic surface. The compound that is initially supplied to the plate can be either an oily ink or an aqueous component, but from the aspect of preventing contamination by the component of the image recording layer that is removed from the aqueous component, it is preferable to initially supply an oily ink. Thus, the lithographic printing plate precursor is on-press developed on the press and directly used for multiple printing. As the oily ink and the aqueous component, a general printing ink and dampening solution for lithographic printing are preferably used.

[0827] As the laser for image exposure of the lithographic printing plate precursor according to the present application, a light source having a wavelength of 750 nm to 1,400 nm is preferably used. The light source having a wavelength of 750 nm to 1,400 nm can be preferably used as the light source described above.

[0828] <Printing step>

[0829] The lithographic printing method according to the present application includes a printing step of supplying a printing ink to a lithographic printing plate and printing a recording medium.

[0830] There is no particular limitation on the printing ink, and various known inks can be used as needed. Also, as the printing ink, an oily ink or an ultraviolet-curable ink (UV ink) is preferably selected.

[0831] Also, in the printing step, a fountain solution can be supplied as needed.

[0832] Also, in the printing step, it is not necessary to stop the printing machine, and the printing can be continuously performed in the on-press development step or the development with the developing solution step.

[0833] There is no particular limitation on the recording medium, and a known recording medium can be used as needed.

[0834] In the method for producing a lithographic printing plate from a lithographic printing plate precursor according to the present application and the lithographic printing method according to the present application, the entire surface of the lithographic printing plate precursor can be heated as needed before exposure, during exposure, or from exposure to development. By this heating, the image-forming reaction in the image-recording layer can be promoted, and advantages such as an increase in sensitivity or printing durability, stabilization of sensitivity, and the like can be obtained. As for the heating before development, it is preferable to perform it under mild conditions at 150°C or lower. If the above is done, problems such as hardening of the non-image area can be prevented. As for the heating after development, it is preferable to use very strong conditions, and it is preferable to be in the range of 100°C to 500°C. If it is in the above range, sufficient image enhancement can be obtained, and problems such as deterioration of the support, thermal decomposition of the image area, and the like can be suppressed.

[0835] (Coloring agent)

[0836] The coloring agent according to the present application is a coloring agent represented by Formula 1 or Formula 2 below, is preferably a coloring agent of a compound having a Group 13 element, and is more preferably a coloring agent of an organic compound having a Group 13 element.

[0837] Also, the coloring agent according to the present application is preferably a coloring agent of a boron compound, and is more preferably a coloring agent of an organic boron compound.

[0838] [Chemical Formula 48]

[0839]

[0840] In Formula 1 and Formula 2, R 1 ~R 7 each independently represents a hydrogen atom or a monovalent organic group, L 1 and L 2 represent a divalent organic group, L 1R 2 and R 3 Two or more groups in, L 2 R 4 and R 6 Two or more groups in, and L 2 R 5 and R 7 Two or more groups in it can be linked together to form a ring structure.

[0841] The preferred embodiments of the colorants represented by Formula 1 or Formula 2 above are the same as the preferred embodiments of the compounds represented by Formula 1 or Formula 2 above, except as described below.

[0842] The colorant involved in this invention may contain only one colorant represented by Formula 1 or Formula 2 above, or it may contain two or more colorants.

[0843] From the viewpoint of colorimetry, the content of the colorimetric agent represented by Formula 1 or Formula 2 in the colorimetric agent involved in the present invention is preferably 0.1% to 100% by mass, more preferably 1% to 100% by mass, and particularly preferably 10% to 100% by mass, relative to the total mass of the colorimetric agent.

[0844] The colorant involved in this invention may also contain additives.

[0845] As an additive, known additives can be used, such as solvents, antioxidants, and dispersants.

[0846] Example

[0847] The present invention will now be described in detail through examples, but the invention is not limited thereto. In these examples, unless otherwise specified, "%" and "parts" refer to "mass %" and "parts by mass," respectively. Furthermore, in polymeric compounds, except for specifically defined polymeric compounds, the molecular weight is the weight-average molecular weight (Mw), and the ratio of repeating structural units is the molar percentage. The weight-average molecular weight (Mw) is a value determined as a polystyrene conversion value based on gel permeation chromatography (GPC).

[0848] Furthermore, C-1 to C-17 used in this embodiment are the same compounds as those described above.

[0849] Furthermore, in the following chemical structural formula, Me represents methyl and Ph represents phenyl.

[0850] <Method for determining the ratio of ketone bodies or imine bodies>

[0851] A sample 1.0 mg was dissolved in 0.5 mL of deuterated chloroform CDCl3 (manufactured by FUJIFILM Wako Pure Chemical Corporation), and NMR (manufactured by Bruker) measurement was performed at 25°C. The peak of the CH2group or the CHR group (R represents an arbitrary group corresponding to the compound contained in the sample to be measured) of the ketone body and the CH group of the enol body are different, and therefore the proportion (mole %) of the ketone body was calculated from the integral ratio. The imine body was also calculated by the same method.

[0852] < Synthesis of C-1 >

[0853] [Chemical Formula 49]

[0854]

[0855] In a 100 mL three-necked flask, 2,5-dimethylpyrazine 5.0 g (46.3 mmol, manufactured by Tokyo Chemical Industry Co., Ltd.), potassium tert-butoxide 15.6 g (t-BuOK, 138.8 mmol, manufactured by FUJIFILM Wako Pure Chemical Corporation), dimethylformamide (DMF) 30 mL (manufactured by FUJIFILM Wako Pure Chemical Corporation) were added, and heating stirring was performed at 70°C for 1 hour. Next, ethyl 4-dimethylaminobenzoate 13.4 g (69.4 mmol, manufactured by FUJIFILM Wako Pure Chemical Corporation) was added, and heating stirring was performed at 70°C for 4 hours. After the completion of the reaction, cooling was performed to room temperature (25°C, the same applies hereinafter). Next, an aqueous ammonium chloride solution 100 mL (manufactured by FUJIFILM Wako Pure Chemical Corporation) was added, and extraction was performed 3 times with 100 mL of diisopropyl ether (manufactured by FUJIFILM Wako Pure Chemical Corporation). Magnesium sulfate 20 g (manufactured by FUJIFILM Wako Pure Chemical Corporation) was added to the extracted diisopropyl ether layer, stirring was performed for 10 minutes, and then filtration was performed to remove the magnesium sulfate. Next, column chromatography (developing solvent: ethyl acetate / hexane = 1 / 2) was performed on the solid obtained by concentration under reduced pressure using a rotary evaporator, and the target fraction was again concentrated under reduced pressure using a rotary evaporator, thereby obtaining the target substance 2.0 g at a yield of 16.9%.

[0856] < Synthesis of C-2 and C-6 to C-15 >

[0857] Synthesis was performed in accordance with the synthesis of C-1, except that 2,5-dimethylpyrazine, 4-dimethylaminobenzoic acid ethyl ester was changed.

[0858] <Synthesis of C-3>

[0859] [Chemical Formula 50]

[0860]

[0861] In a three-necked flask, 6 mL (3 mmol, manufactured by Tokyo Chemical Industry Co., Ltd.) of a 0.5 mol / L toluene solution of Tebbe’s reagent, 6 mL of benzene were added. Then, 0.45 g (3.07 mmol, manufactured by Tokyo Chemical Industry Co., Ltd.) of 4-dimethylamino cyanide was added, and heating and stirring were performed at 60°C for 72 h. After cooling to room temperature, 10 g of sodium sulfate decahydrate (manufactured by FUJIFILM Wako Pure Chemical Corporation) was added, and stirring was performed for 30 minutes. The obtained solution was filtered, and the filtrate was concentrated under reduced pressure. The obtained solid was separated by column chromatography (developing solvent: diisopropyl ether / methylene chloride = 1 / 1), and the target fraction was concentrated under reduced pressure again using a rotary evaporator, thereby obtaining the target substance 0.36 g at a yield of 77.0%.

[0862] <Synthesis of C-4 and C-5>

[0863] Synthesis was performed in accordance with the synthesis of C-3, except that 4-dimethylamino cyanide was changed.

[0864] <Synthesis of C-16>

[0865] [Chemical Formula 51]

[0866]

[0867] After adding 2-cyanomethylpyridine 1.00 g (8.46 mmol, manufactured by Tokyo Chemical Industry Co., Ltd.) and tetrahydrofuran (THF) 50 mL (manufactured by FUJIFILM Wako Pure Chemical Corporation) in a three-necked flask, 60% sodium hydride (NaH) 1.35 g (33.9 mmol, manufactured by Tokyo Chemical Industry Co., Ltd.) was added, and stirring was performed at room temperature for 1 hour. Next, 2-bromopyridine 1.33 g (8.46 mmol, manufactured by Tokyo Chemical Industry Co., Ltd.) was added, and heating reflux was performed for 8 hours. After the reaction was completed, cooling was performed to room temperature, 0.1M (= mol / L) hydrochloric acid aqueous solution (manufactured by FUJIFILM Wako Pure Chemical Corporation) 500 mL was added to make it acidic, and saturated brine 50 mL was added. After extraction was performed three times with 50 mL of chloroform (manufactured by FUJIFILM Wako Pure Chemical Corporation), the obtained solution was concentrated under reduced pressure, and a solid was obtained.

[0868] The obtained solid was separated by column chromatography (developing solvent: dichloromethane), and the target fraction was concentrated under reduced pressure again using a rotary evaporator, whereby 0.20 g of the target was obtained at a yield of 12.1%.

[0869] <SYNTHESIS OF C-17>

[0870] The synthesis of C-17 was performed in accordance with the method described in paragraph 0298 of the specification of U.S. Patent Application Publication No. 2018 / 305552.

[0871] (Employment Examples 1 to 52 and Comparative Examples 1 to 4)

[0872] <MANUFACTURE OF SUPPORT 1>

[0873] A 0.3-mm-thick aluminum alloy sheet of material 1S was subjected to (A-a) mechanical roughening treatment (brushing method) described in paragraph 0126 to (A-i) dirt removal treatment in an acidic aqueous solution described in paragraphs 0134 of Japanese Patent Application Publication No. 2012-158022.

[0874] Next, each of the treatment conditions of the (A-j) first-stage anodization treatment described in paragraph 0135 to the (A-m) third-stage anodization treatment described in paragraph 0138 of Japanese Patent No. 2012-158022 was appropriately adjusted, and an anodized film was formed, which was used as the support 1.

[0875] In addition, water washing treatment was performed between all of the treatment processes, and drainage was performed by pinch rollers after the water washing treatment.

[0876] The details of the obtained support 1 were summarized.

[0877] Support 1: L * a * b * L in the lightness in the color system * : 83, average diameter of the large-diameter hole portion in the micropore at the anodized film surface: 35 nm (depth: 100 nm), average diameter of the small-diameter hole portion in the micropore at the communication position: 10 nm (depth: 1,000 nm), ratio of the depth of the large-diameter hole portion to the average diameter of the large-diameter hole portion: 2.9

[0878] <Production of Support 2>

[0879] - Alkaline etching treatment -

[0880] Etching treatment was performed by spraying an aqueous caustic soda solution having a caustic soda concentration of 26 mass% and an aluminum ion concentration of 6.5 mass% onto an aluminum plate using a spray at a temperature of 70°C. Then, water washing based on the spray was performed. The amount of aluminum dissolved from the surface on which the electrochemical roughening treatment was performed was 5 g / m 2 .

[0881] - Stain removal treatment using an acidic aqueous solution (first stain removal treatment) -

[0882] Next, a stain removal treatment was performed using an acidic aqueous solution. As the acidic aqueous solution used for the stain removal treatment, an aqueous solution of sulfuric acid at 150 g / L was used. The liquid temperature thereof was 30°C. The acidic aqueous solution was sprayed onto the aluminum plate using a spray, and a stain removal treatment was performed for 3 seconds. Then, water washing treatment was performed.

[0883] - Electrochemical roughening treatment -

[0884] Next, an electrochemical roughening treatment was performed using an electrolyte solution with a hydrochloric acid concentration of 14 g / L, an aluminum ion concentration of 13 g / L, and a sulfuric acid concentration of 3 g / L, employing alternating current. The electrolyte temperature was 30°C. The aluminum ion concentration was adjusted by adding aluminum chloride. The alternating current waveform was a symmetrical sine wave with a frequency of 50 Hz. The ratio of the anodic reaction time to the cathode reaction time in one cycle of the alternating current was 1:1, and the current density, measured as the peak current of the alternating current waveform, was 75 A / dm³. 2 Furthermore, the electrical charge, calculated as the total charge generated by the aluminum plate participating in the anode reaction, is 450 C / dm. 2 Regarding electrolytic treatment, with a 4-second energizing interval, at 112.5C / dm³ 2 The process was performed in four steps. A carbon electrode was used as the counter electrode in the aluminum plate. Then, a water washing process was carried out.

[0885] -Decontamination treatment using acidic aqueous solution-

[0886] 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 for decontamination was an aqueous solution with a sulfuric acid concentration of 170 g / L and an aluminum ion concentration of 5 g / L. The solution temperature was 30°C.

[0887] -Stage 1 Anodizing Treatment-

[0888] use Figure 3 The structure shown is based on a DC electrolytic anodizing device for the first stage of anodizing treatment, which forms an anodized film of a specified amount.

[0889] In addition, Figure 3 In the anodizing apparatus 610 shown, the aluminum plate 616 is as follows: Figure 3 The aluminum plate 616 is conveyed as indicated by the middle arrow. In the power supply tank 612 containing electrolyte 618, the aluminum plate 616 is charged (+) by the power supply electrode 620. Furthermore, the aluminum plate 616 is conveyed upwards in the power supply tank 612 by roller 622, then downwards by clamping roller 624, and finally conveyed to the electrolytic treatment tank 614 containing electrolyte 626, and then 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 conveyed to subsequent processes. In the anodizing treatment apparatus 610, roller 622, clamping roller 624, and roller 628 constitute a direction-changing mechanism. In the inter-tank section between the power supply tank 612 and the electrolytic treatment tank 614, the aluminum plate 616 is conveyed in a mountain-shaped and inverted U-shaped manner by the aforementioned rollers 622, 624, and 628. The power supply electrode 620 and the electrolysis electrode 630 are connected to the DC power supply 634.

[0890] - Hole Enlargement Treatment-

[0891] The aluminum plate that had undergone the above 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 for 3 seconds, and then subjected to a pore-enlarging treatment. It was then rinsed with water using a sprayer.

[0892] -Stage 2 Anodizing Treatment-

[0893] use Figure 3 The structure shown is based on a DC electrolytic anodizing device for the second stage of anodizing treatment, which forms an anodized film of a specified amount.

[0894] <Fabrication of Support Body 3>

[0895] -Alkali etching treatment-

[0896] Etching was performed on an aluminum plate by spraying an aqueous solution of caustic soda (26% by mass) and aluminum ions (6.5% by mass) using a sprayer at 70°C. A spray-based water wash was then performed. The aluminum dissolution rate on the surface after electrochemical roughening was 5 g / m². 2 .

[0897] - Decontamination treatment using acidic aqueous solution (first decontamination treatment) -

[0898] Next, a decontamination treatment was performed using an acidic aqueous solution. The acidic aqueous solution used was a 150 g / L sulfuric acid solution at a temperature of 30°C. The acidic aqueous solution was sprayed onto the aluminum plate using a sprayer and the decontamination was performed for 3 seconds. Then, a water rinsing process was carried out.

[0899] -Electrochemical roughening treatment-

[0900] Next, an electrochemical roughening treatment was performed using an electrolyte solution with a hydrochloric acid concentration of 14 g / L, an aluminum ion concentration of 13 g / L, and a sulfuric acid concentration of 3 g / L, employing alternating current. The electrolyte temperature was 30°C. The aluminum ion concentration was adjusted by adding aluminum chloride. The alternating current waveform was a symmetrical sine wave with a frequency of 50 Hz. The ratio of the anodic reaction time to the cathode reaction time in one cycle of the alternating current was 1:1, and the current density, measured as the peak current of the alternating current waveform, was 75 A / dm³. 2 Furthermore, the electrical charge, calculated as the total charge generated by the aluminum plate participating in the anode reaction, is 450 C / dm. 2 Regarding electrolytic treatment, with a 4-second energizing interval, at 112.5C / dm³ 2This was performed in four stages. A carbon electrode was used as the counter electrode in the aluminum plate. Then, a water washing process was performed.

[0901] - Dirt removal process using an acidic aqueous solution

[0902] Next, a dirt removal process was performed using an acidic aqueous solution. Specifically, an acidic aqueous solution was sprayed onto the aluminum plate using a sprayer, and a dirt removal process was performed for 3 seconds. The acidic aqueous solution used for the dirt removal process used a sulfuric acid concentration of 170 g / L and an aluminum ion concentration of 5 g / L. The liquid temperature was 30°C.

[0903] - Anodizing process

[0904] An anodizing process was performed in a sulfuric acid solution using an anodizing device based on direct current electrolysis to become a prescribed oxide film amount.

[0905] <Manufacture of support 4>

[0906] A Hydro 1052 aluminum alloy strip or sheet having a thickness of 0.28 mm (available from Norsk Hydro ASA, Norway) was used as the aluminum-containing support.

[0907] Both the pre-etching and post-etching processes were performed using an alkaline solution under known conditions. With respect to the roughening (or granulation), an electrochemical mechanism was performed in a hydrochloric acid solution at about 23°C to obtain a calculated average roughness (Ra) of 0.5 μm on the plane of the aluminum-containing support. With respect to these processing steps, a continuous process was performed on a typical production line for manufacturing a lithographic printing plate precursor.

[0908] Next, the obtained granulated and etched aluminum-containing support was washed with water and dried, and cut into individual granulated and etched aluminum-containing sheets.

[0909] Next, each sheet was anodized twice, with about 100 liters of an anodizing solution contained in each anodizing process bath. The first anodizing conditions were an electrolyte concentration of 175 g / liter, a temperature of 60°C, a current density of 5.8 A / dm 2 for 21.3 seconds, and the second anodizing conditions were an electrolyte concentration of 280 g / liter, a temperature of 23°C, a current density of 10 A / dm 2 for 18 seconds. The first anodizing process for forming the outer aluminum oxide layer was performed using phosphoric acid as the electrolyte, and the second anodizing process for forming the inner aluminum oxide layer was performed using sulfuric acid as the electrolyte.

[0910] <Method of forming base coat>

[0911] The support described in Table 1 or Table 3 was coated with the undercoat coating solution 1 of the following composition described in Table 1 or Table 3 in such a manner that the dry coating amount became 80 mg / m 2 The undercoat coating solution 1 of the following composition described in Table 1 or Table 3 was coated in such a manner that the dry coating amount became 80 mg / m

[0912] -Composition of undercoat coating solution 1-

[0913] • Undercoat compound (P-1, 11% aqueous solution): 0.10502 parts

[0914] • Hydroxyethyl diimino diacetic acid: 0.01470 parts

[0915] • Sodium ethylenediaminetetraacetate: 0.06575 parts

[0916] • Surfactant (EMALEX 710, manufactured by NIHON EMULSION Co., Ltd.): 0.00159 parts by mass

[0917] • Preservative (Biohope L, manufactured by K•I Chemical Industry Co., LTD.): 0.00149 parts

[0918] • Water: 2.86144 parts

[0919] [Chemical Formula 52]

[0920]

[0921] <Formation of image recording layer>

[0922] The image recording layer coating solution 1 of the composition described in Table 1 to Table 4 was bar coated on the support or undercoat described in Table 1 or Table 3, and dried at 120°C for 40 seconds, thereby forming an image recording layer having a dry coating amount of 1.0 g / m 2

[0923] The image recording layer coating solution 1 is shown below.

[0924] <Composition of image recording layer coating solution 1>

[0925] • Infrared absorber described in Table 1 or Table 3: the amount described in Table 1 or Table 3

[0926] • Color developer described in Table 1 or Table 3: the amount described in Table 1 or Table 3

[0927] • Electron-accepting polymerization initiator described in Table 1 or Table 3: the amount described in Table 1 or Table 3​

[0928] • the compound having a Group 13 element described in Table 1 or Table 3: the amount described in Table 1 or Table 3

[0929] • the chain transfer agent described in Table 1 or Table 3: the amount described in Table 1 or Table 3

[0930] • the compound represented by Formula 1 or Formula 2 described in Table 1 or Table 3: the amount described in Table 1 or Table 3

[0931] • the polymeric compound described in Table 1 or Table 3: the amount described in Table 1 or Table 3

[0932] • the anionic surfactant described in Table 2 or Table 4: the amount described in Table 2 or Table 4

[0933] • the fluorine-based surfactant described in Table 2 or Table 4: the amount described in Table 2 or Table 4

[0934] • the adhesive polymer described in Table 2 or Table 4: the amount described in Table 2 or Table 4

[0935] • the polar organic solvent described in Table 2 or Table 4: the amount described in Table 2 or Table 4

[0936] • the other additive described in Table 2 or Table 4: the amount described in Table 2 or Table 4

[0937] • 2-butanone: 4.2726 parts

[0938] • 1-methoxy-2-propanol: 4.3952 parts

[0939] • methanol: 2.2737 parts

[0940] <Formation of outermost layer>

[0941] Any of the outermost layer coating liquids 1 to 5 described in Table 1 or Table 3 was bar coated on the image recording layer, and dried at 120°C for 30 seconds to form an outermost layer in such a manner that the dry coating amount described in Table 1 or Table 3 was achieved.

[0942] <Outermost layer coating liquid 1>

[0943] • GOHSENX L3266 (manufactured by Mitsubishi Chemical Corporation., solid content: 100%): 0.05000 parts

[0944] • Fine Sphere FS102 (manufactured by Nippon Paint Co., Ltd., solid content: 17%): 0.10000 parts

[0945] • EEMALEX 710 (nonionic surfactant, polyoxyethylene lauryl ether, manufactured by NIHON EMULSION Co., Ltd., solid content: 100%): 0.00350 parts

[0946] • Microgel liquid 2: 0.16670 parts

[0947] • Water: 0.56540 parts

[0948] In addition, GOHSENX L3266 is a sulfonic acid-modified polyvinyl alcohol having a weight average molecular weight of 17,000 as shown below.

[0949] [Chemical Formula 53]

[0950]

[0951] Also, Fine Sphere FS102 is an aqueous dispersion of styrene-acrylic acid copolymer particles as shown below.

[0952] [Chemical Formula 54]

[0953]

[0954] <Composition of the outermost coating liquid 2>

[0955] • GOHSENX L3266 (manufactured by Mitsubishi Chemical Corporation., solid content: 100%): 0.07000 parts

[0956] • Fine Sphere FS102 (manufactured by Nippon Paint Co., Ltd., solid content: 17%): 0.14706 parts

[0957] • EEMALEX 710 (manufactured by NIHON EMULSION Co., Ltd., solid content: 100%): 0.00350 parts

[0958] • Water: 0.50114 parts

[0959] <Composition of the outermost coating liquid 3>

[0960] • Mowiol 4-88 (polyvinyl alcohol, manufactured by KURARAY CO., LTD.): 0.28000 parts

[0961] • Mowiol 8-88 (polyvinyl alcohol, manufactured by KURARAY CO., LTD.): 0.20000 parts

[0962] • IR-6: 0.02000 parts

[0963] • EEMALEX 710 (manufactured by NIHON EMULSION Co., Ltd., solid content: 100%): 0.37500 parts

[0964] • Hydrophobic polymer WP-1 (polyvinylidene chloride aqueous dispersion, Diofan (registered trademark) A50 manufactured by Solvin Co.): 0.20000 parts

[0965] • Water: 6.38000 parts

[0966] Composition of outermost coating liquid 4

[0967] The outermost coating liquid 4 contains each of the following components in the amounts described below, and is prepared with ion exchange water so that the solid content is 6 mass%.

[0968] • wIR-1 (color changeable compound, the following compound): 20 parts

[0969] • WP-1 (hydrophilic polymer, Mowiol 4-88 polyvinyl alcohol, manufactured by KURARAY CO., LTD.): 700 parts

[0970] • WP-2 (hydrophilic polymer, Mowiol 8-88 polyvinyl alcohol, manufactured by KURARAY CO., LTD.): 200 parts

[0971] • L-1 (hydrophobic polymer, polyvinylidene chloride aqueous dispersion, Diofan (registered trademark) A50 manufactured by Solvin Co.): 200 parts

[0972] • F-1 (surfactant, RAPISOL A-80, manufactured by NOF CORPORATION): 5 parts

[0973] • Hydrophobic polymer WP-1 (polyvinylidene chloride aqueous dispersion, Diofan (registered trademark) A50 manufactured by Solvin Co.): 0.20000 parts

[0974] Composition of outermost coating liquid 5

[0975] The outermost coating liquid 5 contains each of the following components in the amounts described below, and is prepared with ion exchange water so that the solid content is 6 mass%.

[0976] • wIR-1 (color changeable compound, the following compound): 20 parts

[0977] • WP-1 (hydrophilic polymer, Mowiol 4-88 polyvinyl alcohol, manufactured by KURARAY CO., LTD.): 700 parts

[0978] • WP-2 (hydrophilic polymer, Mowiol 8-88 polyvinyl alcohol, manufactured by KURARAY CO., LTD.): 200 parts

[0979] • F-1 (surfactant, RAPISOL A-80, manufactured by NOF CORPORATION): 5 parts

[0980] • Hydrophobic polymer WP-1 (polyvinylidene chloride aqueous dispersion, Diofan (registered trademark) A50 manufactured by Solvin Co.): 0.20000 parts

[0981] <Manufacture of Lithographic Printing Plate Precursor>

[0982] As described in Tables 1 to 4, the lithographic printing plate precursors of Examples 1 to 52 and Comparative Examples 1 to 4 were each manufactured according to the support and the forming method of each layer described above.

[0983] <Evaluation of Lithographic Printing Plate Precursor>

[0984] 〔Evaluation of Ink Clouding Inhibitory Property〕

[0985] The lithographic printing plate precursors obtained were exposed (irradiation energy described in Table 2 or Table 4) under the conditions of output power 27 W, outer drum rotation speed 450 rpm, and resolution 2,400 dpi (dot per inch (1 inch = 2.54 cm)) by Magnus 800 Quantum manufactured by Kodak Co. equipped with an infrared semiconductor laser. A solid image having an image area ratio of 5% was included in the exposed image.

[0986] The obtained exposed original plate was mounted on a cylinder of a Heidelberger Druckmaschinen AG-made printing machine SX-74 of a sheet size without being subjected to a development treatment. A fountain solution circulation tank of 100 L with a non-woven fabric filter and a temperature control device built in was connected to the printing machine. 80 L of a fountain solution S-Z1 (Fujifilm Corporation-made) of 3.5% was charged in the circulation device, and Fusion-G MK MEDIUM N (DIC Corporation-made) of 200 g was used as a printing ink, and after the fountain solution was supplied 12 times, the ink was supplied, and 300 prints were performed on Tokubishi Art (Mitsubishi Paper Mills Limited-made, continuous amount: 76.5 kg) paper at a printing speed of 10,000 sheets per hour. The above printing was repeated 10 times, and the coloring of the ink was evaluated by comparing the color tone of the ink on the printed paper surface with the color tone of the ink alone. The evaluation criteria are shown below.

[0987] 5: Coloring of the image recording layer was not observed at all in the ink, and the color tone was the same as that of the ink alone.

[0988] 4: Although coloring of the image recording layer was observed a little in the ink, the color tone was the same as that of the ink alone.

[0989] 3: Coloring of the image recording layer was observed in the ink, and the color tone was slightly different from that of the ink alone.

[0990] 2: Coloring of the image recording layer was observed a lot in the ink, and the color tone was different from that of the ink alone.

[0991] 1: Coloring of the image recording layer was obviously observed in the ink, and the color tone was different from that of the ink alone, and the color tone was the same as that of the image recording layer.

[0992] 〔Evaluation of visual recognition over time (ΔL measurement of the exposed part (image part) before and after exposure)〕

[0993] The obtained lithographic printing plate original plate was exposed by a Trendsetter 3244VX (Creo-made) equipped with a water-cooled 40W infrared ray semiconductor laser, under the conditions of an output of 11.5W, an outer drum rotation speed of 220 rpm, and a resolution of 2,400 dpi (dot per inch, 1 inch = 25.4 mm). As for the exposure, it was performed in an environment of 25°C, 50% RH.

[0994] After exposure, the color development of the lithographic printing plate precursor was measured after storage in the dark (30°C, 70% RH) for 72 hours. For the measurement, a spectral colorimeter CM2600d manufactured by Konica Minolta, Inc. and operation software CM-S100W were used, and the measurement was performed by the SCE (Specular Component Exclusion) method. For the visual recognition, L * a * b * The L * value (lightness) of the color system was evaluated in terms of the difference ΔL between the L * value of the exposed portion and the L * value of the unexposed portion. The larger the value of ΔL, the more excellent the visual recognition over time.

[0995]

[0996]

[0997]

[0998]

[0999] The details of the abbreviations described in Tables 1 to 4 described above are described below.

[1000] IR-1 to IR-3: the following compounds

[1001] [Chemical Formula 55]

[1002]

[1003] [Chemical Formula 56]

[1004]

[1005] S-2, S-15 to S-17, S-22, and S-23: the following compounds

[1006] [Chemical Formula 57]

[1007]

[1008] [Chemical Formula 58]

[1009]

[1010] Int-1 and Int-2: the following compounds

[1011] Int-3: the following compound (is a photopolymerization initiator, and is a compound having a Group 13 element)

[1012] [Chemical Formula 59]

[1013]

[1014] TPB and TPB-1 to TPB-3: the following compounds

[1015] [Chemical Formula 60]

[1016]

[1017] Ct-1: the following compound

[1018] [Chemical Formula 61]

[1019]

[1020] CC-1: the following compound

[1021] [Chemical Formula 62]

[1022]

[1023] M-1: a compound synthesized by the following synthesis method

[1024] <SYNTHESIS METHOD OF M-1>

[1025] A mixed solution of Takenate D-160N (polyisocyanate-trimethylolpropane adduct, manufactured by Mitsui Chemicals, Inc.) 4.7 parts by mass, ARONIX M-403 (manufactured by TOAGOSEI CO., LTD.) in an amount such that the NCO value of Takenate D-160N and the hydroxyl value of ARONIX M-403 become 1:1, t-butylbenzoquinone 0.02 parts by mass, and methyl ethyl ketone 11.5 parts by mass was heated to 65°C. NEOSTANN U-600 (bismuth-based polycondensation catalyst, manufactured by NITTOKASEI CO., LTD.) 0.11 parts by mass was added to the reaction solution, and heating was performed at the same temperature for 4 hours. The reaction solution was cooled to room temperature (25°C), and methyl ethyl ketone was added, whereby a urethane acrylate solution having a solid content of 50% by mass was synthesized.

[1026] Next, a molecular weight fraction of the urethane acrylate solution was performed using a recycling-type GPC (apparatus: LC908-C60, columns: JAIGEL-1H-40 and 2H-40 (manufactured by Japan Analytical Industry.)) with tetrahydrofuran (THF) eluent. The weight average molecular weight was 20,000.

[1027] M-2 to M-6: the following compounds

[1028] [Chemical Formula 63]

[1029]

[1030] [Chemical Formula 64]

[1031]

[1032] [Chemical Formula 65]

[1033]

[1034] A-1: the following compound

[1035] HPC: hydroxypropyl cellulose, Klucel M, manufactured by Hercules Inc.

[1036] [Chemical Formula 66]

[1037]

[1038] W-1: the following compound

[1039] [Chemical Formula 67]

[1040]

[1041] Microgel liquid 1: a microgel liquid obtained by the following synthesis method

[1042] < Synthesis method of microgel liquid 1 >

[1043] • microgels (polymer particles): 2.640 parts

[1044] • distilled water: 2.425 parts

[1045] The following shows a preparation method of the microgels used in the above microgel liquid.

[1046] - Preparation of polyvalent isocyanate compound -

[1047] To a suspension solution of isophorone diisocyanate 17.78 parts (80 molar equivalents) and the following polyvalent phenol compound (1) 7.35 parts (20 molar equivalents) in ethyl acetate (25.31 parts), bismuth tris (2-ethylhexanoate) (NEOSTANN U-600, manufactured by NITTO KASEI CO., LTD.) 0.043 parts was added and stirred. At the time when the heat generation was suppressed, the reaction temperature was set to 50°C, and stirred for 3 hours to obtain an ethyl acetate solution of the polyvalent isocyanate compound (1) (50 mass%).

[1048] - Preparation of microgels -

[1049] The following oil phase ingredients and water phase ingredients were mixed, and emulsified using a homogenizer at 12,000 rpm for 10 minutes. After the obtained emulsion was stirred at 45°C for 4 hours, 5.20 g of a 10 mass% aqueous solution of 1,8-diazabicyclo[5.4.0]undec-7-ene-octanoate (U-CAT SA102, manufactured by San-Apro Ltd.) was added, stirred at room temperature for 30 minutes, and left to stand at 45°C for 24 hours. The solid content concentration was adjusted to 20 mass% with distilled water, thereby obtaining an aqueous dispersion of microgels (1). The average particle diameter was 0.28 μm as a result of measurement by a light scattering method.

[1050] ~ Oil phase ingredients ~

[1051] (In component 1) Ethyl acetate: 12.0 parts

[1052] (In component 2) An adduct of trimethylolpropane (6 mole equivalents) and xylene diisocyanate (18 mole equivalents) to which a mono-terminal methylated polyoxyethylene (1 mole equivalent, number of repeating units of oxyethylene: 90) was added (50 mass% ethyl acetate solution, manufactured by Mitsui Chemicals, Inc.): 3.76 parts

[1053] (In component 3) Polyisocyanate compound (1) (as a 50 mass% ethyl acetate solution): 15.0 parts

[1054] (In component 4) A 65 mass% ethyl acetate solution of dipentaerythritol pentaacrylate (SR-399, manufactured by Sartomer Company, Inc.): 11.54 parts

[1055] (In component 5) A 10% ethyl acetate solution of a sulfonate surfactant (PIONIN A-41-C, manufactured by Takemoto Oil & Fat Co., Ltd.): 4.42 parts

[1056] ~ Water phase ingredients ~

[1057] Distilled water: 46.87 parts

[1058] Microgel liquid 2: A microgel liquid obtained by the following synthesis method

[1059] <Production of microgel liquid 2>

[1060] - Preparation of oil phase ingredients -

[1061] A mixed polyfunctional isocyanate compound (PM-200: manufactured by Wanhua Chemical Group Co., Ltd.): 6.66 g; a 50 mass% ethyl acetate solution of "Takenate (registered trademark) D-116N (adduct of trimethylolpropane (TMP), m-xylylene diisocyanate (XDI), and polyethylene glycol monomethyl ether (EO90) (the following structure))" manufactured by Mitsui Chemicals, Inc.: 5.46 g; a 65 mass% ethyl acetate solution of dipentaerythritol pentaacrylate (SR-399, manufactured by Sartomer Company, Inc.): 11.24 g; ethyl acetate: 14.47 g; and PIONIN (registered trademark) A-41-C manufactured by Takemoto Oil & Fat Co., Ltd.: 0.45 g were stirred for 15 minutes at room temperature (25°C) to obtain an oil phase component.

[1062] [Chemical Formula 68]

[1063]

[1064] -Preparation of an aqueous phase component-

[1065] As the aqueous phase component, distilled water 47.2 parts was prepared.

[1066] -Preparation of a microgel-

[1067] The aqueous phase component was added to the oil phase component and mixed, and the obtained mixture was emulsified at 12,000 rpm for 16 minutes using a homogenizer to obtain an emulsion.

[1068] To the obtained emulsion, distilled water 16.8 parts was added, and the obtained liquid was stirred at room temperature for 10 minutes.

[1069] Next, the stirred liquid was heated to 45°C, and the liquid was stirred for 4 hours while maintaining the liquid temperature at 45°C, whereby ethyl acetate was distilled off from the above liquid. Next, 1,8-diazabicyclo[5.4.0]undec-7-ene-octanoate (U-CAT SA102, manufactured by San-Apro Ltd.) 10 mass% aqueous solution 5.12 g was added, stirred at room temperature for 30 minutes, and left to stand at 45°C for 24 hours. The solid component concentration was adjusted to 20 mass% with distilled water, and a microgel liquid 2 was obtained. The volume average particle diameter of the microgel liquid 2 was measured by a laser diffraction / scattering type particle size distribution measuring device LA-920 (manufactured by HORIBA, Ltd.), and the result was 165 nm.

[1070] P-1: polyvinyl alcohol, S-LEC BX-5Z manufactured by SEKISUI CHEMICAL CO., LTD.

[1071] P-2: Polyvinyl alcohol, S-LEC BL10 manufactured by SEKISUI CHEMICAL CO., LTD.

[1072] Polymer particle 1: Resin particle containing resin shown below (n = 45, Mw = 50,000)

[1073] [Chemical Formula 69]

[1074]

[1075] < Synthesis of Polymer Particle 1 >

[1076] In a 4-necked flask, a dispersion unit was added: 10.0 parts of the following compound B-1 (n = 45), 85.0 parts of distilled water, and 240.0 parts of n-propanol, and heating stirring was performed at 70°C under nitrogen.

[1077] Next, to the 4-necked flask, a mixture of 20.0 parts of the following compound A-1, 70.0 parts of the following compound A-2, and 0.7 parts of 2,2'-azobisisobutyronitrile, which had been mixed beforehand, was added dropwise over 2 hours.

[1078] After the dropwise addition, the reaction was continued for 5 hours without opening the flask, then 0.5 parts of 2,2'-azobisisobutyronitrile was added, and the temperature was raised to 80°C. Every 6 hours, 0.4 parts of 2,2'-azobisisobutyronitrile was added, and the reaction was continued for a total of 19 hours.

[1079] The reaction solution was allowed to cool naturally to room temperature (25°C), and a dispersion liquid of polymer particle 1 was obtained (23% of solid content).

[1080] [Chemical Formula 70]

[1081]

[1082] The median particle diameter of the polymer particle 1 was 150 nm, and the coefficient of variation was 23%.

[1083] Also, regarding the dispersibility of the polymer particle 1, as a result of confirmation by the method described above, the polymer particle 1 was a particle having water dispersibility, and was a particle having organic solvent dispersibility.

[1084] DMSO: Dimethyl sulfoxide

[1085] NMP: N-methyl pyrrolidone

[1086] O-1 to O-3: The following compounds

[1087] [Chemical Formula 71]

[1088]

[1089] From the results described in Tables 1 to 4, it was found that the lithographic printing plate precursor according to the present embodiment was a lithographic printing plate precursor excellent in ink turbidity inhibitory property and in visual recognition degree of the exposed portion over time, as compared with the lithographic printing plate precursors according to the comparative examples.

[1090] (Example 101)

[1091] <Production of color-developing reagent using C-1>

[1092] [Chemical Formula 72]

[1093]

[1094] In a 50 mL three-necked flask, C-1 0.3 g (1.2 mmol), THF 3.0 mL, triphenylborane 0.3 g (1.3 mmol, manufactured by sigma aldrich) were added, and stirred at room temperature for 4 hours. After completion of the reaction, the solid obtained by concentration under reduced pressure using a rotary evaporator was separated by column chromatography (developing solvent: ethyl acetate / hexane = 1 / 2), and the target fraction was again concentrated under reduced pressure using a rotary evaporator, whereby the target 0.45 g was obtained at a yield of 91.3%.

[1095] It is known that C-1 forms a complex with an organic compound having a Group 13 element or a decomposition product thereof, and a color change due to the formation of the complex is observed, and functions as a color-developing agent.

[1096] (Examples 102 to 117)

[1097] <Production of color-developing reagent using C-2 to C-17>

[1098] The color-developing reagent was produced in accordance with the production of color-developing reagent using C-1, except that C-1 was changed to any one of C-2 to C-17.

[1099] It is known that C-2 to C-17 each form a complex with an organic compound having a Group 13 element or a decomposition product thereof, and a color change due to the formation of the complex is observed, and functions as a color-developing agent.

[1100] The invention of Japanese Patent Application No. 2021-030880 filed on February 26, 2021 is incorporated in its entirety into the present specification by reference.

[1101] All of the literature, patent applications and technical standards cited in this specification are hereby incorporated by reference to the same extent as if each individual publication, application, or document was specifically and individually indicated to be incorporated by reference.

[1102] Symbol explanation

[1103] 12a, 12b - aluminum support, 14 - base coat layer, 16 - image recording layer, 18 - aluminum plate, 20a, 20b - anodized film, 22a, 22b - micropores, 24 - large diameter hole portion, 26 - small diameter hole portion, D - depth of large diameter hole portion, 610 - anodizing treatment device, 612 - power supply tank, 614 - electrolytic treatment tank, 616 - aluminum plate, 618, 26 - electrolytic solution, 620 - power supply electrode, 622, 628 - rollers, 624 - pinch roller, 630 - electrolytic electrode, 632 - tank wall, 634 - direct current power source.

Claims

1. An on-machine developing type offset printing plate master, which has the following characteristics: Support body; and The image recording layer on the support body The image recording layer comprises compounds represented by Formula 1 or Formula 2 below, as well as organic compounds having elements of Group 13. In Equations 1 and 2, R 1 ~R 7 Each can independently represent a hydrogen atom or a monovalent organic group, L 1 and L 2 L represents a divalent organic group. 1 R 2 and R 3 Two or more groups in, L 2 R 4 and R 6 Two or more groups in, and L 2 R 5 and R 7 Two or more groups can be optionally linked to form a ring structure. The organic compounds containing Group 13 elements include boron compounds. The compound represented by Formula 1 or Formula 2 is a compound having one or more of the following structures: a 1,3-diimine structure, a ketone structure having a heteroaromatic group having a nitrogen atom at the β position and a nitrogen atom at the ortho position, or a methine structure having two or more heteroaromatic groups having a nitrogen atom at the ortho position.

2. The on-machine developing type lithographic printing plate original according to claim 1, wherein, The organic compound containing a Group 13 element is an electron-donating polymerization initiator.

3. The on-machine developing type lithographic printing plate original according to claim 2, wherein, The electron-donating polymerization initiator has electron-withdrawing groups.

4. The on-machine developing type lithographic printing plate original according to any one of claims 1 to 3, wherein, The proportion of the ketone or imine body of the compound represented by Formula 1 or Formula 2 at 25°C is 10 mol% or more.

5. The on-machine developing type lithographic printing plate original according to any one of claims 1 to 3, wherein, The compounds represented by Formula 1 or Formula 2 include compounds having a ring structure.

6. The on-machine developing type lithographic printing plate original according to any one of claims 1 to 3, wherein, The compounds represented by Formula 1 or Formula 2 include compounds having two or more ring structures.

7. The on-machine developable lithographic printing plate original according to any one of claims 1 to 3, wherein, The compounds represented by Formula 1 or Formula 2 are compounds having electron-donating groups on an aromatic ring.

8. The on-machine developing type lithographic printing plate original according to any one of claims 1 to 3, wherein, The content of the compound represented by Formula 1 or Formula 2 is 0.05% to 2.5% by mass relative to the total mass of the image recording layer.

9. The on-machine developing type lithographic printing plate original according to any one of claims 1 to 3, wherein, The image recording layer also contains an electron-dependent polymerization initiator.

10. The on-machine developing type lithographic printing plate original according to claim 9, wherein, The electron-accepting polymerization initiator comprises a compound represented by the following formula (II), In equation (II), X A R represents a halogen atom. A It represents an aryl group.

11. The on-machine developable lithographic printing plate original according to any one of claims 1 to 3, wherein, The organic compounds containing Group 13 elements comprise compounds formed by the formation of countersalts from cations having electron-accepting polymerization initiator structures and anions having electron-donating polymerization initiator structures.

12. The on-machine developable lithographic printing plate original according to any one of claims 1 to 3, wherein, The image recording layer also contains a polar organic solvent.

13. The on-machine developing type lithographic printing plate original according to claim 12, wherein, The polar organic solvent is at least one solvent selected from dimethyl sulfoxide and N-methylpyrrolidone.

14. A method for producing a lithographic printing plate, comprising: The process of exposing the machine-developable lithographic printing plate original as described in any one of claims 1 to 13 into an image; and A process of supplying at least one of printing ink and dampening solution to remove the image recording layer from the non-image area on a printing press.

15. A method for offset printing, comprising: The process of exposing the machine-developable lithographic printing plate original as described in any one of claims 1 to 13 into an image; A process of supplying at least one of printing ink and dampening solution to produce a lithographic printing plate by removing the image recording layer (excluding the image portion) on a printing press; and The process of printing using the obtained lithographic printing plate.

16. A colorant, represented by formula 1 or formula 2 below, In Equations 1 and 2, R 1 ~R 7 Each can independently represent a hydrogen atom or a monovalent organic group, L 1 and L 2 L represents a divalent organic group. 1 R 2 and R 3 Two or more groups in, L 2 R 4 and R 6 Two or more groups in, and L 2 R 5 and R 7 Two or more groups can be optionally linked to form a ring structure. The colorant represented by Formula 1 or Formula 2 is a compound having one or more of the following structures: a 1,3-diimine structure, a ketone structure having a heteroaromatic group having a nitrogen atom at the β position and a nitrogen atom at the ortho position, or a methine structure having two or more heteroaromatic groups having a nitrogen atom at the ortho position.

17. The colorant according to claim 16, wherein, The proportion of the colorant represented by Formula 1 or Formula 2 at 25°C is 10 mol% or more, consisting of ketone bodies or imine bodies.

18. The colorant according to claim 16 or 17, wherein, The colorants represented by Formula 1 or Formula 2 contain compounds having a cyclic structure.

19. The colorant according to claim 16 or 17, wherein, The colorant represented by Formula 1 or Formula 2 comprises a compound having two or more ring structures.

20. The colorant according to claim 16 or 17, wherein, The colorant represented by Formula 1 or Formula 2 is a compound having an electron-donating group on an aromatic ring.

Images