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

Abstract

The present application provides 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 color developing compound capable of undergoing a color developing reaction with a decomposition product generated by exposure of the image recording layer, 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 1C or Formula 2C and an electron-donating polymerization initiator, and a method for producing a lithographic printing plate or a lithographic printing method using the on-press development type lithographic printing plate precursor. In Formula 1C and Formula 2C, R 1C ~R 4C each independently represents a monovalent organic group, L 1C and L 2C each independently represents a divalent organic group, A C represents OH or NR 5C R 6C , R 5C and R 6C each independently represents a monovalent organic group.

Description

TECHNICAL FIELD

[0001] The present application relates to a planographic printing plate precursor of on-press development type, a method for producing a planographic printing plate, and a planographic printing method. BACKGROUND

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

[0003] In order to produce this planographic printing plate, conventionally, a planographic printing plate precursor (PS plate) in which an oleophilic photosensitive resin layer (image-recording layer) is provided on a hydrophilic support has been widely used. Generally, a planographic printing plate is obtained by producing a plate by the following method: after the planographic 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 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, a method in which, after a planographic printing plate precursor is exposed to light, it is directly mounted to a printing machine without 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 planographic printing plate precursor that can be used for such on-press development is referred to as "on-press development type planographic 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 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 in which the exposure portion is excellent in visual recognition.

[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] Means for solving the technical problem

[0014] Among the means for solving the above-described problem, the following means are included.

[0015] <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 color developing compound capable of undergoing a color development reaction with a decomposition product generated by exposure of the image recording layer.

[0016] <2> 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 1C or Formula 2C below and an electron-donating polymerization initiator.

[0017] [Chemical Formula 1]

[0018]

[0019] In Formula 1C and Formula 2C, R 1C to R 4C independently represent a monovalent organic group, L 1C and L 2C independently represent a divalent organic group, A C represents OH or NR 5C R 6C , R 5C and R 6C independently represent a hydrogen atom or a monovalent organic group, and the dotted portion represents a portion that can be a double bond.

[0020] <3> 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 1C or Formula 2C below or a complex having an anion obtained by removing one hydrogen atom from the compound represented by Formula 1C or Formula 2C as a ligand, when the image recording layer is exposed with infrared rays having a wavelength of 830 nm at an energy density of 110 mJ / cm 2

[0021] [Chemical Formula 2]

[0022] ​

[0023] in Formulae 1C and 2C, R 1C ~R 4C each independently represents a monovalent organic group, L 1C and L 2C each independently represents a divalent organic group, A C represents OH or NR 5C R 6C , R 5C and R 6C each independently represents a hydrogen atom or a monovalent organic group, and the dotted portion represents a portion which can be a double bond.

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

[0025] the brightness change ΔL of the exposed portion after the storage for 6 hours under the conditions of 30°C, 70% RH after the exposure based on the infrared rays having a wavelength of 830 nm is 3 or more when the exposure is performed at an energy density of 110 mJ / cm 2

[0026] <5> The on-press development type lithographic plate precursor according to <1>, <3> or <4>, wherein

[0027] the image recording layer further contains a polymerization initiator.

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

[0029] the polymerization initiator contains an electron-donating polymerization initiator.

[0030] <7> The on-press development type lithographic plate precursor according to <2> or <6>, wherein

[0031] the electron-donating polymerization initiator contains a boron compound.

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

[0033] the electron-donating polymerization initiator contains a tetraphenylborate compound.

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

[0035] the color development reaction is a complex formation reaction.

[0036] <10> The on-press development type lithographic plate precursor according to <1>, wherein ​

[0037] The above image-recording layer further contains a polymerization initiator,

[0038] The decomposition product produced by the above exposure is a decomposition product produced by exposure of the above polymerization initiator.

[0039] <11> The on-press development type lithographic plate precursor according to <1> or <10>, wherein

[0040] The above color-developing compound is a compound having one or more ketone structures.

[0041] <12> The on-press development type lithographic plate precursor according to <1>, <10> or <11>, wherein

[0042] The above color-developing compound is a compound represented by Formula 1C and / or Formula 2C below.

[0043] [Chemical Formula 3]

[0044]

[0045] In Formula 1C and Formula 2C, R 1C ~R 4C each independently represents a monovalent organic group, L 1C and L 2C each independently represents a divalent organic group, A C represents OH or NR 5C R 6C , R 5C and R 6C each independently represents a hydrogen atom or a monovalent organic group, and the dotted portion represents a portion that can be a double bond.

[0046] <13> The on-press development type lithographic plate precursor according to <1>, wherein

[0047] The content of the above color-developing compound is 0.05 to 2.5 mass% relative to the total mass of the above image-recording layer.

[0048] <14> The on-press development type lithographic plate precursor according to <2> or <12>, wherein

[0049] The total content of the compound represented by Formula 1C or Formula 2C above is 0.05 to 2.5 mass% relative to the total mass of the above image-recording layer.

[0050] <15> The on-press development type lithographic plate precursor according to any one of <1> to <14>, wherein

[0051] The above image-recording layer further contains an infrared absorber.

[0052] <16> The on-press development type lithographic plate precursor according to any one of <1> to <15>, wherein

[0053] The above image recording layer further contains an acid color developer.

[0054] <17> The on-press development type lithographic plate precursor according to <16>, wherein

[0055] The above acid color developer contains a compound represented by the following formula (Le-8).

[0056] [Chemical Formula 4]

[0057]

[0058] In formula (Le-8), 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, Rb1and Rb2independently 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.

[0059] <18> The on-press development type lithographic plate precursor according to <17>, wherein

[0060] The above Rc1and the above Rc2are each independently a phenyl group having a substituent at at least one ortho position and an electron-donating group at a para position.

[0061] <19> The on-press development type lithographic plate precursor according to <16>, wherein

[0062] The above acid color developer contains a compound represented by the following formula (Le-10).

[0063] [Chemical Formula 5]

[0064]

[0065] In 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.

[0066] <20> The on-press development type lithographic plate precursor according to <19>, wherein

[0067] The above Ar1is each independently an aryl group having an electron-donating group, or a heteroaryl group having an electron-donating group, and the above Ar2is each independently a phenyl group having a substituent at at least one ortho position and an electron-donating group at a para position.

[0068] <21> The on-press development type lithographic plate precursor according to any one of <5> to <8> and <10>, wherein

[0069] The image recording layer described above further contains an electron-accepting polymerization initiator as the polymerization initiator described above.

[0070] <22> The on-press development type lithographic plate precursor according to <21>, wherein

[0071] The electron-accepting polymerization initiator described above is an onium salt compound.

[0072] <23> The on-press development type lithographic plate precursor according to <21>, wherein

[0073] The electron-accepting polymerization initiator described above contains a compound represented by the following formula (II).

[0074] [Chemical Formula 6]

[0075]

[0076] In formula (II), X A represents a halogen atom, R A represents an aryl group.

[0077] <24> The on-press development type lithographic plate precursor according to <5> or <10>, wherein

[0078] The polymerization initiator described above contains a compound in which a cation having an electron-accepting polymerization initiator structure and an anion having an electron-donating polymerization initiator structure form a counter salt.

[0079] <25> The on-press development type lithographic plate precursor according to any one of <1> to <24>, which has an outermost layer on the image recording layer, the outermost layer containing a color changeable compound.

[0080] <26> The on-press development type lithographic plate precursor according to <25>, wherein

[0081] The color changeable compound described above contains a compound that develops color due to infrared exposure.

[0082] <27> The on-press development type lithographic plate precursor according to any one of <1> to <3>, wherein

[0083] The image recording layer described above further contains an infrared absorber and an electron-donating polymerization initiator, the value of the HOMO of the infrared absorber - the HOMO of the electron-donating polymerization initiator being 0.70 eV or less.

[0084] <28> The on-press development type lithographic plate precursor according to any one of <1> to <3>, wherein

[0085] The image recording layer further contains an infrared absorber and an electron-accepting polymerization initiator, and the value of LUMO of the electron-accepting polymerization initiator minus the value of LUMO of the infrared absorber is 0.70 eV or less.

[0086] <29> The on-press development type lithographic plate precursor according to any one of <1> to <28>, wherein

[0087] The image recording layer further contains a polymerizable compound.

[0088] <30> The on-press development type lithographic plate precursor according to <29>, wherein

[0089] The polymerizable compound contains a polymerizable compound having 7 or more functional groups.

[0090] <31> The on-press development type lithographic plate precursor according to <29> or <30>, wherein

[0091] The polymerizable compound contains a polymerizable compound having 10 or more functional groups.

[0092] <32> The on-press development type lithographic plate precursor according to any one of <1> to <31>, wherein

[0093] The support has an aluminum plate and an anodized film of aluminum disposed on the aluminum plate, the anodized film being located on the image recording layer side more than 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.

[0094] <33> The on-press development type lithographic plate precursor according to <32>, wherein

[0095] The micropores are composed of a large-diameter pore portion and a small-diameter pore portion, the 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, the 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.

[0096] <34> 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 <33> to an image; 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 from a non-image area.

[0097] <35> 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 <33> to an image; a step of producing a lithographic printing plate by supplying at least one selected from a printing ink and a dampening solution on a printing machine to remove the image recording layer from a non-image area; and a step of printing using the obtained lithographic printing plate.

[0098] Effects of the Invention

[0099] According to an embodiment of the present application, it is possible to provide an on-press development type lithographic printing plate precursor in which the exposed portion is excellent in visual recognition.

[0100] Further, according to another embodiment of the present application, it is possible 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. BRIEF DESCRIPTION OF DRAWINGS

[0101] Figure 1 is a schematic cross-sectional view of an embodiment of an aluminum support body preferably used in the present application.

[0102] Figure 2 is a schematic cross-sectional view of an embodiment of an aluminum support body having an anodized film.

[0103] Figure 3 is a schematic view of an anodizing treatment device used in an anodizing treatment in a manufacturing method of an aluminum support body having an anodized film. DETAILED DESCRIPTION

[0104] Hereinafter, the contents of the present application will be described in detail. The description of the constituent elements described below is made based on representative embodiments of the present application, but the present application is not limited to such embodiments.

[0105] Further, 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.

[0106] Further, in the notation of groups (radicals) in the present specification, the notation not marked with "substituted" or "unsubstituted" includes not only groups having no substituents (unsubstituted groups), but also groups having substituents (substituted groups). For example, "alkyl group" includes not only alkyl groups having no substituents (unsubstituted alkyl groups), but also alkyl groups having substituents (substituted alkyl groups).

[0107] In the present specification, "(meth)acrylic acid" is a term used as a meaning including both of acrylic acid and methacrylic acid, and "(meth)acryloyl group" is a term used as a meaning including both of acryloyl group and methacryloyl group.

[0108] Also, the term "step" in the present specification includes not only a single step, but also a case where the step cannot be clearly distinguished from other steps, as long as the intended purpose of the step can be achieved. Also, in the present application, "mass%" and "weight%" are defined identically, and "mass parts" and "weight parts" are defined identically.

[0109] As long as not particularly limited, each component in the composition or each constitutional unit in the polymer in the present application can be contained singly or in combination of two or more.

[0110] Also, in the present application, as for the amount of each component in the composition or each constitutional unit in the polymer, in the 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 not particularly mentioned, 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.

[0111] Also, in the present application, a combination of two or more of the preferable modes is more preferable.

[0112] Also, as long as not particularly mentioned, the weight average molecular weight (Mw) and the number average molecular weight (Mn) in the present application are the molecular weight converted to 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.

[0113] In the present application, the term "lithographic printing plate precursor" includes not only a lithographic printing plate precursor, but also a waste plate precursor. Also, the term "lithographic printing plate" includes not only a lithographic printing plate produced by performing an operation such as exposure, development, and the like 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, for example, in the case where a part of a page is printed in monochrome or in two colors in color newspaper printing.

[0114] In the present application, "excellent printing durability" means that the number of printable sheets of a lithographic printing plate is large, and hereinafter, the printing durability when using a UV-curable ink (UV ink) as an ink during printing will be referred to as "UV printing durability".

[0115] Hereinafter, the present application will be described in detail.

[0116] (On-press developing type lithographic printing plate precursor)

[0117] The first embodiment of the on-press developing type lithographic printing plate precursor (also simply referred to as "lithographic printing plate precursor") according to the present application has a support and an image recording layer on the support, and the image recording layer contains a color developing compound capable of undergoing a color developing reaction with a decomposition product generated by exposure of the image recording layer.

[0118] The second embodiment of 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, and the image recording layer contains a compound represented by Formula 1C or Formula 2C below and an electron-donating polymerization initiator.

[0119] The third embodiment of 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, and the image recording layer contains a compound represented by Formula 1C or Formula 2C below or a complex having an anion obtained by removing one hydrogen atom from the compound represented by Formula 1C or Formula 2C as a ligand. 2 The image recording layer exposed to infrared light having a wavelength of 830 nm at an energy density of 110 mJ / cm

[0120] [Chemical Formula 7]

[0121]

[0122] In Formula 1C and Formula 2C, R 1C to R 4C independently represent a monovalent organic group, L 1C and L 2C independently represent a divalent organic group, A C represents OH or NR 5C R 6C , R 5C and R 6C independently represent a hydrogen atom or a monovalent organic group, and the dotted portion represents a portion that can be a double bond.

[0123] In addition, in the present specification, as long as not particularly stated, in the case of being simply referred to as "on-press developable lithographic printing plate precursor" or "lithographic printing plate precursor", all of the above-described first embodiment, the above-described second embodiment, and the above-described third embodiment are described. Also, as long as not particularly stated, in the case of being simply referred to as "image recording layer" and the like, all of the image recording layers and the like of the above-described first embodiment, the above-described second embodiment, and the above-described third embodiment are described.

[0124] Also, the on-press developable lithographic printing plate precursor according to the present application can be a negative type lithographic printing plate precursor or a positive type lithographic printing plate precursor, but is preferably a negative type lithographic printing plate precursor.

[0125] The present inventors and others have found that, in the conventional on-press developable lithographic printing plate precursor, the visual recognition of the exposed portion is sometimes insufficient.

[0126] As a result of intensive studies by the present inventors and others, it has been found that, by adopting the above-described structure, an on-press developable lithographic printing plate precursor having excellent visual recognition of the exposed portion can be provided.

[0127] The detailed mechanism by which the above-described effects are obtained is not clear, but is presumed as follows.

[0128] In the above-described first embodiment, the above-described image recording layer contains the above-described color developing compound, whereby the above-described color developing compound captures the decomposition product generated by exposure and develops color, and the degree of color development or color change in the exposed portion becomes higher, and thus it is inferred that the visual recognition of the exposed portion is excellent.

[0129] In the above-described second embodiment, the above-described image recording layer contains the compound represented by the above-described Formula 1C or Formula 2C, whereby the compound represented by the above-described Formula 1C or Formula 2C captures the decomposition product generated from the electron-donating polymerization initiator by exposure and develops color, and the degree of color development or color change in the exposed portion becomes higher, and thus it is inferred that the visual recognition of the exposed portion is excellent.

[0130] In the above-described third embodiment, the above-described image recording layer exposed with an infrared ray having a wavelength of 830 nm at an energy density of 110 mJ / cm 2 The above-described image recording layer exposed with an infrared ray having a wavelength of 830 nm at an energy density of 110 mJ / cm

[0131] Next, the details of each component of the lithographic printing plate precursor according to the present application will be described.

[0132] <image recording layer>

[0133] In the first embodiment of the on-press development type lithographic printing plate precursor according to the present application, the above-mentioned image recording layer contains a color developing compound capable of undergoing a color developing reaction with a decomposition product generated by exposure of the above-mentioned image recording layer.

[0134] In the second embodiment of the on-press development type lithographic printing plate precursor according to the present application, the above-mentioned image recording layer contains a compound represented by the above-mentioned Formula 1C or Formula 2C and an electron-donating polymerization initiator.

[0135] In the third embodiment of the on-press development type lithographic printing plate precursor according to the present application, the above-mentioned image recording layer exposed at an energy density of 110 mJ / cm 2 with infrared rays having a wavelength of 830 nm contains a compound represented by the above-mentioned Formula 1C or Formula 2C or a complex having an anion obtained by removing one hydrogen atom from the compound represented by the above-mentioned Formula 1C or Formula 2C as a ligand.

[0136] The image recording layer used in the present application is preferably a negative type image recording layer, more preferably a water-soluble or water-dispersible negative type image recording layer.

[0137] With regard to 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.

[0138] In the lithographic printing plate precursor according to the present application, from the viewpoint of improving the visual recognition of the exposed portion, the change in lightness ΔL of the portion subjected to the above-mentioned exposure, after storage for 6 hours under conditions of 30°C, 70% RH after the above-mentioned pre-exposure and the above-mentioned post-exposure, when exposure is performed at an energy density of 110 mJ / cm 2 with infrared rays having a wavelength of 830 nm, is preferably 3 or more, more preferably 4 or more, further preferably 5 or more, and particularly preferably 7.5 or more.

[0139] As the upper limit of the change in lightness ΔL, for example, 20.0 can be given.

[0140] Also, particularly in the case where the outermost layer contains a color changing compound, it is preferred that the above-mentioned preferred numerical range of the change in lightness ΔL be satisfied.

[0141] The change in lightness ΔL is measured by the following method.

[0142] The Luxel PLATESETTER T-9800, manufactured by FUJIFILM Graphic Systems Co., Ltd., equipped with an 830nm infrared semiconductor laser, achieved an energy density of 110mJ / cm² under the following conditions: 99.5% output, 220rpm external drum speed, and 2,400dpi resolution (dots per inch, 1 inch = 25.4mm). 2 The original offset printing plate is exposed under the following conditions. Exposure is performed at 25°C and 50% RH.

[0143] The brightness change of the exposed part of the original lithographic printing plate before exposure and the original lithographic printing plate after exposure and storage at 30℃ and 70%RH for 6 hours were measured.

[0144] The measurements were performed using an eXact spectrochromatic meter manufactured by X-Rite Inc. Using L... * a * b * L in color scheme * Value (brightness), which determines the L value of the exposed area. * The value of L is related to the exposed or unexposed portion before exposure. * The absolute value of the difference in values ​​is taken as the change in brightness ΔL.

[0145] [Chromatoglycans, compounds represented by formula 1C or formula 2C]

[0146] In a first embodiment of the on-machine developing type lithographic printing plate original involved in the present invention, the image recording layer contains a color-developing compound capable of reacting with the decomposition products generated by exposure of the image recording layer.

[0147] Furthermore, the preferred embodiment of the chromogenic compound is a compound represented by formula 1C or formula 2C.

[0148] In this invention, "color reaction" refers to the chemical reaction that occurs along with the color development or color change phenomenon.

[0149] There are no particular limitations on the decomposition products generated by the exposure of the image recording layer described above. However, from the viewpoint of visual recognizability of the exposed part, it is preferable to be a decomposition product generated by the exposure of a polymerization initiator or a decomposition product generated by the exposure of an infrared absorber. More preferably, it is a decomposition product generated by the exposure of a polymerization initiator. In particular, it is preferable to be a decomposition product generated by the exposure of an electron-donating polymerization initiator.

[0150] Furthermore, the decomposition products generated by exposure of the aforementioned image recording layer not only include the decomposition products generated by exposure of the aforementioned image recording layer, but also include compounds generated by further decomposition or modification of the aforementioned decomposition products.

[0151] Further, from the viewpoint of visual recognition of the exposed portion, the above-mentioned color development reaction is preferably a complex formation reaction, and more preferably a boron complex formation reaction.

[0152] An example of the above-mentioned color development reaction is shown below. An example of the color development reaction when sodium tetraphenylborate is decomposed to produce boric acid as a decomposition product resulting from exposure of the image-recording layer using curcumin as the color-developing compound is shown below. Due to keto-enol tautomerism, curcumin produces an enol form as an equilibrium. By reacting the above-mentioned enol form with boric acid, the following boron complex (Complex) is produced, resulting in a color development reaction from curcumin (yellow) to the following boron complex (red).

[0153] Further, the following shows an example of hydrolysis to boric acid, but for example, diphenyl monohydroxyboron, monophenyl dihydroxyboron, or the like can form a complex with curcumin, and triphenylboron can coordinate with the enol form of curcumin as a ligand of zero valence to form a complex.

[0154] [Chemical Formula 8]

[0155]

[0156] As the above-mentioned color-developing compound, from the viewpoint of visual recognition of the exposed portion and color tone reproducibility, a compound having one or more ketone structures is preferred, a compound having one or more 1,3-diketone structures, β-hydroxy ketone structures, or β-amino ketone structures is more preferred, a compound having one or more 1,3-diketone structures or β-hydroxy ketone structures is further preferred, and a compound having one or more 1,3-diketone structures is particularly preferred.

[0157] Further, as the above-mentioned color-developing compound, a compound having one or more 1-hydroxy-3-amino structures or 1-hydroxy-3-imino structures can also be mentioned.

[0158] Further, as the above-mentioned color-developing compound, from the viewpoint of visual recognition of the exposed portion and color tone reproducibility, a compound having an aromatic ring structure is preferred, a compound having two or more aromatic ring structures is more preferred, a compound having two to four aromatic ring structures is further preferred, and a compound having two aromatic ring structures is particularly preferred.

[0159] As the above-mentioned aromatic ring structure, from the viewpoint of visual recognition of the exposed portion and color tone reproducibility, at least one selected from a benzene ring structure and a naphthalene ring structure is preferred, and a benzene ring structure is more preferred.

[0160] Further, the above-mentioned color-developing compound can be a salt or a hydrate.

[0161] Further, in the case where the above-mentioned color developing compound reacts with a decomposition product generated by exposure of the above-mentioned image recording layer to form a complex, in the above-mentioned complex, it can be a monodentate ligand or a polydentate ligand, but from the viewpoints of complex formation, visual recognition of the exposed portion, and color tone reproducibility, it is preferable to be a polydentate ligand, more preferable to be a bidentate to hexadentate ligand, further preferable to be a bidentate to tetradentate ligand, particularly preferable to be a bidentate or tridentate ligand, and most preferable to be a bidentate ligand.

[0162] In the first embodiment of the on-press development type lithographic printing plate precursor according to the present application, from the viewpoints of visual recognition of the exposed portion and color tone reproducibility, as the above-mentioned color developing compound, it is preferable to contain a compound represented by the following Formula 1C or Formula 2C, and more preferable to contain a compound represented by the following Formula 1C.

[0163] In the second embodiment of the on-press development type lithographic printing plate precursor according to the present application, the above-mentioned image recording layer contains a compound represented by the following Formula 1C or Formula 2C, and preferably contains a compound represented by the following Formula 1C.

[0164] In the third embodiment of the on-press development type lithographic printing plate precursor according to the present application, from the viewpoints of visual recognition of the exposed portion and color tone reproducibility, the above-mentioned image recording layer preferably contains a compound represented by the following Formula 1C or Formula 2C, and more preferably contains a compound represented by the following Formula 1C.

[0165] Further, in the third embodiment of the on-press development type lithographic printing plate precursor according to the present application, it is preferable that, after exposure, a compound represented by the following Formula 1C or Formula 2C reacts with a decomposition product generated by exposure of the above-mentioned image recording layer to form a complex having a ligand of zero valence of a compound represented by the following Formula 1C or Formula 2C or a ligand of one valence of an anion obtained by removing one hydrogen atom from a compound represented by the following Formula 1C or Formula 2C, and more preferably a compound represented by the following Formula 1C or Formula 2C reacts with a decomposition product generated by exposure of the above-mentioned image recording layer to form a complex having a ligand of one valence of an anion obtained by removing one hydrogen atom from a compound represented by the following Formula 1C or Formula 2C.

[0166] [Chemical Formula 9]

[0167]

[0168] In Formula 1C and Formula 2C, R 1C ~R 4C each independently represents a monovalent organic group, L 1C and L 2C each independently represents a divalent organic group, A Crepresents an OH group or an NR group 5C R 6C , R 5C and R 6C each independently represent a hydrogen atom or a monovalent organic group, and the dotted line portion represents a portion which can be a double bond.

[0169] In Formula 1C, two or more of R 1C , L 1C and R 2C may be bonded to form a ring structure.

[0170] In Formula 2C, two or more of R 3C , L 2C , R 4C , R 5C and R 6C may be bonded to form a ring structure.

[0171] From the viewpoint of visual recognition and color tone reproducibility of the exposed portion, R 1C and R 2C in Formula 1C each independently preferably are a monovalent organic group having an aromatic ring, more preferably an aryl group or an alkenyl group having an aryl group, and particularly preferably a 2-arylvinyl group.

[0172] Further, the aryl group can have a substituent, and from the viewpoint of visual recognition and color tone reproducibility of the exposed portion, it is preferred that the aryl group have one or more groups selected from a group consisting of a hydroxy group and an alkoxy group as a substituent, more preferred that the aryl group have one or more groups selected from a group consisting of a hydroxy group and an alkoxy group as a substituent, and particularly preferred that the aryl group have a hydroxy group and an alkoxy group as a substituent.

[0173] Further, the number of carbon atoms (the number of carbon atoms) of R 1C and R 2C in Formula 1C each independently preferably is 6 to 50, more preferably 6 to 20, and particularly preferably 8 to 20.

[0174] Further, R 1C and R 2C in Formula 1C preferably are the same group.

[0175] From the viewpoint of visual recognition and color tone reproducibility of the exposed portion, L 1C in Formula 1C preferably is an alkylene group having an alkylene group or an acyloxy group, and more preferably a methylene group or an acyloxymethylene group.

[0176] Further, as the acyloxy group, from the viewpoint of visual recognition of the exposed portion, an acyloxy group having 1 to 10 carbon atoms is preferred, an acyloxy group having 1 to 4 carbon atoms is more preferred, and an acetyloxy group is particularly preferred.

[0177] From the viewpoint of visual recognition and color tone reproducibility of the exposed portion, R in formula 2C 3C Preferably, it is a monovalent organic group having an aromatic ring, more preferably an aryl group or an alkenyl group having an aryl group.

[0178] In formula 2C, from the viewpoint of visual recognition and color tone reproducibility of the exposed portion, L 2C bonded to form an aromatic ring, more preferably L 4C bonded to form a benzene ring. 2C bonded to form an aromatic ring, more preferably L 4C bonded to form a benzene ring.

[0179] In formula 2C, R 3C and R 4C preferably have a carbon atom number of 6 to 50, more preferably 6 to 30, and particularly preferably 6 to 20, respectively.

[0180] In formula 2C, L 2C , from the viewpoint of visual recognition and color tone reproducibility of the exposed portion, it is preferably an alkylene group having an alkylene group or an acyloxy group, more preferably a methylene group or an acyloxymethylene group, in the case where it is not bonded to R 4C .

[0181] Further, as the acyloxy group, from the viewpoint of visual recognition of the exposed portion, it is preferably an acyloxy group having a carbon atom number of 1 to 10, more preferably an acyloxy group having a carbon atom number of 1 to 4, and particularly preferably an acetyloxy group.

[0182] In formula 2C, L 2C preferably forms a ring member of an aromatic ring structure by bonding to R 4C .

[0183] From the viewpoint of visual recognition and color tone reproducibility of the exposed portion, the compound represented by formula 2C is preferably a compound having a 1-hydroxyanthraquinone structure or a 1-aminoanthraquinone structure, more preferably a compound having a 1-hydroxyanthraquinone structure.

[0184] In formula 2C, A C preferably is OH or NHR 6C , more preferably OH.

[0185] In NR 5C R 6C of formula 2C, R 5C preferably is a hydrogen atom, an alkyl group, or an aryl group, more preferably a hydrogen atom or an alkyl group, and particularly preferably a hydrogen atom.

[0186] In NR 5C R 6C of formula 2C, R 6CPreferably, it is a hydrogen atom, an alkyl group or an anthraquinonyl group, more preferably an anthraquinonyl group, and particularly preferably a 1-anthraquinonyl group.

[0187] As the above-mentioned color-developing compound, specifically, for example, curcumin (C-1 described later in the examples), demethoxycurcumin (C-2 described later in the examples), alizarin (C-3 described later in the examples), imino dianthraquinone (C-4 described later in the examples), carminic acid (C-5 described later in the examples), azomethine H (C-6 described later in the examples), 1,3-bis(4-methoxyphenyl)-l,3-propanedione (C-7 described later in the examples), 4-methoxychalcone (C-8 described later in the examples), 1,3-bis(4-dimethylaminophenyl)-l,3-propanedione (C-9 described later in the examples), acetoxycurcumin (C-10 described later in the examples), and the like can be preferably selected.

[0188] The above-mentioned color-developing compound can be used singly or two or more kinds can be used simultaneously.

[0189] Further, the compound represented by the above-mentioned formula 1C or formula 2C can be used singly or two or more kinds can be used simultaneously.

[0190] Furthermore, the above-mentioned complex can be formed singly or two or more kinds can be formed.

[0191] From the viewpoint of visual recognition and color tone reproducibility of the exposed portion, the content of the above-mentioned color-developing compound 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%, with respect to the total mass of the above-mentioned image recording layer.

[0192] Further, from the viewpoint of visual recognition and color tone reproducibility of the exposed portion, the compound represented by the above-mentioned formula 1C or formula 2C 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%, with respect to the total mass of the above-mentioned image recording layer.

[0193] Furthermore, from the viewpoint of visual recognition and color tone reproducibility of the exposed portion, the content of the above-mentioned complex in the above-mentioned image recording layer exposed with infrared rays having a wavelength of 830 nm at an energy density of 110 mJ / cm 2 The content of the above-mentioned complex in the above-mentioned image recording layer exposed with infrared rays having a wavelength of 830 nm at an energy density of 110 mJ / cm

[0194] The content M of the above-mentioned color-developing compound (preferably a compound represented by the above-mentioned Formula 1C or Formula 2C) in the above-mentioned image-recording layer C to the content M of the above-mentioned electron-donating polymerization initiator I The molar ratio of the content M of the above-mentioned color-developing compound (preferably a compound represented by the above-mentioned Formula 1C or Formula 2C) in the above-mentioned image-recording layer C to the content M of the above-mentioned electron-donating polymerization initiator I = 0.001 to 1, more preferably M C to the content M of the above-mentioned electron-donating polymerization initiator I = 0.01 to 0.8, particularly preferably M C to the content M of the above-mentioned electron-donating polymerization initiator I = 0.05 to 0.5.

[0195] The content M of the above-mentioned color-developing compound (preferably a compound represented by the above-mentioned Formula 1C or Formula 2C) in the above-mentioned image-recording layer C to the content M of the above-mentioned electron-donating polymerization initiator DI The molar ratio of the content M of the above-mentioned color-developing compound (preferably a compound represented by the above-mentioned Formula 1C or Formula 2C) in the above-mentioned image-recording layer C to the content M of the above-mentioned electron-donating polymerization initiator DI = 0.001 to 1.5, more preferably M C to the content M of the above-mentioned electron-donating polymerization initiator DI = 0.01 to 1, particularly preferably M C to the content M of the above-mentioned electron-donating polymerization initiator DI = 0.05 to 0.8.

[0196] (Infrared absorber)

[0197] The image-recording layer in the present application preferably further contains an infrared absorber.

[0198] There is no particular limitation on the infrared absorber, and pigments and dyes, for example, can be mentioned.

[0199] As the dye that 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. Edited, published in 45 years 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, pyrilium salts, metal thiol complexes, and the like can be mentioned.

[0200] As the preferred dye among these dyes, cyanine pigments, squarylium dyes, pyrilium salts, nickel thiol complexes, indocyanine pigments can be mentioned. More preferably, cyanine pigments, indocyanine pigments are mentioned. Among them, particularly preferably, cyanine pigments are mentioned.

[0201] As the above-mentioned infrared absorber, a cationic polymethine dye having an oxygen atom, a nitrogen atom, or a halogen atom at a meta position is preferable. As the cationic polymethine dye, a cyanine dye, a pyrylium dye, a thiopyrylium dye, an azulene dye, and the like are preferable, and from the viewpoints of easiness of obtaining, solvent solubility at the time of introduction reaction, and the like, a cyanine dye is preferable.

[0202] 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 exemplified, 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 preferable, and in particular, 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 are preferable.

[0203] 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 preferable.

[0204] Further, as the above-mentioned infrared absorber, a decomposable compound which is described later as a color-changing compound for the outermost layer and which is decomposed by infrared exposure can also be preferably used.

[0205] From the viewpoints 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.

[0206] From the viewpoints 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.

[0207] The infrared absorber can be used singly or in combination of two or more.

[0208] Also, as the infrared absorber, a pigment and a dye can be used in combination.

[0209] The content of the infrared absorber is preferably 0.1 to 10.0 mass% and more preferably 0.5 to 5.0 mass% with respect to the total mass of the image recording layer.

[0210] [Polymerization initiator]

[0211] The image recording layer in the first or third embodiment of the lithographic printing plate precursor according to the present application preferably further contains a polymerization initiator.

[0212] As the above-mentioned polymerization initiator in the first or third embodiment of the lithographic printing plate precursor according to the present application, an electron-donating polymerization initiator is preferred, and an electron-accepting polymerization initiator and an electron-donating polymerization initiator are more preferred.

[0213] Also, from the viewpoint of visual recognition and tone reproducibility of the exposed portion, the image recording layer in the first or third embodiment of the lithographic printing plate precursor according to the present application preferably further contains a polymerization initiator, the decomposition product generated by the above-mentioned exposure is a decomposition product generated by exposure of the above-mentioned polymerization initiator, and more preferably further contains an electron-donating polymerization initiator, the decomposition product generated by the above-mentioned exposure is a decomposition product generated by exposure of the above-mentioned electron-donating polymerization initiator.

[0214] Further, in the image recording layer in the second embodiment of the lithographic printing plate precursor according to the present application, from the viewpoint of visual recognition and tone reproducibility of the exposed portion, the decomposition product generated by exposure of the electron-donating polymerization initiator is preferably subjected to a color development reaction with the compound represented by the above-mentioned Formula 1C or Formula 2C, and a complex is formed.

[0215] [Electron-donating polymerization initiator (polymerization aid)]

[0216] The image recording layer in the first or third embodiment of the lithographic printing plate precursor according to the present application preferably further contains an electron-donating polymerization initiator (also referred to as "polymerization aid") as the polymerization initiator.

[0217] The image recording layer in the second embodiment of the lithographic printing plate precursor according to the present application contains an electron-donating polymerization initiator as the polymerization initiator.

[0218] The electron-donating polymerization initiator is a compound that, when an electron of the infrared absorber is excited or moves within the molecule by infrared exposure, donates one electron to the orbital from which the electron of the infrared absorber is detached by intermolecular electron movement, and generates a polymerization initiator species such as a radical.

[0219] As the electron-donating polymerization initiator, an electron-donating radical polymerization initiator is preferable.

[0220] From the viewpoints of visual recognition and color tone reproducibility of the exposed portion, the above-mentioned electron-donating polymerization initiator preferably contains a boron compound, more preferably a borate compound, further preferably a tetraaryl borate compound, and particularly preferably a tetraphenyl borate compound.

[0221] As the borate compound, from the viewpoints of visual recognition and color development, a tetraaryl borate compound or a monoalkyl triaryl borate compound is preferable, and a tetraaryl borate compound is more preferable.

[0222] Further, as the borate compound, from the viewpoints of print durability and visual recognition, a tetraaryl borate compound having one or more electron-donating groups or electron-withdrawing groups is preferable, and a tetraaryl borate compound having one electron-donating group or electron-withdrawing group in each aryl group is more preferable.

[0223] As the above-mentioned electron-donating group, from the viewpoints of print durability and visual recognition, an alkyl group or an alkoxy group is preferable, and an alkoxy group is more preferable.

[0224] 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.

[0225] As the counter cation of the borate compound, there is no particular limitation, but an alkali metal ion or a tetraalkyl ammonium ion is preferable, and a sodium ion, a potassium ion, or a tetrabutyl ammonium ion is more preferable.

[0226] Further, as the counter cation of the borate compound, among the infrared absorbers described in the present specification, a cationic polyformylmethine dye can be mentioned. For example, as the counter cation of a cyanine dye, the above-mentioned borate compound can be used.

[0227] As the borate compound, specifically, sodium tetraphenyl borate is preferable.

[0228] The following shows preferred specific examples of B-1 to B-9 as electron-donating polymerization initiators, and of course, is not limited to these. Further, in the following chemical formulas, Ph represents a phenyl group, and Bu represents an n-butyl group.

[0229] [Chemical Formula 10]

[0230]

[0231] Further, from the viewpoint of improving sensitivity, the highest occupied molecular orbital (HOMO) of the electron-donating polymerization initiator is preferably -6.00 eV or more, more preferably -5.95 eV or more, further preferably -5.93 eV or more, and particularly preferably more than -5.90 eV.

[0232] Further, as an upper limit, it is preferably -5.00 eV or less, and more preferably -5.40 eV or less.

[0233] The electron-donating polymerization initiator can be used alone or in combination of two or more.

[0234] The content of the 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 sensitivity and print durability.

[0235] Further, from the viewpoint of UV print durability, the content of the electron-donating polymerization initiator in the image-recording layer is preferably more than the content of the infrared absorber, more preferably 1.1 to 5 times the content of the infrared absorber, and particularly preferably 1.5 to 3 times the content of the infrared absorber.

[0236] In the present application, the polymerization initiator can be a compound in which an electron-donating polymerization initiator and an electron-accepting polymerization initiator form a counter salt.

[0237] For example, in the present application, a compound in which an anion in the electron-donating polymerization initiator and a 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.

[0238] 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.

[0239] In the case where the image-recording layer contains an anion that is an electron-donating polymerization initiator and a cation that is an electron-accepting polymerization initiator (i.e., in the case where a compound that forms the above counter salt is contained), the image-recording layer contains an electron-accepting polymerization initiator and the above electron-donating polymerization initiator.

[0240] Further, a compound that forms a counter salt with an electron-donating polymerization initiator and an electron-accepting polymerization initiator can be used as an electron-donating polymerization initiator, and can also be used as an electron-accepting polymerization initiator.

[0241] Further, a compound that forms a counter salt with an electron-donating polymerization initiator and an electron-accepting polymerization initiator can be used in combination with the electron-donating polymerization initiator described above, and can also be used in combination with the electron-accepting polymerization initiator described above.

[0242] The image recording layer in the present application further 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-described infrared absorber - HOMO of the above-described 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.

[0243] Further, the negative value means that the HOMO of the above-described electron-donating polymerization initiator is higher than the HOMO of the above-described infrared absorber.

[0244] 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.

[0245] First, free counter ions in the compound that is the calculation target are excluded from the calculation target. For example, in a cationic electron-accepting polymerization initiator and a cationic infrared absorber, the counter anion is excluded from the calculation target, and in an anionic electron-donating polymerization initiator, the counter cation is excluded from the calculation target. The free mentioned here means that the compound that is the target is not linked to the counter ion thereof by a covalent bond.

[0246] The structure optimization was performed under DFT (B3LYP / 6-31G(d)) using quantum chemistry calculation software Gaussian16.

[0247] Regarding the MO energy calculation, the optimal structure obtained by the above-described structure optimization was used, and the calculation was performed under DFT (B3LYP / 6-31+G(d,p) / PCM (solvent = methanol)) using quantum chemistry calculation software Gaussian16. Further, for a compound containing iodine, the calculation was performed under DFT (B3LYP / DGD ZVP / PCM (solvent = methanol)).

[0248] The optimal structure mentioned here means the structure that is the most stable in terms of the total energy obtained by DFT calculation. The structure optimization is repeated as necessary, and thereby the most stable structure is found.

[0249] The MO energy Ebare (unit: Hartree) obtained by the above MO energy calculation is converted into Escaled (unit: eV), which is used as the value of HOMO and LUMO in the present application, according to the following formula.

[0250] [Calculation formula of HOMO] Escaled = 0.823168 x 27.2114 x Ebare - 1.07634

[0251] [Calculation formula of LUMO] Escaled = 0.820139 x 27.2114 x Ebare - 1.086039

[0252] Further, 27.2114 is a coefficient for converting Hartree into eV, and 0.823168 and -1.07634 used in the calculation of HOMO and 0.820139 and -1.086039 used in the calculation of LUMO are adjustment coefficients, and are determined in a manner so as to match the calculated values of HOMO and LUMO of the compound to be calculated with the measured values.

[0253] [Electron-accepting polymerization initiator]

[0254] The image recording layer in the present application preferably further contains an electron-accepting polymerization initiator as a polymerization initiator.

[0255] The electron-accepting polymerization initiator is a compound which generates a polymerization initiator species such as a radical by accepting one electron through intermolecular electron transfer when the electron of the infrared absorber is excited by infrared exposure.

[0256] The electron-accepting polymerization initiator is a compound which 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 and the like can be appropriately selected and used.

[0257] As the electron-accepting polymerization initiator, a radical polymerization initiator is preferred, and an onium salt compound is more preferred.

[0258] Further, as the electron-accepting polymerization initiator, an infrared photosensitive polymerization initiator is preferred.

[0259] 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.

[0260] Further, as the compound having a halogenated alkyl group, from the viewpoint of improving sensitivity and UV printing durability, a compound having a perhaloalkylsulfonyl group is preferred, a compound having a trihalomethylsulfonyl group is more preferred, and a compound having a tribromomethylsulfonyl group is particularly preferred.

[0261] Among the above-mentioned electron-accepting polymerization initiators, from the viewpoint of curability, oxime ester compounds and onium salt compounds can be given as preferred electron-accepting polymerization initiators. Among them, from the viewpoint of printing durability, iodonium salt compounds, sulfonium salt compounds, or azinium salt compounds are preferred, iodonium salt compounds or sulfonium salt compounds are more preferred, and iodonium salt compounds are particularly preferred.

[0262] Specific examples of these compounds are shown below, but the present application is not limited thereto.

[0263] As examples of the iodonium salt compound, a diaryliodonium salt compound is preferred, and a diphenyl iodonium salt compound substituted with an electron-donating group such as an alkyl group or an alkoxy group is particularly preferred. Further, an unsymmetrical diphenyl iodonium salt compound is preferred. 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-perfluorobutylsulfonate, 4-octyloxyphenyl-2,4,6-trimethoxyphenyl iodonium hexafluorophosphate, and bis(4-tert-butylphenyl)iodonium tetraphenylborate can be given.

[0264] Further, as examples of the counter anion of the iodonium salt compound and the sulfonium salt compound, sulfonate anions, carboxylate anions, tetrafluoroborate anions, hexafluorophosphate anions, p-toluenesulfonate anions, p-toluenesulfonate anions, sulfonamide anions, or sulfonimide anions can be given.

[0265] Among them, sulfonamide anions or sulfonimide anions are preferred, and sulfonimide anions are more preferred.

[0266] As the sulfonamide anion, arylsulfonamide anions are preferred.

[0267] Further, as the sulfonimide anion, diarylsulfonimide anions are preferred.

[0268] As specific examples of the sulfonamide anion or the sulfonimide anion, the compounds described in International Publication No. 2019 / 013268 can be given.

[0269] Further, as the above-mentioned electron-accepting polymerization initiator, from the viewpoints of the visual recognition over time after exposure, the developability, and the UV print durability in the obtained lithographic printing plate, it is preferable to contain a compound represented by the following formula (II) or formula (III), and particularly preferable to contain a compound represented by formula (II).

[0270] [Chemical Formula 11]

[0271]

[0272] In formula (II) and formula (III), X A represents a halogen atom, R A , R A1 , and R A2 each independently represent a monovalent hydrocarbon group having 1 to 20 carbon atoms.

[0273] R A in formula (II) is preferably an aryl group.

[0274] As X A in formula (II) and formula (III), a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom can be given. Among these, a chlorine atom or a bromine atom is preferable because of the excellent sensitivity, and a bromine atom is particularly preferable.

[0275] Further, in formula (II) and formula (III), R A , R A1 , and R A2 each independently are preferably an aryl group, and more preferably an aryl group substituted with an amido group from the viewpoint of the balance between the sensitivity and the storage stability.

[0276] Further, as the above-mentioned electron-accepting polymerization initiator, it is particularly preferable to contain a compound represented by formula (IV).

[0277] [Chemical Formula 12]

[0278]

[0279] In formula (IV), X A represents a halogen atom, R A3 , and R A4 each independently represent a monovalent hydrocarbon group having 1 to 20 carbon atoms, and pA and qA each independently represent an integer of 1 to 5. Among these, pA + qA = 2 to 6.

[0280] As specific examples of the electron-accepting polymerization initiator, compounds represented by the following formulae, and the like can be given, but the present application is not limited to these.

[0281] [Chemical Formula 13]

[0282]

[0283] [Chemical Formula 14]

[0284]

[0285] [Chemical Formula 15]

[0286]

[0287] [Chemical Formula 16]

[0288]

[0289] [Chemical Formula 17]

[0290]

[0291] [Chemical Formula 18]

[0292]

[0293] [Chemical Formula 19]

[0294]

[0295] 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.

[0296] Also, as a lower limit, it is preferably -3.80 eV or more, more preferably -3.50 eV or more.

[0297] The electron-accepting polymerization initiator can be used singly or in combination of two or more.

[0298] The content of the electron-accepting polymerization initiator is preferably 0.1 to 50 mass%, more preferably 0.5 to 30 mass%, particularly preferably 0.8 to 20 mass%, relative to the total mass of the image-recording layer.

[0299] The image-recording layer in the present application further contains an infrared absorber and an electron-accepting polymerization initiator, and from the viewpoint of improving sensitivity and print durability, the value of LUMO of the above-mentioned electron-accepting polymerization initiator minus LUMO of the above-mentioned 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, most preferably 0.70 to 0.30 eV.

[0300] In addition, a negative value means that the LUMO of the above-mentioned infrared absorber is higher than the LUMO of the above-mentioned electron-accepting polymerization initiator.

[0301] 〔Polymerizable compound〕

[0302] The image-recording layer in the present application preferably further contains a polymerizable compound.

[0303] In the present application, the polymerizable compound refers to a compound having a polymerizable group.

[0304] There is no particular limitation on the polymerizable group as long as it is a publicly known polymerizable group, but it is preferably an ethylenically unsaturated group. Also, as the polymerizable group, it can be a radical polymerizable group or a cationic polymerizable group, but it is preferably a radical polymerizable group.

[0305] As the radical polymerizable group, (meth)acryloyl group, allyl group, vinylphenyl group, vinyl group, etc. can be given, and from the viewpoint of reactivity, (meth)acryloyl group is preferred.

[0306] The molecular weight (weight average molecular weight in the case of having a molecular weight distribution) of the polymerizable compound is preferably 50 or greater and less than 2,500.

[0307] The polymerizable compound used in the present application can be, for example, 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.

[0308] As the ethylenically unsaturated compound, it is preferably a compound having at least one terminal ethylenically unsaturated bond, and more preferably a compound having two or more terminal ethylenically unsaturated bonds. The polymerizable compound has, for example, a chemical form such as a monomer, a prepolymer (dimer, trimer, or oligomer), or a mixture thereof.

[0309] Among them, as the above polymerizable compound, from the viewpoint of UV printing durability, it is preferred to contain a polymerizable compound having 3 or more functions, more preferably a polymerizable compound having 7 or more functions, and further preferably a polymerizable compound having 10 or more functions. Also, from the viewpoint of UV printing durability in the obtained lithographic printing plate, the above polymerizable compound preferably contains an ethylenically unsaturated compound having 3 or more functions (preferably 7 or more functions, and more preferably 10 or more functions), and further preferably contains a (meth)acrylate compound having 3 or more functions (preferably 7 or more functions, and more preferably 10 or more functions).

[0310] Also, as the above polymerizable compound, from the viewpoint of on-press developability and contamination inhibition, it is preferred to contain a polymerizable compound having 2 or less functions, more preferably a polymerizable compound having 2 functions, and particularly preferably a (meth)acrylate compound having 2 functions.

[0311] From the viewpoint of print durability, on-press developability, and contamination inhibitory property, the content of the polyfunctional or less polyfunctional compound (preferably a difunctional polyfunctional compound) is preferably 5% by mass or more and 100% by mass or less, more preferably 10% by mass or more and 100% by mass or less, and particularly preferably 50% by mass or more and 100% by mass or less, relative to the total mass of the polyfunctional compound in the above-mentioned image-recording layer.

[0312] <<oligomer>>

[0313] As the polyfunctional compound contained in the image-recording layer, a polyfunctional compound which is an oligomer (hereinafter, also simply referred to as "oligomer") is preferable.

[0314] In the present application, the oligomer means a polyfunctional 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 polyfunctional group.

[0315] From the viewpoint of excellent chemical resistance and UV print durability, the molecular weight of the oligomer is preferably 1,000 or more and 5,000 or less.

[0316] Further, from the viewpoint of improving UV print durability, the number of polyfunctional 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.

[0317] Further, the upper limit of the number of polyfunctional groups in the oligomer is not particularly limited, but the number of polyfunctional groups is preferably 20 or less.

[0318] From the viewpoint of UV print durability and on-press developability, the number of polyfunctional groups in the oligomer is preferably 7 or more, and the molecular weight is 1,000 or more and 10,000 or less, and more preferably the number of polyfunctional groups is 7 or more and 20 or less, and the molecular weight is 1,000 or more and 5,000 or less.

[0319] In addition, a polymer component which can be generated in the process of producing the oligomer can be contained.

[0320] From the viewpoint of UV print 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 more preferably has a compound having a urethane bond.

[0321] In the present application, the epoxy residue means a structure formed from an epoxy group, and for example, means the same structure as that obtained by the reaction of an acid group (carboxylic acid group, etc.) with an epoxy group.

[0322] As an example of the compound having a urethane bond as 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.

[0323] [Chemical Formula 20]

[0324]

[0325] 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 represents a bonding position to other structures.

[0326] 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. Furthermore, the above alkylene group can have a branched chain or a ring structure, but is preferably a linear alkylene group.

[0327] 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.

[0328] [Chemical Formula 21]

[0329]

[0330] In formula (Ae-1) and formula (Ae-2), R each independently represents an acryloyloxy group or a methacryloyloxy group, and the wavy line portion represents a bonding position to the wavy line portion in formula (Ac-1) and formula (Ac-2).

[0331] Furthermore, as the compound having a urethane bond, a compound in which a polymerizable group is introduced to a polyurethane obtained by the reaction of a polyisocyanate compound and a polyol compound by a high molecular reaction can be used.

[0332] 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.

[0333] The number of polymerizable groups in the compound having an ester bond as an example of the oligomer is preferably 3 or more, and further preferably 6 or more.

[0334] As an example of the oligomer, a compound having an epoxy residue, preferably a compound containing a hydroxyl group within the compound.

[0335] Further, the number of polymerizable groups in the compound having an epoxy residue is preferably 2 to 6, more preferably 2 to 3.

[0336] As the compound having an epoxy residue described above, for example, it is possible to obtain by reacting acrylic acid with a compound having an epoxy group.

[0337] Specific examples of the oligomer are exemplified in the following, but the oligomer used in the present application is not limited thereto.

[0338] As the oligomer, commercially available products can be used, and as examples, there can be mentioned 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 not limited thereto.

[0339] 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 to 100% by mass, more preferably 50% by mass to 100% by mass, and further preferably 80% by mass to 100% by mass, with respect to the total mass of the polymerizable compound in the image-recording layer.

[0340] <<Low Molecular Polymerizable Compound>>

[0341] The polymerizable compound can further include a polymerizable compound other than the oligomer described above.

[0342] 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, it can be a monomer, a dimer, a trimer, or a mixture thereof, or the like.

[0343] Further, as the low molecular polymerizable compound, from the viewpoint of chemical resistance, it is preferable to be at least one polymerizable compound selected from a polymerizable compound having 3 or more ethylenically unsaturated groups and a polymerizable compound having an isocyanurine ring structure.

[0344] In the present application, the low molecular weight polymerizable compound means 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.

[0345] As the molecular weight of the low molecular weight polymerizable compound, from the viewpoint of excellent chemical resistance, UV print durability, and inhibition of on-press development residue, it is preferably 100 or more and less than 600, more preferably 300 or more and less than 600, and further preferably 400 or more and less than 600.

[0346] In the case where the polymerizable compound contains a low molecular weight polymerizable compound as a polymerizable compound other than the oligomer (in the case of containing two or more kinds of low molecular weight polymerizable compounds, 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 oligomer to the low molecular weight polymerizable compound (oligomer / low molecular weight polymerizable compound) is preferably 10 / 1 to 1 / 10, more preferably 10 / 1 to 3 / 7, and further preferably 10 / 1 to 7 / 3, on a mass basis.

[0347] Further, as the low molecular weight polymerizable compound, the polymerizable compound described in paragraphs 0082 to 0086 of International Publication No. 2019 / 013268 can also be preferably used.

[0348] The structure of the polymerizable compound, the method of use alone or in combination, the amount of addition, and the like can be arbitrarily set.

[0349] Among them, from the viewpoint of UV print durability, the image recording layer preferably contains two or more kinds of polymerizable compounds.

[0350] 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%, relative to the total mass of the image recording layer.

[0351] [Particles]

[0352] From the viewpoints of development properties and UV print durability, the image recording layer in the present application preferably further contains particles. As the particles, they can be inorganic particles or organic particles.

[0353] Among them, as the particles, organic particles are preferably contained, and resin particles are more preferably contained.

[0354] 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.

[0355] <<Resin particles>>

[0356] As the resin particles, for example, there can be mentioned 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, but among them, an addition polymerization type resin particle or a polyaddition type resin particle is preferable.

[0357] Also, as the resin particles, from the viewpoint of being able to be heat-fused, there can be particles containing a thermoplastic resin (i.e., thermoplastic resin particles).

[0358] Also, the resin particles can be in the form of a microcapsule, a microgel (i.e., crosslinked resin particles), or the like.

[0359] As the resin particles, it is preferable to be selected from among a thermoplastic resin particle, a thermally reactive resin particle, a resin particle having a polymerizable group, a microcapsule and a microgel (crosslinked resin particle) containing a hydrophobic compound. Among them, a resin particle having a polymerizable group is preferable.

[0360] In an especially preferable embodiment, the resin particles contain at least one olefinic unsaturated group. Due to 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.

[0361] 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.

[0362] As a specific example of the resin constituting the thermoplastic resin particles, there can be mentioned a homopolymer or copolymer of a monomer such as ethylene, styrene, vinyl chloride, methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate, vinylidene chloride, acrylonitrile, vinylcarbazole, an acrylate or methacrylate having a polyalkylene structure, or a mixture thereof.

[0363] As the thermoplastic resin particles, from the viewpoints of ink adhesion and UV print durability, it is preferable to contain a resin having a constitutional unit formed from an aromatic vinyl compound and a constitutional unit having a nitrile group.

[0364] 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.

[0365] 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.

[0366] 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.

[0367] The constitutional unit having a nitrile group is preferably introduced using a monomer having a nitrile group.

[0368] As the monomer having a nitrile group, an acrylonitrile compound can be mentioned, and (meth)acrylonitrile is preferred.

[0369] As the constitutional unit having a nitrile group, a constitutional unit formed from (meth)acrylonitrile is preferred.

[0370] 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 further preferably 60 to 85% by mass, relative to the total mass of the resin.

[0371] Further, in the case where the resin contained in the thermoplastic resin particles contains the constitutional unit formed from the aromatic vinyl compound and the constitutional unit having a nitrile group, the content ratio of the constitutional unit formed from the aromatic vinyl compound and the constitutional unit having a nitrile group (constitutional unit formed from the aromatic vinyl compound : 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.

[0372] 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.

[0373] 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.

[0374] The content of the constitutional unit formed from the N-vinyl heterocyclic compound is preferably 5 to 50 mass% and more preferably 10 to 40 mass% relative to the total mass of the thermoplastic resin.

[0375] 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.

[0376] Specifically, the content of the constitutional unit having an acidic group in the thermoplastic resin is preferably 20 mass% or less, more preferably 10 mass% or less, and further preferably 5 mass% or less. The lower limit of the above content is not particularly limited and can be 0 mass%.

[0377] Further, 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.

[0378] In the present application, the acid value is found by a measurement method in compliance with JIS K0070:1992.

[0379] From the viewpoint of ink adhesion, the resin contained in the thermoplastic resin particles can contain a constitutional unit containing a hydrophobic group.

[0380] As the above hydrophobic group, an alkyl group, an aryl group, an aralkyl group, and the like can be given.

[0381] 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.

[0382] The content of the constitutional unit having a hydrophobic group in the resin contained in the thermoplastic resin particles is preferably 5 to 50 mass% and more preferably 10 to 30 mass% relative to the total mass of the resin.

[0383] 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.

[0384] 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.

[0385] 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.

[0386] 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.

[0387] 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.

[0388] 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.

[0389] Also, from the viewpoint of on-press developability, as the above hydrophilic group, a group represented by formula Z described below is preferred.

[0390] Among the hydrophilic groups possessed by the thermoplastic resin, a group represented by formula PO described below is preferred.

[0391] [Chemical Formula 22]

[0392]

[0393] 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.

[0394] 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.

[0395] 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.

[0396] In formula PO, n is preferably an integer of 1 to 10, and more preferably an integer of 1 to 4.

[0397] The content of the constitutional unit having a hydrophilic group is preferably 5% by mass to 60% by mass, and more preferably 10% by mass to 30% by mass, with respect to the total mass of the resin.

[0398] The resin contained in the thermoplastic resin particles can further contain other constitutional units. As the other constitutional units, constitutional units other than the above-described constitutional units can be contained without particular limitation, and for example, constitutional units formed of an acrylamide compound, a vinyl ether compound, or the like can be mentioned.

[0399] 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.

[0400] As the thermally reactive resin particles, resin particles having a thermally reactive group can be mentioned. The thermally reactive resin particles form a hydrophobic region by crosslinking based on thermal reaction and a change in functional group at the time of crosslinking.

[0401] 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 mentioned, but a polymerizable group is preferred, and as examples thereof, an ethylenically unsaturated group (for example, an acryloyl group, a methacryloyl group, a vinyl group, an allyl group, or the like) that undergoes a radical polymerization reaction, a cationically polymerizable group (for example, a vinyl group, a vinyloxy group, an epoxy group, an oxetanyl group, or the like) that undergoes a cationic polymerization reaction, an isocyanate group or a block thereof that undergoes an addition reaction, an epoxy group, a vinyloxy group, and a functional group having an active hydrogen atom as a reaction target thereof (for example, an amino group, a hydroxyl group, a carboxyl group, or the like), a carboxyl group that undergoes a condensation reaction and a hydroxyl group or an amino group as a reaction target thereof, an anhydride that undergoes a ring-opening addition reaction and an amino group or a hydroxyl group as a reaction target thereof, or the like can be mentioned.

[0402] As the resin having the above-described thermally reactive group, an addition polymerization type resin, a polyaddition type resin, or a polycondensation type resin can be mentioned, and a thermoplastic resin can also be mentioned.

[0403] As the microcapsule, for example, a microcapsule that contains at least a part of the constituent components (preferably, a hydrophobic compound) of the image recording layer in the inside thereof, as described in Japanese Patent Application Publication No. 2001-277740, 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 constituent components of the image recording layer is contained in the inside of the microcapsule, and the hydrophilic component (i.e., a hydrophilic compound) is contained in the outside of the microcapsule.

[0404] The microgel (crosslinked resin particles) can contain a part of the constituent components of the image recording layer in 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.

[0405] In order to obtain the microcapsule containing the constituent component of the image recording layer, a publicly known synthesis method can be applied.

[0406] 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.

[0407] In order to obtain the microcapsule containing the constituent component of the image recording layer, a publicly known synthesis method can be applied

[0408] 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.

[0409] As the above polyhydric phenol compound, a compound having a plurality of benzene rings having a phenolic hydroxyl group is preferred.

[0410] 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.

[0411] 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.

[0412] 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.

[0413] <<Group represented by Formula Z>>

[0414] The resin particle in the present application preferably has a group represented by the following Formula Z as a hydrophilic group.

[0415] * - Q - W - Y Formula Z

[0416] 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.

[0417] Also, it is preferable that the hydrophilic structures included in Formula Z each include a polyalkylene oxide structure.

[0418] Q in 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.

[0419] Also, Q in Formula Z is preferably an alkylene group, an arylene group, an ester bond, an amide bond, or a group obtained by combining two or more of these, and more preferably a phenylene group, an ester bond, or an amide bond.

[0420] The divalent group having a hydrophilic structure in W in 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. R W represents a hydrogen atom or an alkyl group.

[0421] The divalent group having a hydrophobic structure in W in 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-. R WA each independently represents a linear, branched, or cyclic alkylene group having 6 to 120 carbon atoms, a halogenated alkylene 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.

[0422] The monovalent group having a hydrophilic structure in Y in 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 Wgroup represented by the formula Z. Among them, as the monovalent group having a hydrophilic structure, a group containing a polyalkylene oxide structure is preferable, and 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.

[0423] The monovalent group having a hydrophobic structure in Y of the 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 arylalkyl 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.

[0424] In the resin particle having a group represented by the formula Z, from the viewpoints 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.

[0425] In addition, the group represented by the formula Z can function as a dispersibility group for improving the dispersibility of the resin particle.

[0426] From the viewpoints 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.

[0427] 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.

[0428] The above polymerizable group can be a cationic polymerizable group or a free radical polymerizable group, but from the viewpoint of reactivity, a free radical polymerizable group is preferable.

[0429] 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.

[0430] Further, the resin constituting the resin particles having a polymerizable group preferably has a constituting unit having a polymerizable group.

[0431] Further, the polymerizable group can be introduced to the surface of the resin particles by a polymer reaction.

[0432] Further, from the viewpoints of print durability, ink receptivity, on-press developability, and development residue inhibitory property 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.

[0433] [Chemical Formula 23]

[0434]

[0435] In formula (Iso), n represents an integer of 0 to 10.

[0436] 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.

[0437] 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.

[0438] Further, in the following reaction, a compound (a compound having active hydrogen) reactive with isocyanate groups such as an alcohol compound and an amine compound is added, whereby the structure of the alcohol compound and the amine compound can also be introduced into the addition polymerization type resin having a urea bond.

[0439] As the compound having the above-described active hydrogen, a compound having the above-described active hydrogen is preferably selected.

[0440] [Chemical Formula 24]

[0441]

[0442] 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).

[0443] [Chemical Formula 25]

[0444]

[0445] In formula (PETA), the wavy line portion indicates a bonding position with other structures.

[0446] <SYNTHESIS OF RESIN PARTICLES>

[0447] The method of synthesizing the resin particles is not particularly limited, and can be any method that can synthesize the particles using the various resins described above. As the method of synthesizing the resin particles, for example, there can be mentioned publicly known methods such as emulsion polymerization, suspension polymerization, dispersion polymerization, soap-free polymerization, microemulsion polymerization, and the like.

[0448] Further, in the synthesis of the resin particles, publicly known methods of synthesizing microcapsules, microgels (crosslinked resin particles), and the like can be used.

[0449] <MEAN PARTICLE DIAMETER>

[0450] The mean 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.

[0451] The mean 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 is calculated. In addition, in the case of non-spherical particles, the circular equivalent diameter of the particles on the photograph is taken as the mean particle diameter.

[0452] In addition, the mean particle diameter of the particles in the present application is the volume average particle diameter unless otherwise specified.

[0453] The particles (preferably resin particles) can be used singly or in combination of two or more.

[0454] 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.

[0455] [OTHER COMPONENTS]

[0456] The image recording layer in the present application can contain other components in addition to the components described above.

[0457] As other components, there can be mentioned a binder polymer, a color developer, a chain transfer agent, a low-molecular hydrophilic compound, a sensitizing agent, other additives, and the like.

[0458] As other components, there can be mentioned a colorant, an ink-out agent, a polymerization inhibitor, a higher fatty acid derivative, a plasticizer, an inorganic particle, a low-molecular hydrophilic compound, and the like disclosed in paragraphs 0181 to 0190 of Japanese Patent Application Publication No. 2009-255434.

[0459] Further, as other compounds, there can be mentioned a hydrophobizing precursor (a microparticle capable of converting the image recording layer into hydrophobic upon application of heat), a low-molecular hydrophilic compound, a sensitizing agent (for example, a phosphonium compound, a nitrogen-containing low-molecular compound, an ammonium group-containing polymer), and a chain transfer agent disclosed in paragraphs 0191 to 0217 of Japanese Patent Application Publication No. 2012-187907.

[0460] Binder Polymer

[0461] The image recording layer can contain a binder polymer as needed.

[0462] 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.

[0463] Further, as for the binder polymer, the ammonium salt-containing polymer in the sensitizing agent and the polymer used as a surfactant are excluded.

[0464] 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.

[0465] 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.

[0466] As the on-press development binder polymer, a binder polymer having an alkylene oxide chain is preferred. 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).

[0467] In the case where the poly(alkylene oxide) site is in the main chain, a polyurethane resin is preferred.

[0468] As the polymer 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.

[0469] Further, as another preferable example of the binder polymer, a high molecular compound having a core moiety of a polyfunctional mercaptan of 6 or more and 10 or less and having a polymer chain bonded to the core moiety via a thioether bond, and the polymer chain having a polymerizable group can be given (hereinafter, also referred to as a star-shaped high molecular compound).

[0470] As the star-shaped high molecular compound, for example, a compound described in Japanese Patent Application Publication No. 2012-148555 can be preferably used.

[0471] 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 in 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.

[0472] 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 the 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 in 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.

[0473] 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.

[0474] 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. Further, a lipophilic polymer and a hydrophilic polymer can also be used in combination.

[0475] 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.

[0476] The binder polymer can be used singly or in combination of two or more.

[0477] 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%, with respect to the total mass of the image recording layer.

[0478] - Color developer -

[0479] The image recording layer in the present application preferably further contains a color developer, more preferably further contains an acid color developer. Also, as the color developer, a leuco compound is preferably contained.

[0480] 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 the 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 the 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 leuco 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 preferred.

[0481] 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.

[0482] 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.

[0483] 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, red, purple, blue, or dark green is preferable.

[0484] Also, from the viewpoints of visual recognition and visual recognition of the exposed part, the above acid color developer is preferably a leuco colorant.

[0485] As the above leuco colorant, there is no particular limitation as long as it is a colorant having a leuco structure, but it preferably has a helical structure, more preferably has a spironolactone ring structure.

[0486] Further, as the above-mentioned colorless dye, from the viewpoints of visual recognition and visual recognition of the exposed portion, a colorless dye having a phthalide structure or a fluoran parent structure is preferred.

[0487] Further, from the viewpoints of visual recognition and visual recognition of the exposed portion, the above-mentioned colorless dye having a phthalide 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).

[0488] [Chemical Formula 26]

[0489]

[0490] 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 10 independently represent a hydrogen atom, a halogen atom or a monovalent organic group, Y1and Y2independently represent C or N, X1is not present in the case where Y1is N, and X4is not present in the case where Y2is N, Ralrepresents a hydrogen atom, an alkyl group or an alkoxy group, and Rb1to Rb4independently represent a hydrogen atom, an alkyl group, an aryl group or a heteroaryl group.

[0491] As the electron-donating group in ERG of formulae (Le-1) to (Le-3), 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 monoarylmonoheteroaryl amino group, an alkoxy group, an aryloxy group, a heteroaryloxy group or an alkyl group is preferred, more preferably 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 monoarylmonoheteroaryl amino group, an alkoxy group or an aryloxy group, and further preferably a monoalkylmonoaryl amino group, a diarylamino group, a diheteroarylamino group or a monoarylmonoheteroaryl amino group, and particularly preferably a monoalkylmonoaryl amino group.

[0492] Further, as the electron-donating group of the above-mentioned ERG, from the viewpoints of color developability and visual recognition of the exposed portion, a di-substituted 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 di-substituted 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 di-substituted 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 di-substituted 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.

[0493] Further, in the present application, the ortho position in an aryl group or a heteroaryl group other than a phenyl group means a bonding position (e.g., 2-position, etc.) 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.

[0494] Further, as the electron-donating group of 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.

[0495] From the viewpoints of color developability and visual recognition of the exposed portion, X1to X4in Formula (Le-1) to Formula (Le-3) are each independently preferably a hydrogen atom or a chlorine atom, and more preferably a hydrogen atom.

[0496] From the viewpoints of color developability and visual recognition of the exposed portion, X5to X 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 heteroarylamino group, a dialkylamino group, a monoalkylmonoaryl amino group, a monoalkylmonoheteroaryl amino group, a diarylamino group, a diheteroarylamino group, a monoarylm onoheteroarylamino 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, and particularly preferably a hydrogen atom.

[0497] From the viewpoints of color developability and visual recognition of the exposed portion, at least one of Y1and Y2in Formula (Le-1) to Formula (Le-3) is preferably C, and more preferably both of Y1and Y2are C.

[0498] From the viewpoints of color developability and visual recognition of the exposed portions, Ral in the formula (Le-1) to (Le-3) is preferably an alkyl group or an alkoxy group, more preferably an alkoxy group, and particularly preferably a methoxy group.

[0499] From the viewpoints of color developability and visual recognition of the exposed portions, Rbl to Rb4 in the formula (Le-1) to (Le-3) are each independently preferably a hydrogen atom or an alkyl group, more preferably an alkyl group, and particularly preferably a methyl group.

[0500] Also, from the viewpoints of color developability and visual recognition of the exposed portions, the above-mentioned leuco dye having a phthalide structure or a fluoran parent structure is more preferably a compound represented by any one of the following formulae (Le-4) to (Le-6), and further preferably a compound represented by the following formula (Le-5).

[0501] [Chemical Formula 27]

[0502]

[0503] In the formulae (Le-4) to (Le-6), ERG each independently represents an electron-donating group, Xl to X4 each independently represent a hydrogen atom, a halogen atom, or a dialkylanilino group, Yl and Y2 each independently represent C or N, Xl is not present when Yl is N, X4 is not present when Y2 is N, Ral represents a hydrogen atom, an alkyl group, or an alkoxy group, and Rbl to Rb4 each independently represent a hydrogen atom, an alkyl group, an aryl group, or a heteroaryl group.

[0504] ERG, Xl to X4, Yl, Y2, Ral, and Rbl to Rb4 in the formulae (Le-4) to (Le-6) each have the same meaning as ERG, Xl to X4, Yl, Y2, Ral, and Rbl to Rb4 in the formulae (Le-1) to (Le-3), respectively, and the preferable modes are also the same.

[0505] Also, from the viewpoints of color developability and visual recognition of the exposed portions, the above-mentioned leuco dye having a phthalide structure or a fluoran parent structure is more preferably a compound represented by any one of the following formulae (Le-4) to (Le-6), and further preferably a compound represented by the following formula (Le-5).

[0506] [Chemical Formula 28]

[0507]

[0508] In formulae (Le-7) to (Le-9), X1to X4independently represent a hydrogen atom, a halogen atom or a dialkylanilino group, Y1and Y2independently represent C or N, X1is not present when Y1is N, and X4is not present when 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.

[0509] X1to X4, Y1and Y2in formulae (Le-7) to (Le-9) have the same meanings as X1to X4, Y1and Y2in formulae (Le-1) to (Le-3), and the preferable modes are also the same.

[0510] From the viewpoints of color development and visual recognition of the exposed portions, 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.

[0511] From the viewpoints of color development and visual recognition of the exposed portions, Rb1to Rb4in formulae (Le-7) to (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.

[0512] From the viewpoints of color development and visual recognition of the exposed portions, Rc1and Rc2in formula (Le-8) are each independently preferably a phenyl group or an alkylphenyl group, and more preferably a phenyl group.

[0513] Also, from the viewpoints of color development and visual recognition of the exposed portions, Rc1and Rc2in formula (Le-8) are each independently 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 substituent in Rc1and Rc2, the substituent described later can be mentioned.

[0514] Also, in formula (Le-8), from the viewpoints of color development and visual recognition of the exposed portions, X1to X4are preferably hydrogen atoms, and Y1and Y2are preferably C.

[0515] Furthermore, in formula (Le-8), from the viewpoints of color development and visual recognition of the exposed portions, Rb1and Rb2are each independently preferably an aryl group substituted with an alkyl group or an alkoxy group.

[0516] Further, in formula (Le-8), Rb1and Rb2independently represent an aryl group or a heteroaryl group from the viewpoint of color development and visual recognition of the exposed portion, and 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 the para position.

[0517] Further, the above-mentioned electron-donating group in Rb1, Rb2, Rc1, and Rc2is preferably 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 diheteroaryl amino group, a monoarylmoheteroaryl amino group, an alkoxy group, an aryloxy group, a heteroaryloxy group, or an alkyl group from the viewpoint of color development and visual recognition of the exposed portion, and is more preferably an alkoxy group, an aryloxy group, a heteroaryloxy group, or an alkyl group, and particularly preferably an alkoxy group.

[0518] Further, the acid color developer preferably contains a compound represented by the following formula (Le-10) from the viewpoint of color development and visual recognition of the exposed portion.

[0519] [Chemical Formula 29]

[0520]

[0521] In 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.

[0522] Ar1in formula (Le-10) has the same meaning as Rb1and Rb2in formulae (Le-7) to (Le-9), and the preferred modes are also the same.

[0523] Ar2in formula (Le-10) has the same meaning as Rc1and Rc2in formulae (Le-7) to (Le-9), and the preferred modes are also the same.

[0524] The alkyl group in formulae (Le-1) to (Le-9) can be linear, branched, or cyclic.

[0525] Further, the number of carbon atoms of the alkyl group in formulae (Le-1) to (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.

[0526] The number of carbon atoms of the aryl group in formulae (Le-1) to (Le-10) is preferably from 6 to 20, more preferably from 6 to 10, and particularly preferably from 6 to 8.

[0527] As the aryl group in the formulae (Le-1) to (Le-10), specifically, a phenyl group, a naphthyl group, an anthryl group, a phenanthryl group, and the like, each of which can have a substituent, can be given.

[0528] As the heteroaryl group in the formulae (Le-1) to (Le-10), specifically, a furyl group, a pyridyl group, a pyrimidyl group, a pyrazolyl group, a thiophenyl group, and the like, each of which can have a substituent, can be given.

[0529] Further, each of 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 the formulae (Le-1) to (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 monoalkylmonoarylamino group, 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.

[0530] As the above-mentioned colorless dye having a phthalide structure or a fluorane parent structure which can be preferably used, the following compounds can be given.

[0531] [Chemical Formula 30]

[0532]

[0533] [Chemical Formula 31]

[0534]

[0535] [Chemical Formula 32]

[0536]

[0537] [Chemical Formula 33]

[0538]

[0539] [Chemical Formula 34]

[0540]

[0541] [Chemical Formula 35]

[0542]

[0543] [Chemical Formula 36]

[0544]

[0545] [Chemical Formula 37]

[0546]

[0547] [Chemical Formula 38]

[0548]

[0549] As the acid color developer, 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 formed film is good.

[0550] As the colorless dye that can be preferably used, the following compounds can be mentioned from the viewpoint of visual recognition and visual recognition of the exposed portion.

[0551] [Chemical Formula 39]

[0552]

[0553] These color developers can be used singly, and two or more kinds of components can also be used in combination.

[0554] The content of the color developer is preferably 0.5 to 10 mass% and more preferably 1 to 5 mass% relative to the total mass of the image recording layer.

[0555] (Formation of image recording layer)

[0556] The image recording layer in the lithographic printing plate precursor according to the present application can be formed, for example, by preparing a coating solution by dispersing or dissolving the necessary components described above in a known solvent, and coating the coating solution on a support by a known method such as bar coater coating, and drying, as described in paragraphs 0142 to 0143 of Japanese Patent Application Publication No. 2008-195018. 2 ~ 3.0 g / m 2 Within this range, good sensitivity and good film properties of the image recording layer can be obtained.

[0557] 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 given. The solvent can be used singly or in combination of two or more. The solid content concentration in the coating solution is preferably 1 to 50 mass%.

[0558] The coating amount (solid content) of the image recording layer after coating and drying varies depending on the use, but is preferably 0.3 to 3.0 g / m 2 ~ 3.0 g / m 2 .

[0559] Further, the film thickness of the image recording layer in the lithographic printing plate precursor according to the present application is preferably 0.1 to 3.0 μm and more preferably 0.3 to 2.0 μm.

[0560] 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).

[0561] <outermost layer>

[0562] The on-press development type lithographic printing plate precursor according to the present application preferably has an outermost layer on the above-mentioned image recording layer.

[0563] Also, from the viewpoint of visual recognition, the above-mentioned outermost layer preferably contains a color changeable compound.

[0564] Also, the above-mentioned 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.

[0565] The above-mentioned 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.

[0566] <color changeable compound>

[0567] Also, the above-mentioned outermost layer preferably contains a color changeable compound.

[0568] The above-mentioned outermost layer can contain, in addition to the color changeable compound, a water-soluble polymer, a hydrophobic polymer, a sensitizing agent, an acid generator, an infrared absorber, and the like, preferably contains a color changeable compound and a water-soluble polymer, and more preferably contains a color changeable compound, a water-soluble polymer, and a hydrophobic polymer.

[0569] 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.

[0570] Specifically, as the color changeable compound in the present application, (1) a compound in which the absorption in the visible light region increases due to infrared exposure compared to before infrared exposure, (2) a compound which has absorption in the visible light region due to infrared exposure, and (3) a compound which does not have absorption in the visible light region due to infrared exposure can be mentioned.

[0571] In addition, the infrared in the present application is light having a wavelength of 750 nm to 1 mm, and preferably light having a wavelength of 750 nm to 1,400 nm.

[0572] As the color changeable compound, a compound which develops color due to infrared exposure is preferable.

[0573] Further, as the color changeable compound, a decomposable compound which decomposes due to infrared exposure is preferable, and a decomposable compound which decomposes by heat, electron transfer or both caused by infrared exposure is preferable.

[0574] More specifically, the color changeable compound in the present application is preferably a compound which decomposes due to infrared exposure (more preferably decomposes by heat, electron transfer or both caused by infrared exposure), and a compound in which absorption in the visible region increases or absorption is shortened and has absorption in the visible region compared to before infrared exposure.

[0575] 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.

[0576] Hereinafter, a decomposable compound which is an example of the color changeable compound will be described.

[0577] As the decomposable compound, a compound which absorbs at least a part of light in the infrared wavelength region (wavelength region of 750 nm to 1 mm, 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.

[0578] More specifically, the decomposable compound is preferably a compound which decomposes due to infrared exposure and generates a compound having a large absorption wavelength in the wavelength region of 500 nm to 600 nm.

[0579] From the viewpoint of improving the visual recognition of the exposed portion, the decomposable compound is preferably a cyanine dye having a group which decomposes by infrared exposure (specifically, R 1 in the following Formulae 1-1 to 1-7).

[0580] 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.

[0581] [Chemical Formula 40]

[0582]

[0583] In Formula 1-1, R 1 represents a group represented by any one of the following Formulae 2-1 to 4-1, R 11 to R 18 independently represent a hydrogen atom, a halogen atom, -Ra , -OR b , -SR c , or -NR d R e , R a ~ R e each independently represent a hydrocarbon group, A1, A2, and a plurality of R 11 ~ R 18 may be linked to form a single ring or multiple rings, A1and A2each independently represent an oxygen atom, a sulfur atom, or a nitrogen atom, n 11 and n 12 each independently represent an integer of 0 to 5, wherein the sum of n 11 and n 12 is 2 or more, n 13 and n 14 each independently represent 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 for neutralizing a charge.

[0584] [Chemical Formula 41]

[0585]

[0586] In Formulae 2-1 to 4-1, R 20 , R 30 , R 41 , and R 42 each independently represent an alkyl group or an aryl group, Zb represents a counter ion for neutralizing a charge, and the wavy line represents a bonding site with the group represented by L in Formula 1-1.

[0587] 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.

[0588] In Formula 1-1, R 1 represents a group represented by any one of Formulae 2-1 to 4-1.

[0589] 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.

[0590] 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.

[0591] As the group represented by R R20The alkyl group indicated is preferably an alkyl group having 1 to 30 carbon atoms, more preferably an alkyl group having 1 to 15 carbon atoms, and even more preferably an alkyl group having 1 to 10 carbon atoms.

[0592] The alkyl groups mentioned above can be straight-chain, branched, or have a cyclic structure.

[0593] As a result of R 20 The aryl group represented is preferably an aryl group with 6 to 30 carbon atoms, more preferably an aryl group with 6 to 20 carbon atoms, and even more preferably an aryl group with 6 to 12 carbon atoms.

[0594] As R 20 From the point of view of visual recognizability, alkyl groups are preferred.

[0595] Furthermore, from the perspective of visual recognizability and color rendering, as a result of R 20 The alkyl group indicated is preferably a secondary alkyl group or a tertiary alkyl group, with a preference for a tertiary alkyl group.

[0596] Moreover, from the perspective of decomposition and visual recognition, as a product of R 20 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.

[0597] Hereinafter, specific examples of groups represented by Formula 2-1 above are 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.

[0598] [Chemical Formula 42]

[0599]

[0600] In Equation 3-1, R 30 The wavy line indicates an alkyl or aryl group, and the wavy line indicates the bonding site with the group represented by L in Formula 1-1.

[0601] As a result of R 30 The alkyl and aryl groups represented are related to R in formula 2-1. 20 The alkyl and aryl groups are represented by the same terms, and the preferred methods are also the same.

[0602] From the perspective of visual recognition and color rendering, as a result of R 30 The alkyl group indicated is preferably a secondary alkyl group or a tertiary alkyl group, with a preference for a tertiary alkyl group.

[0603] Furthermore, from the perspective of decomposition and visual recognition, as a result of R 30The alkyl group represented by R is preferably a substituted alkyl group, more preferably a fluorine-substituted alkyl group, further preferably a perfluoroalkyl group, and particularly preferably a trifluoromethyl group.

[0604] Moreover, from the viewpoints of decomposability and visual recognition, the aryl group represented by R 30 The alkyl group represented by R is preferably a substituted alkyl group, more preferably a fluorine-substituted alkyl group, further preferably a perfluoroalkyl group, and particularly preferably a trifluoromethyl group.

[0605] Moreover, from the viewpoints of decomposability and visual recognition, the aryl group represented by R 30 The aryl group represented by R is preferably a substituted aryl group, and as the substituent, an alkyl group (preferably an alkyl group having 1 to 4 carbon atoms), an alkoxy group (preferably an alkoxy group having 1 to 4 carbon atoms), or the like can be mentioned.

[0606] Hereinafter, specific examples of the group represented by the above Formula 3-1 will be shown, but the present application is not limited to these. In the following structural formulae, • indicates the bonding site with the group represented by L in Formula 1-1.

[0607] [Chemical Formula 43]

[0608]

[0609] In Formula 4-1, R 41 and R 42 independently represent an alkyl group or an aryl group, Zb represents a counter ion for neutralizing a charge, and the wavy line portion indicates the bonding site with the group represented by L in Formula 1-1.

[0610] The alkyl group and the aryl group represented by R 41 or R 42 are the same as the alkyl group and the aryl group represented by R 20 in Formula 2, and the preferable modes are also the same.

[0611] The alkyl group represented by R 41 is preferably an alkyl group from the viewpoints of decomposability and visual recognition.

[0612] The alkyl group represented by R 42 is preferably an alkyl group from the viewpoints of decomposability and visual recognition.

[0613] The alkyl group represented by R 41 is preferably an alkyl group having 1 to 8 carbon atoms, more preferably an alkyl group having 1 to 4 carbon atoms, and particularly preferably a methyl group from the viewpoints of decomposability and visual recognition.

[0614] The alkyl group represented by R 42 is preferably a secondary alkyl group or a tertiary alkyl group, and preferably a tertiary alkyl group from the viewpoints of visual recognition and color development.

[0615] Also, from the viewpoints of decomposition and visual recognition, as 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 tert-butyl.

[0616] 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.

[0617] 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.

[0618] Hereinafter, specific examples of the group represented by Formula 4-1 described above will be given, but the present application is not limited to these. In the structural formulae described below, • indicates a bonding site with the group represented by L in Formula 1-1.

[0619] [Chemical Formula 44]

[0620]

[0621] In Formula 1-1, L is preferably an oxygen atom or -NR 10 , and particularly preferably an oxygen atom.

[0622] Also, 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. Also, the alkyl group represented by R 10 may be linear, branched, or cyclic.

[0623] In the alkyl group, a methyl group or a cyclohexyl group is preferred.

[0624] 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. Also, these aryl groups can have a substituent.

[0625] In Formula 1-1, R 11 to R 18 each independently represent a hydrogen atom, -R a , -OR b , -SR c , or -NR d R e.

[0626] R a R e The hydrocarbon group represented by R is preferably 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.

[0627] The above hydrocarbon group can be linear, can have a branched chain, and can have a ring structure.

[0628] The above hydrocarbon group is particularly preferably an alkyl group.

[0629] The above alkyl group is preferably an alkyl group having 1 to 30 carbon atoms, more preferably an alkyl group having 1 to 15 carbon atoms, and further preferably an alkyl group having 1 to 10 carbon atoms.

[0630] The above alkyl group can be linear, can have a branched chain, and can have a ring structure.

[0631] Specific examples of the above alkyl group 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, a 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.

[0632] Among the above alkyl groups, a methyl group, an ethyl group, a propyl group, or a butyl group is preferable.

[0633] The above alkyl group can have a substituent.

[0634] 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.

[0635] R 11 R 14 are each independently preferably a hydrogen atom or an -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.

[0636] wherein R 11 and R 13 are preferably an alkyl group, and more preferably the two are linked to form a ring. As the above formed ring, it can be a monocyclic ring or a polycyclic ring. As the formed ring, specific examples include monocyclic rings such as a cyclopentene ring, a cyclopentadiene ring, a cyclohexene ring, a cyclohexadiene ring, and polycyclic rings such as an indene ring and an indole ring.

[0637] Furthermore, in A1 + R bonded to the bonded carbon atom 12 Preferred and R 15 or R 16 (preferably 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 (preferably R) 18 They are connected to form a ring.

[0638] In Equation 1-1, n is preferred. 13 R is 1. 16 -R a (i.e., hydrocarbon group).

[0639] 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.

[0640] In Equation 1-1, n is preferred. 14 R is 1. 18 -R a (i.e., hydrocarbon group).

[0641] 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.

[0642] 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.

[0643] R in Equation 1-1 15 and R 17 Preferably, they are the same group. And, R 15 and R 17 Preferred is -R a (i.e., hydrocarbon group), more preferably alkyl, and even more preferably substituted alkyl.

[0644] In the compounds represented by formula 1-1, from the viewpoint of improving water solubility, R15 and R 17 is preferably a substituted alkyl group.

[0645] as represented by R 15 or R 17 As the substituted alkyl group represented by R

[0646] [Chemical Formula 45]

[0647]

[0648] -R W2 -CO2M (a2)

[0649] -R W3 -PO3M2 (a3)

[0650] -R W4 -SO3M (a4)

[0651] In the formulae (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(=O)-R W5 , R W5 represents an alkyl group having 1 to 12 carbon atoms, R W2 to R W4 each independently represents 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.

[0652] In the formula (al), as the alkylene group represented by R W0 , ethylene, n-propylene, isopropylene, n-butylene, isobutylene, n-pentylene, iso-pentylene, n-hexylene, iso-hexylene and the like can be mentioned, with ethylene, n-propylene, isopropylene or n-butylene being preferred, and n-propylene being particularly preferred.

[0653] n W1 is preferably 1 to 10, more preferably 1 to 5, and particularly preferably 1 to 3.

[0654] As the alkyl group represented by R W1 , methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, t-butyl, n-pentyl, iso-pentyl, neopentyl, n-hexyl, n-octyl, n-dodecyl and the like can be mentioned, with methyl, ethyl, n-propyl, isopropyl or n-butyl, t-butyl being preferred, methyl or ethyl being further preferred, and methyl being particularly preferred.

[0655] R W5the alkyl group represented by R W1 the alkyl group represented by R W1 the alkyl group represented by R

[0656] The following shows specific examples of the group represented by formula (al), but the present application is not limited to these. In the following structural formulae, Me represents a methyl group, Et represents an ethyl group, and * represents a bonding site.

[0657] [Chemical Formula 46]

[0658]

[0659] In formulae (a2) to (a4), as specific examples of the alkylene group represented by R W2 to R W4 In formula (a3), the two Ms can be the same or different.

[0660] In formula (a3), the two Ms can be the same or different.

[0661] In formulae (a2) to (a4), as the onium group represented by M, there can be mentioned an ammonium group, an iodonium group, a phosphonium group, a sulfonium group, and the like.

[0662] CO2M in formula (a2), PO3M2 in formula (a2), and SO3M in formula (a4) can each have an anion structure dissociated from M. The counter cation of the anion structure can be A1 + in formula 1-1, R 1 -L can contain.

[0663] In the group represented by formulae (al) to (a4), the group represented by formula (al), formula (a2), or formula (a4) is preferred.

[0664] n 11 and n 12 are preferably the same, and each is preferably an integer of 1 to 5, more preferably an integer of 1 to 3, further preferably 1 or 2, and particularly preferably 2.

[0665] A1 and A2 in formula 1-1 each independently represent an oxygen atom, a sulfur atom, or a nitrogen atom, and a nitrogen atom is preferred.

[0666] A1 and A2 in formula 1-1 are preferably the same atom.

[0667] Za in formula 1-1 represents a counter ion that neutralizes a charge.

[0668] If R 11 ~R 18 and R 1 -L are all electrically neutral groups, 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 have two or more anionic structures, Za can also become a counter cation.

[0669] In addition, if the cyanine dye represented by Formula 1-1 is electrically neutral in the entirety of the compound other than Za, Za is not required.

[0670] 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.

[0671] 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.

[0672] 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.

[0673] [Chemical Formula 47]

[0674]

[0675] 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 R22 or R 23 with R 24 may be linked to form a monocyclic or polycyclic ring, L represents an oxygen atom, a sulfur atom or -NR 10 -, R 10 represents a hydrogen atom, an alkyl group or an aryl group, R d1 ~R d4 , W 1 and W 2 each independently represent an alkyl group which can have a substituent, and Za represents a counter ion for neutralizing a charge.

[0676] R 1 in formula 1-2 has the same meaning as R 1 in formula 1-1, and the preferred modes are also the same.

[0677] In formula 1-2, R 19 ~R 22 each independently preferably represent a hydrogen atom, a halogen atom, -R a , -OR b or -CN.

[0678] More specifically, R 19 and R 21 preferably represent a hydrogen atom or -R a .

[0679] Further, R 20 and R 22 preferably represent a hydrogen atom, -R a , -OR b or -CN.

[0680] As -R 19 represented by R 22 ~R a , an alkyl group or an alkenyl group is preferred.

[0681] In the case where R 19 ~R 22 all represent -R a , R 19 and R 20 , and R 21 and R 22 are preferably linked to form a monocyclic or polycyclic ring.

[0682] As the ring formed by linking R 19 and R 20 , or R 21 and R 22 , a benzene ring, a naphthalene ring and the like can be mentioned.

[0683] In formula 1-2, R 23 and R 24 are preferably linked to form a monocyclic or polycyclic ring.

[0684] As R 23 With R 24 The ring formed by the linkage can be a monocyclic or polycyclic ring. Specifically, examples of the formed rings include monocyclic rings such as cyclopentene ring, cyclopentadiene ring, cyclohexene ring, and cyclohexadiene ring, as well as polycyclic rings such as indene ring.

[0685] In equation 1-2, R d1 ~R d4 Preferably, it is an unsubstituted alkyl group. Furthermore, R is preferred. d1 ~R d4 They are all the same group.

[0686] Examples of unsubstituted alkyl groups include those with 1 to 4 carbon atoms, with methyl being preferred.

[0687] In Equation 1-2, from the viewpoint of improving the water solubility of the compound represented by Equation 1-2, W 1 and W 2 Each is preferably a substituted alkyl group, individually and independently.

[0688] As a result of W 1 and W 2 The substituted alkyl group can be any one of the groups represented by formulas (a1) to (a4) in formula 1-1, and the preferred method is also the same.

[0689] Furthermore, from the viewpoint of in-machine developability, W 1 and W 2 Each is preferably an alkyl group having a substituent, and is a group having at least -OCH2CH2-, sulfonyl, a salt of sulfonyl, carboxyl, or a salt of carboxyl.

[0690] Za represents a counterion that neutralizes the charge within a molecule.

[0691] If R 19 ~R 22 R 23 ~R 24 R d1 ~R d4 W 1 W 2 and R 1 If all -L groups are electrically neutral, then 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 the case of R 19 ~R 22 , R 23 ~R 24 , R d1 ~R d4 , W 1 , W 2 , and R 1 In the case where -L has two or more anionic structures, Za can also be a counter cation.

[0692] In addition, if the compound represented by Formula 1-2 is electrically neutral in the entire compound except for Za, Za is not required.

[0693] Examples of Za when it is a counter anion are the same as those in Formula 1-1, and the preferred modes are also the same. Also, examples of Za when it is a counter cation are the same as those in Formula 1-1, and the preferred modes are also the same.

[0694] From the viewpoints of decomposability and visual recognition, the cyanine dye that is a decomposable compound is further preferably a compound represented by any one of the following Formulas 1-3 to 1-7.

[0695] In particular, from the viewpoints of decomposability and visual recognition, it is preferable to be a compound represented by any one of Formula 1-3, Formula 1-5, and Formula 1-6.

[0696] [Chemical Formula 48]

[0697]

[0698] In Formulas 1-3 to 1-7, R 1 represents a group represented by any one of the above Formulas 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 25 , and R 26 each independently represent a hydrogen atom, a halogen 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 25 and R 26may be linked to form a monocyclic or polycyclic ring, L represents an oxygen atom, a sulfur atom, or -NR 10 10 represents a hydrogen atom, an alkyl group, or an aryl group, R d1 d4 1 2 each independently represents an alkyl group which can have a substituent, and Za represents a counter ion for neutralizing a charge.

[0699] R 1 19 22 d1 d4 1 2 1 19 22 d1 d4 1 2

[0700] R 25 26 each independently is preferably a hydrogen atom or an alkyl group, more preferably an alkyl group, and particularly preferably a methyl group.

[0701] Hereinafter, specific examples of cyanine pigments of the decomposable compound will be shown, but the present application is not limited to these.

[0702] [Chemical Formula 49]

[0703]

[0704] Further, as the cyanine pigment of the decomposable compound, an infrared-absorbing compound described in International Publication No. 2019 / 219560 can be preferably used.

[0705] Further, the above-described color changeable compound can include an acid color developer.

[0706] As the acid color developer, the acid color developer described in the image recording layer as the acid color developer can be used, and the preferable modes are the same.

[0707] The color changeable compound can be used alone or two or more components can be used in combination.

[0708] As the color changeable compound, the decomposable compound described above and the acid generator described later can be used in combination.

[0709] ​​​​​​​​​​​​​​​​​​​From the viewpoint of visual recognizability, 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.

[0710] From the viewpoint of visual recognizability, the content M of the color changeable compound in the outermost layer described above X is preferably 0.1 or more, more preferably 0.2 or more, and particularly preferably 0.3 or more and 3.0 or less, relative to the content M of the infrared absorber in the image recording layer described above Y X 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.

[0711] - Water-soluble polymer -

[0712] From the viewpoint of development removability (more preferably on-press development), the outermost layer preferably contains a water-soluble polymer.

[0713] 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.

[0714] 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.

[0715] 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.

[0716] 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.

[0717] 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.

[0718] The saponification degree can be measured according to the method described in JIS K 6726: 1994.

[0719] As the water-soluble polymer, polyvinylpyrrolidone can be given as a preferable example.

[0720] ​​As the water-soluble polymer, polyvinyl alcohol and polyvinylpyrrolidone are also preferably used in combination.

[0721] The water-soluble polymer can be used singly or in combination of two or more.

[0722] 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% with respect to the total mass of the outermost layer.

[0723] - Other Components -

[0724] 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, an infrared absorber, and the like.

[0725] Hereinafter, the other components will be described.

[0726] << Hydrophobic Polymer >>

[0727] The above-mentioned outermost layer preferably contains a hydrophobic polymer.

[0728] The hydrophobic polymer refers to a polymer that is less than 1 g or not dissolved in 100 g of pure water at 70°C.

[0729] As the hydrophobic polymer, for example, polyethylene, polystyrene, polyvinyl chloride, polyvinylidene chloride, polyalkyl (meth) acrylate (e.g., polymethyl (meth) acrylate, polyethyl (meth) acrylate, polybutyl (meth) acrylate, and the like), a copolymer obtained by combining raw material monomers of these polymers, and the like can be given.

[0730] Further, as the hydrophobic polymer, it is preferable to contain a polyvinylidene chloride resin.

[0731] Furthermore, as the hydrophobic polymer, it is preferable to contain a styrene-acrylic acid copolymer.

[0732] Furthermore, from the viewpoint of on-press developability, the hydrophobic polymer is preferably a hydrophobic polymer particle.

[0733] The hydrophobic polymer can be used singly or in combination of two or more.

[0734] 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% with respect to the total mass of the outermost layer.

[0735] << Acid Generator >>

[0736] 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.

[0737] 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.

[0738] 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.

[0739] Specifically, as the acid generator, an onium salt compound is preferred from the viewpoint of sensitivity and stability.

[0740] 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.

[0741] Among them, a sulfonate, a carboxylate, BPh4 - , BF4 - , PF6 - , CIO4 - of triarylsulfonium or diaryliodonium are preferred. Here, Ph represents a phenyl group.

[0742] The acid generator can be used alone or in combination with two or more kinds.

[0743] 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.

[0744] 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.

[0745] The outermost layer is formed by coating and drying using a well-known method.

[0746] 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 .

[0747] 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.

[0748] 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.

[0749] The outermost layer can contain a plasticizer for imparting flexibility, a surfactant for improving coatability, inorganic particles for controlling surface slip, and the like.

[0750] <Support>

[0751] The lithographic printing plate precursor according to the present application has a support.

[0752] As the support, a support known for a lithographic printing plate precursor can be appropriately selected and used.

[0753] As the support, a support having a hydrophilic surface (hereinafter, also referred to as "hydrophilic support") is preferred.

[0754] As the support in the present application, an aluminum plate which has been subjected to roughening treatment by a known method and anodization treatment is preferred. That is, the support in the present application preferably has an aluminum plate and an anodized film of aluminum provided on the aluminum plate.

[0755] Further, the support 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, and the average diameter of the micropores at the surface of the anodized film being more than 10 nm and 100 nm or less.

[0756] 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.

[0757] Figure 1 is a schematic cross-sectional view of one embodiment of the aluminum support 12a.

[0758] 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.

[0759] - Anodized Film -

[0760] Next, a preferred mode of the anodized film 20a will be described.

[0761] 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).

[0762] 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 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.

[0763] 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.

[0764] 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.

[0765] 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.

[0766] The shape of the micropores 22a is not particularly limited, and the micropores 22a can have a circular shape, an elliptical shape, a polygonal shape, or the like. Figure 1The core is generally straight tubular (generally cylindrical), but it can also be conical with a diameter that decreases towards the depth direction (thickness direction). Furthermore, the shape of the bottom of the micropore 22a is not particularly limited; it can be curved (convex) or planar.

[0767] In the support, the micropores can be composed of a large-diameter pore portion and a small-diameter pore portion. The large-diameter pore portion extends from the surface of the anodic oxide film to a certain depth, and the small-diameter pore portion communicates with the bottom of the large-diameter pore portion and extends from the communication position to a certain depth.

[0768] For example, such as Figure 2 As shown, the aluminum support 12b can be in the form of an aluminum plate 18 and an anodized film 20b having micropores 22b composed of large-diameter holes 24 and small-diameter holes 26.

[0769] For example, the micropores 22b in the anodic oxide film 20b are composed of large-diameter pores 24 and small-diameter pores 26, wherein the large-diameter pores 24 extend from the surface of the anodic oxide film to a depth of 10 nm to 1000 nm (depth D: reference). Figure 2 The small-diameter hole 26 is connected to the bottom of the large-diameter hole 24 at the position of the hole, and extends further from the connection position to 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.

[0770] -Manufacturing method of support body-

[0771] As a method for manufacturing the support used in this invention, for example, a manufacturing method that sequentially performs the following steps is preferred.

[0772] • Roughening process: The process of roughening the aluminum plate.

[0773] • Anodizing process: The process of anodizing roughened aluminum plates.

[0774] • Hole enlargement process: This process involves contacting the aluminum plate with anodized film obtained in the anodizing process with an acidic or alkaline aqueous solution to enlarge the diameter of the micropores in the anodized film.

[0775] The steps for each process are described in detail below.

[0776] <<Roughening Process>>

[0777] 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.

[0778] <<Anodizing treatment step>>

[0779] 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.

[0780] In the anodizing treatment step, an aqueous solution of sulfuric acid, phosphoric acid, oxalic acid, or the like can be used as the electrolyte. For example, the concentration of sulfuric acid can be cited as 100 g / L to 300 g / L.

[0781] 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 ).

[0782] <<Hole-expanding treatment>>

[0783] The hole-expanding treatment is a treatment (hole diameter enlarging treatment) of enlarging the diameter (hole diameter) of the micropores present in the anodized film formed by the anodizing treatment step described above.

[0784] The hole-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.

[0785] 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 alkylsilicon compound described in Japanese Patent Application Publication No. 6-35174 on the side opposite to the image recording layer, as needed.

[0786] <Undercoat layer>

[0787] 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 to the image-recording layer in the exposed areas, and makes the image-recording layer easy to be peeled from the support in the unexposed areas, 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.

[0788] As the compound used in the primer layer, a polymer having an adsorptive group that can be adsorbed 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.

[0789] 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.

[0790] As the adsorptive group that can be adsorbed 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.

[0791] 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.

[0792] 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.

[0793] As more preferable compounds, there can be mentioned the adsorptive groups which can be adsorbed on the surface of the support, the adsorptive groups described in Japanese Patent Application Publication No. 2005-125749 and Japanese Patent Application Publication No. 2006-188038, the high-molecular polymers having a hydrophilic group and a cross-linking group.

[0794] 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.

[0795] 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.

[0796] Hydrophilic compound

[0797] The undercoat layer preferably contains a hydrophilic compound from the viewpoint of development.

[0798] There is no particular limitation on the hydrophilic compound, and a publicly known hydrophilic compound used in the undercoat layer can be used.

[0799] 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.

[0800] 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 (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.

[0801] As the hydrophilic compound, from the viewpoint of scratch contamination inhibiting property, a hydroxycarboxylic acid or a salt thereof is preferably contained.

[0802] Further, from the viewpoint of scratch contamination inhibiting property, the hydrophilic compound, preferably a hydroxycarboxylic acid or a salt thereof, is preferably contained in the layer on the above-mentioned aluminum support. Further, the layer on the above-mentioned aluminum support 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.

[0803] As the layer on the above-mentioned aluminum support, as the layer in contact with the above-mentioned aluminum support, 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, for example, an outermost layer or an image recording layer.

[0804] 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.

[0805] 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.

[0806] 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.

[0807] The 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).

[0808] The above-described hydroxycarboxylic acid or salt thereof is preferably represented by the following formula (HC).

[0809] R HC (OH) mhc (COOM HC ) nhc Formula (HC)

[0810] 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 nhc is 2 or more, M HC may be the same, or different.

[0811] In formula (HC), as the organic group having mhc+nhc valence represented by R HC mhc+nhc-valent hydrocarbon groups, and the like. The hydrocarbon group can have a substituent and / or a linking group.

[0812] 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 connected by any one of amide bond, ether bond, urethane bond, urea bond and ester bond.

[0813] 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.

[0814] Furthermore, from the viewpoint of scratch contamination inhibitory property, M HC Preferably, it is an alkali metal or onium, more preferably an alkali metal.

[0815] The total number of mhc and nhc is preferably 3 or more, more preferably 3 to 8, and further preferably 4 to 6.

[0816] 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.

[0817] 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, syringic 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.

[0818] Among these, as the hydroxycarboxylic acid or the hydroxycarboxylic acid constituting the salt of the hydroxycarboxylic acid, from the viewpoint of scratch contamination inhibitory properties, 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.

[0819] Further, as the compound having one carboxyl group and two or more hydroxyl groups, gluconic acid or shikimic acid is preferable.

[0820] As the compound having two or more carboxyl groups and one hydroxyl group, citric acid or malic acid is preferable.

[0821] As the compound having two or more carboxyl groups and hydroxyl groups, respectively, tartaric acid is preferable.

[0822] Among these, as the hydroxycarboxylic acid, gluconic acid is particularly preferable.

[0823] The hydrophilic compound can be used singly or in combination of two or more.

[0824] 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.

[0825] In the base coat layer, in addition to the above-mentioned base coat layer compound, in order to prevent contamination over time, a chelating agent, a secondary or tertiary amine, a polymerization inhibitor, or the like can also be contained.

[0826] The base coat layer can be applied by a publicly known method.

[0827] 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 .

[0828] The lithographic printing plate precursor according to the present application can have other layers in addition to the above.

[0829] 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.

[0830] (Method for producing lithographic printing plate and lithographic printing method)

[0831] 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 imagewise (exposure step) and a step of supplying at least one selected from the group consisting of printing ink and dampening water on a printing machine to remove the image recording layer of the non-image area from the exposed lithographic printing plate precursor (on-press development step).

[0832] 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 imagewise (exposure step) and a step of supplying at least one selected from the group consisting of printing ink and dampening water on a printing machine to remove the image recording layer of the non-image area from the exposed lithographic printing plate precursor (on-press development step).

[0833] <Exposure step>

[0834] 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 imagewise and forming exposed areas and unexposed areas. The lithographic printing plate precursor according to the present application is preferably exposed imagewise 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.

[0835] 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.

[0836] As to 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.

[0837] <On-press development step>

[0838] The production method of the 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 printing press to remove the image recording layer from the non-image area.

[0839] Next, the on-press development method will be described.

[0840] <On-press development method>

[0841] 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 printing press and removing the image recording layer from the non-image area.

[0842] That is, if the image exposure is performed on the lithographic printing plate precursor, and then, without performing any development treatment, the lithographic printing plate precursor is directly mounted on the printing press, or if the image exposure is performed on the printing press after the lithographic printing plate precursor is mounted on the printing press, and then, the oily ink and the 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, the 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 the oily ink or the 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 the oily ink. Thus, the lithographic printing plate precursor is on-press developed on the printing press and directly used for multi-printing. As the oily ink and the aqueous component, a general printing ink and dampening solution for lithographic printing are preferably used.

[0843] As the laser for the 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.

[0844] <Printing step>

[0845] 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.

[0846] There is no particular limitation on the printing ink, and various known inks can be used as needed. Also, as the printing ink, an oil-based ink or an ultraviolet-curable ink (UV ink) is preferably selected.

[0847] Also, in the printing step, a dampening solution can be supplied as needed.

[0848] 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.

[0849] There is no particular limitation on the recording medium, and known recording media can be used as needed.

[0850] 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.

[0851] Examples

[0852] Hereinafter, the present application will be described in detail by examples, but the present application is not limited thereto. In the present examples, the " % " and the " part " mean " mass % " and " mass part ", respectively, unless otherwise specified. In the high molecular compound, the molecular weight is the weight average molecular weight (Mw), and the ratio of the structural repeating unit is the mole percentage, unless otherwise specified. Also, the weight average molecular weight (Mw) is a value determined as a polystyrene conversion value based on the gel permeation chromatography (GPC) method.

[0853] (Examples 1 to 24 and Comparative Examples 1 and 2)

[0854] <Production of Support (1)>

[0855] To an aluminum alloy sheet of the material 1S having a thickness of 0.3 mm, the (A-a) mechanical roughening treatment (brushing method) described in paragraph 0126 to the (A-i) dirt removal treatment in an acidic aqueous solution described in paragraph 0134 of Japanese Patent Application Publication No. 2012-158022 were applied.

[0856] Next, each of the treatment conditions of the (A-j) first-stage anodizing treatment described in paragraph 0135 to the (A-m) third-stage anodizing treatment described in paragraph 0138 of Japanese Patent Application Publication No. 2012-158022 was appropriately adjusted, and an anodic oxide film was formed, which was used as the support (1).

[0857] In addition, water washing treatment was applied between all the treatment processes, and drainage was performed by pinch rollers after the water washing treatment.

[0858] The details of the obtained support (1) were summarized.

[0859] Support (1): L * a * b * L in the lightness in the color system * : 83, average diameter of the large-diameter pore portion in the micropore at the oxide film surface: 35 nm (depth: 100 nm), average diameter of the small-diameter pore portion in the micropore at the communication position: 10 nm (depth: 1,000 nm), ratio of the depth of the large-diameter pore portion to the average diameter of the large-diameter pore portion: 2.9

[0860] <Manufacture of Support (2)>

[0861] -Alkaline etching treatment-

[0862] 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% to an aluminum sheet at a temperature of 70°C using a sprayer. Then, water washing based on the sprayer was performed. The amount of aluminum dissolved from the surface on which the electrochemical roughening treatment was performed was 5 g / m 2 .

[0863] -Dirt removal treatment using an acidic aqueous solution (first dirt removal treatment)-

[0864] Next, dirt removal treatment was performed using an acidic aqueous solution. As the acidic aqueous solution used for the dirt 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 to an aluminum sheet using a sprayer, and dirt removal treatment was performed for 3 seconds. Then, water washing treatment was performed.

[0865] -Electrochemical roughening treatment-

[0866] 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 positive and negative phases, a frequency of 50 Hz, and the ratio of the anodic reaction time to the cathode reaction time in one cycle was 1:1. 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.

[0867] -Decontamination treatment using acidic aqueous solution-

[0868] 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.

[0869] -Stage 1 Anodizing Treatment-

[0870] 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.

[0871] 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.

[0872] - hole expansion treatment -

[0873] The aluminum plate subjected to the anodizing treatment described above was immersed in a caustic soda aqueous solution having a temperature of 40°C, a caustic soda concentration of 5 mass%, and an aluminum ion concentration of 0.5 mass%, and subjected to a hole expansion treatment under the conditions shown in Table 1. Then, water washing based on a spray was performed.

[0874] - 2nd stage anodizing treatment -

[0875] Using Figure 3 The 2nd stage anodizing treatment was performed using the anodizing apparatus based on direct current electrolysis shown in the structure, and an anodized film having a prescribed film thickness was formed.

[0876] <Manufacture of support (3)>

[0877] - alkaline etching treatment -

[0878] Etching treatment was performed by spraying a caustic soda aqueous solution having a caustic soda concentration of 26 mass% and an aluminum ion concentration of 6.5 mass% to the aluminum plate at a temperature of 70°C using a spray. Then, water washing based on a spray was performed. The amount of aluminum dissolution from the surface subjected to the electrochemical roughening treatment was 5 g / m 2 .

[0879] - dirt removal treatment using an acidic aqueous solution (1st dirt removal treatment) -

[0880] Next, a dirt removal treatment was performed using an acidic aqueous solution. As the acidic aqueous solution used for the dirt 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 to the aluminum plate using a spray, and a dirt removal treatment was performed for 3 seconds. Then, a water washing treatment was performed.

[0881] - electrochemical roughening treatment -

[0882] Next, an electrochemical roughening treatment was performed using an electrolyte having a hydrochloric acid concentration of 14 g / L, an aluminum ion concentration of 13 g / L, and a sulfuric acid concentration of 3 g / L, and using an alternating current. The liquid temperature of the electrolyte was 30°C. The aluminum ion concentration was adjusted by adding aluminum chloride. The waveform of the alternating current was a sine wave symmetrical with respect to the positive and negative waveforms, the frequency was 50 Hz, the anodic reaction time and the cathodic reaction time in one period of the alternating current were 1 : 1, and the current density was 75 A / dm 2 , based on the peak value of the current waveform of the alternating current. Also, the electric quantity was 450 C / dm 2 , based on the sum of the electric quantity of the aluminum plate participating in the anodic reaction, and the electrolysis treatment was performed with an electric current interval of 4 seconds. 2This was performed in four stages. A carbon electrode was used as the counter electrode in the aluminum plate. Then, a water washing treatment was performed.

[0883] - Dirt removal treatment using an acidic aqueous solution

[0884] Next, a dirt removal treatment was performed using an acidic aqueous solution. Specifically, the acidic aqueous solution was sprayed onto the aluminum plate using a sprayer, and a dirt removal treatment was performed for 3 seconds. The acidic aqueous solution used for the dirt removal treatment was an aqueous solution having a sulfuric acid concentration of 170 g / L and an aluminum ion concentration of 5 g / L. The liquid temperature was 30°C.

[0885] - Anodizing treatment

[0886] An anodizing treatment was performed in a sulfuric acid solution using an anodizing device based on direct current electrolysis to become a prescribed oxide film amount.

[0887] <Manufacture of the support (4)>

[0888] 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.

[0889] Both the pre-etching and post-etching processes were performed using an alkaline solution under known conditions. As to the roughening (or graining), 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. As to these treatment processes, a continuous process was performed on a typical production line for manufacturing a lithographic printing plate precursor.

[0890] Next, the obtained grained and etched aluminum-containing support was washed with water and dried, and cut into individual grained and etched aluminum-containing sheets.

[0891] Next, each sheet was subjected to 2 anodizing treatments, and about 100 liters of an anodizing solution was contained in each anodizing treatment bath. The 1st 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 2nd 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 1st anodizing process for forming the outer aluminum oxide layer was performed using phosphoric acid as the electrolyte, and the 2nd anodizing process for forming the inner aluminum oxide layer was performed using sulfuric acid as the electrolyte.

[0892] <Method for forming the primer layer>

[0893] On the support structure listed in Table 1, the dry coating amount is 80 mg / m². 2 The primer coating solution with the following composition is applied and dried in an oven at 100°C for 30 seconds to form the primer coating.

[0894] -Composition of the primer coating solution-

[0895] • Compound for primer coating (P-1, 11% aqueous solution): 0.10502 parts

[0896] Hydroxyethyldiiminodiacetic acid: 0.01470 parts

[0897] • Sodium ethylenediaminetetraacetate: 0.06575 parts

[0898] Surfactant (EMALEX 710, manufactured by NIHON EMULSION Co., Ltd.): 0.00159 parts by weight

[0899] • Preservative (manufactured by Biohope L, K·I Chemical Industry Co., LTD.): 0.00149 parts

[0900] Water: 2.86144 portions

[0901] [Chemical Formula 50]

[0902] P-1

[0903]

[0904] <Formation of Image Recording Layer>

[0905] Any one of the image recording layer coating solutions (1) to (18) listed in Table 1 was applied to the support or base layer listed in Table 1 and dried at 120°C for 40 seconds to form a dry coating with a coating weight of 1.0 g / m². 2 Image recording layer.

[0906] The following shows the image recording layer coating liquids (1) to (18).

[0907] <Composition of image recording layer coating solutions (1) to (10)>

[0908] • Infrared absorber IR-1: 0.02000 parts

[0909] • The colorimetric reagent listed in Table 1: 0.02500 parts

[0910] • Electron-accepted polymerization initiator Int-1: 0.11000 parts

[0911] • Electron-donating polymerization initiator TPB: 0.02500 parts

[0912] • Chain transfer agent Ct-1: 0.04000 parts

[0913] • Color developing compounds C-1 to C-10 described in Table 1: 0.00500 parts

[0914] • Polymerizable compound M-1: 0.17500 parts

[0915] • Polymerizable compound M-2: 0.10000 parts

[0916] • Anionic surfactant A-1: 0.01200 parts

[0917] • Fluorine-based surfactant W-1: 0.00416 parts

[0918] • 2-butanone: 4.2726 parts

[0919] • 1-methoxy-2-propanol: 4.3952 parts

[0920] • Methanol: 2.2737 parts

[0921] • Microgel liquid 1: 2.3256 parts

[0922] In addition, the image recording layer coating liquids (1) to (10) each used any one of the color developing compounds C-1 to C-10 described in Table 1.

[0923] [Chemical Formula 51]

[0924]

[0925] [Chemical Formula 52]

[0926]

[0927] [Chemical Formula 53]

[0928]

[0929] [Chemical Formula 54]

[0930]

[0931] [Chemical Formula 55]

[0932]

[0933] [Chemical Formula 56]

[0934]

[0935] [Chemical Formula 7]

[0936]

[0937] Synthesis method of polymerizable compound M-1

[0938] 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 NITTO KASEI 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.

[0939] Next, using a recycling-type GPC (apparatus: LC908-C60, columns: JAIGEL-1H-40 and 2H-40 (manufactured by Japan Analytical Industry.)), a molecular weight fraction of the urethane acrylate solution was performed with tetrahydrofuran (THF) eluent. The weight average molecular weight was 20,000.

[0940] Synthesis method of microgel liquid 1

[0941] • Microgels (polymer particles): 2.640 parts

[0942] • Distilled water: 2.425 parts

[0943] The preparation method of the microgels used in the above microgel liquid is shown below.

[0944] Preparation of polyvalent isocyanate compound

[0945] 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 stirring was performed. The reaction temperature was set at 50°C at the time when the heat generation was suppressed, and stirring was performed for 3 hours, and an ethyl acetate solution (50% by mass) of the polyvalent isocyanate compound (1) was obtained.

[0946] Preparation of microgels

[0947] 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.

[0948] ~ Oil phase ingredients ~

[0949] (Ingredient 1) Ethyl acetate: 12.0 parts

[0950] (Ingredient 2) Adduct of trimethylolpropane (6 mole equivalents) and xylene diisocyanate (18 mole equivalents), and addition of a mono-terminal methylated polyoxyethylene (1 mole equivalent, number of repeating units of oxyethylene: 90) to the adduct (50 mass% ethyl acetate solution, manufactured by Mitsui Chemicals, Inc.): 3.76 parts

[0951] (Ingredient 3) Polyisocyanate compound (1) (as a 50 mass% ethyl acetate solution): 15.0 parts

[0952] (Ingredient 4) 65 mass% ethyl acetate solution of dipentaerythritol pentaacrylate (SR-399, manufactured by Sartomer Company, Inc.): 11.54 parts

[0953] (Ingredient 5) 10% ethyl acetate solution of sulfonate type surfactant (PIONIN A-41-C, manufactured by Takemoto Oil & Fat Co., Ltd.): 4.42 parts

[0954] ~ Water phase ingredients ~

[0955] Distilled water: 46.87 parts

[0956] Composition of image recording layer coating liquids (11) to (13)

[0957] • Infrared absorber IR-2: 0.02000 parts

[0958] • Color developer described in Table 1: 0.02500 parts

[0959] • Electron-accepting polymerization initiator Int-1: 0.11000 parts

[0960] • Electron-donating polymerization initiator TPB: 0.02500 parts

[0961] • Chain transfer agent Ct-1: 0.04000 parts

[0962] • Color developing compound C-1: (0.00250 parts of image recording layer coating solution (10), 0.00500 parts of image recording layer coating solution (11), 0.01000 parts of image recording layer coating solution (12))

[0963] • Polymerizable compound M-1: 0.20000 parts

[0964] • Polymerizable compound M-2: 0.10000 parts

[0965] • Anionic surfactant A-1: 0.05000 parts

[0966] • Fluorine-based surfactant W-1: 0.00416 parts

[0967] • 2-butanone: 5.01138 parts

[0968] • 1-methoxy-2-propanol: 2.98309 parts

[0969] • Methanol: 2.20525 parts

[0970] • Microgel liquid 1: 0.58140 parts

[0971] • Microgel liquid 2: 2.32560 parts

[0972] [Chemical Formula 58]

[0973]

[0974] Preparation of microgel liquid 2

[0975] Preparation of oil phase component

[0976] A mixture of 110 parts of the polyfunctional isocyanate 110 of the following structure, 5.1 parts of a 50 mass% ethyl acetate solution of D-116N (Takenate (registered trademark) D-116N manufactured by Mitsui Chemicals, Inc., an adduct of trimethylolpropane (TMP), m-xylylene diisocyanate (XDI) and polyethylene glycol monomethyl ether (E090); the structure is shown below.), 10 parts of SR-399E (di-pentaerythritol pentaacrylate manufactured by Sartomer Company, Inc.), and 19 parts of ethyl acetate was stirred for 15 minutes at room temperature (25°C, hereinafter the same) to obtain an oil phase component.

[0977] [Chemical Formula 59]

[0978]

[0979] [Chemical Formula 60]

[0980]

[0981] -Preparation of an aqueous phase component-

[0982] As the aqueous phase component, 43.1 parts of distilled water was prepared.

[0983] -Microcapsule formation step-

[0984] The aqueous phase component was added to the oil phase component and mixed, and the obtained mixture was emulsified at 12,000 rpm for 12 minutes using a homogenizer to obtain an emulsion.

[0985] The obtained emulsion was added to 10 parts of distilled water, and the obtained liquid was stirred for 30 minutes at room temperature.

[0986] 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 the ethyl acetate was distilled off from the liquid. Next, the liquid from which the ethyl acetate was distilled off was heated to 50°C, and the liquid was stirred for 24 hours while maintaining the liquid temperature at 50°C, whereby the microcapsules were formed in the liquid. Next, the liquid containing the microcapsules was diluted with distilled water so that the solid content concentration became 20 mass%, whereby an aqueous dispersion of the microcapsules (microgel liquid 2) was obtained. The volume average particle diameter of the microcapsules was in the range of 0.10 μm to 0.20 μm.

[0987] <Composition of the image recording layer coating liquid (14)>

[0988] • Electron-accepting polymerization initiator Int-2: 0.060 parts by weight

[0989] • Infrared absorber IR-3: 0.026 parts by weight

[0990] • Electron-donating polymerization initiator TPB: 0.050 parts by weight

[0991] • Color-developing compound C-1: 0.0005 parts by weight

[0992] • Polymerizable compound M-2: 0.250 parts by weight

[0993] • Polymerizable compound M-3: 0.250 parts by weight

[0994] • Binder polymer (S-LEC BX-5Z manufactured by SEKISUI CHEMICAL CO., LTD., a part of which is acetylated polyvinyl butyral): 0.150 parts by weight

[0995] • 1-methoxy-2-propanol: 4.988 parts

[0996] • 2-butanone: 9.262 parts

[0997] [Chemical Formula 61]

[0998]

[0999] [Chemical Formula 62]

[1000]

[1001] <Composition of image recording layer coating liquid (15)>

[1002] Electron-accepting polymerization initiator Int-3: 0.041 parts

[1003] Color-developing compound C-1: 0.005 parts

[1004] Infrared absorber IR-4: 0.027 parts

[1005] Infrared absorber IR-5: 0.015 parts

[1006] Polymerizable compound M-4: 0.100 parts

[1007] Polymerizable compound M-5: 0.096 parts

[1008] Polymerizable compound M-6: 0.096 parts

[1009] Polymer particle 1: 0.300 parts

[1010] Color developer S-2: 0.041 parts

[1011] Hydroxypropyl cellulose: 0.030 parts

[1012] n-propanol: 5.168 parts

[1013] 2-butanone: 6.460 parts

[1014] 1-methoxy-2-propanol: 1.615 parts

[1015] methanol: 2.907 parts

[1016] [Chemical Formula 63]

[1017]

[1018] In addition, Int-3 is a salt formed from 0.5 molar equivalent of each of the two cations described above and 1 molar equivalent of the anion described above.

[1019] [Chemical Formula 64]

[1020]

[1021] [Chemical Formula 65]

[1022]

[1023] [Chemical Formula 66]

[1024]

[1025] [Polymer particles]

[1026] Polymer particles 1: resin particles containing the resin shown below (n = 45, Mw = 50,000)

[1027] [Chemical Formula 67]

[1028]

[1029] [Synthesis of polymer particles 1]

[1030] A dispersion unit was prepared by adding to a 4-necked flask: Compound B-1 (n = 45) shown below: 10.0 parts, distilled water: 85.0 parts, and n-propanol: 240.0 parts, and heating and stirring at 70°C under a nitrogen atmosphere.

[1031] Next, a mixture of Compound A-1 (20.0 parts), Compound A-2 (70.0 parts), and 2,2'-azobisisobutyronitrile (0.7 parts) was added dropwise to the 4-necked flask over 2 hours.

[1032] After the dropwise addition, the reaction was continued for 5 hours without opening the flask, and then 2,2'-azobisisobutyronitrile (0.5 parts) was added and the temperature was raised to 80°C. 2,2'-azobisisobutyronitrile (0.4 parts) was added every 6 hours, and the reaction was continued for a total of 19 hours.

[1033] The reaction solution was naturally cooled to room temperature (25°C) to obtain a dispersion of polymer particles 1 (23% of solid content).

[1034] [Chemical Formula 68]

[1035]

[1036] The median particle diameter of the polymer particles 1 was 150 nm, and the coefficient of variation was 23%.

[1037] Further, regarding the dispersibility of the polymer particles 1, the result confirmed by the method described above was that the polymer particles 1 were particles having water dispersibility, and were particles having organic solvent dispersibility.

[1038] [Chemical Formula 69]

[1039]

[1040] <Composition of image recording layer coating solution (16)>

[1041] • Electron-accepting polymerization initiator Int-2: 0.060 parts by weight

[1042] • Color developing agent described in Table 1: 0.025 parts

[1043] • Infrared absorber IR-3: 0.026 parts by weight

[1044] • Electron-donating polymerization initiator TPB: 0.050 parts by weight

[1045] • Color developing compound C-1: 0.0005 parts by weight

[1046] • Polymerizable compound M-2: 0.250 parts by weight

[1047] • Polymerizable compound M-3: 0.250 parts by weight

[1048] • Binder polymer (S-LEC BX-5Z manufactured by SEKISUI CHEMICAL CO., LTD., a part of which is acetylated polyvinyl butyral): 0.150 parts by weight

[1049] • 1-methoxy-2-propanol: 4.988 parts

[1050] • 2-butanone: 9.262 parts

[1051] <Composition of image recording layer coating solution (17)>

[1052] • Infrared absorber IR-1: 0.02000 parts

[1053] • Color developer S-1: 0.02500 parts

[1054] • Electron-accepting polymerization initiator Int-1: 0.11000 parts

[1055] • Electron-donating polymerization initiator TPB: 0.02500 parts

[1056] • Chain transfer agent Ct-1: 0.04000 parts

[1057] • Polymerizable compound M-1: 0.17500 parts

[1058] • Polymerizable compound M-2: 0.10000 parts

[1059] • Anionic surfactant A-1: 0.01200 parts

[1060] • Fluorine-based surfactant W-1: 0.00416 parts

[1061] • 2-butanone: 4.2726 parts

[1062] • 1-methoxy-2-propanol: 4.3952 parts

[1063] • Methanol: 2.2737 parts

[1064] • Microgel liquid 1: 2.3256 parts

[1065] <Composition of the image recording layer coating liquid (18)>

[1066] • Infrared absorber IR-1: 0.02000 parts

[1067] • Color developer S-1: 0.02500 parts

[1068] • Electron-accepting polymerization initiator Int-1: 0.11000 parts

[1069] • Chain transfer agent Ct-1: 0.04000 parts

[1070] • Color developing compound C-1: 0.00500 parts

[1071] • Polymerizable compound M-1: 0.17500 parts

[1072] • Polymerizable compound M-2: 0.10000 parts

[1073] • Anionic surfactant A-1: 0.01200 parts

[1074] • Fluorine-based surfactant W-1: 0.00416 parts

[1075] • 2-butanone: 4.2726 parts

[1076] • 1-methoxy-2-propanol: 4.3952 parts

[1077] • methanol: 2.2737 parts

[1078] • microgel liquid 1: 2.3256 parts

[1079] Composition of image recording layer coating liquid (19)

[1080] Electron-accepting polymerization initiator Int-3: 0.041 parts

[1081] Color developing compound C-1: 0.005 parts

[1082] Infrared absorber IR-4: 0.027 parts

[1083] Infrared absorber IR-5: 0.015 parts

[1084] Polymerizable compound M-4: 0.100 parts

[1085] Polymerizable compound M-5: 0.096 parts

[1086] Polymerizable compound M-6: 0.096 parts

[1087] Polymer particles 1: 0.300 parts

[1088] Color developer S-22 (compound described below): 0.041 parts

[1089] Hydroxypropyl cellulose: 0.030 parts

[1090] n-propanol: 5.168 parts

[1091] 2-butanone: 6.460 parts

[1092] 1-methoxy-2-propanol: 1.615 parts

[1093] Methanol: 2.907 parts

[1094] [Chemical Formula 70]

[1095]

[1096] Formation of outermost layer

[1097] Any one of the outermost layer coating liquids (1) to (3) described in Table 1 was bar coated on the image recording layer, and dried at 120°C for 30 seconds, so that the dry coating amount of the lithographic printing plate precursors 1 to 13, 18, 19, 24 and 25 became 0.20 g / m 2The dry coating amount of the lithographic printing plate precursors 14, 20, and 21 became 0.70 g / m 2 The dry coating amount of the lithographic printing plate precursor 16 became 0.10 g / m 2 The outermost layer was formed in this manner.

[1098] <Outermost layer coating liquid (1)>

[1099] • GOHSENX L3266 (manufactured by Mitsubishi Chemical Corporation., solid content: 100%) : 0.05000 parts

[1100] • Fine Sphere FS102 (manufactured by Nippon Paint Co., Ltd., solid content: 17%) : 0.10000 parts

[1101] • EMALEX 710 (nonionic surfactant, polyoxyethylene lauryl ether, manufactured by NIHON EMULSION Co., Ltd., solid content: 100%) : 0.00350 parts

[1102] • Microgel liquid 2: 0.16670 parts

[1103] • Water: 0.56540 parts

[1104] In addition, GOHSENX L3266 is a sulfonic acid-modified polyvinyl alcohol having a weight average molecular weight of 17,000 as shown below.

[1105] [Chemical Formula 71]

[1106]

[1107] In addition, Fine Sphere FS102 is a water dispersion of a styrene-acrylic acid copolymer particle as shown below.

[1108] [Chemical Formula 72]

[1109]

[1110] <Composition of outermost layer coating liquid (2)>

[1111] • GOHSENX L3266 (manufactured by Mitsubishi Chemical Corporation., solid content: 100%) : 0.07000 parts

[1112] • Fine Sphere FS102 (manufactured by Nippon Paint Co., Ltd., solid content: 17%) : 0.14706 parts

[1113] • EEMALEX 710 (manufactured by NIHON EMULSION Co., Ltd., solid content: 100%) : 0.00350 parts

[1114] • Water: 0.50114 parts

[1115] Composition of the outermost coating liquid (3)

[1116] • Mowiol 4-88 (polyvinyl alcohol, manufactured by KURARAY CO., LTD.): 0.28000 parts

[1117] • Mowiol 8-88 (polyvinyl alcohol, manufactured by KURARAY CO., LTD.): 0.20000 parts

[1118] • Infrared absorber IR-6: 0.02000 parts

[1119] • EEMALEX 710 (manufactured by NIHON EMULSION Co., Ltd., solid content: 100%) : 0.37500 parts

[1120] • Hydrophobic polymer WP-1 (polyvinylidene chloride aqueous dispersion, Diofan (registered trademark) A50 manufactured by Solvin Co.): 0.20000 parts

[1121] • Water: 6.38000 parts

[1122] Preparation of the lithographic printing plate precursor

[1123] The lithographic printing plate precursors 1 to 26 of Examples 1 to 24 and Comparative Examples 1 and 2 were prepared according to the support and the method of forming each layer as described in Table 1, respectively.

[1124] Evaluation of the lithographic printing plate precursor

[1125] 〔Visual recognition evaluation (measurement of ΔL of the exposed part (image part) before and after exposure)〕

[1126] The obtained lithographic printing plate precursors were exposed by Trendsetter 32 44VX manufactured by Creo Co. under the conditions of output 11.5 W, outer drum rotation speed 220 rpm, and resolution 2,400 dpi (dot per inch, 1 inch = 25.4 mm) with a water-cooled 40 W infrared semiconductor laser. As for the exposure, it was performed in an environment of 25°C and 50% RH.

[1127] The color development of the lithographic printing plate precursor was measured immediately after exposure and after 6 hours of storage in the dark (30°C, 70% RH) after exposure. For the measurement, a spectral colorimeter CM-2600d manufactured by Konica Minolta, Inc. and an operation software CM-S100W were used, and the measurement was performed by the SCE (Specular Component Excluded) method. For the visual recognition, L * a * b * The L * value (lightness) of the color system was evaluated based on the difference ΔL between the L * value of the exposed portion and the L * value of the unexposed portion. The evaluation results are shown in Table 1. The larger the value of ΔL, the more excellent the visual recognition.

[1128] 〔Tone Reproduction Evaluation〕

[1129] The obtained lithographic printing plate precursor was exposed by a Luxel PLATE SETTER T-6000 III manufactured by Fujifilm Corporation, under the conditions of an outer drum rotation speed of 1000 rpm, a laser output of 70%, and a resolution of 2400 dpi. The exposed image contained a solid image and a 50% dot image of a frequency modulation screening of 20 μm dots.

[1130] The exposed lithographic printing plate precursor was not subjected to a development treatment, but was mounted on a plate cylinder of a printing machine LITHRONE 26 manufactured by KOMORI Corporation. A fountain solution of Ecolity-2 (manufactured by Fujifilm Corporation) / tap water = 2 / 98 (volume ratio) and a Values-G (N) black ink (manufactured by DIC GRAPHICS CORPORATION.) were supplied by a standard automatic printing start method of the LITHRONE 26, and printing was performed on Tokubishi Art paper (continuous amount: 76.5 k, manufactured by Mitsubishi Paper Mills Limited) at a printing speed of 10,000 sheets per hour.

[1131] The screened area of the 50% dot image was measured using a Gretag densitometer, and the dot gain amount (%) of the 50% dot was calculated based on the difference between the measured value of the screened area and the original dot % (= 50%). This value was used to evaluate the tone reproduction. The closer the value to 0%, the more excellent the tone reproduction. Furthermore, if the value is 5% or less, the tone reproduction is more excellent.

[1132]

[1133] In addition, "-" in Table 1 indicates that the corresponding layer is not formed.

[1134] Also, the image recording layers after exposure in Examples 1 to 24 each contain the above-mentioned color developing compound or a complex having an anion obtained by removing one hydrogen atom from the above-mentioned color developing compound as a ligand.

[1135] From the results described in Table 1, it was found that the lithographic printing plate precursors according to the present application can provide a lithographic printing plate precursor in which the visual recognition of the exposed portion is excellent compared to the lithographic printing plate precursors according to the comparative examples.

[1136] Also, from the results described in Table 1, it was found that the tone reproduction of the lithographic printing plate precursors according to the present application is also excellent.

[1137] The entire contents of Japanese Patent Application No. 2020-104530 filed on June 17, 2020 and Japanese Patent Application No. 2021-002135 filed on January 8, 2021 are incorporated herein by reference.

[1138] All of the literature documents, patent applications and technical standards described in the present specification are incorporated herein by reference to the same extent as if each literature document, patent application and technical standard is specifically and individually incorporated herein by reference.

[1139] Symbol Explanation

[1140] 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 lithographic printing plate master, comprising a support and an image recording layer on the support, The image recording layer contains a color-developing compound capable of reacting with decomposition products generated by exposure through the image recording layer. The chromogenic compound is a compound represented by the following formula 1C and / or formula 2C. In Equations 1C and 2C, R 1C ~R 4C Each independently represents a monovalent organic group, L 1C and L 2C Each of the two independently represents a divalent organic group, A. C Indicates OH or NR 5C R 6C R 5C and R 6C Each element represents either a hydrogen atom or a monovalent organic group, and the dashed line represents a portion that is optionally a double bond. The on-machine developing type lithographic printing plate original is at 110mJ / cm 2 When the energy density is exposed to infrared light at a wavelength of 830 nm, the brightness change ΔL of the exposed portion before and after exposure, after being stored at 30°C and 70%RH for 6 hours, is 3 or more.

2. An on-machine developing type lithographic printing plate master, comprising a support and an image recording layer on the support, The image recording layer comprises a compound represented by Formula 1C or Formula 2C and an electron-donating polymerization initiator. In Equations 1C and 2C, R 1C ~R 4C Each independently represents a monovalent organic group, L 1C and L 2C Each of the two independently represents a divalent organic group, A. C Indicates OH or NR 5C R 6C R 5C and R 6C Each element represents either a hydrogen atom or a monovalent organic group, and the dashed line represents a portion that is optionally a double bond. The on-machine developing type lithographic printing plate original is at 110mJ / cm 2 When the energy density is exposed to infrared light at a wavelength of 830 nm, the brightness change ΔL of the exposed portion before and after exposure, after being stored at 30°C and 70%RH for 6 hours, is 3 or more.

3. An on-machine developing type lithographic printing plate master, comprising a support and an image recording layer on the support, At 110mJ / cm 2 The image recording layer, exposed to infrared light at a wavelength of 830 nm, contains a compound represented by Formula 1C or Formula 2C, or a complex having an anion as a ligand obtained by removing one hydrogen atom from a compound represented by Formula 1C or Formula 2C. In Equations 1C and 2C, R 1C ~R 4C Each independently represents a monovalent organic group, L 1C and L 2C Each of the two independently represents a divalent organic group, A. C Indicates OH or NR 5C R 6C R 5C and R 6C Each element represents either a hydrogen atom or a monovalent organic group, and the dashed line represents a portion that is optionally a double bond. The on-machine developing type lithographic printing plate original is at 110mJ / cm 2 When the energy density is exposed to infrared light at a wavelength of 830 nm, the brightness change ΔL of the exposed portion before and after exposure, after being stored at 30°C and 70%RH for 6 hours, is 3 or more.

4. The on-machine developing type lithographic printing plate original according to claim 1 or 3, wherein, The image recording layer also contains a polymerization initiator.

5. The on-machine developing type lithographic printing plate original according to claim 4, wherein, The polymerization initiator includes an electron-donating polymerization initiator.

6. The on-machine developing type lithographic printing plate original according to claim 2 or 5, wherein, The electron-donating polymerization initiator contains a boron compound.

7. The on-machine developing type lithographic printing plate original according to claim 6, wherein, The electron-donating polymerization initiator comprises a tetraphenylborate compound.

8. The on-machine developing type lithographic printing plate original according to claim 1, wherein, The colorimetric reaction is a complexation reaction.

9. The on-machine developing type lithographic printing plate original according to claim 1, wherein, The image recording layer also contains a polymerization initiator. The decomposition products generated by the exposure are the decomposition products generated by the exposure of the polymerization initiator.

10. The on-machine developing type lithographic printing plate original according to claim 1 or 9, wherein, The chromogenic compound is a compound having one or more ketone structures.

11. The on-machine developing type lithographic printing plate original according to claim 1, wherein, The content of the colorimetric compound is 0.05% to 2.5% by mass relative to the total mass of the image recording layer.

12. The on-machine developing type lithographic printing plate original according to claim 1 or 2, wherein, The total content of the compound represented by Formula 1C or Formula 2C is 0.05% to 2.5% by mass relative to the total mass of the image recording layer.

13. 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 infrared absorber.

14. The on-machine developable lithographic printing plate original according to any one of claims 1 to 3, wherein, The image recording layer also contains an acid developer.

15. The on-machine developing type lithographic printing plate original according to claim 14, wherein, The acid colorimetric agent comprises a compound represented by the following formula (Le-8), In formula (Le-8), X1 to X4 independently represent hydrogen atoms, halogen atoms or dialkylaniline groups, Y1 and Y2 independently represent C or N, X1 does not exist when Y1 is N, X4 does not exist when Y2 is N, Rb1 and Rb2 independently represent hydrogen atoms, alkyl, aryl or heteroaryl groups, and Rc1 and Rc2 independently represent aryl or heteroaryl groups.

16. The on-machine developing type lithographic printing plate original according to claim 15, wherein, Rc1 and Rc2 are each independently a phenyl group having a substituent at at least one ortho position and an electron-donating group at the para position.

17. The on-machine developing type lithographic printing plate original according to claim 14, wherein, The acid colorimetric agent comprises a compound represented by the following formula (Le-10), In formula (Le-10), Ar1 independently represents aryl or heteroaryl, and Ar2 independently represents aryl with substituents at at least one ortho position, or heteroaryl with substituents at at least one ortho position.

18. The on-machine developing type lithographic printing plate original according to claim 17, wherein, Ar1 is independently an aryl group having an electron-donating group or a heteroaryl group having an electron-donating group, and Ar2 is independently a phenyl group having a substituent at at least one ortho position and an electron-donating group at the para position.

19. The on-machine developing type lithographic printing plate original according to claim 4, wherein, The image recording layer also includes an electron-accepting polymerization initiator as the polymerization initiator.

20. The on-machine developing type lithographic printing plate original according to claim 19, wherein, The electron-accepting polymerization initiator is an onium salt compound.

21. The on-machine developing type lithographic printing plate original according to claim 19, 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.

22. The on-machine developing type lithographic printing plate original according to claim 4, wherein, The polymerization initiator comprises a compound formed by a cation having an electron-accepting polymerization initiator structure and an anion having an electron-donating polymerization initiator structure to form a counter salt.

23. The on-machine developing type lithographic printing plate original according to any one of claims 1 to 3, having an outermost layer on the image recording layer, The outermost layer contains a color-changing compound.

24. The on-machine developing type lithographic printing plate original according to claim 23, wherein, The color-changing compound includes compounds that develop color upon exposure to infrared light.

25. The on-machine developable lithographic printing plate original according to any one of claims 1 to 3, wherein, The image recording layer also includes an infrared absorber and an electron-donating polymerization initiator. The HOMO value of the infrared absorber and the HOMO value of the electron-donating polymerization initiator are below 0.70 eV.

26. The on-machine developable lithographic printing plate original according to any one of claims 1 to 3, wherein, The image recording layer also includes an infrared absorber and an electron-accepting polymerization initiator. The LUMO of the electron-accepting polymerization initiator and the LUMO of the infrared absorber are both below 0.70 eV.

27. The on-machine developable lithographic printing plate original according to any one of claims 1 to 3, wherein, The image recording layer also contains polymeric compounds.

28. The on-machine developing type lithographic printing plate original according to claim 27, wherein, The polymeric compound comprises polymeric compounds with seven or more functions.

29. The on-machine developing type lithographic printing plate original according to claim 27, wherein, The polymeric compound comprises polymeric compounds with 10 or more functions.

30. The on-machine developable lithographic printing plate original according to any one of claims 1 to 3, wherein, The support has an aluminum plate and an anodized aluminum film disposed on the aluminum plate. The anodic oxide film is located closer to the image recording layer than the aluminum plate. The anodic oxide film has micropores extending along the depth direction from the surface of the image recording layer side. The average diameter of the micropores on the surface of the anodic oxide film is greater than 10 nm and less than 100 nm.

31. The on-machine developing type lithographic printing plate original according to claim 30, wherein, The micropores consist of a large-diameter pore portion and a small-diameter pore portion. The large-diameter pore portion extends from the surface of the anodic oxide film to a depth of 10 nm to 1000 nm. The small-diameter pore portion is connected to the bottom of the large-diameter pore portion and extends from the connection point to a depth of 20 nm to 2000 nm. The average diameter of the large-diameter aperture on the surface of the anodic oxide film is 15 nm to 100 nm. The average diameter of the small-diameter hole at the connecting position is less than 13 nm.

32. 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 31 into an image; and A process of supplying at least one of printing ink and dampening solution to a printing press to remove the image recording layer from the non-image area.

33. 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 31 into an image; The process of producing a lithographic printing plate by supplying at least one of printing ink and dampening solution to a printing press to remove the image recording layer (excluding the image portion); and The process of printing using the obtained lithographic printing plate.

Images