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

Abstract

The present invention provides an on-press developable lithographic printing plate precursor, and a method for producing a lithographic printing plate or a lithographic printing method using the on-press developable lithographic printing plate precursor. The on-press developable lithographic printing plate precursor comprises a support, an image recording layer, and an outermost layer in sequence. The image recording layer comprises an infrared absorber, an electron-donating polymerization initiator, and a polymerizable compound. The HOMO value of the infrared absorber and the HOMO value of the electron-donating polymerization initiator are 0.60 eV or less, and the outermost layer comprises a color-changing compound.

Description

Technical Field

[0001] The present invention relates to an on-press developing type planographic printing plate precursor, a method for producing a planographic printing plate and a planographic printing method. Background Art

[0002] Typically, a lithographic printing plate consists of an oleophilic image area that accepts ink during the printing process, and a hydrophilic non-image area that accepts fountain solution. Lithographic printing is a method that exploits the mutual repulsion between water and oil-based inks. This creates a difference in ink adhesion on the plate's surface, allowing the ink to adhere only to the image area. The ink is then transferred to a printed substrate, such as paper, to achieve printing.

[0003] To produce such lithographic printing plates, a lithographic printing plate precursor (PS plate) having an oleophilic photosensitive resin layer (image-recording layer) provided on a hydrophilic support has been widely used. Typically, a lithographic printing plate is obtained by exposing the lithographic printing plate precursor to an original image, such as a high-contrast film, leaving the image-recording layer as the image area. The remaining unnecessary image-recording layer is then removed by dissolving with an alkaline developer or organic solvent, exposing the hydrophilic support surface to form a non-image area.

[0004] Furthermore, as concern for the global environment increases, environmental problems associated with waste liquids associated with wet processes such as development processes have become apparent.

[0005] To address these environmental issues, efforts are underway to simplify and eliminate processing in development and platemaking. One simpler production method is "on-press development." Specifically, after exposing the lithographic printing plate precursor, it is directly loaded onto a printing press without undergoing conventional development. Unnecessary portions of the image-recording layer are removed during the initial stages of the normal printing process.

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

[0007] Examples of conventional lithographic printing plate precursors include those described in Patent Document 1 or Patent Document 2.

[0008] Patent Document 1 describes a negative-working lithographic printing plate precursor in which a top coat layer contains an infrared absorber having a thermally decomposable group.

[0009] Furthermore, Patent Document 2 describes a negative-working lithographic printing plate precursor in which a developer is contained in a top coat layer.

[0010] Patent Document 1: International Publication No. 2019 / 219560

[0011] Patent Document 2: U.S. Patent Application Publication No. 2010 / 0009130 Summary of the Invention

[0012] Technical issues to be solved by the invention

[0013] An object of one embodiment of the present invention is to provide an on-press developable lithographic printing plate precursor having excellent UV plate abrasion resistance.

[0014] 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-mentioned on-press development type lithographic printing plate precursor.

[0015] Means for solving technical problems

[0016] Means for solving the above-mentioned problems include the following.

[0017] <1> An on-press developable lithographic printing plate precursor comprises, in order, a support, an image recording layer, and an outermost layer, wherein the image recording layer comprises an infrared absorber, an electron-donating polymerization initiator, and a polymerizable compound, wherein the HOMO value of the infrared absorber minus the HOMO value of the electron-donating polymerization initiator is 0.60 eV or less, and the outermost layer comprises a color-changing compound.

[0018] <2> according to <1> In the on-press developable lithographic printing plate precursor, a value of HOMO of the infrared absorber minus HOMO of the electron-donating polymerization initiator is 0.50 eV or less.

[0019] <3> according to <1> or <2> In the on-press developable lithographic printing plate precursor, the HOMO of the infrared absorber is -5.30 eV or less.

[0020] <4> according to <1> to <3> The on-press development type lithographic printing plate precursor according to any one of the preceding claims, wherein the infrared absorber comprises a compound represented by Formula 1 below.

[0021] [Chemical Formula 1]

[0022]

[0023] In Formula 1, R1 and R2 each independently represent a hydrogen atom or an alkyl group, R1 and R2 may be linked to each other to form a ring, R3 to R6 each independently represent a hydrogen atom or an alkyl group, R7 and R8 each independently represent an alkyl group or an aryl group, Y1 and Y2 each independently represent an oxygen atom, a sulfur atom, -NR0- or a dialkylmethylene group, R0 represents a hydrogen atom, an alkyl group or an aryl group, Ar1 and Ar2 each independently represent a group forming a benzene ring or a naphthalene ring which may have a group represented by Formula 2 described later, and A1 represents -NR9R 10 , -X1-L1 or a group represented by formula 2 described later, R9 and R 10 Each independently represents an alkyl group, an aryl group, an alkoxycarbonyl group or an arylsulfonyl group, X1 represents an oxygen atom or a sulfur atom, L1 represents a hydrocarbon group, a heteroaryl group or a group whose bond to X1 is broken by heat or infrared exposure, Za represents a counter ion for neutralizing the charge, and at least one of Ar1 and Ar2 has a group represented by the following formula 2.

[0024] -X Type 2

[0025] In formula 2, X represents a halogen atom, -C(=O)-X2-R 11 、-C(=O)-NR 12 R 13 、-OC(=O)-R 14 、-CN、-SO2NR 15 R 16 or perfluoroalkyl, X2 represents a single bond or an oxygen atom, R 11 and R 14 Each independently represents an alkyl group or an aryl group, R 12 、R 13 、R 15 and R 16 Each independently represents a hydrogen atom, an alkyl group or an aryl group.

[0026] <5> according to <4> In the on-press developing type planographic printing plate precursor, at least one of Ar1 and Ar2 in Formula 1 has a bromine atom.

[0027] <6> according to <4> or <5> The on-press developing type planographic printing plate precursor, wherein X in the above formula 2 is a fluorine atom, a chlorine atom, a bromine atom or -C(=O)OR 17 .

[0028] In addition, R 17 represents an alkyl group or an aryl group.

[0029] <7> according to <1> to <6> The on-press developable lithographic printing plate precursor according to any one of the preceding claims, wherein the electron donating polymerization initiator has a HOMO greater than -5.90 eV.

[0030] <8> according to <1> to <7> The on-press developable lithographic printing plate precursor according to any one of the preceding claims, wherein the polymerizable compound comprises a difunctional or less polymerizable compound.

[0031] <9> according to <1> to <8> The on-press development type lithographic printing plate precursor described in any one of the preceding claims, wherein the image recording layer further comprises polyvinyl acetal.

[0032] <10> according to <1> to <9> The on-press developable lithographic printing plate precursor according to any one of the preceding claims, wherein the outermost layer comprises a hydrophobic polymer.

[0033] <11> according to <10> In the on-press developable lithographic printing plate precursor, the hydrophobic polymer is hydrophobic polymer particles.

[0034] <12> according to <1> to <11> The on-press developed lithographic printing plate precursor according to any one of the preceding claims, which is subjected to a treatment at 110 mJ / cm 2 When exposure is performed with infrared rays having a wavelength of 830 nm at an energy density of , a brightness change ΔL before and after the exposure is 2.0 or more.

[0035] <13> according to <1> to <12> The on-press developable lithographic printing plate precursor according to any one of the preceding claims, wherein the color-changing compound includes a compound that develops color upon exposure to infrared rays.

[0036] <14> according to <1> to <13> The on-press developable lithographic printing plate precursor according to any one of the preceding claims, wherein the color-changing compound includes a decomposable compound that decomposes upon exposure to infrared rays.

[0037] <15> according to <1> to <14> The on-press developable lithographic printing plate precursor according to any one of the preceding claims, wherein the color-changing compound is a cyanine pigment.

[0038] <16> according to <1> to <15> The on-press development type lithographic printing plate precursor according to any one of the preceding claims, wherein the color-changing compound is a compound represented by the following formula 1-1.

[0039] [Chemical Formula 2]

[0040]

[0041] In formula 1-1, R 1 represents a group represented by any of the following formulas 2-1 to 4-1, R 11 ~R 18 Each independently represents a hydrogen atom, a halogen atom, -R a 、-OR b 、-SR c or -NRd R e , R a ~R e Each independently represents a hydrocarbon group, A1, A2 and multiple R 11 ~R 18 They may be linked to form a monocyclic or polycyclic ring, A1 and A2 each independently represent an oxygen atom, a sulfur atom or a nitrogen atom, n 11 and n 12 Each independently represents an integer from 0 to 5, wherein n 11 and n 12 The total of n is 2 or more, 13 and n 14 Each independently represents 0 or 1, L represents an oxygen atom, a sulfur atom or -N(R 10 )-,R 10 represents a hydrogen atom, an alkyl group or an aryl group, and Za represents a counter ion for neutralizing the charge.

[0042] [Chemical Formula 3]

[0043]

[0044] In formula 2-1 to formula 4-1, R 20 、R 30 、R 41 and R 42 Each independently represents an alkyl group or an aryl group, Zb represents a counter ion for neutralizing the charge, and the wavy line represents a bonding site with the group represented by L in the above formula 1-1.

[0045] <17> according to <16> In the on-press developing type planographic printing plate precursor, the color-changing compound is a compound represented by the following formula 1-2.

[0046] [Chemical Formula 4]

[0047]

[0048] In formula 1-2, R 1 represents a group represented by any of the above formulas 2-1 to 4-1, R 19 ~R 22 Each independently represents 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 represents -R a , R a ~R e Each independently represents a hydrocarbon group, R19 With R 20 、R 21 With R 22 or R 23 With R 24 They can be linked to form a monocyclic or polycyclic ring, L represents an oxygen atom, a sulfur atom or -N(R 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 represents an alkyl group which may have a substituent, and Za represents a counter ion for neutralizing the charge.

[0049] <18> according to <16> or <17> In the on-press development type planographic printing plate precursor, the color-changing compound is a compound represented by any one of the following formulas 1-3 to 1-7.

[0050] [Chemical Formula 5]

[0051]

[0052] In formulas 1-3 to 1-7, R 1 represents a group represented by any of the above formulas 2-1 to 4-1, R 19 ~R 22 Each independently represents 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 represents a hydrogen atom, a halogen atom or -R a , R a ~R e Each independently represents a hydrocarbon group, R 19 With R 20 、R 21 With R 22 or R 25 With R 26 They can be linked to form a monocyclic or polycyclic ring, L represents an oxygen atom, a sulfur atom or -N(R 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 represents an alkyl group which may have a substituent, and Za represents a counter ion for neutralizing the charge.

[0053] <19> according to <17> or <18> The on-press developing type planographic printing plate precursor, wherein W in the above formulas 1-2 to 1-7 1 and W 2 Each independently represents an alkyl group having a substituent, and is a group having at least -OCH2CH2-, a sulfo group, a salt of a sulfo group, a carboxyl group, or a salt of a carboxyl group as the substituent.

[0054] <20> according to <1> to <19> The on-press developable lithographic printing plate precursor according to any one of the preceding claims, wherein the image recording layer further comprises an electron-accepting polymerization initiator.

[0055] <21> according to <20> In the on-press developing type planographic printing plate precursor, the electron-accepting polymerization initiator is an onium salt compound.

[0056] <22> according to <20> The on-press developing type planographic printing plate precursor, wherein the electron-accepting polymerization initiator comprises a compound represented by the following formula (II):

[0057] [Chemical Formula 6]

[0058]

[0059] In formula (I), X A Represents a halogen atom, R A Represents an aryl group.

[0060] <23> according to <20> to <22> The on-press developable lithographic printing plate precursor according to any one of the preceding claims, wherein a value of LUMO of the electron-accepting polymerization initiator minus LUMO of the infrared absorber is 0.45 eV or more.

[0061] <24> according to <1> to <23> The on-press developable lithographic printing plate precursor according to any one of the preceding claims, wherein the polymerizable compound comprises a hexafunctional or higher-functional polymerizable compound.

[0062] <25> according to <1> to <24> The on-press developable lithographic printing plate precursor according to any one of the preceding claims, wherein the polymerizable compound comprises a decafunctional or higher polymerizable compound.

[0063] <26> according to <1> to <25> The on-machine development type lithographic printing plate precursor described in any one of the preceding claims, wherein the support body comprises an aluminum plate and an anodized aluminum film disposed on the aluminum plate, the anodized aluminum film being located closer to the image recording layer than the aluminum plate, the anodized aluminum film having micropores extending in a depth direction from the surface on the image recording layer side, the average diameter of the micropores at the surface of the anodized aluminum film being greater than 10 nm and less than 100 nm.

[0064] <27> according to <26> The on-machine development type lithographic printing plate precursor, wherein the above-mentioned micropores are composed of a large-diameter pore portion and a small-diameter pore portion, the above-mentioned large-diameter pore portion extends from the surface of the above-mentioned anodized film to a depth of 10nm to 1,000nm, the above-mentioned small-diameter pore portion is connected to the bottom of the above-mentioned large-diameter pore portion and extends from the connected position to a depth of 20nm to 2,000nm, the average diameter of the above-mentioned large-diameter pore portion at the surface of the above-mentioned anodized film is 15nm to 100nm, and the average diameter of the above-mentioned small-diameter pore portion at the above-mentioned connected position is less than 13nm.

[0065] <28> A method for producing a lithographic printing plate, comprising: <1> to <27> The step of exposing the on-press developed lithographic printing plate precursor to an image shape; and supplying at least one selected from printing ink and fountain solution on the printing press to remove the image recording layer in the non-image area.

[0066] <29> A lithographic printing method comprising: <1> to <27> The process of exposing the on-press developed lithographic printing plate precursor to an image shape as described in any one of the above; the process of supplying at least one selected from printing ink and fountain solution on the printing press to remove the image recording layer of the non-image part to make a lithographic printing plate; and the process of printing using the obtained lithographic printing plate.

[0067] Effects of the Invention

[0068] According to one embodiment of the present invention, it is possible to provide an on-press developable lithographic printing plate precursor having excellent UV plate abrasion resistance.

[0069] Furthermore, according to another embodiment of the present invention, there can be provided a method for producing a lithographic printing plate or a lithographic printing method using the above-mentioned on-press development type lithographic printing plate precursor. BRIEF DESCRIPTION OF THE DRAWINGS

[0070] Figure 1 This is a schematic cross-sectional view of one embodiment of an aluminum support preferably used in the present invention.

[0071] Figure 2 This is a schematic cross-sectional view of one embodiment of an aluminum support having an anodic oxide film.

[0072] Figure 3 This is a graph showing an example of an alternating waveform current waveform used in an electrochemical roughening treatment in a method for producing an aluminum support having an anodic oxide film.

[0073] Figure 4 This is a side view showing an example of a radial type unit in an electrochemical roughening treatment using alternating current in a method for producing an aluminum support having an anodic oxide film.

[0074] Figure 5 This is a side view conceptually showing a step of brushing and graining used in a mechanical roughening treatment in a method for producing an aluminum support having an anodic oxide film.

[0075] Figure 6 This is a schematic diagram of an anodizing treatment apparatus used for anodizing treatment in a method for producing an aluminum support having an anodized film. DETAILED DESCRIPTION

[0076] The following describes the present invention in detail. The following description of the components is based on representative embodiments of the present invention, but the present invention is not limited to these embodiments.

[0077] In addition, in this specification, "to" which shows a numerical range is used to mean that the numerical values described before and after it are included as a lower limit and an upper limit.

[0078] In the numerical ranges described in stages throughout the present invention, the upper limit or lower limit described in one numerical range may be replaced by the upper limit or lower limit of another numerical range described in stages. Furthermore, in the numerical ranges described in the present invention, the upper limit or lower limit of the numerical range may be replaced by the value shown in the Examples.

[0079] Furthermore, in the notation of groups (atomic groups) in this specification, the notation not indicating substitution or unsubstituted includes not only groups without substitution but also groups with substitution. For example, "alkyl" includes not only alkyl groups without substitution (unsubstituted alkyl groups) but also alkyl groups with substitution (substituted alkyl groups).

[0080] In this specification, “(meth)acrylic acid” is a term used to include both acrylic acid and methacrylic acid, and “(meth)acryloyl” is a term used to include both acryloyl and methacryloyl.

[0081] Furthermore, the term "process" as used in this specification encompasses not only independent processes but also processes that cannot be clearly distinguished from other processes, as long as the intended purpose of the process is achieved. Furthermore, in the present invention, "mass %" and "weight %" have the same meaning, and "parts by mass" and "parts by weight" have the same meaning.

[0082] Unless otherwise specified, each component in the composition or each structural unit in the polymer in the present invention may be contained alone or in combination of two or more.

[0083] Moreover, in the present invention, when there are multiple substances or constituent units corresponding to the components in the composition or the constituent units in the polymer, the amount of each component in the composition or the constituent units in the polymer refers to the total amount of the corresponding multiple substances present in the composition or the corresponding multiple constituent units present in the polymer, unless otherwise specified.

[0084] Furthermore, in the present invention, a combination of two or more preferred embodiments is a more preferred embodiment.

[0085] Unless otherwise specified, the weight average molecular weight (Mw) and number average molecular weight (Mn) in the present invention are molecular weights calculated using polystyrene as a standard substance, using a gel permeation chromatography (GPC) analyzer using TSKgel GMHxL, TSKgel G4000HxL, or TSKgel G2000HxL (all trade names manufactured by TOSOH CORPORATION) columns, and using a differential refractometer with a solvent of THF (tetrahydrofuran).

[0086] In the present invention, the term "lithographic printing plate precursor" includes not only lithographic printing plate precursors but also discarded plate precursors. Furthermore, the term "lithographic printing plate" includes not only lithographic printing plates produced by exposure, development, and other operations as needed from lithographic printing plate precursors, but also discarded plates. Discarded plates do not necessarily require exposure and development. Furthermore, discarded plates refer to lithographic printing plate precursors used to mount on unused plate cylinders, for example, when printing a portion of a page in single or two-color format in color newspaper printing.

[0087] In the present invention, “excellent printing durability” means that the lithographic printing plate can print a large number of sheets. Hereinafter, the printing durability when UV ink is used as the ink for printing is also referred to as “UV printing durability”.

[0088] Hereinafter, the present invention will be described in detail.

[0089] (On-press developed lithographic printing plate precursor)

[0090] The on-press development type lithographic printing plate precursor involved in the present invention (also simply referred to as "lithographic printing plate precursor") has a support body, an image recording layer and an outermost layer in sequence, the above-mentioned image recording layer contains an infrared absorber, an electron-donating polymerization initiator and a polymerizable compound, the HOMO value of the above-mentioned infrared absorber - the HOMO value of the above-mentioned electron-donating polymerization initiator is less than 0.60 eV, and the above-mentioned outermost layer contains a color-changing compound.

[0091] Furthermore, the on-press developing type lithographic printing plate precursor according to the present invention is preferably a negative-working lithographic printing plate precursor.

[0092] As with the lithographic printing plate precursors described in previous patent documents 1 or 2, the present inventors have discovered that if an outermost layer containing a color-changing compound is provided in the lithographic printing plate precursor, the outermost layer absorbs the exposure energy during infrared exposure, and the amount of light reaching the image recording layer is reduced, resulting in a problem of plate wear being easily caused, especially when ultraviolet curing ink (UV ink) is used.

[0093] As a result of intensive research, the present inventors have found that the above-mentioned structure can provide an on-press developable lithographic printing plate precursor having excellent plate wear resistance (also referred to as "UV plate wear resistance") even when using UV ink.

[0094] The detailed mechanism by which the above-mentioned effects are obtained is not clear, but is presumed as follows.

[0095] It is inferred that since the image recording layer contains an infrared absorber, an electron donating polymerization initiator and a polymerizable compound, the HOMO value of the above-mentioned infrared absorber - the HOMO value of the above-mentioned electron donating polymerization initiator is 0.60 eV or less, electron donation from the electron donating polymerization initiator to the infrared absorber is likely to occur, and polymerization initiating species are likely to be generated, thereby fully curing the image recording layer in the exposed part and improving the strength. Even when UV ink is used, the plate wear inhibition (also called "UV plate wear inhibition") is excellent.

[0096] Plate wear refers to a phenomenon in which the image area of a lithographic printing plate becomes thinner and partially loses ink. This serves as an indicator: the greater the number of prints required before plate wear occurs, the less likely it is to occur.

[0097] Hereinafter, the details of each component of the lithographic printing plate precursor according to the present invention will be described.

[0098] <Image Recording Layer>

[0099] The lithographic printing plate precursor involved in the present invention has a support, an image recording layer and an outermost layer in sequence, and the above-mentioned image recording layer contains an infrared absorber, an electron-donating polymerization initiator and a polymerizable compound, and the value of the HOMO of the above-mentioned infrared absorber minus the HOMO of the above-mentioned electron-donating polymerization initiator is less than 0.60 eV.

[0100] The image recording layer used in the present invention is preferably a negative image recording layer, more preferably a water-soluble or water-dispersible negative image recording layer.

[0101] In the lithographic printing plate precursor according to the present invention, it is preferred that the unexposed portion of the image recording layer be removable by at least one of a fountain solution and a printing ink from the viewpoint of on-press developability.

[0102] [Relationship between infrared absorbers and electron-donating polymerization initiators]

[0103] In the image recording layer of the present invention, the value of HOMO of the above-mentioned infrared absorber - HOMO of the above-mentioned electron-donating polymerization initiator is 0.60 eV or less. From the viewpoint of UV plate abrasion inhibition, improved sensitivity and printing durability, it is preferably 0.55 eV or less, more preferably 0.50 eV or less, and particularly preferably 0.50 eV to -0.10 eV.

[0104] In addition, a negative value means that the HOMO of the electron donating polymerization initiator is higher than the HOMO of the infrared absorber.

[0105] In the present invention, the MO (molecular orbital) energies of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) are calculated by the following method.

[0106] First, free counterions in the compound being calculated are excluded from the calculation. For example, in cationic electron-accepting polymerization initiators and cationic infrared absorbers, counter anions are excluded from the calculation, while in anionic electron-donating polymerization initiators, counter cations are excluded from the calculation. Free, as used herein, means that the compound being calculated is not covalently bonded to its counterion.

[0107] The structure optimization was performed using the quantum chemical calculation software Gaussian 16 under DFT (B3LYP / 6-31G(d)).

[0108] MO energy calculations were performed using the quantum chemical calculation software Gaussian 16 under DFT (B3LYP / 6-31+G(d, p) / PCM (solvent = methanol)) using the optimal structure obtained by the above-mentioned structural optimization. Furthermore, for compounds containing iodine, calculations were performed under DFT (B3LYP / DGD ZVP / PCM (solvent = methanol)) conditions.

[0109] The optimal structure here refers to the structure with the most stable total energy obtained by DFT calculation. The optimal structure is found by repeating the structural optimization as needed.

[0110] The MO energy Ebare (unit: Hartree) obtained by the above MO energy calculation is converted into Escaled (unit: eV) used as the value of HOMO and LUMO in the present invention according to the following formula.

[0111] [Calculation formula for HOMO] Escaled = 0.823168 × 27.2114 × Ebare - 1.07634

[0112] [Calculation formula for LUMO] Escaled = 0.820139 × 27.2114 × Ebare - 1.086039

[0113] In addition, 27.2114 is a coefficient used only for converting Hartree values to eV, 0.823168 and -1.07634 used in calculating HOMO, and 0.820139 and -1.086039 used in calculating LUMO are adjustment coefficients, and are determined so that the calculated HOMO and LUMO values of the compound to be calculated match the measured values.

[0114] Hereinafter, the details of each component contained in the image recording layer will be described.

[0115] 〔Infrared absorber〕

[0116] The image recording layer in the present invention contains an infrared absorber.

[0117] The infrared absorber is not particularly limited, and examples thereof include pigments and dyes.

[0118] As dyes that can be used as infrared absorbers, commercially available dyes and known dyes described in documents such as "Dye Handbook" (edited by The Society of Synthetic Organic Chemistry, Japan, published in 1977) 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, quinoneimine dyes, methine dyes, cyanine dyes, squarylium dyes, pyrylium salts, and metal thiol complexes can be mentioned.

[0119] Preferred dyes among these dyes include cyanine dyes, squarylium dyes, pyrylium salts, nickel thiol complexes, and indocyanine dyes. More preferred dyes include cyanine dyes and indocyanine dyes. Among them, cyanine dyes are particularly preferred.

[0120] As the above-mentioned infrared absorber, preferably a cationic polymethine dye having an oxygen atom, a nitrogen atom or a halogen atom at the meta position. As the cationic polymethine dye, preferably cyanine dye, pyrylium dye, thiopyridinium dye, azulene dye etc. are mentioned. From the viewpoint of the ease of acquisition, the solvent solubility during the introduction reaction etc., cyanine dye is preferably used.

[0121] Specific examples of cyanine pigments include compounds described in paragraphs 0017 to 0019 of Japanese Patent Application Laid-Open No. 2001-133969, paragraphs 0016 to 0021 of Japanese Patent Application Laid-Open No. 2002-023360, and paragraphs 0012 to 0037 of Japanese Patent Application Laid-Open No. 2002-040638. Preferably, the compounds described in paragraphs 0034 to 0041 of Japanese Patent Application Laid-Open No. 2002-278057 and paragraphs 0080 to 0086 of Japanese Patent Application Laid-Open No. 2008-195018 are mentioned. Particularly preferably, the compounds described in paragraphs 0035 to 0043 of Japanese Patent Application Laid-Open No. 2007-90850 and the compounds described in paragraphs 0105 to 0113 of Japanese Patent Application Laid-Open No. 2012-206495 are mentioned.

[0122] Furthermore, compounds described in paragraphs 0008 to 0009 of JP-A-5005 and paragraphs 0022 to 0025 of JP-A-2001-222101 can also be preferably used. As pigments, compounds described in paragraphs 0072 to 0076 of JP-A-2008-195018 are preferred.

[0123] Furthermore, the infrared absorber preferably contains a compound represented by Formula 1 below.

[0124] [Chemical Formula 7]

[0125]

[0126] In Formula 1, R1 and R2 each independently represent a hydrogen atom or an alkyl group, R1 and R2 may be linked to each other to form a ring, R3 to R6 each independently represent a hydrogen atom or an alkyl group, R7 and R8 each independently represent an alkyl group or an aryl group, Y1 and Y2 each independently represent an oxygen atom, a sulfur atom, -NR0- or a dialkylmethylene group, R0 represents a hydrogen atom, an alkyl group or an aryl group, Ar1 and Ar2 each independently represent a group forming a benzene ring or a naphthalene ring which may have a group represented by Formula 2 described later, and A1 represents -NR9R 10 , -X1-L1 or a group represented by formula 2 described later, R9 and R 10Each independently represents an alkyl group, an aryl group, an alkoxycarbonyl group or an arylsulfonyl group, X1 represents an oxygen atom or a sulfur atom, L1 represents a hydrocarbon group, a heteroaryl group or a group whose bond to X1 is broken by heat or infrared exposure, Za represents a counter ion for neutralizing the charge, and at least one of Ar1 and Ar2 has a group represented by the following formula 2.

[0127] -X Type 2

[0128] In formula 2, X represents a halogen atom, -C(=O)-X2-R 11 、-C(=O)-NR 12 R 13 、-OC(=O)-R 14 、-CN、-SO2NR 15 R 16 or perfluoroalkyl, X2 represents a single bond or an oxygen atom, R 11 and R 14 Each independently represents an alkyl group or an aryl group, R 12 、R 13 、R 15 and R 16 Each independently represents a hydrogen atom, an alkyl group or an aryl group.

[0129] Ar1 and Ar2 each independently represent a group forming a benzene ring or a naphthalene ring. The benzene ring and the naphthalene ring may have a substituent other than -X. Examples of the substituent include an alkyl group, an alkoxy group, an aryloxy group, an amino group, an alkylthio group, an arylthio group, a carboxyl group, a carboxylate group, a sulfo group, a sulfonate group, and combinations thereof, but an alkyl group is preferred.

[0130] Furthermore, in Formula 1, at least one of Ar1 and Ar2 has a group represented by the above-mentioned Formula 2. From the viewpoint of printing durability, visual recognition, and the temporal storage stability (temporal stability) of the coating liquid for forming the image recording layer, it is preferred that both Ar1 and Ar2 have a group represented by the above-mentioned Formula 2.

[0131] In formula 2, X represents a halogen atom, -C(=O)-X2-R 11 、-C(=O)-NR 12 R 13 、-OC(=O)-R 14 、-CN、-SO2NR 15 R 16 or perfluoroalkyl, preferably a halogen atom, -C(=O)-X2-R 11 、-C(=O)-NR 12 R 13 、-OC(=O)-R 14, CN or -SO2NR 15 R 16 , more preferably a halogen atom, -C(=O)-OR 11 、-C(=O)-NR 12 R 13 or -OC(=O)-R 14 , more preferably a halogen atom, -C(=O)-OR 11 or -OC(=O)-R 14 , more preferably a fluorine atom, a chlorine atom, a bromine atom or -C(=O)OR 17 , particularly preferably a chlorine atom or a bromine atom.

[0132] Furthermore, X substituted by Ar1, X substituted by Ar2, and X substituted by A1 may be the same group or different groups. Furthermore, from the viewpoints of printing durability, visual recognition, and temporal stability, X substituted by Ar1 and X substituted by Ar2 are preferably the same group.

[0133] X2 represents a single bond or an oxygen atom, preferably an oxygen atom.

[0134] R 11 and R 14 Each independently represents an alkyl group or an aryl group, preferably an alkyl group having 1 to 12 carbon atoms or an aryl group having 6 to 12 carbon atoms, and more preferably an alkyl group having 1 to 12 carbon atoms.

[0135] R 12 、R 13 、R 15 and R 16 Each independently represents a hydrogen atom, an alkyl group or an aryl group, preferably a hydrogen atom, an alkyl group having 1 to 12 carbon atoms or an aryl group having 6 to 12 carbon atoms, more preferably a hydrogen atom or an alkyl group having 1 to 12 carbon atoms, further preferably an alkyl group having 1 to 12 carbon atoms.

[0136] R 17 represents an alkyl group or an aryl group, preferably an alkyl group having 1 to 12 carbon atoms or an aryl group having 6 to 12 carbon atoms, more preferably an alkyl group having 1 to 12 carbon atoms.

[0137] A1 means -NR9R 10 , -X1-L1 or -X, preferably -NR9R from the viewpoint of printing durability, visual recognition and temporal stability 10 or -X1-L1, more preferably -NR 18 R 19 、-SR 20 .

[0138] Furthermore, from the viewpoint of UV plate abrasion inhibition and UV printing durability, A1 is preferably -X, more preferably a halogen atom, further preferably a chlorine atom or a bromine atom, and particularly preferably a chlorine atom.

[0139] R9 and R 10 Each independently represents an alkyl group, an aryl group, an alkoxycarbonyl group or an arylsulfonyl group, preferably an alkyl group having 1 to 12 carbon atoms or an aryl group having 6 to 12 carbon atoms, more preferably an alkyl group having 1 to 12 carbon atoms.

[0140] X1 represents an oxygen atom or a sulfur atom. When L1 is a hydrocarbon group or a heteroaryl group, it is preferably a sulfur atom. L1 is preferably a group whose bond with X1 is cleaved by heat or infrared exposure.

[0141] L1 represents a hydrocarbon group, a heteroaryl group, or a group whose bond to X1 is cleaved by heat or infrared exposure. From the viewpoint of printing durability, a hydrocarbon group or a heteroaryl group is preferred, an aryl group or a heteroaryl group is more preferred, and a heteroaryl group is further preferred.

[0142] Furthermore, from the viewpoint of visibility and suppression of fading over time, L1 is preferably a group whose bond with X1 is cleaved by heat or infrared exposure.

[0143] The group whose bond to X1 is cleaved by heat or infrared exposure will be described later.

[0144] R 18 and R 19 Each independently represents an aryl group, preferably an aryl group having 6 to 20 carbon atoms, and more preferably a phenyl group.

[0145] R 20 represents a hydrocarbon group or a heteroaryl group, preferably an aryl group or a heteroaryl group, more preferably a heteroaryl group.

[0146] As L1 and R 20 The heteroaryl group in is preferably the following groups.

[0147] [Chemical Formula 8]

[0148]

[0149] R1~R 10 The alkyl group in R0 is preferably an alkyl group having 1 to 30 carbon atoms, more preferably an alkyl group having 1 to 15 carbon atoms, and further preferably an alkyl group having 1 to 10 carbon atoms. The alkyl group may be linear, branched, or have a ring structure.

[0150] Specific examples include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, hexadecyl, octadecyl, eicosyl, isopropyl, isobutyl, sec-butyl, tert-butyl, isopentyl, neopentyl, 1-methylbutyl, isohexyl, 2-ethylhexyl, 2-methylhexyl, cyclohexyl, cyclopentyl, and 2-norbornyl.

[0151] Among these alkyl groups, a methyl group, an ethyl group, a propyl group or a butyl group is particularly preferred.

[0152] Furthermore, the alkyl group may have a substituent. 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 combinations thereof.

[0153] As R9, R 10 、R 18 、R 19 The aryl group in R0 is preferably an aryl group having 6 to 30 carbon atoms, more preferably an aryl group having 6 to 20 carbon atoms, and further preferably an aryl group having 6 to 12 carbon atoms.

[0154] Furthermore, the aryl group may have a substituent. Examples of the substituent include an alkyl group, 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 combinations thereof.

[0155] Specific examples of the aryl group include a phenyl group, a naphthyl group, a p-tolyl group, a p-chlorophenyl group, a p-fluorophenyl group, a p-methoxyphenyl group, a p-dimethylaminophenyl group, a p-methylthiophenyl group, and a p-phenylthiophenyl group.

[0156] Among these aryl groups, phenyl, p-methoxyphenyl, p-dimethylaminophenyl or naphthyl is preferred.

[0157] R1 and R2 are preferably linked to form a ring.

[0158] When R1 and R2 are linked to form a ring, the number of ring members is preferably 5 or 6, more preferably 6. Furthermore, the ring formed by linking R1 and R2 is preferably a hydrocarbon ring which may have an ethylenically unsaturated bond.

[0159] Y1 and Y2 each independently represent an oxygen atom, a sulfur atom, -NR0- or a dialkylmethylene group, preferably -NR0- or a dialkylmethylene group, more preferably a dialkylmethylene group.

[0160] R0 represents a hydrogen atom, an alkyl group or an aryl group, and is preferably an alkyl group.

[0161] R7 and R8 are preferably the same group.

[0162] Furthermore, R7 and R8 are each independently preferably a linear alkyl group or an alkyl group having a sulfonate group at the terminal, and more preferably a methyl group, an ethyl group, or a butyl group having a sulfonate group at the terminal.

[0163] Furthermore, the counter cation of the sulfonate group may be a cation on the nitrogen atom in Formula 1, or an alkali metal cation or an alkaline earth metal cation.

[0164] Furthermore, from the viewpoint of improving the water solubility of the compound represented by Formula 1, R7 and R8 are each independently preferably an alkyl group having an anionic structure, more preferably an alkyl group having a carboxylate group or a sulfonate group, and even more preferably an alkyl group having a sulfonate group at the terminal.

[0165] Furthermore, from the perspective of lengthening the maximum absorption wavelength of the compound represented by Formula 1 and improving visual recognition and printing durability in lithographic printing plates, R7 and R8 are each independently preferably an alkyl group having an aromatic ring, more preferably an alkyl group having an aromatic ring at the end, and particularly preferably 2-phenylethyl, 2-naphthylethyl or 2-(9-anthryl)ethyl.

[0166] R3 to R6 each independently represent a hydrogen atom or an alkyl group, and preferably a hydrogen atom.

[0167] Furthermore, from the viewpoint of visual recognition, UV plate wear inhibition and UV printing durability, the compound represented by Formula 1 preferably has one or more halogen atoms, more preferably at least one selected from A1, Ar1 and Ar2 has one or more halogen atoms, and particularly preferably A1, Ar1 and Ar2 each have one or more halogen atoms.

[0168] Moreover, from the viewpoint of visual recognition, UV plate wear inhibition and UV printing durability, the compound represented by Formula 1 more preferably has 2 or more halogen atoms, further preferably has 3 or more halogen atoms, and particularly preferably has 3 or more and 6 or less halogen atoms.

[0169] Furthermore, as the halogen atom, preferably a chlorine atom or a bromine atom is mentioned.

[0170] Moreover, from the viewpoint of stability over time, UV plate wear inhibition, GLV suitability and UV printing durability, the compound represented by Formula 1 preferably has a halogen atom in at least one of Ar1 and Ar2, more preferably has a chlorine atom or a bromine atom in at least one of Ar1 and Ar2, further preferably has a bromine atom in at least one of Ar1 and Ar2, and particularly preferably has a bromine atom in both Ar1 and Ar2.

[0171] Za represents a counter ion for neutralizing the charge. When representing an anion species, examples thereof include sulfonate ion, carboxylate ion, tetrafluoroborate ion, hexafluorophosphate ion, perchlorate ion, sulfonamide anion, sulfonylimide anion, etc. When representing a cation species, alkali metal ion, alkaline earth metal ion, ammonium ion, pyridinium ion, or sulfonium ion is preferred, sodium ion, potassium ion, ammonium ion, pyridinium ion, or sulfonium ion is more preferred, sodium ion, potassium ion, or ammonium ion is further preferred, and sodium ion, potassium ion, or trialkylammonium ion is particularly preferred.

[0172] Among them, from the viewpoint of printing durability and visual recognition, Za is preferably an organic anion containing a carbon atom, more preferably a sulfonate ion, carboxylate ion, sulfonamide anion or sulfonimide anion, further preferably a sulfonamide anion or sulfonimide anion, and particularly preferably a sulfonimide anion.

[0173] R1 to R8, R0, A1, Ar1, Ar2, Y1 and Y2 can have an anionic structure or a cationic structure. If R1 to R8, R0, A1, Ar1, Ar2, Y1 and Y2 are all electrically neutral groups, Za is a monovalent counter anion. However, for example, when R1 to R8, R0, A1, Ar1, Ar2, Y1 and Y2 have two or more anionic structures, Za can also become a counter cation.

[0174] Furthermore, in Formula 1, if the parts other than Za are electrically neutral, Za may be absent.

[0175] As the sulfonamide anion, an arylsulfonamide anion is preferred.

[0176] Furthermore, as the sulfonyl imide anion, a bisarylsulfonyl imide anion is preferred.

[0177] Specific examples of the sulfonamide anion or the sulfonimide anion are shown below, but the present invention is not limited thereto. In the following specific examples, Ph represents a phenyl group, Me represents a methyl group, and Et represents an ethyl group.

[0178] [Chemical Formula 9]

[0179]

[0180] From the viewpoint of visual recognition, the group whose bond to X1 is cleaved by heat or infrared exposure is preferably a group represented by any of the following formulae (1-1) to (1-7), and more preferably a group represented by any of the following formulae (1-1) to (1-3).

[0181] [Chemical Formula 10]

[0182]

[0183] In formulas (1-1) to (1-7), ● represents a bonding site with X1 in formula 1, and R 10 Each independently represents a hydrogen atom, an alkyl group, an alkenyl group, an aryl group, -OR 14 、-NR 15 R 16 or -SR 17 , R 11 Each independently represents a hydrogen atom, an alkyl group or an aryl group, R 12 Represents aryl, -OR 14 、-NR 15 R 16 、-SR 17 、-C(=O)R 18 、-OC(=O)R 18 or halogen atoms, R 13 represents an aryl group, an alkenyl group, an alkoxy group or an onium group, R 14 ~R 17 Each independently represents a hydrogen atom, an alkyl group or an aryl group, R 18 Each independently represents an alkyl group, an aryl group, -OR 14 、-NR 15 R 16 or -SR 17 , Z 1 Represents a counter ion that neutralizes the charge.

[0184] R 10 、R 11 and R 14 ~R 18 When it is an alkyl group, the preferred embodiment is the same as R 2 ~R 9 and R 0 The preferred manner of the alkyl group in is the same.

[0185] R 10 and R 13 The number of carbon atoms of the alkenyl group in is preferably 1-30, more preferably 1-15, and even more preferably 1-10.

[0186] R 10 ~R 18 When it is an aryl group, the preferred embodiment is the same as R 0 The preferred manner for the aryl group in is the same.

[0187] From the perspective of visual recognition, R in formula (1-1) 10 Preferably, alkyl, alkenyl, aryl, -OR 14 、-NR 15 R 16 or -SR 17 , more preferably alkyl, -OR 14、-NR 15 R 16 or -SR 17 , further preferably alkyl or -OR 14 , especially preferably -OR 14 .

[0188] Furthermore, in formula (1-1), R 10 In the case of an alkyl group, the alkyl group is preferably an alkyl group having an arylthio group or an alkoxycarbonyl group at the α-position.

[0189] In formula (1-1), R 10 For-OR 14 In the case of R 14 An alkyl group is preferred, an alkyl group having 1 to 8 carbon atoms is more preferred, an isopropyl group or a tert-butyl group is further preferred, and a tert-butyl group is particularly preferred.

[0190] From the perspective of visual recognition, R in formula (1-2) 11 Preferred is a hydrogen atom.

[0191] Furthermore, from the perspective of visual recognition, R in formula (1-2) 12 Preferably -C(=O)OR 14 、-OC(=O)OR 14 or a halogen atom, more preferably -C(=O)OR 14 OR-OC(=O)OR 14 In formula (1-2), R 12 -C(=O)OR 14 OR-OC(=O)OR 14 In the case of R 14 An alkyl group is preferred.

[0192] From the perspective of visual recognition, R in formula (1-3) 11 Each of R is independently preferably a hydrogen atom or an alkyl group, and at least one R in formula (1-3) 11 More preferably, it is an alkyl group.

[0193] And, R 11 The alkyl group in is preferably an alkyl group having 1 to 10 carbon atoms, more preferably an alkyl group having 3 to 10 carbon atoms.

[0194] Moreover, R 11 The alkyl group in is preferably a branched alkyl group or a cycloalkyl group, more preferably a secondary alkyl group or a tertiary alkyl group, or a cycloalkyl group, and further preferably isopropyl, cyclopentyl, cyclohexyl or tert-butyl.

[0195] Furthermore, from the perspective of visual recognition, R in formula (1-3) 13It is preferably an aryl group, an alkoxy group or an onium group, more preferably a p-dimethylaminophenyl group or a pyridinium group, and further preferably a pyridinium group.

[0196] As R 13 The onium group in the formula (I) may be a pyridinium group, an ammonium group, a sulfonium group, or the like. The onium group may have a substituent. Examples of the substituent include an alkyl group, an alkoxy group, an aryloxy group, an amino group, an alkylthio group, an arylthio group, a halogen atom, a carboxyl group, a sulfo group, an alkoxycarbonyl group, an aryloxycarbonyl group, and combinations thereof. An alkyl group, an aryl group, and combinations thereof are preferred.

[0197] Among them, a pyridinium group is preferred, and an N-alkyl-3-pyridinium group, an N-benzyl-3-pyridinium group, an N-(alkoxypolyalkyleneoxyalkyl)-3-pyridinium group, an N-alkoxycarbonylmethyl-3-pyridinium group, an N-alkyl-4-pyridinium group, an N-benzyl-4-pyridinium group, an N-(alkoxypolyalkyleneoxyalkyl)-4-pyridinium group, an N-alkoxycarbonylmethyl-4-pyridinium group, -pyridinium or N-alkyl-3,5-dimethyl-4-pyridinium, further preferably N-alkyl-3-pyridinium or N-alkyl-4-pyridinium, especially preferably N-methyl-3-pyridinium, N-octyl-3-pyridinium, N-methyl-4-pyridinium or N-octyl-4-pyridinium, most preferably N-octyl-3-pyridinium or N-octyl-4-pyridinium.

[0198] And, in R 13 In the case of a pyridinium group, examples of the counter anion include sulfonate ion, carboxylate ion, tetrafluoroborate ion, hexafluorophosphate ion, p-toluenesulfonate ion, and perchlorate ion, with p-toluenesulfonate ion and hexafluorophosphate ion being preferred.

[0199] From the perspective of visual recognition, R in formula (1-4) 10 Preferably, an alkyl group or an aryl group, more preferably 2 R 10 One of the groups is an alkyl group and the other is an aryl group.

[0200] From the perspective of visual recognition, R in formula (1-5) 10 It is preferably an alkyl group or an aryl group, more preferably an aryl group, and still more preferably a p-methylphenyl group.

[0201] From the perspective of visual recognition, R in formula (1-6) 10 Each independently is preferably an alkyl group or an aryl group, more preferably a methyl group or a phenyl group.

[0202] From the perspective of visual recognition, Z in formula (1-7) 1 , any counter ion that neutralizes the charge may be used, and the compound as a whole may be included in the above-mentioned Za.

[0203] Z 1 Preferred are sulfonate ions, carboxylate ions, tetrafluoroborate ions, hexafluorophosphate ions, p-toluenesulfonate ions, or perchlorate ions, and more preferred are p-toluenesulfonate ions or hexafluorophosphate ions.

[0204] Furthermore, the group whose bond to X1 is cleaved by heat or infrared exposure is particularly preferably a group represented by formula (1-8).

[0205] [Chemical Formula 11]

[0206]

[0207] In formula (1-8), ● represents the bonding site with X1 in formula 1, R 19 and R 20 Each independently represents an alkyl group, and Za' represents a counter ion for neutralizing the charge.

[0208] The pyridinium ring in formula (1-8) and the ring containing R 20 The bonding position of the hydrocarbon group is preferably at the 3-position or 4-position of the pyridinium ring, and more preferably at the 4-position of the pyridinium ring.

[0209] R 19 and R 20 The alkyl group in the group may be linear, branched, or have a ring structure.

[0210] Furthermore, the alkyl group may have a substituent, and preferred examples of the substituent include an alkoxy group and a terminal alkoxypolyalkyleneoxy group.

[0211] R 19 An alkyl group having 1 to 12 carbon atoms is preferred, a linear alkyl group having 1 to 12 carbon atoms is more preferred, a linear alkyl group having 1 to 8 carbon atoms is further preferred, and a methyl group or an n-octyl group is particularly preferred.

[0212] R 20 An alkyl group having 1 to 8 carbon atoms is preferred, a branched alkyl group having 3 to 8 carbon atoms is more preferred, an isopropyl group or a tert-butyl group is further preferred, and an isopropyl group is particularly preferred.

[0213] Za' may be any counter ion that neutralizes the charge, and the compound as a whole may be included in the above-mentioned Za.

[0214] Za' 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 p-toluenesulfonate ion or a hexafluorophosphate ion.

[0215] Preferred specific examples of the compound represented by Formula 1 include core structures A-1 to A-54, counter anions B-1 to B-10, and counter cations C-1 to C-3, but the present invention is not limited thereto. Specific examples of the compound represented by Formula 1 include compounds comprising one each of the core structures A-1 to A-9, A-11 to A-20, and A-22 to A-54 and counter anions B-1 to B-10, and compounds comprising one each of the core structures A-10 and A-21 and counter cations C-1 to C-3.

[0216] [Chemical Formula 12]

[0217]

[0218] [Chemical Formula 13]

[0219]

[0220] [Chemical Formula 14]

[0221]

[0222] [Chemical Formula 15]

[0223]

[0224] [Chemical Formula 16]

[0225]

[0226] [Chemical Formula 17]

[0227]

[0228] [Chemical Formula 18]

[0229]

[0230] [Chemical Formula 19]

[0231]

[0232] [Chemical Formula 20]

[0233]

[0234] [Chemical Formula 21]

[0235]

[0236] [Chemical Formula 22]

[0237]

[0238] [Chemical Formula 23]

[0239]

[0240] Furthermore, as the compound represented by Formula 1, the following compounds can also be preferably used. - represents the p-toluenesulfonate anion.

[0241] [Chemical Formula 24]

[0242]

[0243] [Chemical Formula 25]

[0244]

[0245] [Chemical Formula 26]

[0246]

[0247] The method for producing the compound represented by Formula 1 is not particularly limited and can be produced by referring to known methods for producing cyanine pigments. In addition, the method described in International Publication No. 2016 / 027886 can also be preferably used.

[0248] From the viewpoint of printing 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.

[0249] The infrared absorbent may be used alone or in combination of two or more.

[0250] Furthermore, as the infrared absorber, a pigment and a dye may be used in combination.

[0251] The content of the infrared absorber is preferably 0.1% by mass to 10.0% by mass, more preferably 0.5% by mass to 5.0% by mass, relative to the total mass of the image recording layer.

[0252] 〔Electron-donating polymerization initiator (polymerization aid)〕

[0253] The image recording layer in the present invention contains an electron donating polymerization initiator (also referred to as a "polymerization aid") as a polymerization initiator.

[0254] The electron-donating polymerization initiator is a compound that generates polymerization initiating species such as free radicals by donating an electron to an orbital from which an electron of the infrared absorber is released through intermolecular electron transfer when the electron of the infrared absorber is excited or moves within the molecule by infrared exposure.

[0255] As the electron donating polymerization initiator, an electron donating radical polymerization initiator is preferred.

[0256] From the viewpoint of printing durability, the image recording layer preferably contains a borate compound.

[0257] As the borate compound, from the viewpoint of visibility and color development, a tetraaryl borate compound or a monoalkyltriaryl borate compound is preferred, and a tetraaryl borate compound is more preferred.

[0258] Furthermore, from the viewpoint of UV plate abrasion inhibition, printing durability, and visual recognition, the borate compound is preferably a tetraaryl borate compound having one or more electron-donating groups, and more preferably a tetraaryl borate compound having one electron-donating group in each aryl group.

[0259] The electron-donating group is preferably an alkyl group or an alkoxy group, and more preferably an alkoxy group, from the viewpoint of UV plate abrasion inhibition, printing durability, and visibility.

[0260] The counter cation of the borate compound is not particularly limited, but is preferably an alkali metal ion or a tetraalkylammonium ion, and more preferably a sodium ion, a potassium ion, or a tetrabutylammonium ion.

[0261] Furthermore, as the counter cation of the borate compound, in the infrared absorber described in this specification, a cationic polymethine dye may be used. For example, as the counter cation of the cyanine dye, the above-mentioned borate compound may be used.

[0262] Specifically, as the borate compound, preferably, sodium tetraphenylborate is used.

[0263] Preferred specific examples of electron-donating polymerization initiators B-1 to B-9 are shown below, but the present invention is not limited thereto. In the following chemical formula, Ph represents a phenyl group, and Bu represents an n-butyl group.

[0264] [Chemical Formula 27]

[0265]

[0266] Furthermore, from the perspective of improving sensitivity and preventing plate wear, the highest occupied molecular orbital (HOMO) of the electron-donating polymerization initiator is preferably above -6.00 eV, more preferably above -5.95 eV, further preferably above -5.93 eV, and particularly preferably above -5.90 eV.

[0267] Furthermore, the upper limit is preferably -5.00 eV or less, and more preferably -5.40 eV or less.

[0268] The electron donating polymerization initiator may be used alone or in combination of two or more.

[0269] The content of the electron-donating polymerization initiator is preferably 0.01 to 30% by mass, more preferably 0.05 to 25% by mass, and even more preferably 0.1 to 20% by mass, relative to the total mass of the image recording layer, from the viewpoint of sensitivity and printing durability.

[0270] Furthermore, from the viewpoint of UV plate abrasion inhibition and UV printing durability, the content of the electron-donating polymerization initiator in the image recording layer is preferably greater 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.

[0271] In the present invention, the polymerization initiator may be a compound in which an electron-donating polymerization initiator and an electron-accepting polymerization initiator form a counter salt.

[0272] For example, in the present invention, a compound in which an anion in an electron-donating polymerization initiator and a cation in an 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.

[0273] Preferred embodiments of the anion in the electron-donating polymerization initiator and the cation in the electron-accepting polymerization initiator are the same as the preferred embodiments of the anion in the electron-donating polymerization initiator and the cation in the electron-accepting polymerization initiator described above.

[0274] When the image recording layer contains an anion as an electron donating polymerization initiator and a cation as an electron accepting polymerization initiator (ie, contains a compound forming the counter salt), the image recording layer contains the electron accepting polymerization initiator and the electron donating polymerization initiator.

[0275] Furthermore, a compound in which an electron-donating polymerization initiator and an electron-accepting polymerization initiator form a counter salt can be used as either the electron-donating polymerization initiator or the electron-accepting polymerization initiator.

[0276] Furthermore, a compound in which an electron-donating polymerization initiator and an electron-accepting polymerization initiator form a counter salt may be used in combination with the electron-donating polymerization initiator described above, or may be used in combination with the electron-accepting polymerization initiator described above.

[0277] 〔Electron-accepting polymerization initiator〕

[0278] The image recording layer in the present invention preferably further contains an electron-accepting polymerization initiator as a polymerization initiator.

[0279] The electron-accepting polymerization initiator is a compound that, when electrons of an infrared absorber are excited by infrared ray exposure, accepts an electron through intermolecular electron transfer to generate a polymerization initiating species such as a radical.

[0280] The electron-accepting polymerization initiator is a compound that generates polymerization initiating species such as radicals or cations by energy from light, heat, or both. Known thermal polymerization initiators, compounds having bonds with low bond dissociation energy, photopolymerization initiators, and the like can be appropriately selected and used.

[0281] As the electron-accepting polymerization initiator, a radical polymerization initiator is preferred, and an onium salt compound is more preferred.

[0282] Furthermore, as the electron-accepting polymerization initiator, an infrared-sensitive polymerization initiator is preferable.

[0283] Furthermore, from the viewpoint of UV plate abrasion suppression, sensitivity improvement, and UV printing durability, the electron-accepting polymerization initiator is preferably an iodonium salt compound or a compound having an alkyl halide, and more preferably a compound having an alkyl halide.

[0284] Furthermore, as the compound having a halogenated alkyl group, from the viewpoint of UV plate abrasion inhibition, improved sensitivity and UV printing durability, a compound having a perhalogenated alkylsulfonyl group is preferred, a compound having a trihalogenated methylsulfonyl group is more preferred, and a compound having a tribromomethylsulfonyl group is particularly preferred.

[0285] Among the above-mentioned electron-accepting polymerization initiators, preferred examples include oxime ester compounds and onium salt compounds from the perspective of curability. Among them, from the perspective 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.

[0286] Specific examples of these compounds are shown below, but the present invention is not limited thereto.

[0287] Examples of the iodonium salt compound include preferably diaryliodonium salt compounds, and more preferably diphenyliodonium salt compounds substituted with an electron-donating group such as an alkyl group or an alkoxy group. Furthermore, asymmetric diphenyliodonium salt compounds are preferred. Specific examples include diphenyliodonium hexafluorophosphate, 4-methoxyphenyl-4-(2-methylpropyl)phenyliodonium hexafluorophosphate, 4-(2-methylpropyl)phenyl-p-tolyliodonium hexafluorophosphate, 4-hexyloxyphenyl-2,4,6-trimethoxyphenyliodonium hexafluorophosphate, 4-hexyloxyphenyl-2,4-diethoxyphenyliodonium tetrafluoroborate, 4-octyloxyphenyl-2,4,6-trimethoxyphenyliodonium 1-perfluorobutanesulfonate, 4-octyloxyphenyl-2,4,6-trimethoxyphenyliodonium hexafluorophosphate, and bis(4-tert-butylphenyl)iodonium tetraphenylborate.

[0288] Examples of counter anions of the iodonium salt compound and the sulfonium salt compound include sulfonate anion, carboxylate anion, tetrafluoroborate anion, hexafluorophosphate anion, p-toluenesulfonate anion, p-toluenesulfonate anion, sulfonamide anion, and sulfonylimide anion.

[0289] Among them, the sulfonamide anion or the sulfonimide anion is preferred, and the sulfonimide anion is more preferred.

[0290] As the sulfonamide anion, an arylsulfonamide anion is preferred.

[0291] Furthermore, as the sulfonyl imide anion, a bisarylsulfonyl imide anion is preferred.

[0292] Specific examples of the sulfonamide anion or the sulfonylimide anion include the compounds described in International Publication No. 2019 / 013268.

[0293] Furthermore, as the above-mentioned electron-accepting polymerization initiator, from the viewpoint of visual recognizability over time after exposure, developability, and UV printing durability in the obtained lithographic printing plate, it is preferred to include a compound represented by the following formula (II) or formula (III), and it is particularly preferred to include a compound represented by formula (II).

[0294] [Chemical Formula 28]

[0295]

[0296] In formula (II) and formula (III), X A Represents a halogen atom, R A 、R A1 and R A2 Each independently represents a monovalent hydrocarbon group having 1 to 20 carbon atoms.

[0297] R in formula (II) A Preferred is aryl.

[0298] As X in formula (II) and formula (III) A , fluorine atom, chlorine atom, bromine atom and iodine atom can be mentioned. Among these, chlorine atom or bromine atom is preferred because of its excellent sensitivity, and bromine atom is particularly preferred.

[0299] Furthermore, in formula (II) and formula (III), R A , RA 1 and R A2 Each of these groups is independently preferably an aryl group, and among these, an aryl group substituted with an amide group is more preferred from the viewpoint of excellent balance between sensitivity and storage stability.

[0300] Furthermore, as the electron-accepting polymerization initiator, it is particularly preferred to contain a compound represented by formula (IV).

[0301] [Chemical Formula 29]

[0302]

[0303] In formula (IV), X A Represents a halogen atom, R A3 and R A4 Each independently represents a hydrogen atom or a monovalent hydrocarbon group having 1 to 20 carbon atoms, and pA and qA each independently represent an integer of 1 to 5. However, pA+qA=2 to 6.

[0304] Specific examples of the electron-accepting polymerization initiator include the compounds shown below, but the present invention is not limited to these.

[0305] [Chemical formula 30]

[0306]

[0307] [Chemical Formula 31]

[0308]

[0309] [Chemical Formula 32]

[0310]

[0311] [Chemical Formula 33]

[0312]

[0313] [Chemical Formula 34]

[0314]

[0315] [Chemical Formula 35]

[0316]

[0317] [Chemical Formula 36]

[0318]

[0319] From the viewpoint of improving sensitivity and preventing plate wear, 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.

[0320] Furthermore, the lower limit is preferably -3.80 eV or higher, and more preferably -3.50 eV or higher.

[0321] The electron-accepting polymerization initiator may be used alone or in combination of two or more.

[0322] The content of the electron-accepting polymerization initiator is preferably 0.1 to 50% by mass, more preferably 0.5 to 30% by mass, and particularly preferably 0.8 to 20% by mass, relative to the total mass of the image recording layer.

[0323] [Relationship between electron-accepting polymerization initiators and infrared absorbers]

[0324] In the image recording layer of the present invention, from the viewpoint of improving sensitivity and printing durability, the value of LUMO of the above-mentioned electron-accepting polymerization initiator - LUMO of the above-mentioned infrared absorber is preferably 0.45 eV or more, more preferably 0.58 eV or more, further preferably 0.62 eV or more, particularly preferably 0.62 eV to 1.00 eV, and most preferably 0.62 eV to 0.95 eV.

[0325] In addition, a negative value means that the LUMO of the infrared absorber is higher than the LUMO of the electron-accepting polymerization initiator.

[0326] 〔Polymerizable compounds〕

[0327] The image recording layer in the present invention contains a polymerizable compound.

[0328] In the present invention, the polymerizable compound refers to a compound having a polymerizable group.

[0329] The polymerizable group is not particularly limited as long as it is a known polymerizable group, but is preferably an ethylenically unsaturated group. Furthermore, the polymerizable group may be a free radical polymerizable group or a cationic polymerizable group, but is preferably a free radical polymerizable group.

[0330] Examples of the radical polymerizable group include a (meth)acryloyl group, an allyl group, a vinylphenyl group, and a vinyl group. From the viewpoint of reactivity, a (meth)acryloyl group is preferred.

[0331] The molecular weight (weight average molecular weight when there is a molecular weight distribution) of the polymerizable compound is preferably 50 or more and less than 2,500.

[0332] The polymerizable compound used in the present invention may be, for example, a radical polymerizable compound or a cation polymerizable compound, and is preferably an addition polymerizable compound (ethylenically unsaturated compound) having at least one ethylenically unsaturated bond.

[0333] The ethylenically unsaturated compound is preferably a compound having at least one terminal ethylenically unsaturated bond, and more preferably a compound having two or more terminal ethylenically unsaturated bonds. The polymerizable compound has a chemical form such as a monomer, a prepolymer, i.e., a dimer, a trimer, or an oligomer, or a mixture thereof.

[0334] Among these, the polymerizable compound preferably contains a trifunctional or higher polymerizable compound, more preferably a heptafunctional or higher polymerizable compound, and even more preferably a decafunctional or higher polymerizable compound, from the perspective of UV printing durability. Furthermore, from the perspective of UV printing durability of the resulting lithographic printing plate, the polymerizable compound preferably contains a trifunctional or higher (preferably heptafunctional or higher, more preferably decafunctional or higher) ethylenically unsaturated compound, and even more preferably contains a trifunctional or higher (preferably heptafunctional or higher, more preferably decafunctional or higher) (meth)acrylate compound.

[0335] Furthermore, from the viewpoint of on-press developability and contamination suppression, the polymerizable compound preferably contains a difunctional or lower-functional polymerizable compound, more preferably contains a difunctional polymerizable compound, and particularly preferably contains a difunctional (meth)acrylate compound.

[0336] From the viewpoints of printing durability, on-press developability and contamination suppression, the content of the difunctional or lower polymerizable compound (preferably a difunctional polymerizable compound) is preferably 5% by mass to 100% by mass, more preferably 10% by mass to 100% by mass, and particularly preferably 50% by mass to 100% by mass, relative to the total mass of the polymerizable compound in the image recording layer.

[0337] Low Polymer

[0338] The polymerizable compound contained in the image recording layer preferably contains a polymerizable compound that is an oligomer (hereinafter, also simply referred to as "oligomer").

[0339] In the present invention, the oligomer refers to a polymerizable compound having a molecular weight (weight average molecular weight when there is a molecular weight distribution) of 600 or more and 10,000 or less and containing at least one polymerizable group.

[0340] From the viewpoint of excellent chemical resistance and UV printing durability, the molecular weight of the oligomer is preferably 1,000 or more and 5,000 or less.

[0341] Furthermore, from the viewpoint of improving UV printing durability, the number of polymerizable groups in one molecule of the oligomer is preferably 2 or more, more preferably 3 or more, further preferably 6 or more, and particularly preferably 10 or more.

[0342] Furthermore, the upper limit of the number of polymerizable groups in the oligomer is not particularly limited, but the number of polymerizable groups is preferably 20 or less.

[0343] From the viewpoint of UV printing durability and on-press developability, the oligomer preferably has 7 or more polymerizable groups and a molecular weight of 1,000 or more and 10,000 or less, and more preferably has 7 or more and 20 or less polymerizable groups and a molecular weight of 1,000 or more and 5,000 or less.

[0344] Furthermore, the polymer component that may be generated in the process of producing the oligomer may be contained.

[0345] From the viewpoints of UV printing durability, visibility, and on-press developability, the oligomer preferably comprises at least one selected from compounds having a urethane bond, compounds having an ester bond, and compounds having an epoxy residue, and more preferably comprises a compound having a urethane bond.

[0346] In the present invention, the epoxy residue refers to a structure formed of an epoxy group, and for example, refers to the same structure as that obtained by the reaction of an acid group (carboxylic acid group, etc.) with an epoxy group.

[0347] As an example of the oligomer, the compound having a urethane bond is preferably a compound having at least a group represented by the following formula (Ac-1) or formula (Ac-2), and more preferably a compound having at least a group represented by the following formula (Ac-1).

[0348] [Chemical Formula 37]

[0349]

[0350] In formula (Ac-1) and formula (Ac-2), L 1 ~L 4Each independently represents a divalent hydrocarbon group having 2 to 20 carbon atoms, and the wavy line portion indicates a bonding position to other structures.

[0351] As L 1 ~L 4 , are each independently preferably an alkylene group having 2 to 20 carbon atoms, more preferably an alkylene group having 2 to 10 carbon atoms, and still more preferably an alkylene group having 4 to 8 carbon atoms. Furthermore, the alkylene group may have a branched or cyclic structure, but is preferably a straight-chain alkylene group.

[0352] It is preferred that the wavy line portion in formula (Ac-1) or formula (Ac-2) is independently directly bonded to the wavy line portion in the group represented by the following formula (Ae-1) or formula (Ae-2).

[0353] [Chemical Formula 38]

[0354]

[0355] 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).

[0356] Furthermore, as the compound having a urethane bond, a compound obtained by introducing a polymerizable group into a polyurethane obtained by a reaction between a polyisocyanate compound and a polyol compound through a polymer reaction can be used.

[0357] For example, a 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 with a polyisocyanate compound.

[0358] The number of polymerizable groups in the compound having an ester bond as an example of the oligomer is preferably 3 or more, more preferably 6 or more.

[0359] The compound having an epoxy residue as an example of the oligomer is preferably a compound containing a hydroxyl group within the compound.

[0360] Furthermore, the number of polymerizable groups in the compound having an epoxy residue is preferably 2 to 6, more preferably 2 to 3.

[0361] The compound having an epoxy residue can be obtained, for example, by reacting acrylic acid with a compound having an epoxy group.

[0362] Specific examples of the oligomer are shown below, but the oligomer used in the present invention is not limited thereto.

[0363] As the oligomer, commercially available products can be used, and examples thereof include UA-510H, UA-306H, UA-306I, and UA-306T (all manufactured by KYOEISHA CHEMICAL CO., LTD.), UV-1700B, UV-6300B, and 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, and EBECRYL 860 (all manufactured by DAICEL-ALLNEX LTD.), but are not limited thereto.

[0364] From the viewpoint of improving chemical resistance, UV printing durability, and suppression 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 even more preferably 80% by mass to 100% by mass, relative to the total mass of the polymerizable compound in the image recording layer.

[0365] Low molecular weight polymerizable compounds

[0366] The polymerizable compound may contain polymerizable compounds other than the above-mentioned oligomers.

[0367] As polymerizable compounds other than oligomers, low molecular weight polymerizable compounds are preferred from the viewpoint of chemical resistance. The low molecular weight polymerizable compounds may be in the chemical form of monomers, dimers, trimers, or mixtures thereof.

[0368] Furthermore, the low-molecular polymerizable compound is preferably at least one polymerizable compound selected from polymerizable compounds having three or more ethylenically unsaturated groups and polymerizable compounds having an isocyanurate ring structure, from the viewpoint of chemical resistance.

[0369] In the present invention, the low-molecular polymerizable compound refers to a polymerizable compound having a molecular weight (weight average molecular weight when there is a molecular weight distribution) of 50 or more and less than 600.

[0370] The molecular weight of the low molecular weight polymerizable compound is preferably 100 or more and less than 600, more preferably 300 or more and less than 600, and even more preferably 400 or more and less than 600, from the viewpoint of excellent chemical resistance, UV printing durability, and suppression of on-press development residue.

[0371] When the polymerizable compound contains a low molecular weight polymerizable compound as a polymerizable compound other than the oligomer (the total amount when two or more low molecular weight polymerizable compounds are contained), from the viewpoint of chemical resistance, UV printing durability and suppression of on-press development residue, the ratio of the oligomer to the low molecular weight polymerizable compound (oligomer / low molecular weight polymerizable compound) is preferably 10 / 1 to 1 / 10 on a mass basis, more preferably 10 / 1 to 3 / 7, and even more preferably 10 / 1 to 7 / 3.

[0372] Furthermore, as the low-molecular polymerizable compound, the polymerizable compounds described in paragraphs 0082 to 0086 of International Publication No. 2019 / 013268 can also be preferably used.

[0373] -Specific compound B2-

[0374] The low-molecular polymerizable compound may include a compound having one or two ethylenically unsaturated groups (hereinafter also referred to as specific compound B2).

[0375] Preferred embodiments of the ethylenically unsaturated group contained in the specific compound B2 are the same as those of the ethylenically unsaturated group in the specific compound B1.

[0376] Furthermore, from the viewpoint of suppressing a decrease in on-press developability, the specific compound B2 is preferably a compound having two ethylenically unsaturated bond groups (ie, a bifunctional polymerizable compound).

[0377] As the specific compound B2, from the viewpoint of on-press developability and printing durability, a methacrylate compound, that is, a compound having a methacryloyloxy group is preferred.

[0378] From the viewpoint of on-press developability, the specific compound B2 preferably contains an alkyleneoxy structure or a urethane bond.

[0379] The molecular weight (weight average molecular weight when having a molecular weight distribution) of the specific compound B2 is preferably 50 or more and less than 1,000, more preferably 200 to 900, and even more preferably 250 to 800.

[0380] Specific examples of the specific compound B2 are given below, but the specific compound B2 used in the present invention is not limited to these. In the compound of (2) below, for example, n+m=10.

[0381] [Chemical Formula 39] (1)

[0383]

[0384] (2)

[0385] (3)

[0386] (4)

[0387] As the specific compound B2, the commercially available products shown below can be used, but the specific compound B2 used in the present invention is not limited to these.

[0388] Specific examples of the specific compound B2 include ethoxylated bisphenol A dimethacrylates such as BPE-80N (the compound of (1) above), BPE-100, BPE-200, and BPE-500 manufactured by Shin-Nakamura Chemical, Co., Ltd., and CN104 (the compound of (1) above) manufactured by Sartomer Company, Inc.

[0389] Specific examples of the specific compound B2 include ethoxylated bisphenol A diacrylates such as A-BPE-10 (the compound of (2) above) and A-BPE-4 manufactured by Shin-Nakamura Chemical Co., Ltd.

[0390] Specific examples of the specific compound B2 include bifunctional methacrylates such as FST 510 manufactured by AZ Electronics.

[0391] Here, the above-mentioned "FST 510" is a reaction product of 1 mol of 2,2,4-trimethylhexamethylene diisocyanate and 2 mol of hydroxyethyl methacrylate, and is an 82% by mass methyl ethyl ketone solution of the compound of the above-mentioned (3).

[0392] From the viewpoint of on-press developability and printing durability, the content of the specific compound B2 is preferably 1 to 60% by mass, more preferably 5 to 55% by mass, and even more preferably 5 to 50% by mass, relative to the total mass of the image recording layer.

[0393] When using the specific compound B2, the content of the specific compound B2 in the image recording layer relative to the total mass of the polymerizable compound is preferably 10% by mass to 100% by mass, more preferably 50% by mass to 100% by mass, and even more preferably 80% by mass to 100% by mass.

[0394] The details of the polymerizable compound such as the structure, whether to use the compound alone or in combination, and the amount to be added can be arbitrarily set.

[0395] Among them, from the viewpoint of UV printing durability, the image recording layer preferably contains two or more polymerizable compounds.

[0396] The content of the polymerizable compound (the total content of the polymerizable compounds when two or more polymerizable compounds are contained) is preferably 5% by mass to 75% by mass, more preferably 10% by mass to 70% by mass, and even more preferably 15% by mass to 60% by mass relative to the total mass of the image recording layer.

[0397] 〔particle〕

[0398] From the viewpoint of developability and UV printing durability, the image recording layer in the present invention preferably contains particles. The particles may be inorganic particles or organic particles.

[0399] Among these, the particles preferably include organic particles, and more preferably include resin particles.

[0400] As the inorganic particles, known inorganic particles can be used, and metal oxide particles such as silica particles and titania particles can be preferably used.

[0401] Resin Particles

[0402] Examples of resin particles include particles containing addition polymerization type resins (i.e., addition polymerization type resin particles), particles containing addition polymerization type resins (i.e., addition polymerization type resin particles), particles containing condensation type resins (i.e., condensation type resin particles), etc. However, among these, addition polymerization type resin particles or addition polymerization type resin particles are preferred.

[0403] Furthermore, the resin particles may be particles containing a thermoplastic resin (ie, thermoplastic resin particles) from the viewpoint of enabling thermal fusion.

[0404] Furthermore, the resin particles may be in the form of microcapsules, microgels (ie, cross-linked resin particles), or the like.

[0405] The resin particles are preferably selected from thermoplastic resin particles, thermoreactive resin particles, resin particles having polymerizable groups, microcapsules containing hydrophobic compounds, and microgels (crosslinked resin particles). Among them, resin particles having polymerizable groups are preferred.

[0406] In a particularly preferred embodiment, the resin particles contain at least one ethylenically unsaturated group. The presence of such resin particles can improve the printing durability of the exposed portion and the on-press developability of the unexposed portion.

[0407] Preferred thermoplastic resin particles include those described in Research Disclosure No. 33303 of January 1992, Japanese Patent Application Laid-Open Nos. 9-123387, 9-131850, 9-171249, and 9-171250, and European Patent No. 931647.

[0408] Specific examples of the resin constituting the thermoplastic resin particles include homopolymers or copolymers of monomers such as ethylene, styrene, vinyl chloride, methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate, vinylidene chloride, acrylonitrile, vinylcarbazole, and acrylates or methacrylates having a polyalkylene structure, or mixtures thereof.

[0409] The thermoplastic resin particles preferably contain a resin having a structural unit composed of an aromatic vinyl compound and a structural unit having a nitrile group, from the viewpoint of ink acceptability and UV printing durability.

[0410] The aromatic vinyl compound may be any compound having a structure in which a vinyl group is bonded to an aromatic ring, and examples thereof include styrene compounds and vinylnaphthalene compounds. Styrene compounds are preferred, and styrene is more preferred.

[0411] Examples of the styrene compound include styrene, p-methylstyrene, p-methoxystyrene, β-methylstyrene, p-methyl-β-methylstyrene, α-methylstyrene, and p-methoxy-β-methylstyrene, and styrene is preferred.

[0412] From the viewpoint of ink adherence, the content of the structural unit formed from the aromatic vinyl compound is preferably greater than the content of the structural unit having a nitrile group described later, and is more preferably 15% to 85% by mass, and even more preferably 30% to 70% by mass, relative to the total mass of the thermoplastic resin.

[0413] The structural unit having a nitrile group is preferably introduced using a monomer having a nitrile group.

[0414] Examples of the monomer having a nitrile group include acrylonitrile compounds, and preferably (meth)acrylonitrile.

[0415] As the structural unit having a nitrile group, a structural unit composed of (meth)acrylonitrile is preferred.

[0416] From the viewpoint of ink adherence, the content of the structural unit having a nitrile group is preferably less than the content of the structural unit formed from the above-mentioned aromatic vinyl compound, and is more preferably 55% to 90% by mass, and even more preferably 60% to 85% by mass, relative to the total mass of the resin.

[0417] Furthermore, when the resin contained in the thermoplastic resin particles contains constituent units formed from an aromatic vinyl compound and constituent units having a nitrile group, the content ratio of the constituent units formed from the aromatic vinyl compound and the constituent units having a nitrile group (constituent units formed from an aromatic vinyl compound:constituent units having a nitrile group) is preferably 5:5 to 9:1, more preferably 6:4 to 8:2, on a mass basis.

[0418] From the viewpoint of UV printing durability and chemical resistance, the resin contained in the thermoplastic resin particles preferably further has a structural unit composed of an N-vinyl heterocyclic compound.

[0419] Examples of the N-vinyl heterocyclic compound include N-vinylpyrrolidone, N-vinylcarbazole, N-vinylpyrrole, N-vinylphenothiazine, N-vinylsuccinimide, N-vinylphthalimide, N-vinylcaprolactam, and N-vinylimidazole, with N-vinylpyrrolidone being preferred.

[0420] The content of the structural unit formed from the N-vinyl heterocyclic compound is preferably 5% by mass to 50% by mass, more preferably 10% by mass to 40% by mass, relative to the total mass of the thermoplastic resin.

[0421] The resin contained in the thermoplastic resin particles may contain a structural unit having an acidic group, but preferably does not contain a structural unit having an acidic group from the viewpoint of on-press developability and ink adherence.

[0422] Specifically, the content of the structural unit having an acidic group in the thermoplastic resin is preferably 20% by mass or less, more preferably 10% by mass or less, and even more preferably 5% by mass or less. The lower limit of the content is not particularly limited and may be 0% by mass.

[0423] The acid value of the thermoplastic resin is preferably 160 mgKOH / g or less, more preferably 80 mgKOH / g or less, and even more preferably 40 mgKOH / g or less. The lower limit of the acid value is not particularly limited and may be 0 mgKOH / g.

[0424] In the present invention, the acid value is determined by a measurement method in accordance with JIS K00070:1992.

[0425] From the viewpoint of ink adherence, the resin contained in the thermoplastic resin particles may contain a structural unit containing a hydrophobic group.

[0426] Examples of the hydrophobic group include an alkyl group, an aryl group, and an aralkyl group.

[0427] The structural unit containing a hydrophobic group is preferably a structural unit formed from an alkyl (meth)acrylate compound, an aryl (meth)acrylate compound, or an arylalkyl (meth)acrylate compound, and more preferably a structural unit formed from an alkyl (meth)acrylate compound.

[0428] The content of the structural unit having a hydrophobic group in the resin contained in the thermoplastic resin particles is preferably 5% by mass to 50% by mass, more preferably 10% by mass to 30% by mass, relative to the total mass of the resin.

[0429] From the viewpoint of UV printing durability and on-press developability, the thermoplastic resin contained in the thermoplastic resin particles preferably has a hydrophilic group.

[0430] The hydrophilic group is not particularly limited as long as it has a hydrophilic structure, and examples thereof include acid groups such as a carboxyl group, a hydroxyl group, an amino group, a nitrile group, and a polyalkylene oxide structure.

[0431] From the viewpoint of UV printing durability and on-press developability, the hydrophilic group is preferably a group having a polyalkylene oxide structure, a group having a polyester structure, or a sulfonic acid group. A group having a polyalkylene oxide structure or a sulfonic acid group is more preferred, and a group having a polyalkylene oxide structure is still more preferred.

[0432] As the 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.

[0433] Furthermore, from the viewpoint of on-press developability, among the hydrophilic groups, the polyalkylene oxide structure preferably has a polypropylene oxide structure, and more preferably has a polyethylene oxide structure and a polypropylene oxide structure.

[0434] From the viewpoint of on-press developability, the number of alkylene oxide structures in the polyalkylene oxide structure is preferably 2 or more, more preferably 5 or more, further preferably 5 to 200, and particularly preferably 8 to 150.

[0435] Furthermore, from the viewpoint of on-press developability, the hydrophilic group is preferably a group represented by Formula Z described later.

[0436] Among the hydrophilic groups possessed by the thermoplastic resin, a group represented by the following formula PO is preferred.

[0437] [Chemical Formula 40]

[0438]

[0439] In the formula PO, L P Each independently represents an alkylene group, R Prepresents a hydrogen atom or an alkyl group, and n represents an integer of 1 to 100.

[0440] In the formula PO, L P Each independently preferably is ethylene, 1-methylethylene or 2-methylethylene, and more preferably is ethylene.

[0441] In the formula PO, R P It 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.

[0442] In the formula PO, n is preferably an integer of 1-10, and more preferably an integer of 1-4.

[0443] The content of the structural unit having a hydrophilic group is preferably 5% by mass to 60% by mass, more preferably 10% by mass to 30% by mass, relative to the total mass of the resin.

[0444] The resin contained in the thermoplastic resin particles may further contain other structural units. Other structural units may include structural units other than the above-mentioned structural units without particular limitation, and examples thereof include structural units formed from acrylamide compounds, vinyl ether compounds, and the like.

[0445] The content of other structural units in the resin contained in the thermoplastic resin particles is preferably 5% by mass to 50% by mass, more preferably 10% by mass to 30% by mass, relative to the total mass of the resin.

[0446] Examples of the thermoreactive resin particles include resin particles having thermoreactive groups. The thermoreactive resin particles form hydrophobic regions by crosslinking due to a thermal reaction and by changes in functional groups during crosslinking.

[0447] The thermoreactive group in the resin particles having a thermoreactive group may be any functional group that undergoes any reaction as long as it can form a chemical bond, but a polymerizable group is preferred. Examples thereof include ethylenically unsaturated groups that undergo free radical polymerization (e.g., acryloyl, methacryloyl, vinyl, allyl, etc.), cationic polymerizable groups (e.g., vinyl, vinyloxy, epoxy, oxetanyl, etc.), isocyanate groups or their blocks that undergo addition reactions, epoxy groups, vinyloxy groups, and functional groups having active hydrogen atoms that are the reaction targets of these groups (e.g., amino groups, hydroxyl groups, carboxyl groups, etc.), carboxyl groups that undergo condensation reactions and hydroxyl groups or amino groups that are the reaction targets, acid anhydrides that undergo ring-opening addition reactions and amino groups or hydroxyl groups that are the reaction targets, and the like.

[0448] The resin having the heat-reactive group may be an addition polymerization type resin, an addition polymerization type resin, a condensation polymerization type resin, or a thermoplastic resin.

[0449] Preferred microcapsules include, for example, those described in Japanese Patent Application Laid-Open Nos. 2001-277740 and 2001-277742, which contain at least a portion of the components of the image recording layer (preferably a hydrophobic compound). A preferred embodiment of the image recording layer containing microcapsules as resin particles is a structure in which the hydrophobic component (i.e., the hydrophobic compound) of the components of the image recording layer is contained within the microcapsules, and the hydrophilic component (i.e., the hydrophilic compound) is contained on the outside of the microcapsules.

[0450] The microgel (crosslinked resin particles) can contain a portion of the components of the image-recording layer on at least one of its surface or interior. In particular, reactive microgels having polymerizable groups on their surfaces are preferred from the perspectives of the sensitivity of the lithographic printing plate precursor and the printing durability of the resulting lithographic printing plate.

[0451] In order to obtain microcapsules containing the constituent components of the image recording layer, a known synthesis method can be applied.

[0452] The microgel (crosslinked resin particles) can contain a portion of the components of the image-recording layer on at least one of its surface or interior. In particular, reactive microgels having polymerizable groups on their surfaces are preferred from the perspectives of the sensitivity of the lithographic printing plate precursor and the printing durability of the resulting lithographic printing plate.

[0453] In order to obtain a microgel containing constituent components of the image recording layer, a known synthesis method can be applied.

[0454] From the viewpoint of printing durability, stain resistance, and storage stability of the resulting lithographic printing plate, the resin particles are preferably addition-polymerized resin particles obtained by reacting a polyvalent isocyanate compound, which is an adduct of a polyvalent phenol compound having two or more hydroxyl groups in its molecule and isophorone diisocyanate, with a compound having active hydrogen.

[0455] As the polyphenol compound, a compound having a plurality of benzene rings having a phenolic hydroxyl group is preferable.

[0456] The compound having active hydrogen is preferably a polyol compound or a polyamine compound, more preferably a polyol compound, and even more preferably at least one compound selected from propylene glycol, glycerol, and trimethylolpropane. Water can also be used as the active hydrogen compound. When water is used, the amine produced by the reaction of isocyanate groups with water can form a urea bond, thereby forming particles.

[0457] Preferred examples of resin particles obtained by reacting a polyvalent isocyanate compound, which is an adduct of a polyvalent phenol compound having two or more hydroxyl groups in its molecule and isophorone diisocyanate, and a compound having active hydrogen include those described in paragraphs 0230 to 0234 of International Publication No. 2018043259.

[0458] Furthermore, from the perspective of printing durability and solvent resistance of the resulting lithographic printing plate, the resin particles are preferably addition-polymerized resin particles having a hydrophobic main chain and comprising both i) a structural unit having a nitrile group directly bonded to the hydrophobic main chain and ii) a structural unit having a pendant group containing a hydrophilic polyalkylene oxide segment. Specifically, the particles described in paragraph 0156 of JP-A-2019-64269 are preferred.

[0459] <<Group represented by formula Z>>

[0460] The resin particles in the present invention preferably have a group represented by the following formula Z as a hydrophilic group.

[0461] *-QWY Type Z

[0462] 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, any of W and Y has a hydrophilic structure, and * represents a bonding site with another structure.

[0463] Furthermore, it is preferred that the hydrophilic structures included in formula Z all include a polyalkylene oxide structure.

[0464] Q in the above formula Z is preferably a divalent linking group having 1 to 20 carbon atoms, and more preferably a divalent linking group having 1 to 10 carbon atoms.

[0465] Furthermore, Q in the above 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.

[0466] The divalent group having a hydrophilic structure in W of the above formula Z is preferably a group containing a polyalkylene oxide structure, more preferably a polyalkyleneoxy group or a group having -CH2CH2NR bonded to one end of the polyalkyleneoxy group. W - group. In addition, R W represents a hydrogen atom or an alkyl group.

[0467] The divalent group having a hydrophobic structure in W of the above formula Z is preferably -R WA -、-OR WA -O-、-RW NR WA -NR W -、-OC(=O)-R WA -O-or-OC(=O)-R WA -O-. In addition, 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.

[0468] The monovalent group having a hydrophilic structure in Y of the above formula Z is preferably -OH, -C(=O)OH, a polyalkyleneoxy group having a hydrogen atom or an alkyl group at the end, or a polyalkyleneoxy group having a hydrogen atom or an alkyl group at the other end thereof bonded with -CH2CH2N(R W Among them, as a monovalent group having a hydrophilic structure, a group containing a polyalkylene oxide structure is preferred, and -CH2CH2N(R W )-group.

[0469] The monovalent group having a hydrophobic structure in Y of the above formula Z is preferably a linear, branched or cyclic alkyl group having 6 to 120 carbon atoms, a halogenated alkyl group having 6 to 120 carbon atoms, an aryl group having 6 to 120 carbon atoms, an alkaryl group (alkylaryl group) having 6 to 120 carbon atoms, an aralkyl group having 6 to 120 carbon atoms, -OR WB 、-C(=O)OR WB or -OC(=O)R WB . R WB It represents an alkyl group having 6 to 20 carbon atoms.

[0470] In the resin particles having a group represented by the above formula Z, from the viewpoints of printing durability, ink adhesion, and on-press developability, it is more preferred that W is a divalent group having a hydrophilic structure, more preferably Q is a phenylene group, an ester bond, or an amide bond, W is a polyalkyleneoxy group, and Y is a polyalkyleneoxy group having a terminal hydrogen atom or an alkyl group.

[0471] Furthermore, the group represented by formula Z can function as a dispersibility group that improves the dispersibility of the resin particles.

[0472] From the perspectives of printing durability and on-press developability, the resin particles in the present invention preferably have polymerizable groups (preferably ethylenically unsaturated groups), and more preferably include resin particles having polymerizable groups on the surface. The use of resin particles having polymerizable groups can easily suppress plate wear (preferably UV plate wear) and improve printing durability (preferably UV printing durability).

[0473] From the viewpoint of printing durability, the resin particles in the present invention are preferably resin particles having a hydrophilic group and a polymerizable group.

[0474] The polymerizable group may be a cationically polymerizable group or a radically polymerizable group, but is preferably a radically polymerizable group from the viewpoint of reactivity.

[0475] The polymerizable group is not particularly limited as long as it is a polymerizable group. However, from the viewpoint of reactivity, an ethylenically unsaturated group is preferred, a vinylphenyl (styryl) group, a (meth)acryloyloxy group, or a (meth)acrylamide group is more preferred, and a (meth)acryloyloxy group is particularly preferred.

[0476] Furthermore, the resin constituting the resin particles having a polymerizable group preferably includes a structural unit having a polymerizable group.

[0477] In addition, polymerizable groups can be introduced onto the surface of the resin particles by polymer reaction.

[0478] Furthermore, from the perspectives of printing durability, ink adherence, on-press developability, and suppressing development residue during on-press development, the resin particles preferably comprise an addition-polymerized resin having a urea bond, more preferably comprise an addition-polymerized resin having a structure obtained by reacting at least an isocyanate compound represented by the following formula (Iso) with water, and particularly preferably comprise an addition-polymerized resin having a structure obtained by reacting at least an isocyanate compound represented by the following formula (Iso) with water, and having a polyethylene oxide structure and a polypropylene oxide structure as the polyoxyalkylene structure. Furthermore, the particles comprising the addition-polymerized resin having a urea bond are preferably microgels.

[0479] [Chemical Formula 41]

[0480]

[0481] In formula (Iso), n represents an integer of 0-10.

[0482] As an example of the reaction between the isocyanate compound represented by the above formula (Iso) and water, the reaction shown below can be mentioned. In the following example, n=0 and a 4,4-isomer is used.

[0483] As shown below, when the isocyanate compound represented by the above formula (Iso) is reacted with water, a portion of the isocyanate groups in the water are hydrolyzed to generate amino groups. The generated amino groups then react with the isocyanate groups to form urea bonds, thereby forming a dimer. The following reaction is then repeated to form an addition-polymerized resin having urea bonds.

[0484] Furthermore, in the following reaction, by adding a compound reactive with an isocyanate group (a compound having active hydrogen), such as an alcohol compound or an amine compound, the structure of the alcohol compound or amine compound can be introduced into the addition-polymerized resin having a urea bond.

[0485] As the compound having active hydrogen, preferably, the compounds having active hydrogen mentioned above are mentioned.

[0486] [Chemical Formula 42]

[0487]

[0488] Furthermore, the polyaddition resin having a urea bond preferably has an ethylenically unsaturated group, and more preferably has a group represented by the following formula (PETA).

[0489] [Chemical Formula 43]

[0490]

[0491] In formula (PETA), the wavy line portion indicates the bonding position to other structures.

[0492] Synthesis of Resin Particles

[0493] The method for synthesizing the resin particles is not particularly limited, as long as it is a method capable of synthesizing the particles using the various resins described above. Examples of the method for synthesizing the resin particles include well-known methods for synthesizing resin particles, such as emulsion polymerization, suspension polymerization, dispersion polymerization, soap-free polymerization, and microemulsion polymerization.

[0494] Furthermore, for the synthesis of the resin particles, a known method for synthesizing microcapsules, a method for synthesizing microgels (cross-linked resin particles), or the like can be used.

[0495] Average particle size

[0496] The average particle size of the particles is preferably 0.01 μm to 3.0 μm, more preferably 0.03 μm to 2.0 μm, and even more preferably 0.10 μm to 1.0 μm. Within this range, good resolution and temporal stability can be obtained.

[0497] The average particle size of the particles is measured by light scattering or by taking an electron micrograph of the particles, measuring the particle sizes of 5,000 particles in total on the photograph, and calculating the average value. For non-spherical particles, the equivalent circle diameter of the particles in the photograph is used.

[0498] In addition, the average particle size of the particles in the present invention refers to the volume average particle size unless otherwise specified.

[0499] The particles (preferably resin particles) may be used alone or in combination of two or more.

[0500] From the viewpoint of developability and printing durability, the content of particles (preferably resin particles) relative to the total mass of the image recording layer is preferably 5% by mass to 90% by mass, more preferably 10% by mass to 90% by mass, further preferably 20% by mass to 90% by mass, and particularly preferably 50% by mass to 90% by mass.

[0501] [Other ingredients]

[0502] The image recording layer in the present invention may contain other components in addition to the components already described.

[0503] Examples of other components include a binder polymer, a color developer, a chain transfer agent, a low-molecular-weight hydrophilic compound, a sensitizer, and other additives.

[0504] Examples of other components include colorants disclosed in paragraphs 0181 to 0190 of JP-A-2009-255434, printout agents, polymerization inhibitors, higher fatty acid derivatives, plasticizers, inorganic particles, and low-molecular-weight hydrophilic compounds.

[0505] In addition, other compounds include the hydrophobizing precursors disclosed in paragraphs 0191 to 0217 of JP-A-2012-187907 (fine particles capable of converting the image recording layer into a hydrophobic state when heat is applied), low-molecular-weight hydrophilic compounds, sensitizers (e.g., phosphonium compounds, nitrogen-containing low-molecular-weight compounds, ammonium group-containing polymers), and chain transfer agents.

[0506] -Binder polymer-

[0507] The image-recording layer may contain a binder polymer as needed.

[0508] Here, the binder polymer refers to a polymer other than resin particles, that is, a polymer that is not in a particle shape.

[0509] Furthermore, regarding the binder polymer, ammonium salt-containing polymers in sensitizers and polymers used as surfactants are excluded.

[0510] As the binder polymer, known binder polymers (eg, (meth)acrylic resins, polyvinyl acetals, polyurethane resins, etc.) used in the image recording layer of the lithographic printing plate precursor can be preferably used.

[0511] As an example, a binder polymer used in an on-press development type planographic printing plate precursor (hereinafter also referred to as a binder polymer for on-press development) will be described in detail.

[0512] As a binder polymer for on-press development, a binder polymer having an alkylene oxide chain is preferred. The binder polymer having an alkylene oxide chain may have a poly(alkylene oxide) moiety in the main chain or in a side chain. Furthermore, it may be a graft polymer having a poly(alkylene oxide) moiety in a side chain, or a block copolymer comprising a block composed of repeating units containing poly(alkylene oxide) and a block composed of repeating units not containing poly(alkylene oxide).

[0513] When the main chain has a poly(alkylene oxide) moiety, a polyurethane resin is preferred.

[0514] Examples of the main chain polymer when having a poly(alkylene oxide) moiety in a side chain include (meth)acrylic resins, polyvinyl acetal resins, polyurethane resins, polyurea resins, polyimide resins, polyamide resins, epoxy resins, polystyrene resins, novolac-type phenolic resins, polyester resins, synthetic rubbers, and natural rubbers, with (meth)acrylic resins being particularly preferred.

[0515] Furthermore, as other preferred examples of binder polymers, there can be cited polymer compounds (hereinafter also referred to as star-shaped polymer compounds) having a polyfunctional thiol having more than 6 functions and less than 10 functions as a core portion, a polymer chain bonded to the core portion via a sulfide bond, and the polymer chain having a polymerizable group.

[0516] As the star-shaped polymer compound, for example, the compounds described in JP-A-2012-148555 can be preferably used.

[0517] Examples of star-shaped polymer compounds include compounds having polymerizable groups such as ethylenically unsaturated bonds in the main chain or side chain, preferably in the side chain, for improving the film strength of the image area, as described in Japanese Patent Application Laid-Open No. 2008-195018. The polymerizable groups in the star-shaped polymer compound form crosslinks between molecules of the star-shaped polymer compound, accelerating curing.

[0518] As the polymerizable group, preferably, an ethylenically unsaturated group such as (meth) acrylic acid, vinyl, allyl, vinylphenyl (styryl), or an epoxy group, etc., from the viewpoint of polymerization reactivity, more preferably a (meth) acrylic acid, vinyl, vinylphenyl (styryl), and particularly preferably a (meth) acrylic acid. These groups can be introduced into the polymer by polymer reaction or copolymerization. Specifically, for example, the reaction of a polymer having a carboxyl group on the side chain with glycidyl methacrylate, or the reaction of a polymer having an epoxy group with a carboxylic acid containing an ethylenically unsaturated group such as methacrylic acid can be utilized.

[0519] The molecular weight of the binder polymer is preferably a weight average molecular weight (Mw) of 2,000 or more, more preferably 5,000 or more, and even more preferably 10,000 to 300,000, as a polystyrene conversion value determined by GPC.

[0520] As the binder polymer, a hydrophilic polymer such as polyacrylic acid, polyvinyl alcohol, or polyvinyl acetal described in JP-A-2008-195018 may be used in combination as needed. Furthermore, a lipophilic polymer and a hydrophilic polymer may also be used in combination.

[0521] Among them, the image recording layer preferably contains polyvinyl acetal from the viewpoint of on-press developability. Preferred examples of polyvinyl acetal include polyvinyl butyral.

[0522] Polyvinyl acetal is a resin obtained by acetalizing the hydroxyl groups of polyvinyl alcohol with aldehyde.

[0523] In particular, polyvinyl butyral obtained by acetalizing (ie, butyralizing) the hydroxyl groups of polyvinyl alcohol with butyraldehyde is preferred.

[0524] The polyvinyl acetal preferably includes a structural unit represented by the following (a) formed by acetalizing a hydroxyl group of polyvinyl alcohol with an aldehyde.

[0525] [Chemical Formula 44]

[0526] (a)

[0527]

[0528] Here, R represents the residue of an aldehyde used for acetalization.

[0529] Examples of R include a hydrogen atom, an alkyl group, and the like, and an ethylenically unsaturated group as described below.

[0530] The content of the structural unit represented by the above-mentioned (a) (also referred to as the amount of ethylene groups in the main chain contained in the structural unit represented by the above-mentioned (a) and also referred to as the degree of acetalization) is preferably 50 mol% to 90 mol%, more preferably 55 mol% to 85 mol%, and further preferably 55 mol% to 80 mol%, relative to all the structural units of the polyvinyl acetal (the total amount of ethylene groups in the main chain).

[0531] The degree of acetalization refers to a value expressed as a percentage of the mole fraction obtained by dividing the amount of ethylene groups to which acetal groups are bonded (the amount of ethylene groups in the main chain contained in the structural unit represented by (a) above) by the total amount of ethylene groups in the main chain.

[0532] The same also applies to the content of each structural unit of polyvinyl acetal described later.

[0533] From the viewpoint of improving printing durability, the polyvinyl acetal preferably has an ethylenically unsaturated group.

[0534] Here, the ethylenically unsaturated group possessed by the polyvinyl acetal is not particularly limited. From the viewpoints of reactivity, on-press developability, and printing durability, it is preferably at least one group selected from a vinylphenyl group (styryl group), a vinyl ester group, a vinyl ether group, an allyl group, a (meth)acryloyloxy group, and a (meth)acrylamide group, and more preferably a vinyl group, an allyl group, a (meth)acryloyloxy group, or the like.

[0535] From the viewpoint of improving printing durability, the polyvinyl acetal preferably contains a structural unit having an ethylenically unsaturated group.

[0536] The structural unit having an ethylenically unsaturated group may be a structural unit having an acetal ring as described above, or may be a structural unit other than a structural unit having an acetal ring.

[0537] Among them, polyvinyl acetal is preferably a compound having an ethylenically unsaturated group introduced into the acetal ring from the viewpoint of increasing the crosslinking density during exposure. That is, in the structural unit represented by (a), R preferably has an ethylenically unsaturated group.

[0538] When the structural unit having an ethylenically unsaturated group is a structural unit other than the structural unit having an acetal ring, for example, it may be a structural unit having an acrylate group, specifically, it may be a structural unit represented by the following (d).

[0539] [Chemical Formula 45]

[0540] (d)

[0541]

[0542] When the structural unit having an ethylenically unsaturated group is a structural unit other than the structural unit having an acetal ring, the content of the structural unit (also referred to as the acrylate group amount) is preferably 1 mol% to 15 mol%, more preferably 1 mol% to 10 mol%, based on all the structural units of the polyvinyl acetal.

[0543] The polyvinyl acetal preferably contains a structural unit having a hydroxyl group from the viewpoint of on-press developability, etc. That is, the polyvinyl acetal preferably contains a structural unit derived from vinyl alcohol.

[0544] Examples of the structural unit having a hydroxyl group include the structural unit represented by the following (b).

[0545] [Chemical Formula 46]

[0546] (b)

[0547]

[0548] The content of the structural unit represented by (b) (also referred to as the hydroxyl group content) is preferably 5 mol% to 50 mol%, more preferably 10 mol% to 40 mol%, and further preferably 20 mol% to 40 mol%, relative to all the structural units of the polyvinyl acetal, from the viewpoint of on-press developability.

[0549] The polyvinyl acetal may further contain other structural units.

[0550] As another structural unit, a structural unit having an acetyl group can be mentioned, for example, and specifically, a structural unit represented by the following (c) can be mentioned.

[0551] [Chemical Formula 47]

[0552] (c)

[0553]

[0554] The content of the structural unit represented by (c) (also referred to as acetyl group content) is preferably 0.5 to 10 mol%, more preferably 0.5 to 8 mol%, and further preferably 1 to 3 mol%, based on all structural units of the polyvinyl acetal.

[0555] Here, the degree of acetalization, the amount of acrylate groups, the amount of hydroxyl groups, and the amount of acetyl groups can be determined as follows.

[0556] That is, through 1 The mol content was calculated from the proton peak area ratios of the methyl or methylene site of the acetal, the methyl site of the acrylate group, the methyl site of the hydroxyl group, and the methyl site of the acetyl group by H NMR measurement.

[0557] The weight average molecular weight of the polyvinyl acetal is preferably 18,000 to 150,000.

[0558] The solubility parameter (also called SP value) of the polyvinyl acetal is preferably 17.5 MPa. 1 / 2 ~20.0MPa 1 / 2 , more preferably 18.0 MPa 1 / 2 ~19.5MPa 1 / 2 .

[0559] Here, the solubility parameter (unit: (MPa) 1 / 2 )" uses Hansen solubility parameters.

[0560] Regarding the Hansen solubility parameter, the solubility parameter introduced by Hildebrand is divided into three components: the dispersion term δd, the polar term δp, and the hydrogen bonding term δh, and is expressed in three-dimensional space. However, in the present invention, the solubility parameter is expressed by δ (unit: (MPa) 1 / 2 ) represents a solubility parameter (hereinafter also referred to as an SP value), and a value calculated using the following formula was used.

[0561] δ(MPa) 1 / 2 =(δd 2 +δp 2 +δh 2 ) 1 / 2

[0562] Hansen and his research successors determined a large number of these dispersion terms δd, polar terms δp, and hydrogen bonding terms δh, which are detailed in the Polymer Handbook (fourth edition), VII-698 to 711. Furthermore, details on Hansen solubility parameter values are described in "Hansen Solubility Parameters: A Users Handbook" by Charles M. Hansen (CRC Press, 2007).

[0563] In the present invention, regarding the Hansen solubility parameters in a partial structure of a compound, values estimated from the chemical structure using the computer software "Hansen Solubility Parameters in Practice (HSPiP ver. 4.1.07)" can also be used.

[0564] In the present invention, when the compound is an addition polymerization type, condensation polymerization type, or other polymer, the total amount is expressed by multiplying the SP value of each monomer unit by the mole fraction. When the compound is a low molecular weight compound having no monomer units, the SP value of the entire compound is used.

[0565] In the present invention, the SP value of a polymer can be calculated based on the molecular structure of the polymer by the Hoy method described in the Polymer Handbook (fourth edition).

[0566] Specific examples of the polyvinyl acetal [P-1 to P-3] are given below, but the polyvinyl acetal used in the present invention is not limited to these.

[0567] In the following structure, "l" is 50 mol% to 90 mol%, "m" is 0.5 mol% to 10 mol%, "n" is 5 mol% to 50 mol%, and "o" is 1 mol% to 15 mol%.

[0568] [Chemical Formula 48]

[0569] P-1

[0570]

[0571] P-2

[0572]

[0573] P-3

[0574]

[0575] As the polyvinyl acetal, a commercially available product can be used.

[0576] Examples of commercially available polyvinyl acetal include the S-LEC series manufactured by SEKISUI CHEMICAL CO., LTD. (specifically, S-LEC BX-L, BX-1, BX-5, BL-7Z, BM-1, BM-5, BH-6, and BH-3).

[0577] The binder polymers may be used alone or in combination of two or more.

[0578] The binder polymer may be contained in any amount in the image recording layer, but the content of the binder polymer is preferably 1 to 90% by mass, more preferably 5 to 80% by mass, relative to the total mass of the image recording layer.

[0579] -Developer-

[0580] The image recording layer in the present invention preferably contains a developer, more preferably an acid developer, and preferably contains a colorless compound.

[0581] As used herein, a "developer" refers to a compound having the property of developing or fading color upon stimulation by light, acid, or the like, thereby changing the color of the image-recording layer. Furthermore, an "acid developer" refers to a compound having the property of developing or fading color upon heating while receiving protons from an electron-accepting compound (e.g., an acid). Acid developers are particularly preferably colorless compounds having a partial skeleton such as a lactone, lactam, sultone, spiropyran, ester, or amide, which undergo rapid ring-opening or cleavage upon contact with an electron-accepting compound.

[0582] Examples of such acid developers include compounds described in paragraphs 0184 to 0191 of JP-A-2019-18412.

[0583] Among them, from the viewpoint of visibility, the color developer used in the present invention is preferably at least one compound selected from the group consisting of spiropyran compounds, spirooxazine compounds, spirolactone compounds, and spirolactam compounds.

[0584] The hue of the pigment after color development preferably has a maximum absorption wavelength in the range of 450 to 650 nm from the viewpoint of visibility, and the hue is preferably red, purple, blue, or dark green.

[0585] Furthermore, from the viewpoint of visibility and visibility of the exposed portion, the acid developer is preferably a colorless dye.

[0586] The colorless pigment is not particularly limited as long as it has a colorless structure, but preferably has a helical structure, and more preferably has a spirolactone ring structure.

[0587] Furthermore, the colorless dye is preferably a colorless dye having a phthalide structure or a fluoran matrix structure from the viewpoint of visibility and visibility of the exposed portion.

[0588] Moreover, from the perspective of visual recognition and visual recognition of the exposed part, the above-mentioned colorless pigment having a phthalide structure or a fluoran matrix structure is preferably a compound represented by any of the following formulas (Le-1) to (Le-3), and more preferably a compound represented by the following formula (Le-2).

[0589] [Chemical Formula 49]

[0590]

[0591] In formula (Le-1) to formula (Le-3), ERG each independently represents an electron-donating group, X1 to X4 each independently represents a hydrogen atom, a halogen atom or a dialkylaniline group, and X5 to X 10 Each independently represents a hydrogen atom, a halogen atom or a monovalent organic group, Y1 and Y2 each independently represent C or N, when Y1 is N, X1 does not exist, when Y2 is N, X4 does not exist, Ra1 represents a hydrogen atom, an alkyl group or an alkoxy group, and Rb1 to Rb4 each independently represent a hydrogen atom, an alkyl group or an aryl group.

[0592] As the electron-donating group in the ERG of formula (Le-1) to formula (Le-3), from the viewpoint of visual recognition and visual recognition of the exposed part, it is preferably an amino group, an alkylamino group, an arylamino group, a dialkylamino group, a monoalkylmonoarylamino group, a diarylamino group, an alkoxy group, an aryloxy group or an alkyl group, more preferably an amino group, an alkylamino group, an arylamino group, a dialkylamino group, a monoalkylmonoarylamino group, a diarylamino group, an alkoxy group or an aryloxy group, further preferably an arylamino group, a monoalkylmonoarylamino group or a diarylamino group, and particularly preferably an arylamino group or a monoalkylmonoarylamino group.

[0593] From the viewpoint of visibility and visibility of the exposed portion, X1 to X4 in Formulae (Le-1) to (Le-3) are each independently preferably a hydrogen atom or a chlorine atom, and more preferably a hydrogen atom.

[0594] From the viewpoint of visibility and visibility of the exposed portion, X5 to X6 in formula (Le-2) or formula (Le-3) are 10 Each independently selected from the group consisting of a hydrogen atom, a halogen atom, an alkyl group, an aryl group, an amino group, an alkylamino group, an arylamino group, a dialkylamino group, a monoalkylmonoarylamino group, a diarylamino group, a hydroxyl group, an alkoxy group, an aryloxy group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group and a cyano group is preferred; a hydrogen atom, a halogen atom, an alkyl group, an aryl group, an alkoxy group and an aryloxy group is more preferred; a hydrogen atom, a halogen atom, an alkyl group and an aryl group is further preferred; and a hydrogen atom is particularly preferred.

[0595] From the viewpoint of visibility and visibility of the exposed portion, at least one of Y1 and Y2 in Formulas (Le-1) to (Le-3) is preferably C, and both Y1 and Y2 are more preferably C.

[0596] From the viewpoint of visibility and visibility of the exposed portion, Ra1 in formula (Le-3) is preferably an alkyl group or an alkoxy group, more preferably an alkoxy group, and particularly preferably a methoxy group.

[0597] From the viewpoint of visibility and visibility of the exposed portion, Rb1 to Rb4 in formula (Le-1) are each independently preferably a hydrogen atom or an alkyl group, more preferably an alkyl group, and particularly preferably a methyl group.

[0598] Furthermore, from the perspective of visual recognizability and visual recognizability of the exposed portion, the above-mentioned colorless pigment having a phthalide structure or a fluoran parent structure is more preferably a compound represented by any of the following formulas (Le-4) to (Le-6), and further preferably a compound represented by the following formula (Le-5).

[0599] [Chemical Formula 50]

[0600]

[0601] In formulas (Le-4) to (Le-6), ERG independently represents an electron-donating group, X1 to X4 independently represent a hydrogen atom, a halogen atom or a dialkylaniline group, Y1 and Y2 independently represent C or N, when Y1 is N, X1 does not exist, and when Y2 is N, X4 does not exist, Ra1 represents a hydrogen atom, an alkyl group or an alkoxy group, and Rb1 to Rb4 independently represent a hydrogen atom, an alkyl group or an aryl group.

[0602] ERG, X1~X4, Y1, Y2, Ra1 and Rb1~Rb4 in formula (Le-4) to formula (Le-6) have the same meanings as ERG, X1~X4, Y1, Y2, Ra1 and Rb1~Rb4 in formula (Le-1) to formula (Le-3), and the preferred embodiments are also the same.

[0603] Moreover, from the perspective of visual recognizability and visual recognizability of the exposed portion, the above-mentioned colorless pigment having a phthalide structure or a fluoran matrix structure is further preferably a compound represented by any of the following formulas (Le-7) to (Le-9), and is particularly preferably a compound represented by the following formula (Le-8).

[0604] [Chemical Formula 51]

[0605]

[0606] In formulas (Le-7) to (Le-9), X1 to X4 each independently represent a hydrogen atom, a halogen atom or a dialkylaniline group, Y1 and Y2 each independently represent C or N, when Y1 is N, X1 does not exist, and when Y2 is N, X4 does not exist, Ra1 to Ra4 each independently represent a hydrogen atom, an alkyl group or an alkoxy group, Rb1 to Rb4 each independently represent a hydrogen atom, an alkyl group or an aryl group, and Rc1 and Rc2 each independently represent an aryl group.

[0607] X1 to X4, Y1 and Y2 in formulas (Le-7) to (Le-9) have the same meanings as X1 to X4, Y1 and Y2 in formulas (Le-1) to (Le-3), and preferred embodiments are also the same.

[0608] From the viewpoint of visibility and visibility of the exposed portion, Ra1 to Ra4 in formula (Le-7) are each independently preferably an alkyl group or an alkoxy group, more preferably an alkoxy group, and particularly preferably a methoxy group.

[0609] From the perspective of visual recognition and visual recognition of the exposed part, Rb1 to Rb4 in formula (Le-7) to formula (Le-9) are each independently preferably a hydrogen atom, an alkyl group, or an aromatic group substituted by an alkyl group or an alkoxy group, more preferably a hydrogen atom or an alkyl group, and particularly preferably a hydrogen atom or a methyl group.

[0610] From the viewpoint of visibility and visibility of the exposed portion, Rc1 and Rc2 in formula (Le-8) are each independently preferably a phenyl group or an alkylphenyl group, and more preferably a phenyl group.

[0611] Furthermore, in formula (Le-8), from the viewpoint of visibility and visibility of the exposed portion, it is preferred that X1 to X4 are hydrogen atoms, and Y1 and Y2 are C.

[0612] Furthermore, in formula (Le-8), from the viewpoint of visibility and visibility of the exposed portion, Rb1 and Rb2 are each independently preferably a hydrogen atom, an alkyl group, or an aryl group substituted with an alkyl group or an alkoxy group, and more preferably a hydrogen atom or an alkyl group.

[0613] The alkyl groups in formula (Le-1) to formula (Le-9) may be linear, branched, or have a ring structure.

[0614] Furthermore, the number of carbon atoms in the alkyl groups in formula (Le-1) to formula (Le-9) is preferably 1 to 20, more preferably 1 to 8, further preferably 1 to 4, and particularly preferably 1 or 2.

[0615] The number of carbon atoms in the aryl group in formula (Le-1) to formula (Le-9) is preferably 6 to 20, more preferably 6 to 10, and particularly preferably 6 to 8.

[0616] Furthermore, each of the monovalent organic groups, alkyl groups, aryl groups, dialkylanilino groups, alkylamino groups, and alkoxy groups in Formulas (Le-1) to (Le-9) may have a substituent. Examples of the substituent include alkyl groups, aryl groups, halogen atoms, amino groups, alkylamino groups, arylamino groups, dialkylamino groups, monoalkylmonoarylamino groups, diarylamino groups, hydroxyl groups, alkoxy groups, aryloxy groups, acyl groups, alkoxycarbonyl groups, aryloxycarbonyl groups, and cyano groups. Furthermore, these substituents may be further substituted with these substituents.

[0617] Examples of the colorless dye having a phthalide structure or a fluoran matrix structure that can be preferably used include the following compounds.

[0618] [Chemical Formula 52]

[0619]

[0620] [Chemical Formula 53]

[0621]

[0622] [Chemical Formula 54]

[0623]

[0624] [Chemical Formula 55]

[0625]

[0626] [Chemical Formula 56]

[0627]

[0628] As the acid developer, commercially available products may be used, including ETAC, RED500, RED520, CVL, S-205, BLACK305, BLACK400, BLACK100, BLACK500, H-7001, GREEN300, NIRBLACK78, BLUE220, H-3035, BLUE203, ATP, H-1046, and H-2114 (all manufactured by Fukui Yamada Chemical Co., Ltd.), ORANGE-DCF, Vermilion-DCF, PINK-DCF, RED-DCF, BLMB, CVL, GREEN-DCF, and TH-107 (all manufactured by HODOGAYA CHEMICAL Co., Ltd.), ODB, ODB-2, ODB-4, ODB-250, ODB-BlackXV, Blue-63, Blue-502, GN-169, GN-2, Green-118, Red-40, Red-8 (all manufactured by YAMAMOTO CHEMICALS INC.), crystal violet lactone (manufactured by Tokyo Chemical Industry Co., Ltd.), etc. Among these commercially available products, ETAC, S-205, BLACK305, BLACK400, BLACK100, BLACK500, H-7001, GREEN300, NIRBLACK78, H-3035, ATP, H-1046, H-2114, GREEN-DCF, Blue-63, GN-169, and crystal violet lactone are preferred because the films formed therefrom have good visible light absorbance.

[0629] As the colorless dye that can be preferably used, the following compounds can be mentioned from the viewpoint of visibility and visibility of the exposed portion.

[0630] [Chemical Formula 57]

[0631]

[0632] These color developers may be used alone or in combination of two or more.

[0633] The content of the developer is preferably 0.5% by mass to 10% by mass, more preferably 1% by mass to 5% by mass, relative to the total mass of the image recording layer.

[0634] [Formation of image recording layer]

[0635] The image recording layer in the lithographic printing plate precursor according to the present invention can be formed, for example, by dispersing or dissolving the necessary components described above in a known solvent to prepare a coating solution, applying the coating solution to a support by a known method such as bar coating, and drying the coating solution. The coating weight (solid content) of the image recording layer after coating and drying varies depending on the intended use, but is preferably 0.3 g / m2. 2 ~3.0g / m 2 Within this range, good sensitivity and good film properties of the image recording layer can be obtained.

[0636] As the solvent, a known solvent can be used. Specific examples include water, acetone, methyl ethyl ketone (2-butanone), cyclohexane, ethyl acetate, ethylene dichloride, tetrahydrofuran, toluene, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol dimethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, acetylacetone, cyclohexanone, diacetone alcohol, ethylene glycol monomethyl ether acetate, ethylene glycol ethyl ether acetate, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether acetate, 1-methoxy-2-propanol, 3-methoxy-1-propanol, methoxymethoxyethanol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, 3-methoxypropyl acetate, N,N-dimethylformamide, dimethyl sulfoxide, γ-butyrolactone, methyl lactate, and ethyl lactate. The solvent may be used alone or in combination of two or more. The solid content concentration in the coating liquid is preferably 1% by mass to 50% by mass.

[0637] The coating weight (solid content) of the image recording layer after coating and drying varies depending on the application, but is preferably 0.3 g / m2 from the viewpoint of obtaining good sensitivity and good film properties of the image recording layer. 2~3.0g / m 2 .

[0638] Furthermore, the film thickness of the image recording layer in the lithographic printing plate precursor according to the present invention is preferably 0.1 μm to 3.0 μm, more preferably 0.3 μm to 2.0 μm.

[0639] In the present invention, the thickness of each layer in the lithographic printing plate precursor is confirmed by preparing a slice cut perpendicularly to the surface of the lithographic printing plate precursor and observing the cross section of the slice with a scanning microscope (SEM).

[0640] <Outermost layer>

[0641] The on-press developing type lithographic printing plate precursor according to the present invention comprises a support, an image recording layer, and an outermost layer in this order, wherein the outermost layer contains a color-changing compound.

[0642] The outermost layer is the outermost layer on the image recording layer side of the support in the on-press development type lithographic printing plate precursor.

[0643] The outermost layer may have functions such as preventing scratches in the image recording layer and preventing ablation during high-intensity laser exposure, in addition to suppressing the image formation inhibitory reaction by blocking oxygen.

[0644] -Color-changing compounds-

[0645] Furthermore, the outermost layer contains a color-changing compound.

[0646] In addition to the color-changing compound, the outermost layer may also contain other components such as water-soluble polymers, hydrophobic polymers, sensitizers, acid generators, infrared absorbers, etc., preferably containing color-changing compounds and water-soluble polymers, more preferably containing color-changing compounds, water-soluble polymers and hydrophobic polymers.

[0647] In the lithographic printing plate precursor according to the present invention, from the viewpoint of improving the visibility of the exposed portion, the exposure time is 110 mJ / cm 2 When exposure is performed based on infrared rays with a wavelength of 830 nm at an energy density of , the brightness change ΔL before and after exposure is preferably 2.0 or more, more preferably 3.0 or more, further preferably 5.0 or more, particularly preferably 8.0 or more, and most preferably 10.0 or more.

[0648] The upper limit of the lightness change ΔL is, for example, 20.0.

[0649] Furthermore, particularly when the outermost layer includes a color-changing compound, it is preferable that the aforementioned preferred numerical range of the lightness change ΔL is satisfied.

[0650] The measurement of the lightness change ΔL was performed by the following method.

[0651] The images were taken with a Luxel PLATESETTER T-9800 manufactured by FUJIFILM Graphic Systems Co., Ltd., equipped with an infrared semiconductor laser having a wavelength of 830 nm, at an output of 99.5%, an external drum rotation speed of 220 rpm (revolutions per minute), a resolution of 2,400 dpi (dots per inch, 1 inch = 25.4 mm), and an energy density of 110 mJ / cm 2 The lithographic printing plate precursor was exposed under an environment of 25° C. and 50% RH.

[0652] The change in lightness of the lithographic printing plate precursor before and after exposure was measured.

[0653] The measurement was performed using a spectrocolorimeter eXact manufactured by X-Rite Inc. * a * b * L in color system * Value (brightness), the exposure part of the L * The value is different from the L value of the exposed part or the unexposed part before exposure. * The absolute value of the difference between the two values is taken as the brightness change ΔL.

[0654] In the present invention, a "color-changing compound" refers to a compound whose absorption in the visible light region (wavelength: 400 nm to less than 750 nm) changes upon exposure to infrared light. That is, in the present invention, "color change" refers to a change in absorption in the visible light region (wavelength: 400 nm to less than 750 nm) upon exposure to infrared light.

[0655] Specifically, the color-changing compound in the present invention includes (1) a compound whose absorption in the visible light region increases due to infrared exposure compared to before infrared exposure, (2) a compound that has absorption in the visible light region due to infrared exposure, and (3) a compound that has no absorption in the visible light region due to infrared exposure.

[0656] In addition, the infrared ray in the present invention is a light ray having a wavelength of 750 nm to 1 mm, preferably a light ray having a wavelength of 750 nm to 1,400 nm.

[0657] As the color-changing compound, a compound that develops color upon exposure to infrared rays is preferably included.

[0658] Furthermore, the color-changing compound preferably contains a decomposable compound that decomposes upon exposure to infrared rays, and more preferably contains a decomposable compound that decomposes by heat, electron transfer, or both caused by exposure to infrared rays.

[0659] More specifically, the color-changing compound in the present invention is preferably a compound that decomposes due to infrared exposure (more preferably decomposes by heat, electron transfer, or both caused by infrared exposure), and has increased absorption in the visible light region or shortened absorption compared to before infrared exposure and has absorption in the visible light region.

[0660] Here, "decomposition by electron transfer" means that electrons excited from the HOMO (highest occupied molecular orbital) of the color-changing compound to the LUMO (lowest unoccupied molecular orbital) by infrared exposure are transferred to an electron-accepting group (a group with a potential close to the LUMO) within the molecule, followed by decomposition.

[0661] Hereinafter, a decomposable compound will be described as an example of a color-changing compound.

[0662] The decomposable compound may be any compound that absorbs at least a portion of light in the infrared wavelength region (750 nm to 1 mm, preferably 750 nm to 1,400 nm) and decomposes, but preferably has a maximum absorption wavelength in the 750 nm to 1,400 nm wavelength region.

[0663] More specifically, the decomposable compound is preferably a compound that decomposes upon exposure to infrared rays to generate a compound having a maximum absorption wavelength in the wavelength range of 500 nm to 600 nm.

[0664] From the viewpoint of improving the visibility of the exposed portion, the decomposable compound is preferably a cyanine dye having a group (specifically, R1 in the following formulas 1-1 to 1-7) that decomposes upon exposure to infrared rays.

[0665] As the decomposable compound, from the viewpoint of improving the visibility of the exposed portion, a compound represented by the following formula 1-1 is more preferable.

[0666] [Chemical Formula 58]

[0667]

[0668] In formula 1-1, R 1 represents a group represented by any of the following formulas 2-1 to 4-1, R 11 ~R 18 Each independently represents a hydrogen atom, a halogen atom, -R a 、-ORb 、-SR c or -NR d R e , R a ~R e Each independently represents a hydrocarbon group, A1, A2 and multiple R 11 ~R 18 They may be linked to form a monocyclic or polycyclic ring, A1 and A2 each independently represent an oxygen atom, a sulfur atom or a nitrogen atom, n 11 and n 12 Each independently represents an integer from 0 to 5, wherein n 11 and n 12 The total of n is 2 or more, 13 and n 14 Each independently represents 0 or 1, 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 the charge.

[0669] [Chemical Formula 59]

[0670]

[0671] In formula 2-1 to formula 4-1, R 20 、R 30 、R 41 and R 42 Each independently represents an alkyl group or an aryl group, Zb represents a counter ion for neutralizing the charge, and the wavy line represents a bonding site with the group represented by L in the above formula 1-1.

[0672] If the compound represented by Formula 1-1 is exposed to infrared light, R 1 -L bond breaks, L becomes =O, =S or =NR 10 , thus changing color.

[0673] In formula 1-1, R 1 It represents a group represented by any of the above formulae 2-1 to 4-1.

[0674] 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 respectively.

[0675] 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.

[0676] As R 20The alkyl group represented by 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.

[0677] The above-mentioned alkyl group may be linear, branched, or have a ring structure.

[0678] As R 20 The aryl group represented by is preferably an aryl group having 6 to 30 carbon atoms, more preferably an aryl group having 6 to 20 carbon atoms, and further preferably an aryl group having 6 to 12 carbon atoms.

[0679] As R 20 , from the viewpoint of visual recognition, an alkyl group is preferred.

[0680] Furthermore, from the perspective of visual recognition and color rendering, as a 20 The alkyl group represented by is preferably a secondary alkyl group or a tertiary alkyl group, and is preferably a tertiary alkyl group.

[0681] Furthermore, from the perspective of decomposability and visual recognition, 20 The alkyl group represented by 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, particularly preferably an isopropyl group or a tert-butyl group, and most preferably a tert-butyl group.

[0682] Specific examples of the group represented by the above formula 2-1 are given below, but the present invention is not limited thereto. In the following structural formula, ● represents a bonding site to the group represented by L in formula 1-1.

[0683] [Chemical Formula 60]

[0684]

[0685] In formula 3-1, R 30 represents an alkyl group or an aryl group, and the wavy line portion represents a bonding site with the group represented by L in Formula 1-1.

[0686] As R 30 The alkyl and aryl groups represented by R in formula 2-1 20 The alkyl group and aryl group represented are the same, and the preferred embodiments are also the same.

[0687] From the perspective of visual recognition and color rendering, as the 30 The alkyl group represented by is preferably a secondary alkyl group or a tertiary alkyl group, and is preferably a tertiary alkyl group.

[0688] Furthermore, from the perspective of decomposability and visual recognition, 30The alkyl group represented by 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, particularly preferably an isopropyl group or a tert-butyl group, and most preferably a tert-butyl group.

[0689] Moreover, from the perspective of decomposability and visual recognition, 30 The alkyl group represented by is preferably a substituted alkyl group, more preferably a fluorine-substituted alkyl group, further preferably a perfluoroalkyl group, and particularly preferably a trifluoromethyl group.

[0690] From the perspective of decomposability and visual recognition, R 30 The aryl group represented by is preferably a substituted aryl group, and examples of the substituent include an alkyl group (preferably an alkyl group having 1 to 4 carbon atoms) and an alkoxy group (preferably an alkoxy group having 1 to 4 carbon atoms).

[0691] Specific examples of the group represented by the above formula 3-1 are given below, but the present invention is not limited thereto. In the following structural formula, ● represents a bonding site to the group represented by L in formula 1-1.

[0692] [Chemical Formula 61]

[0693]

[0694] In formula 4-1, R 41 and R 42 Each independently represents an alkyl group or an aryl group, Zb represents a counter ion for neutralizing the charge, and the wavy line portion represents a bonding site with the group represented by L in Formula 1-1.

[0695] As R 41 or R 42 The alkyl and aryl groups represented by R in formula 2 20 The alkyl group and aryl group represented are the same, and the preferred embodiments are also the same.

[0696] As R 41 , from the viewpoint of decomposability and visual recognition, an alkyl group is preferred.

[0697] As R 42 , from the viewpoint of decomposability and visual recognition, an alkyl group is preferred.

[0698] From the perspective of decomposability and visual recognition, as the 41 The alkyl group represented by 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.

[0699] From the perspective of visual recognition and color rendering, as the 42 The alkyl group represented by is preferably a secondary alkyl group or a tertiary alkyl group, and is preferably a tertiary alkyl group.

[0700] Furthermore, from the perspective of decomposability and visual recognition, 42 The alkyl group represented by 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, particularly preferably an isopropyl group or a tert-butyl group, and most preferably a tert-butyl group.

[0701] Zb in Formula 4-1 may be any counter ion for neutralizing the charge, and may be included in Za in Formula 1-1 as the entire compound.

[0702] Zb is preferably a sulfonate ion, a carboxylate ion, a tetrafluoroborate ion, a hexafluorophosphate ion, a p-toluenesulfonate ion or a perchlorate ion, more preferably a tetrafluoroborate ion.

[0703] Specific examples of the group represented by the above formula 4-1 are given below, but the present invention is not limited thereto. In the following structural formula, ● represents a bonding site to the group represented by L in formula 1-1.

[0704] [Chemical Formula 62]

[0705]

[0706] In formula 1-1, L is preferably an oxygen atom or -NR 10 -, with an oxygen atom being particularly preferred.

[0707] And, -NR 10 -R in 10 Alkyl is preferred. 10 The alkyl group represented by is preferably an alkyl group having 1 to 10 carbon atoms. 10 The alkyl group represented by may be linear, branched, or have a ring structure.

[0708] Among the alkyl groups, methyl or cyclohexyl is preferred.

[0709] In-NR 10 -R in 10 In the case of an aryl group, an aryl group having 6 to 30 carbon atoms is more preferable, an aryl group having 6 to 20 carbon atoms is more preferable, and an aryl group having 6 to 12 carbon atoms is further preferable. These aryl groups may have a substituent.

[0710] In formula 1-1, R 11 ~R 18 Each independently represents a hydrogen atom, -R a 、-OR b 、-SR c or -NR d R e.

[0711] By R a ~R e The hydrocarbon group represented by is preferably a hydrocarbon group having 1 to 30 carbon atoms, more preferably a hydrocarbon group having 1 to 15 carbon atoms, and still more preferably a hydrocarbon group having 1 to 10 carbon atoms.

[0712] The above-mentioned hydrocarbon group may be linear, branched, or have a ring structure.

[0713] As the above-mentioned hydrocarbon group, an alkyl group is particularly preferred.

[0714] The alkyl group is preferably an alkyl group having 1 to 30 carbon atoms, more preferably an alkyl group having 1 to 15 carbon atoms, and still more preferably an alkyl group having 1 to 10 carbon atoms.

[0715] The above-mentioned alkyl group may be linear, branched, or have a ring structure.

[0716] Specific examples include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, hexadecyl, octadecyl, eicosyl, isopropyl, isobutyl, sec-butyl, tert-butyl, isopentyl, neopentyl, 1-methylbutyl, isohexyl, 2-ethylhexyl, 2-methylhexyl, cyclohexyl, cyclopentyl, and 2-norbornyl.

[0717] Among the alkyl groups, methyl, ethyl, propyl or butyl is preferred.

[0718] The above-mentioned alkyl group may have a substituent.

[0719] 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 combinations thereof.

[0720] R in Formula 1-1 11 ~R 14 are each independently preferably a hydrogen atom or -R a (i.e., a hydrocarbon group), more preferably a hydrogen atom or an alkyl group, and further preferably a hydrogen atom except in the following cases.

[0721] Among them, R bonded to the carbon atom bonded to the carbon atom bonded to L 11 and R 13 Preferably, an alkyl group is linked to form a ring. The ring formed above may be a monocycle or a polycycle. Specifically, the ring formed includes monocycles such as a cyclopentene ring, a cyclopentadiene ring, a cyclohexene ring, and a cyclohexadiene ring, and polycycles such as an indene ring and an indole ring.

[0722] And, in A1 + R bonded to the carbon atom to which it is bonded 12 Optimum with R 15 or R 16 (Preferably R 16 ) are linked to form a ring, and R bonded to the carbon atom to which A2 is bonded 14 Optimum with R 17 or R 18 (Preferably R 18 ) are connected to form a ring.

[0723] In formula 1-1, preferably n 13 is 1, R 16 -R a (i.e., hydrocarbon group).

[0724] And, R 16 Preferably with A1 + R bonded to the carbon atom to which it is bonded 12 The ring is preferably an indole ring, a pyrylium ring, a thiopyridinium ring, a benzoxazoline ring, or a benzimidazolinium ring. From the perspective of improving the visual recognition of the exposed portion, an indole ring is more preferred. These rings may further have a substituent.

[0725] In formula 1-1, preferably n 14 is 1, R 18 -R a (i.e., hydrocarbon group).

[0726] And, R 18 Preferably, R is bonded to the carbon atom to which A2 is bonded. 14 The ring is preferably an indole ring, a pyran ring, a thiopyran ring, a benzoxazole ring, or a benzimidazole ring. From the perspective of improving the visual recognition of the exposed portion, an indole ring is more preferred. These rings may further have a substituent.

[0727] R in Formula 1-1 16 and R 18 Preferably, they are the same groups. When they form a ring, they preferably form a ring except A1 + and rings other than A2 having the same structure.

[0728] R in Formula 1-1 15 and R 17 Preferably, they are the same group. 15 and R 17 Preferably -R a (i.e., a hydrocarbon group), more preferably an alkyl group, and even more preferably a substituted alkyl group.

[0729] In the compound represented by Formula 1-1, from the viewpoint of improving water solubility, R15 and R 17 A substituted alkyl group is preferred.

[0730] As R 15 or R 17 Examples of the substituted alkyl group include groups represented by any of the following formulae (a1) to (a4).

[0731] [Chemical Formula 63]

[0732]

[0733] -R W2 -CO2M (a2)

[0734] -R W3 -PO3M2 (a3)

[0735] -R W4 -SO3M (a4)

[0736] In formulas (a1) to (a4), R WO represents an alkylene group having 2 to 6 carbon atoms, W represents a single bond or an oxygen atom, n W1 represents an integer from 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 ~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.

[0737] In formula (a1), as R WO Specific examples of the alkylene group represented by include ethylene, n-propylene, isopropylene, n-butylene, isobutylene, n-pentylene, isopentylene, n-hexyl, isohexyl, etc., preferably ethylene, n-propylene, isopropylene or n-butylene, and particularly preferably n-propylene.

[0738] n W1 1-10 are preferred, 1-5 are more preferred, and 1-3 are particularly preferred.

[0739] As R W1 Specific examples of the alkyl group represented by include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, neopentyl, n-hexyl, n-octyl, n-dodecyl, etc., preferably methyl, ethyl, n-propyl, isopropyl or n-butyl, tert-butyl, more preferably methyl or ethyl, and particularly preferably methyl.

[0740] By R W5The alkyl group represented by R W1 The alkyl group represented by R is the same as that represented by W1 The preferred embodiment of the alkyl group represented is the same.

[0741] Specific examples of the group represented by formula (a1) are shown below, but the present invention is not limited thereto. In the following structural formula, Me represents a methyl group, Et represents an ethyl group, and * represents a bonding site.

[0742] [Chemical Formula 64]

[0743]

[0744] In formulas (a2) to (a4), as R W2 ~R W4 Specific examples of the alkylene group represented by include methylene, ethylene, n-propylene, isopropylene, n-butylene, isobutylene, n-pentylene, isopentylene, n-hexyl, isohexyl, n-octylene, and n-dodecylene, among which ethylene, n-propylene, isopropylene, or n-butylene is preferred, and ethylene or n-propylene is particularly preferred.

[0745] In formula (a3), two M's may be the same or different.

[0746] In formulae (a2) to (a4), examples of the onium group represented by M include an ammonium group, an iodonium group, a phosphonium group, and a sulfonium group.

[0747] The CO2M in formula (a2), the PO3M2 in formula (a2), and the SO3M in formula (a4) may all have an anionic structure in which M is dissociated. The counter cation of the anionic structure may be A1 + , or R in formula 1-1 1 -L can contain a cation.

[0748] Among the groups represented by formula (a1) to formula (a4), the group represented by formula (a1), formula (a2) or formula (a4) is preferred.

[0749] n in formula 1-1 11 and n 12 They are preferably the same, and are preferably integers of 1 to 5, more preferably integers of 1 to 3, further preferably 1 or 2, and particularly preferably 2.

[0750] A1 and A2 in Formula 1-1 each independently represent an oxygen atom, a sulfur atom or a nitrogen atom, preferably a nitrogen atom.

[0751] A1 and A2 in Formula 1-1 are preferably the same atom.

[0752] Za in Formula 1-1 represents a counter ion for neutralizing the charge.

[0753] If R 11 ~R 18 and R 1 If all -L groups are neutral, Za becomes a monovalent counter anion. 11 ~R 18 and R 1 -L can have an anionic structure or a cationic structure, for example, in R 11 ~R 18 and R 1 When -L has two or more anionic structures, Za can also serve as a counter cation.

[0754] In addition, if the cyanine dye represented by Formula 1-1 has an electrically neutral structure in the entire compound except Za, Za is not required.

[0755] When Za is a counter anion, examples thereof include sulfonate ion, carboxylate ion, tetrafluoroborate ion, hexafluorophosphate ion, p-toluenesulfonate ion, and perchlorate ion, and tetrafluoroborate ion is preferred.

[0756] When Za is a counter cation, examples include alkali metal ions, alkaline earth metal ions, ammonium ions, pyridinium ions, and sulfonium ions, preferably sodium ions, potassium ions, ammonium ions, pyridinium ions, and sulfonium ions, and more preferably sodium ions, potassium ions, and ammonium ions.

[0757] As the decomposable compound, from the viewpoint of improving the visibility of the exposed portion, a compound represented by the following formula 1-2 (ie, a cyanine dye) is more preferable.

[0758] [Chemical Formula 65]

[0759]

[0760] In formula 1-2, R 1 represents a group represented by any of the above formulas 2-1 to 4-1, R 19 ~R 22 Each independently represents 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 represents a hydrogen atom or -R a , R a ~R e Each independently represents a hydrocarbon group, R 19 With R 20 、R 21 With R22 or R 23 With R 24 They can be linked to form a monocyclic or polycyclic ring, and L represents an oxygen atom, a sulfur atom or -NR 10 -, R10 represents a hydrogen atom, an alkyl group or an aryl group, R d1 ~R d4 、W 1 and W 2 Each independently represents an alkyl group which may have a substituent, and Za represents a counter ion for neutralizing the charge.

[0761] R in Formula 1-2 1 and R in formula 1-1 1 The meaning is the same and the preferred method is also the same.

[0762] In formula 1-2, R 19 ~R 22 Each of the above is preferably independently a hydrogen atom, a halogen atom, -R a 、-OR b or -CN.

[0763] More specifically, R 19 and R 21 Preferably, a hydrogen atom or -R a .

[0764] And, R 20 and R 22 Preferably, a hydrogen atom, -R a 、-OR b or -CN.

[0765] As R 19 ~R 22 -R a , preferably an alkyl or alkenyl group.

[0766] In R 19 ~R 22 All -R a In the case of R 19 With R 20 and R 21 With R 22 linked to form a single ring or multiple rings.

[0767] As R 19 With R 20 or R 21 With R 22 Examples of the ring formed by linking include a benzene ring and a naphthalene ring.

[0768] In Formula 1-2, preferably R 23 With R 24 linked to form a single ring or multiple rings.

[0769] As R 23 With R 24 The ring formed by the connection may be a monocyclic ring or a polycyclic ring. Specific examples of the formed ring include monocyclic rings such as a cyclopentene ring, a cyclopentadiene ring, a cyclohexene ring, and a cyclohexadiene ring, and polycyclic rings such as an indene ring.

[0770] In formula 1-2, R d1 ~R d4 Preferably, it is an unsubstituted alkyl group. d1 ~R d4 are all the same groups.

[0771] Examples of the unsubstituted alkyl group include unsubstituted alkyl groups having 1 to 4 carbon atoms, and among these, a methyl group is preferred.

[0772] In Formula 1-2, from the viewpoint of improving the water solubility of the compound represented by Formula 1-2, W 1 and W 2 Each independently is preferably a substituted alkyl group.

[0773] As W 1 and W 2 The substituted alkyl group represented by may be a group represented by any of formulae (a1) to (a4) in formula 1-1, and preferred embodiments are also the same.

[0774] Furthermore, from the perspective of on-press development, W 1 and W 2 Each of the alkyl groups is independently preferably an alkyl group having a substituent, and is a group having at least -OCH2CH2-, a sulfo group, a salt of a sulfo group, a carboxyl group, or a salt of a carboxyl group as the substituent.

[0775] Za represents a counter ion that neutralizes the charge within the molecule.

[0776] 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 neutral, Za becomes a monovalent counter anion. 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 R 19 ~R 22 、R 23 ~R 24 、R d1 ~R d4 、W 1 、W 2 and R 1 When -L has two or more anionic structures, Za can also serve as a counter cation.

[0777] In addition, if the compound represented by Formula 1-2 has an electrically neutral structure in the entire compound except Za, Za is not required.

[0778] Examples when Za is a counter anion are the same as those for Za in Formula 1-1, and preferred embodiments are also the same. Furthermore, examples when Za is a counter cation are the same as those for Za in Formula 1-1, and preferred embodiments are also the same.

[0779] From the viewpoint of decomposability and visibility, the cyanine dye as the decomposable compound is more preferably a compound represented by any of the following formulas 1-3 to 1-7.

[0780] In particular, from the viewpoint of decomposability and visibility, a compound represented by any of Formula 1-3, Formula 1-5, and Formula 1-6 is preferred.

[0781] [Chemical Formula 66]

[0782]

[0783] In formulas 1-3 to 1-7, R 1 represents a group represented by any of the above formulas 2-1 to 4-1, R 19 ~R 22 Each independently represents 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 represents a hydrogen atom, a halogen atom or -R a , R a ~R e Each independently represents a hydrocarbon group, R 19 With R 20 、R 21 With R 22 or R 25 With R 26They can be linked to form a monocyclic or polycyclic ring, 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, R d1 ~R d4 、W 1 and W 2 Each independently represents an alkyl group which may have a substituent, and Za represents a counter ion for neutralizing the charge.

[0784] R in Formulas 1-3 to 1-7 1 、R 19 ~R 22 、R d1 ~R d4 、W 1 、W 2 And L and R in formula 1-2 1 、R 19 ~R 22 、R d1 ~R d4 、W 1 、W 2 and L have the same meanings and the preferred embodiments are also the same.

[0785] R in Formula 1-7 25 and R 26 Each independently preferably is a hydrogen atom or an alkyl group, more preferably an alkyl group, and particularly preferably a methyl group.

[0786] Specific examples of cyanine dyes as degradable compounds are given below, but the present invention is not limited to these.

[0787] [Chemical Formula 67]

[0788]

[0789] Furthermore, as the cyanine dye serving as the degradable compound, the infrared absorbing compound described in International Publication No. 2019 / 219560 can be preferably used.

[0790] Furthermore, the color-changing compound may contain an acid developer.

[0791] As the acid developer, the acid developers described as the acid developer in the image recording layer can be used, and preferred aspects are the same.

[0792] The color-changing compound may be used alone or in combination of two or more components.

[0793] As the color-changing compound, the decomposable compound described above and the acid generator described below may be used in combination.

[0794] From the viewpoint of visibility, the content of the color-changing compound in the outermost layer is preferably 0.10 to 50 mass %, more preferably 0.50 to 30 mass %, and even more preferably 1.0 to 20 mass % relative to the total mass of the outermost layer.

[0795] From the viewpoint of visual recognition, the content M of the color-changing compound in the outermost layer is X The content M of the infrared absorber in the image recording layer Y Ratio M X / M Y It is preferably 0.1 or more, more preferably 0.2 or more, and particularly preferably 0.3 or more and 3.0 or less.

[0796] -Water-soluble polymer-

[0797] From the viewpoint of development removability (more preferably on-press developability), the outermost layer preferably contains a water-soluble polymer.

[0798] In the present invention, a water-soluble polymer refers to a polymer that dissolves 1 g or more in 100 g of pure water at 70°C and 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.

[0799] Examples of the water-soluble polymer used in the outermost layer include polyvinyl alcohol, modified polyvinyl alcohol, polyvinyl pyrrolidone, water-soluble cellulose derivatives, polyethylene glycol, and poly(meth)acrylonitrile.

[0800] As the modified polyvinyl alcohol, an acid-modified polyvinyl alcohol having a carboxyl group or a sulfonic group can be preferably used. Specific examples include the modified polyvinyl alcohols described in JP-A-2005-250216 and JP-A-2006-259137.

[0801] As the water-soluble polymer, polyvinyl alcohol is preferably used, and among them, polyvinyl alcohol having a saponification degree of 50% or more is more preferably used as the water-soluble polymer.

[0802] The saponification degree is preferably 60% or higher, more preferably 70% or higher, and even more preferably 85% or higher. The upper limit of the saponification degree is not particularly limited and may be 100% or lower.

[0803] The saponification degree can be measured according to the method described in JIS K 6726:1994.

[0804] As the water-soluble polymer, polyvinyl pyrrolidone is preferably mentioned.

[0805] As the water-soluble polymer, it is also preferable to use polyvinyl alcohol and polyvinyl pyrrolidone in combination.

[0806] The water-soluble polymers may be used alone or in combination of two or more.

[0807] When the outermost layer contains a water-soluble polymer, the content of the water-soluble polymer is preferably 1 to 99 mass %, more preferably 3 to 97 mass %, and even more preferably 5 to 95 mass % relative to the total mass of the outermost layer.

[0808] -Other ingredients-

[0809] The outermost layer may contain other components such as a hydrophobic polymer, a sensitizer, an acid generator, and an infrared absorber in addition to the color-changing compound and the water-soluble polymer described above.

[0810] Other components are described below.

[0811] Hydrophobic Polymers

[0812] The outermost layer preferably contains a hydrophobic polymer.

[0813] The hydrophobic polymer refers to a polymer that dissolves less than 1 g or does not dissolve in 100 g of pure water at 70°C.

[0814] Examples of the hydrophobic polymer include polyethylene, polystyrene, polyvinyl chloride, polyvinylidene chloride, polyalkyl (meth)acrylates (e.g., polymethyl (meth)acrylate, polyethyl (meth)acrylate, polybutyl (meth)acrylate, etc.), and copolymers obtained by combining raw material monomers of these polymers.

[0815] Furthermore, the hydrophobic polymer preferably contains a polyvinylidene chloride resin.

[0816] Furthermore, as the hydrophobic polymer, it is preferable to contain a styrene-acrylic acid copolymer.

[0817] Furthermore, from the viewpoint of on-press developability, the hydrophobic polymer is preferably hydrophobic polymer particles.

[0818] The hydrophobic polymer may be used alone or in combination of two or more.

[0819] When the outermost layer contains a hydrophobic polymer, the content of the hydrophobic polymer is preferably 1% by mass to 80% by mass, more preferably 5% by mass to 50% by mass, relative to the total mass of the outermost layer.

[0820] Acid Generator

[0821] When an acid color developer is used as the color-changing compound in the outermost layer, it is preferable to contain an acid generator.

[0822] The "acid generator" in the present invention is a compound that generates an acid by light or heat, and specifically refers to a compound that generates an acid by decomposition upon exposure to infrared rays.

[0823] The acid to be generated is preferably a strong acid having a pKa of 2 or less, such as sulfonic acid and hydrochloric acid. The acid generated by the acid generator can cause the acid color developer described above to change color.

[0824] Specifically, as the acid generator, an onium salt compound is preferred from the viewpoint of sensitivity and stability.

[0825] Specific examples of onium salts preferred as the acid generator include the compounds described in paragraphs 0121 to 0124 of International Publication No. 2016 / 047392.

[0826] Among them, triarylsulfonium or diaryliodonium, sulfonate, carboxylate, BPh4 - 、BF4 - PF6 - 、ClO4 - etc. Here, Ph represents a phenyl group.

[0827] The acid generator may be used alone or in combination of two or more.

[0828] When the outermost layer contains an acid generator, the content of the acid generator is preferably 0.5% by mass to 30% by mass, more preferably 1% by mass to 20% by mass, relative to the total mass of the outermost layer.

[0829] The outermost layer may contain known additives such as a sensitizer, an inorganic layered compound, and a surfactant in addition to the components already described.

[0830] The outermost layer is formed by coating and drying using a known method.

[0831] The coating amount (solid content) of the outermost layer is preferably 0.01 g / m 2 ~10g / m 2 , more preferably 0.02g / m 2 ~3g / m 2 , especially preferably 0.1g / m 2 ~2.0g / m 2 .

[0832] The film thickness of the outermost layer is preferably 0.1 μm to 5.0 μm, more preferably 0.3 μm to 4.0 μm.

[0833] The thickness of the outermost layer is preferably 0.1 to 5.0 times, and more preferably 0.2 to 3.0 times, the thickness of the image recording layer described below.

[0834] The outermost layer may contain known additives such as a plasticizer for imparting flexibility, a surfactant for improving coating properties, and inorganic particles for controlling surface slip.

[0835] <Support>

[0836] The lithographic printing plate precursor according to the present invention has a support.

[0837] The support may be appropriately selected from known supports for lithographic printing plate precursors and used.

[0838] As the support, a support having a hydrophilic surface (hereinafter also referred to as a "hydrophilic support") is preferred.

[0839] The support in the present invention is preferably an aluminum plate that has been roughened and anodized by a known method. That is, the support in the present invention preferably comprises an aluminum plate and an aluminum anodic oxide film disposed on the aluminum plate.

[0840] Furthermore, the support preferably comprises an aluminum plate and an anodized film of aluminum disposed on the aluminum plate, wherein the anodized film is located closer to the image recording layer than the aluminum plate, and the anodized film has micropores extending from the surface of the image recording layer side in a depth direction, and the average diameter of the micropores at the surface of the anodized film is greater than 10 nm and is less than 100 nm.

[0841] Moreover, preferably, the above-mentioned micropores are composed of large-diameter pore portions and small-diameter pore portions, the above-mentioned large-diameter pore portions extend from the surface of the above-mentioned anodized film to a depth of 10nm to 1,000nm, the above-mentioned small-diameter pore portions are connected to the bottom of the above-mentioned large-diameter pore portions, and extend from the connected position to a depth of 20nm to 2,000nm, the average diameter of the above-mentioned large-diameter pore portions at the surface of the above-mentioned anodized film is 15nm to 100nm, and the average diameter of the above-mentioned small-diameter pore portions at the above-mentioned connected position is less than 13nm.

[0842] Figure 1 It is a schematic cross-sectional view of one embodiment of the aluminum support 12a.

[0843] The aluminum support 12a has a laminated structure in which an aluminum plate 18 and an anodic oxide film 20a of aluminum (hereinafter referred to as "anodic oxide film 20a") are laminated in this order. Furthermore, the anodic oxide film 20a in the aluminum support 12a is located closer to the image recording layer than the aluminum plate 18. Specifically, the lithographic printing plate precursor according to the present invention preferably has at least an anodic oxide film, an image recording layer, and a water-soluble resin layer in this order on the aluminum plate.

[0844] -Anodic oxide film-

[0845] Hereinafter, preferred embodiments of the anodic oxide film 20 a will be described.

[0846] The anodic oxide film 20a is formed on the surface of the aluminum plate 18 by anodizing, and has ultrafine pores 22a that are substantially perpendicular to the film surface and uniformly distributed. The pores 22a extend from the surface of the anodic oxide film 20a on the image recording layer side (the surface of the anodic oxide film 20a on the side opposite to the aluminum plate 18) in the thickness direction (on the aluminum plate 18 side).

[0847] The average diameter (average opening diameter) of the micropores 22a on the surface of the anodic oxide film 20a is preferably greater than 10 nm and less than 100 nm. From the perspective of balancing printing durability, stain resistance, and image visibility, the average diameter is 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 may be wider or narrower than the surface layer.

[0848] When the average diameter exceeds 10 nm, printing durability and image visibility are excellent, and when the average diameter is 100 nm or less, printing durability is excellent.

[0849] The average diameter of the micropores 22a is as follows: the surface of the anodic oxide film 20a was observed using a field emission scanning electron microscope (FE-SEM) with a magnification of 150,000 times, with N = 4 images, and 50 locations with a diameter of 400 × 600 nm were measured in the four images obtained. 2 The diameter of the micropores within the range of and the average value are obtained.

[0850] When the shape of the micropore 22a is not circular, the equivalent circle diameter is used. The “equivalent circle diameter” refers to the diameter of a circle assuming the shape of the opening to have the same projected area as the opening.

[0851] The shape of the micropores 22a is not particularly limited. Figure 1The micropore 22a is generally straight (generally cylindrical), but may be conical in shape with a diameter decreasing in the depth direction (thickness direction). The shape of the bottom of the micropore 22a is not particularly limited and may be curved (convex) or flat.

[0852] In the support body (1), the above-mentioned micropores can be composed of a large-diameter pore portion and a small-diameter pore portion, wherein the large-diameter pore portion extends from the surface of the above-mentioned anodized film to a position of a certain depth, and the small-diameter pore portion is connected to the bottom of the above-mentioned large-diameter pore portion and extends from the connected position to a position of a certain depth.

[0853] For example, Figure 2 As shown, the aluminum support 12 b may be in a form including an aluminum plate 18 and an anodic oxide film 20 b having micropores 22 b consisting of large-diameter pores 24 and small-diameter pores 26 .

[0854] For example, the micropores 22b in the anodic oxide film 20b are composed of large-diameter pores 24 and small-diameter pores 26. 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 φ). Figure 2 ), the small-diameter hole portion 26 communicates with the bottom of the large-diameter hole portion 24 and further extends from the communication 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 Laid-Open No. 2019-162855 can be used.

[0855] -Method for manufacturing a support body-

[0856] As a method for producing the support body used in the present invention, for example, a method of performing the following steps in sequence is preferable.

[0857] Roughening process: The process of roughening the aluminum plate

[0858] Anodizing process: Anodizing the roughened aluminum plate

[0859] Pore enlargement step: The aluminum plate having an anodic oxide film obtained in the anodizing step is brought into contact with an acid aqueous solution or an alkaline aqueous solution to enlarge the diameter of the micropores in the anodic oxide film.

[0860] Hereinafter, the steps of each process will be described in detail.

[0861] Roughening process

[0862] The roughening step involves applying a roughening treatment, including electrochemical roughening, to the surface of the aluminum plate. This step is preferably performed before the anodizing step described below, but is unnecessary if the aluminum plate already has a desired surface profile. This step can be performed using the method described in paragraphs 0086 to 0101 of Japanese Patent Application Laid-Open No. 2019-162855.

[0863] 《Anodizing Process》

[0864] The procedure of the anodizing treatment step is not particularly limited as long as the above-mentioned micropores can be obtained, and a known method can be used.

[0865] In the anodizing step, an aqueous solution of sulfuric acid, phosphoric acid, oxalic acid, etc. can be used as an electrolytic cell. For example, the concentration of sulfuric acid can be 100 g / L to 300 g / L.

[0866] The conditions for the anodic oxidation treatment can be appropriately set according to the electrolyte used, but examples thereof include a liquid temperature of 5°C to 70°C (preferably 10°C to 60°C), a current density of 0.5 A / dm 2 ~60A / dm 2 (Preferably 1A / dm 2 ~60A / dm 2 ), voltage 1V~100V (preferably 5V~50V), electrolysis time 1 second~100 seconds (preferably 5 seconds~60 seconds) and film weight 0.1g / m 2 ~5g / m 2 (Preferably 0.2 g / m 2 ~3g / m 2 ).

[0867] Hole expansion treatment

[0868] The pore expansion treatment is a treatment for increasing the diameter (pore size) of micropores present in the anodic oxide film formed by the above-mentioned anodic oxidation treatment step (pore size expansion treatment).

[0869] The pore expansion treatment can be performed by bringing the aluminum plate obtained by the above-mentioned anodizing treatment step into contact with an acid aqueous solution or an alkaline aqueous solution. The contact method is not particularly limited, and examples thereof include immersion and spraying.

[0870] The support may have a back coating layer comprising an organic polymer compound described in Japanese Patent Application Laid-Open No. 5-45885 or a silicon alkoxy compound described in Japanese Patent Application Laid-Open No. 6-35174, on the surface opposite to the image recording layer, as needed.

[0871] <Base Coating>

[0872] The lithographic printing plate precursor of the present invention preferably has an undercoat layer (sometimes also referred to as an intermediate layer) between the image-recording layer and the support. The undercoat layer enhances adhesion between the support and the image-recording layer in the exposed areas and facilitates separation of the image-recording layer from the support in the unexposed areas. Thus, the undercoat layer helps improve developability without compromising printing durability. Furthermore, in the case of infrared laser exposure, the undercoat layer acts as a heat-insulating layer, thereby preventing heat generated by exposure from diffusing to the support and causing a decrease in sensitivity.

[0873] Examples of compounds used in the undercoat layer include polymers having adsorptive groups and hydrophilic groups that can adsorb to the support surface. To improve adhesion to the image-recording layer, polymers having adsorptive and hydrophilic groups, as well as crosslinkable groups, are preferred. The compounds used in the undercoat layer may be low molecular weight compounds or polymers. Two or more compounds may be mixed as needed.

[0874] When 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 crosslinkable group is preferred.

[0875] Preferred adsorbable groups capable of adsorbing to the support surface include phenolic hydroxyl groups, carboxyl groups, -PO3H2, -OPO3H2, -CONHSO2-, -SONHSO2-, and -COCH2COCH3. Preferred hydrophilic groups include sulfonic groups or salts thereof, and salts of carboxyl groups. Preferred crosslinking groups include acryloyl groups, methacryloyl groups, acrylamide groups, methacrylamide groups, and allyl groups.

[0876] The polymer may have a crosslinkable group introduced by forming a salt between a polar substituent of the polymer and a compound having a substituent having a charge opposite to that of the polar substituent and an ethylenically unsaturated bond, and may further be copolymerized with monomers other than the above, preferably hydrophilic monomers.

[0877] Specifically, preferably enumerate the phosphorus compound with olefinic double bond reactive group of writing down in the silane coupling agent with the olefinic double bond reactive group that can addition polymerization in Japanese Unexamined Patent Publication No. 10-282679 communique, Japanese Unexamined Patent Publication No. 2-304441 communique. Also can preferably use the low molecule or the macromolecular compound with crosslinking group (being preferably olefinic unsaturated bond group) of writing down in each communique of Japanese Unexamined Patent Publication No. 2005-238816, Japanese Unexamined Patent Publication No. 2005-125749, Japanese Unexamined Patent Publication No. 2006-239867, Japanese Unexamined Patent Publication No. 2006-215263, with the interactive functional group of support surface and hydrophilic group.

[0878] More preferred compounds include polymers having an adsorbable group adsorbable on the surface of a support, a hydrophilic group, and a crosslinkable group, as described in Japanese Patent Application Laid-Open Nos. 2005-125749 and 2006-188038.

[0879] The content of the ethylenically unsaturated bond group in the polymer used for the primer layer is preferably 0.1 mmol to 10.0 mmol, more preferably 0.2 mmol to 5.5 mmol, per 1 g of the polymer.

[0880] The weight average molecular weight (Mw) of the polymer used in the primer layer is preferably 5,000 or more, and more preferably 10,000 to 300,000.

[0881] -Hydrophilic compounds-

[0882] From the viewpoint of developability, the undercoat layer preferably contains a hydrophilic compound.

[0883] The hydrophilic compound is not particularly limited, and a known hydrophilic compound used in a primer layer can be used.

[0884] Preferred hydrophilic compounds include phosphonic acids having an amino group such as carboxymethyl cellulose and dextrin, organic phosphonic acid, organic phosphoric acid, organic phosphinic acid, amino acids, and hydrochlorides of amines having a hydroxyl group.

[0885] In addition, as hydrophilic compounds, preferred examples include compounds having an amino group or a functional group having polymerization inhibition ability and a group that interacts 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 its salts, hydroxyethylethylenediaminetriacetic acid or its salts, dihydroxyethylethylenediaminediacetic acid or its salts, hydroxyethyliminodiacetic acid, etc. or its salts, etc.).

[0886] As the hydrophilic compound, from the viewpoint of scratch staining inhibition, it is preferred to contain a hydroxycarboxylic acid or a salt thereof.

[0887] Furthermore, from the perspective of scratch stain suppression, a hydrophilic compound, preferably a hydroxycarboxylic acid or a salt thereof, is preferably contained in the layer on the aluminum support. Furthermore, the layer on the aluminum support is preferably located on the side where the image recording layer is formed, and is preferably in contact with the aluminum support.

[0888] As the layer on the aluminum support, preferably, the layer in contact with the aluminum support is a primer layer or an image recording layer. In addition, a layer other than the layer in contact with the aluminum support, such as a protective layer or an image recording layer, may contain a hydrophilic compound, preferably a hydroxycarboxylic acid or a salt thereof.

[0889] In the lithographic printing plate precursor according to the present invention, the image recording layer preferably contains a hydroxycarboxylic acid or a salt thereof from the viewpoint of scratch staining inhibition.

[0890] Furthermore, in the lithographic printing plate precursor according to the present invention, 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, etc.) containing at least a hydroxycarboxylic acid or a salt thereof is also preferred. In this method, the treated hydroxycarboxylic acid or salt thereof can be at least partially detected as contained in a layer (e.g., an image-recording layer or an undercoat layer) on the image-recording layer side in contact with the aluminum support.

[0891] By including a hydroxycarboxylic acid or a salt thereof in a layer on the image recording layer side that contacts the aluminum support, such as a primer layer, the surface on the image recording layer side of the aluminum support can be hydrophilized, and the contact angle with water on the surface on the image recording layer side of the aluminum support based on an aerial water drop method can be easily set to 110° or less, resulting in excellent scratch contamination inhibition.

[0892] Hydroxycarboxylic acid is a general term for organic compounds having one or more carboxyl groups and one or more hydroxyl groups in one molecule, and is also called hydroxy acid, oxyacid, hydroxycarboxylic acid, or alkyd acid (see Iwanami Physical and Chemical Dictionary, 5th edition, published by Iwanami Shoten (1998)).

[0893] The hydroxycarboxylic acid or a salt thereof is preferably represented by the following formula (HC).

[0894] R HC (OH) mhc (COOM HC ) nhc Formula (HC)

[0895] In formula (HC), R HC Represents an organic group with MHC+NHC valence, M HC Each independently represents a hydrogen atom, an alkali metal or an onium, and mhc and nhc each independently represent an integer greater than or equal to 1. When n is greater than or equal to 2, M may be the same or different.

[0896] In formula (HC), as R HC The organic group with MHC+NHC valence represented by includes a hydrocarbon group with MHC+NHC valence, etc. The hydrocarbon group may have a substituent and / or a linking group.

[0897] Examples of the hydrocarbon group include groups with MHC+NHC valences derived from aliphatic hydrocarbons, such as alkylene, alkanetriyl, alkanetetrayl, alkanepentayl, alkenylene, alkenetriyl, alkenetetrayl, alkenepentayl, alkynylene, alkynetriyl, alkynetetrayl, alkynepentayl, and the like; and groups with MHC+NHC valences derived from aromatic hydrocarbons, such as arylene, arenetriyl, arenetetrayl, arenepentayl, and the like. Examples of the substituent include alkyl, alkenyl, alkynyl, aralkyl, and aryl groups. Specific examples of the substituent include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, hexadecyl, octadecyl, eicosyl, isopropyl, isobutyl, sec-butyl, tert-butyl, isopentyl, neopentyl, 1-methylbutyl, isohexyl, 2-ethylhexyl, 2-methylhexyl, cyclohexyl, cyclopentyl, 2-norbornyl, methoxymethyl, methoxyethoxyethyl, allyloxymethyl, phenoxymethyl, acetoxymethyl, benzoyloxy Examples include methyl, benzyl, phenethyl, α-methylbenzyl, 1-methyl-1-phenethyl, p-methylbenzyl, cinnamyl, allyl, 1-propenylmethyl, 2-butenyl, 2-methylallyl, 2-methylpropenylmethyl, 2-propynyl, 2-butynyl, 3-butynyl, phenyl, biphenyl, naphthyl, tolyl, xylyl, mesityl, cumenyl, methoxyphenyl, ethoxyphenyl, phenoxyphenyl, acetoxyphenyl, benzoyloxyphenyl, methoxycarbonylphenyl, ethoxycarbonylphenyl, and phenoxycarbonylphenyl. The linking group is composed of at least one atom selected from hydrogen, carbon, oxygen, nitrogen, sulfur, and halogen atoms, and preferably has 1 to 50 atoms. Specifically, examples include alkylene, substituted alkylene, arylene, and substituted arylene groups, and may have a structure in which a plurality of these divalent groups are linked by amide, ether, urethane, urea, and ester bonds.

[0898] As M HC Examples of the alkali metal represented by include lithium, sodium, potassium, and the like, with sodium being particularly preferred. Examples of the onium include ammonium, phosphonium, and sulfonium, with ammonium being particularly preferred.

[0899] Furthermore, from the perspective of scratch contamination suppression, M HC An alkali metal or onium is preferred, and an alkali metal is more preferred.

[0900] The total number of MHCs and NHCs is preferably 3 or more, more preferably 3 to 8, and even more preferably 4 to 6.

[0901] The molecular weight of the hydroxycarboxylic acid or its salt is preferably 600 or less, more preferably 500 or less, and particularly preferably 300 or less. Furthermore, the molecular weight is preferably 76 or more.

[0902] Specific examples of the hydroxycarboxylic acids or the hydroxycarboxylic acids constituting the salts thereof include 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, leucine, mevalonic acid, pantoic acid, ricinoleic acid, ricinoleic acid, hydroxyethyl ester, quinic acid, shikimic acid, monohydroxybenzoic acid derivatives (salicylic acid, lignoceric acid (high water content), linalool, ... Salicylic acid, hydroxy(methyl)benzoic acid), vanillic acid, syringic acid, etc.), dihydroxybenzoic acid derivatives (pyrocatechuic acid, dihydroxybenzoic acid, protocatechuic acid, gentisic acid, lysine acid, etc.), trihydroxybenzoic acid derivatives (gallic acid, etc.), phenylacetic acid derivatives (mandelic acid, benzilic acid, atrolactic acid, etc.), hydrocinnamic acid derivatives (o-hydroxyphenylpropionic acid, phloric acid, coumaric acid, umbelliferyl acid, caffeic acid, ferulic acid, sinapic acid, hydroxyethyl ester, carminic acid, etc.), etc.

[0903] Among these, the hydroxycarboxylic acid or the hydroxycarboxylic acid constituting the salt of the hydroxycarboxylic acid is preferably a compound having two or more hydroxyl groups, more preferably a compound having three or more hydroxyl groups, further preferably a compound having five or more hydroxyl groups, and particularly preferably a compound having 5 to 8 hydroxyl groups, from the viewpoint of scratch stain inhibition.

[0904] Furthermore, as the compound having one carboxyl group and two or more hydroxyl groups, gluconic acid or shikimic acid is preferred.

[0905] As the compound having two or more carboxyl groups and one hydroxyl group, citric acid or malic acid is preferred.

[0906] As the compound having two or more carboxyl groups and two or more hydroxyl groups, tartaric acid is preferred.

[0907] Among them, gluconic acid is particularly preferred as the hydroxycarboxylic acid.

[0908] The hydrophilic compound may be used alone or in combination of two or more.

[0909] When the primer layer contains a hydrophilic compound, preferably a hydroxycarboxylic acid or a salt thereof, the content of the hydrophilic compound, preferably a hydroxycarboxylic acid or a salt thereof, is preferably 0.01% by mass to 50% by mass, more preferably 0.1% by mass to 40% by mass, and particularly preferably 1.0% by mass to 30% by mass, relative to the total mass of the primer layer.

[0910] The undercoat layer may contain, in addition to the above-mentioned undercoat layer compound, a chelating agent, a secondary or tertiary amine, a polymerization inhibitor, and the like in order to prevent staining over time.

[0911] The primer layer can be applied by a known method.

[0912] The coating amount (solid content) of the primer layer is preferably 0.1 mg / m 2 ~300 mg / m 2 , more preferably 5mg / m2~200mg / m 2 .

[0913] The lithographic printing plate precursor according to the present invention may have other layers in addition to the above-mentioned layers.

[0914] The other layers are not particularly limited and may be known layers. For example, a back coat layer may be provided on the side of the support opposite to the image recording layer side, as needed.

[0915] (Method for producing lithographic printing plate and lithographic printing method)

[0916] The method for producing a lithographic printing plate involved in the present invention preferably includes: a process of exposing the lithographic printing plate precursor involved in the present invention into an image form (exposure process); and a process of supplying at least one selected from printing ink and fountain solution to the exposed lithographic printing plate precursor on a printing press to remove the image recording layer of the non-image part (on-press development process).

[0917] The lithographic printing method involved in the present invention preferably includes: a process of exposing the lithographic printing plate precursor involved in the present invention into an image form (exposure process); a process of supplying at least one selected from printing ink and fountain solution on a printing press to remove the image recording layer of the non-image part to produce a lithographic printing plate (on-press development process); and a process of printing using the obtained lithographic printing plate (hereinafter also referred to as "printing process").

[0918] <Exposure Process>

[0919] The method for producing a lithographic printing plate according to the present invention preferably includes an exposure step of exposing the lithographic printing plate precursor according to the present invention in an imagewise manner to form exposed and unexposed areas. The lithographic printing plate precursor according to the present invention is preferably exposed in an imagewise manner by laser exposure using a transparent original image having a line image, a halftone dot image, or the like, or by laser beam scanning based on digital data.

[0920] A light source with a wavelength of 750 nm to 1,400 nm is preferably used. Solid-state lasers and semiconductor lasers that radiate infrared light are preferred as light sources with a wavelength of 750 nm to 1,400 nm. For infrared lasers, the output power is preferably 100 mW or higher, the exposure time per pixel is preferably within 20 microseconds, and the irradiation energy is preferably 10 mJ / cm 2 ~300mJ / cm 2 In order to shorten the exposure time, it is preferable to use a multi-beam laser device. The exposure mechanism can be any of an inner drum method, an outer drum method, and a flatbed method.

[0921] Image exposure can be performed by a conventional method using a plate-making machine, etc. In the case of on-press development, the lithographic printing plate precursor can be mounted on a printing press and then image exposure can be performed on the printing press.

[0922] <On-press development process>

[0923] The method for producing a lithographic printing plate according to the present invention preferably includes an on-press development step of supplying at least one selected from printing ink and fountain solution on a printing press to remove non-image areas of the image recording layer.

[0924] The on-press development method is described below.

[0925] [On-press development method]

[0926] In the on-press development method, the image-exposed lithographic printing plate precursor is preferably supplied with an oil-based ink and an aqueous component on a printing press, and the image recording layer in the non-image area is removed to produce a lithographic printing plate.

[0927] That is, if after the lithographic printing plate precursor is subjected to image exposure, it is directly mounted on a printing press without any development treatment, or after the lithographic printing plate precursor is mounted on a printing press, image exposure is performed on the printing press, and then an oil-based ink and an aqueous component are supplied and printing is performed, then in the initial stage of printing, in the non-image area, the image recording layer that has not been solidified by the supplied oil-based ink and aqueous component or both is dissolved or dispersed and removed, thereby exposing the hydrophilic surface to this part. On the other hand, in the exposure area, the image recording layer solidified by exposure forms an oil-based ink receiving area with an oleophilic surface. The compound initially supplied to the plate surface can be an oil-based ink or an aqueous component, but from the perspective of preventing contamination by the components of the image recording layer from which the aqueous component has been removed, it is preferred to initially supply an oil-based ink. In this way, the lithographic printing plate precursor is developed on the printing press and used directly in multiple printings. As the oil-based ink and aqueous component, it is preferred to use conventional lithographic printing ink and fountain solution.

[0928] As the laser light source for imagewise exposure of the lithographic printing plate precursor according to the present invention, a light source having a wavelength of 750 nm to 1,400 nm is preferably used.

[0929] <Printing process>

[0930] The planographic printing method according to the present invention includes a printing step of supplying printing ink to a planographic printing plate and printing a recording medium.

[0931] There are no particular limitations on the printing ink, and various known inks can be used as needed. Preferred printing inks include oil-based inks and ultraviolet curable inks (UV inks).

[0932] Furthermore, during the printing step, a fountain solution may be supplied as needed.

[0933] Furthermore, the printing process does not need to stop the printing press, but can be performed continuously during the on-press development process or the developer development process.

[0934] The recording medium is not particularly limited, and a known recording medium can be used as needed.

[0935] In the method for producing a lithographic printing plate from a lithographic printing plate precursor and the lithographic printing method of the present invention, the entire surface of the lithographic printing plate precursor can be heated as needed before, during, or between exposure and development. This heating can promote the image-forming reaction in the image-recording layer, resulting in advantages such as improved sensitivity and printing durability, and stabilization of sensitivity. Heating before development is preferably performed under mild conditions of 150°C or less. This prevents problems such as solidification of non-image areas. Heating after development is preferably performed under very strong conditions, preferably within the range of 100°C to 500°C. Within this range, sufficient image enhancement can be achieved, and problems such as deterioration of the support and thermal decomposition of the image area can be suppressed.

[0936] Example

[0937] Hereinafter, the present invention will be described in detail by way of examples, but the present invention is not limited thereto. In addition, in the present examples, the so-called "%" and "parts" refer to "mass %" and "mass parts" respectively, unless otherwise specified. In addition, in polymer compounds, except for specially specified polymer compounds, the molecular weight is the weight average molecular weight (Mw), and the ratio of the structural repeating unit is the molar percentage. Furthermore, the weight average molecular weight (Mw) is a value measured as a polystyrene conversion value based on the gel permeation chromatography (GPC) method.

[0938] (Examples 1 to 18 and Comparative Examples 1 to 4)

[0939] <Production of Supports A and B>

[0940] Processing A and B

[0941] (Aa) Alkali etching treatment

[0942] The aluminum plate was etched by spraying a caustic soda aqueous solution with a caustic soda concentration of 26% by mass and an aluminum ion concentration of 6.5% by mass at a temperature of 70°C. The plate was then rinsed with water using a spray. The surface was then electrochemically roughened to a concentration of 5 g / m2 of aluminum dissolved thereon. 2 .

[0943] (Ab) Decontamination treatment using an acidic aqueous solution (first decontamination treatment)

[0944] Next, decontamination treatment was performed using an acidic aqueous solution. A 150 g / L sulfuric acid solution was used. The solution temperature was 30°C. The acidic aqueous solution was sprayed onto the aluminum plate using a sprayer for 3 seconds. The plate was then rinsed with water.

[0945] (Ac) Electrochemical roughening treatment

[0946] Next, 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, with alternating current. The electrolyte temperature was 30° C. Aluminum chloride was added to adjust the aluminum ion concentration.

[0947] The waveform of the AC current is a sine wave with symmetrical positive and negative waveforms, a frequency of 50 Hz, a 1:1 ratio between the anode reaction time and the cathode reaction time in one cycle of the AC current, and a current density of 75 A / dm2 based on the peak current of the AC current waveform. 2 The total amount of electricity consumed by the aluminum plate in the anode reaction is 450C / dm 2 For electrolysis, the current was applied at 112.5C / dm 2 This was done in four steps. A carbon electrode was used as the counter electrode for the aluminum plate. The aluminum plate was then rinsed with water.

[0948] (Ad) Alkali etching treatment

[0949] The aluminum plate after electrochemical roughening treatment was etched by spraying a caustic soda aqueous solution with a caustic soda concentration of 5% by mass and an aluminum ion concentration of 0.5% by mass at a temperature of 45°C. The amount of aluminum dissolved on the surface after electrochemical roughening treatment was 0.2 g / m 2 Then, a water washing process was performed.

[0950] (Ae) Decontamination treatment using an acidic aqueous solution

[0951] Next, a decontamination treatment was performed using an acidic aqueous solution. Specifically, the acidic aqueous solution was sprayed onto the aluminum plate using a sprayer for 3 seconds. The acidic aqueous solution used for decontamination had a sulfuric acid concentration of 170 g / L and an aluminum ion concentration of 5 g / L. The solution temperature was 30°C.

[0952] (Af) Stage 1 anodizing treatment

[0953] Utilize based Figure 6 The first stage of anodizing treatment was performed using a direct current electrolytic anodizing apparatus having the structure shown. The anodizing treatment was performed under the conditions shown in the "First Anodizing Treatment" column in Table 1 to form an anodic oxide film having a predetermined film weight.

[0954] (Ag) Hole expansion treatment

[0955] The anodized aluminum plate was immersed in a caustic soda aqueous solution at 40°C, with a caustic soda concentration of 5% by mass and an aluminum ion concentration of 0.5% by mass, for pore expansion under the time conditions shown in Table 1. The plate was then rinsed with water using a sprayer.

[0956] (Ah) Second stage anodizing

[0957] Utilize based Figure 6 The second stage of anodizing was performed using a DC electrolytic anodizing apparatus having the structure shown. Anodizing was performed under the conditions shown in Table 1 under "Second Anodizing," forming an anodic oxide film with a predetermined film thickness. As shown in Table 1, the second stage of anodizing was not performed in surface treatment B.

[0958] [Table 1]

[0959]

[0960] <Production of Supports C to E>

[0961] Surface Treatment C

[0962] (Ca) Mechanical roughening treatment (brush method)

[0963] Use as Figure 5 The apparatus shown in the figure is used to mix the pumice powder suspension (specific gravity 1.1 g / cm 3 ) is supplied to the surface of the aluminum plate as a polishing slurry and mechanical roughening is performed by a rotating bristle brush. Figure 5 In the figure, 1 is an aluminum plate, 2 and 4 are roller brushes (bristle brushes in this embodiment), 3 is abrasive slurry, and 5, 6, 7 and 8 are support rollers.

[0964] In the mechanical roughening treatment, the median particle size (μm) of the abrasive was set to 30 μm, the number of brushes was set to 4, and the brush rotation speed (rpm) was set to 250 rpm. The bristle brush was made of 6 / 10 nylon, with a bristle diameter of 0.3 mm and a bristle length of 50 mm. The brush was made by drilling holes in a φ300 mm stainless steel sleeve and densely planting bristles. The distance between the two support rollers (φ200 mm) at the bottom of the bristle brush was 300 mm. The bristle brush was pressed until the load of the drive motor that rotated the brush increased by 10 kW relative to the load before the bristle brush was pressed against the aluminum plate. The direction of rotation of the brush was the same as the direction of movement of the aluminum plate.

[0965] (Cb) Alkali etching treatment

[0966] The aluminum plate obtained above was etched by spraying a caustic soda aqueous solution having a caustic soda concentration of 26% by mass and an aluminum ion concentration of 6.5% by mass at a temperature of 70°C. The plate was then rinsed with water using a sprayer. The amount of aluminum dissolved was 10 g / m 2 .

[0967] (Cc) Decontamination in acidic aqueous solutions

[0968] Next, desmearing was performed in a nitric acid aqueous solution. The nitric acid aqueous solution used for desmearing was the wastewater from the electrochemical roughening process in the next step. The solution temperature was 35°C. The desmearing solution was sprayed with a sprayer for 3 seconds.

[0969] (Cd) electrochemical roughening treatment

[0970] The electrochemical roughening treatment was carried out continuously using nitric acid electrolysis with an AC voltage of 60Hz. The electrolyte used at this time was an electrolyte prepared by adding aluminum nitrate to an aqueous solution of 10.4g / L nitric acid at a temperature of 35°C and adjusting the aluminum ion concentration to 4.5g / L. The AC power waveform is Figure 3 The waveform shown in the figure is used, and the time tp from zero to peak of the current value is 0.8msec, the duty ratio is 1:1, and the trapezoidal rectangular wave AC is used. The carbon electrode is used as the counter electrode for electrochemical roughening treatment. Ferrite is used as the auxiliary anode. For the electrolytic cell, Figure 4 The electrolytic cell shown. The current density is 30A / dm at the peak current. 2 , so that 5% of the current flowing from the power supply is diverted to the auxiliary anode. 2 ) The total amount of electricity when the aluminum plate is used as the anode is 185C / dm 2 Then, a spray-based water wash was performed.

[0971] (Ce) Alkali etching treatment

[0972] The aluminum plate obtained above was etched by spraying a caustic soda aqueous solution having a caustic soda concentration of 5% by mass and an aluminum ion concentration of 0.5% by mass at a temperature of 50°C. The plate was then rinsed with water using a sprayer. The amount of aluminum dissolved was 0.5 g / m 2 .

[0973] (Cf) Decontamination treatment in acidic aqueous solution

[0974] Next, decontamination treatment was performed in a sulfuric acid aqueous solution. The sulfuric acid aqueous solution used for decontamination treatment had a sulfuric acid concentration of 170 g / L and an aluminum ion concentration of 5 g / L. The solution temperature was 30°C. The decontamination solution was sprayed with a sprayer for 3 seconds.

[0975] (Cg) Electrochemical roughening treatment

[0976] Electrochemical roughening treatment was performed continuously using hydrochloric acid electrolysis with an AC voltage of 60Hz. The electrolyte used was an electrolyte prepared by adding aluminum chloride to an aqueous solution of 6.2g / L hydrochloric acid at a temperature of 35°C and adjusting the aluminum ion concentration to 4.5g / L. The AC power waveform is Figure 3 The waveform shown in the figure was used, and the time tp from zero to peak of the current value was 0.8msec, the duty ratio was 1:1, and the trapezoidal rectangular wave AC was used. The carbon electrode was used as the counter electrode for electrochemical roughening treatment. Ferrite was used as the auxiliary anode. For the electrolytic cell, Figure 4 The electrolytic cell shown.

[0977] The current density is 25A / dm at the peak current. 2 , the amount of electricity in hydrochloric acid electrolysis (C / dm 2 ) The total amount of electricity when the aluminum plate is used as the anode is 63C / dm 2 Then, a spray-based water wash was performed.

[0978] (Ch) Alkali etching

[0979] The aluminum plate obtained above was etched by spraying a caustic soda aqueous solution having a caustic soda concentration of 5% by mass and an aluminum ion concentration of 0.5% by mass at a temperature of 50°C. The plate was then rinsed with water using a sprayer. The amount of aluminum dissolved was 0.1 g / m 2 .

[0980] (Ci) Decontamination treatment in acidic aqueous solution

[0981] Next, a decontamination treatment was performed in a sulfuric acid aqueous solution. Specifically, the wastewater generated during the anodizing process (5 g / L of aluminum ions dissolved in a 170 g / L sulfuric acid aqueous solution) was used for 4 seconds at a temperature of 35°C. The decontamination solution was sprayed using a sprayer for 3 seconds.

[0982] (Cj) Stage 1 anodizing treatment

[0983] Utilize based Figure 6 The first stage of anodizing treatment was carried out in a DC electrolytic anodizing device having the structure shown in FIG. Anodizing treatment was carried out under the conditions shown in Table 1, and an anodized film having a predetermined film thickness was formed. In addition, in the anodizing device 610, the aluminum plate 616 was Figure 6 The aluminum sheet 616 is conveyed as indicated by the arrow in the middle. In the power supply tank 612, which contains electrolyte 618, the aluminum sheet 616 is charged with a positive charge by a power supply electrode 620. The aluminum sheet 616 is conveyed upward by rollers 622 in the power supply tank 612, deflected downward by nip rollers 624, and then conveyed to the electrolytic treatment tank 614, which contains electrolyte 626, where it is deflected horizontally by rollers 628. The aluminum sheet 616 then passes through electrolytic electrodes 630, receiving a negative charge, thereby forming an anodic oxide film on its surface. After leaving the electrolytic treatment tank 614, the aluminum sheet 616 is conveyed to the subsequent process. In the anodizing apparatus 610, a direction-changing mechanism is formed by rollers 622, nip rollers 624, and rollers 628. In the space between the power supply tank 612 and the electrolytic treatment tank 614, the aluminum sheet 616 is conveyed in a mountain-shaped and inverted U-shaped pattern by these rollers 622, 624, and 628. The power supply electrode 620 and the electrolysis electrode 630 are connected to a DC power supply 634 .

[0984] (Ck) Hole expansion treatment

[0985] The anodized aluminum plate was immersed in a caustic soda aqueous solution having a temperature of 35°C, a caustic soda concentration of 5% by mass, and an aluminum ion concentration of 0.5% by mass to perform pore expansion under the conditions shown in Table 1. The plate was then rinsed with water using a sprayer.

[0986] (Cl) Second stage anodizing treatment

[0987] Utilize based Figure 6 The second stage of anodizing treatment was performed using a direct current electrolytic anodizing apparatus having the structure shown. Anodizing treatment was performed under the conditions shown in Table 2 to form an anodic oxide film having a predetermined film thickness.

[0988] (Cm) 3rd stage anodizing treatment

[0989] Utilize based Figure 6 The third stage of anodizing treatment was performed using a direct current electrolytic anodizing apparatus having the structure shown. Anodizing treatment was performed under the conditions shown in Table 2 to form an anodic oxide film having a predetermined film thickness.

[0990] Surface Treatment D:

[0991] [Supporting body having a large-diameter hole portion and a small-diameter hole portion]

[0992] (Da) Alkali etching treatment

[0993] The aluminum plate was etched by spraying a caustic soda (sodium hydroxide) aqueous solution having a concentration of 26% by mass and an aluminum ion concentration of 6.5% by mass at a temperature of 70°C using a spray pipe. The plate was then rinsed with water using a sprayer. The surface was then electrochemically roughened to a concentration of 1.0 g / m2 of aluminum dissolved therein. 2 .

[0994] (Db) Decontamination treatment in an acidic aqueous solution (first decontamination treatment)

[0995] Next, decontamination treatment was performed in an acidic aqueous solution. A 150 g / L sulfuric acid solution was used for decontamination treatment. The solution temperature was 30°C. The decontamination solution was sprayed with a sprayer for 3 seconds. Afterwards, water washing was performed.

[0996] (Dc) Electrochemical roughening treatment in hydrochloric acid aqueous solution

[0997] Next, electrolytic 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, and alternating current. The electrolyte temperature was 30°C. The aluminum ion concentration was adjusted by adding aluminum chloride. The waveform of the alternating current was a sine wave with symmetrical positive and negative waveforms, the frequency was 50 Hz, the anodic reaction time and the cathodic reaction time in one cycle of the alternating current were 1:1, and the current density was 75 A / dm3 based on the peak current of the alternating current waveform. 2 The total amount of electricity consumed by the aluminum plate in the anode reaction is 450C / dm 2 For electrolysis, the current was applied at 125C / dm 2 This was done in four steps. A carbon electrode was used as the counter electrode for the aluminum plate. The aluminum plate was then rinsed with water.

[0998] (Dd) Alkali etching treatment

[0999] The aluminum plate after electrochemical roughening treatment was etched by spraying a caustic soda aqueous solution with a caustic soda concentration of 5% by mass and an aluminum ion concentration of 0.5% by mass at a temperature of 45°C. The amount of aluminum dissolved on the surface after electrochemical roughening treatment was 0.2 g / m 2 Then, a water washing process was performed.

[1000] (De) Decontamination in acidic aqueous solutions

[1001] Next, decontamination treatment was performed in an acidic aqueous solution. The acidic aqueous solution used for decontamination was wastewater from the anodizing process (5.0 g / L of aluminum ions dissolved in a 170 g / L aqueous sulfuric acid solution). The solution temperature was 30°C. The decontamination solution was sprayed using a sprayer for 3 seconds.

[1002] (Df) Stage 1 anodizing

[1003] Utilize based Figure 6 The first stage of anodizing treatment was performed using a direct current electrolytic anodizing apparatus having the structure shown. Anodizing treatment was performed under the conditions shown in Table 2 to form an anodic oxide film having a predetermined film thickness.

[1004] (Dg) Hole expansion treatment

[1005] The anodized aluminum plate was immersed in a caustic soda aqueous solution having a temperature of 35°C, a caustic soda concentration of 5% by mass, and an aluminum ion concentration of 0.5% by mass to perform pore expansion under the conditions shown in Table 1. The plate was then rinsed with water using a sprayer.

[1006] (Dh) Second stage anodizing treatment

[1007] Utilize based Figure 6 The second stage of anodizing treatment was performed using a direct current electrolytic anodizing apparatus having the structure shown. Anodizing treatment was performed under the conditions shown in Table 2 to form an anodic oxide film having a predetermined film thickness.

[1008] Supports C to E shown in Tables 2 and 3 were obtained by the above surface treatment C or D.

[1009] The average diameter (nm) of the large-diameter pores at the surface of the anodic oxide film, the average diameter (nm) of the small-diameter pores at the communicating positions, the depths (nm) of the large-diameter pores and the small-diameter pores, the density of the dents (micropore density, unit: pores / μm) in the anodic oxide film having micropores obtained after the second anodic oxidation treatment step were calculated. 2), and the thickness (nm) of the anodic oxide film from the bottom of the small-diameter hole to the surface of the aluminum plate are summarized in Table 2.

[1010] The average diameter of the micropores (the average diameter of the large-diameter pores and the small-diameter pores) is the value obtained by measuring the diameters of the micropores (large-diameter pores and small-diameter pores) within the range of 400 nm x 600 nm in four images obtained by observing the large-diameter pore surface and the small-diameter pore surface using a 150,000x FE-SEM. Furthermore, in cases where the large-diameter pores are deep and it is difficult to measure the diameter of the small-diameter pores, or when measuring the expanded-diameter pores within the small-diameter pores, the upper portion of the anodic oxide film is cut away and the various diameters are then determined.

[1011] The depth of the micropores (the depth of the large-diameter pores and the small-diameter pores) is the following value, that is, the cross-section of the support body (anodized film) is observed using FE-SEM (observation of the depth of the large-diameter pores: 150,000 times, observation of the depth of the small-diameter pores: 50,000 times), and the depth of any 25 micropores in the obtained image is measured and averaged.

[1012] In Table 2, the film amount (AD) in the first anodizing treatment column and the film amount (AD) in the second anodizing treatment column represent the film amount obtained in each treatment.

[1013] In Table 2, "170 / 5" in the column of component concentration means that the sulfuric acid concentration is 170 g / L and the aluminum ion concentration is 5 g / L. In addition, in Table 2, the temperature unit is "°C" and the current density unit is "A / dm 2 ", time unit is "s", film volume unit is "g / m 2 ”.

[1014] [Table 2]

[1015]

[1016] [Table 3]

[1017]

[1018] <Method for Forming Primer Layers A to C>

[1019] On the supports listed in Tables 4 to 6, the coating amount was set to 20 mg / m 2 Any of the primer coating solutions A to C having the following compositions shown in Tables 4 to 6 was applied in a manner and dried in an oven at 100° C. for 30 seconds to form a primer layer.

[1020] -Composition of Undercoat Layer Coating Liquid A-

[1021] Polymer (U-1) [following structure]: 0.18 parts

[1022] · Hydroxyethyliminodiacetic acid: 0.10 parts

[1023] Water: 61.4 parts

[1024] [Chemical Formula 68]

[1025] (U-1)

[1026]

[1027] -Composition of Undercoat Layer Coating Liquid B-

[1028] Polymer (U-1): 0.14 parts

[1029] Sodium gluconate: 0.07 parts

[1030] Surfactant (EMALEX710, manufactured by NIHON EMULSION Co., Ltd.): 0.0016 parts by mass

[1031] Preservative (Biohope L, manufactured by K.I. Chemical Industry Co., Ltd.): 0.0015 parts

[1032] Water: 3.29 parts

[1033] -Composition of Undercoat Layer Coating Liquid C-

[1034] Polymer (U-1): 0.14 parts

[1035] Chelest400: 0.035 parts

[1036] Chelest3EAF: 0.035 parts

[1037] Surfactant (EMALEX710, manufactured by NIHON EMULSION Co., Ltd.): 0.0016 parts by mass

[1038] Preservative (Biohope L, manufactured by K.I. Chemical Industry Co., Ltd.): 0.0015 parts

[1039] Water: 3.29 parts

[1040] -Synthesis of polymer (U-1)-

[1041] Purification of Monomer M-1

[1042] 420 parts of LIGHT ESTER P-1M (2-methacryloyloxyethyl acid phosphate, manufactured by Kyoeisha Chemical Co., Ltd.), 1,050 parts of diethylene glycol dibutyl ether, and 1,050 parts of distilled water were placed in a separatory funnel, stirred vigorously, and then allowed to stand. After discarding the upper layer, 1,050 parts of diethylene glycol dibutyl ether was added, stirred vigorously, and then allowed to stand. The upper layer was discarded to obtain 1,300 parts of an aqueous solution of monomer M-1 (10.5% by mass based on solids content).

[1043] Synthesis of Polymer (U-1)

[1044] In a three-necked flask, 53.73 parts of distilled water and 3.66 parts of monomer M-2 shown below were added and heated to 55 ° C under a nitrogen environment. Then, the dropwise addition solution 1 shown below was added dropwise over 2 hours, and after stirring for 30 minutes, 0.386 parts of VA-046B (manufactured by FUJIFILM Wako Pure Chemical Corporation) was added, the temperature was raised to 80 ° C, and stirred for 1.5 hours. After the reaction solution was returned to room temperature (25 ° C), a 30% by mass sodium hydroxide aqueous solution was added, and after the pH was adjusted to 8.0, 0.005 parts of 4-hydroxy-2,2,6,6-tetramethylpiperidin-1-oxyl (4-OH-TEMPO) was added. By the above operation, 180 parts of an aqueous solution of polymer (U-1) were obtained. The weight average molecular weight (Mw) as a polyethylene glycol conversion value obtained by gel permeation chromatography (GPC) was 200,000.

[1045] [Chemical Formula 69]

[1046]

[1047] Composition of Dropping Solution 1

[1048] · Aqueous solution of the monomer M-1: 87.59 parts

[1049] ·Monomer M-2: 14.63 parts

[1050] VA-046B (2,2'-azobis[2-(2-imidazolin-2-yl)propane]disulfate dihydrate, manufactured by FUJIFILM Wako Pure Chemical Corporation): 0.386 parts

[1051] Distilled water: 20.95 parts

[1052] <Formation of Image Recording Layer>

[1053] The image recording layer coating liquid having the composition described in Tables 4 to 6 (the image recording layer coating liquid comprises the components described in Tables 4 to 6 and is prepared with a mixed solvent of 1-methoxy-2-propanol (MFG): methyl ethyl ketone (MEK): methanol = 4:4:1 (mass ratio) to have a solid content of 6% by mass) was coated on the support or the undercoat layer with a rod and dried at 120°C for 40 seconds to form a dry coating weight of 1.0 g / m 2 image recording layer.

[1054] The components used in the image recording layer are shown below.

[1055] 〔Infrared absorber〕

[1056] IR-1 to IR-15: Compounds with the following structures

[1057] [Chemical Formula 70]

[1058]

[1059] [Chemical Formula 71]

[1060]

[1061] In addition, Bu represents n-butyl, Ph represents phenyl, Et represents ethyl, TsO - represents the p-toluenesulfonate anion.

[1062] 〔Electron-accepting polymerization initiator〕

[1063] Int-1 to Int-4: Compounds of the following structures, TsO - represents p-toluenesulfonate anion, and Ph represents phenyl.

[1064] [Chemical Formula 72]

[1065]

[1066] 〔Electron-donating polymerization initiator〕

[1067] B-1 to B-9: Compounds with the following structures

[1068] [Chemical Formula 73]

[1069]

[1070] [Chemical Formula 74]

[1071]

[1072] 〔Polymerizable compounds〕

[1073] M-1: The following compound

[1074] M-2: The following compound

[1075] M-3: Dipentaerythritol pentaacrylate, SR-399 manufactured by Sartomer Company, Inc

[1076] M-4: Urethane acrylate, U-15HA manufactured by Shin-Nakamura Chemical Co., Ltd

[1077] M-5: Monomer synthesized by the following synthesis method

[1078] [Chemical formula 75]

[1079]

[1080] [Synthesis of M-5]

[1081] A mixed solution of Takenate D-160N (polyisocyanate-trimethylolpropane adduct, manufactured by Mitsui Chemicals, Inc., 4.7 parts), ARONIX M-403 (manufactured by TOAGOSEI CO., LTD., the amount such that the NCO value of Takenate D-160N and the hydroxyl value of ARONIX M-403 are 1:1), tert-butylbenzoquinone (0.02 parts) and methyl ethyl ketone (11.5 parts) was heated to 65°C. Neostann U-600 (bismuth-based polycondensation catalyst, manufactured by NITTO KASEI CO., LTD., 0.11 parts) was added to the reaction solution, and it was heated at 65°C for 4 hours. The reaction solution was cooled to room temperature (25°C), and methyl ethyl ketone was added thereto, whereby a urethane acrylate solution having a solid content of 50 mass% was synthesized. Using a recycled GPC (equipment: LC908-C60, column: JAIGEL-1H-40 and 2H-40 (manufactured by Japan Analytical Industry)), the molecular weight fraction of the urethane acrylate (M-5) solution was carried out with a eluent of tetrahydrofuran (THF). The weight average molecular weight was 20,000.

[1082] [Binder polymer]

[1083] P-1: Polyvinyl acetal, S-LEC BX-5Z manufactured by SEKISUI CHEMICAL CO., LTD

[1084] P-2: Polyvinyl acetal, S-LEC BL10 manufactured by SEKISUI CHEMICAL CO., LTD

[1085] P-3: Resin synthesized by the following synthesis method

[1086] <Synthesis of Binder Polymer P-3>

[1087] 78.0 parts of 1-methoxy-2-propanol were weighed into a three-necked flask and heated to 70°C under a nitrogen stream. A mixed solution consisting of 52.1 parts of BLEMMER PME-100 (methoxydiethylene glycol monomethacrylate, manufactured by NOFCORPORATION), 21.8 parts of methyl methacrylate, 14.2 parts of methacrylic acid, 2.15 parts of dipentaerythritol hexa(3-mercaptopropionate), 0.38 parts of V-601 (2,2'-azobis(isobutyric acid)dimethyl ester, manufactured by FUJIFILM Wako Pure Chemical Corporation), and 54 parts of 1-methoxy-2-propanol was added dropwise to the reaction vessel over 2 hours and 30 minutes. After the addition was completed, the temperature was raised to 80°C, and the reaction was continued for an additional 2 hours. A mixed solution containing 0.04 parts of V-601 and 4 parts of 1-methoxy-2-propanol was added, and the temperature was raised to 90° C. and the reaction was continued for 2.5 hours. After the reaction was completed, the reaction solution was cooled to room temperature.

[1088] 1-Methoxy-2-propanol: 137.2 parts, 4-hydroxytetramethylpiperidine-N-oxide: 0.24 parts, glycidyl methacrylate: 26.0 parts, and tetraethylammonium bromide: 3.0 parts were added to the reaction solution, stirred uniformly, and then heated at 90°C.

[1089] After 18 hours, the reaction solution was cooled to room temperature (25° C.), and then diluted by adding 99.4 parts of 1-methoxy-2-propanol.

[1090] The binder polymer P-3 obtained in this manner had a solid content concentration of 23% by mass and a polystyrene-equivalent weight average molecular weight of 35,000 as measured by GPC.

[1091] [Chemical Formula 76]

[1092]

[1093] 〔Acid developer〕

[1094] S-1 to S-4: the following compounds

[1095] [Chemical Formula 77]

[1096]

[1097] 〔Hydrophilic compounds〕

[1098] T-1: Tris(2-hydroxyethyl)isocyanurate

[1099] T-2: Compound with the following structure

[1100] T-3: Hydroxypropyl cellulose, Klucel M, manufactured by Hercules

[1101] [Chemical Formula 78]

[1102]

[1103] 〔Surfactant〕

[1104] Surfactant: Anionic surfactant, RAPISOL A-80, manufactured by NOF CORPORATION

[1105] 〔Polymer particles〕

[1106] <Preparation of Polymer Particles R-1>

[1107] Microgel (polymer particles R-1): 2.640 parts

[1108] Distilled water: 2.425 parts

[1109] The method for preparing the microgel is shown below.

[1110] -Preparation of polyisocyanate compounds-

[1111] To a suspension of 17.78 parts (80 molar equivalents) of isophorone diisocyanate and 7.35 parts (20 molar equivalents) of the following polyphenol compound (1) in ethyl acetate (25.31 parts) was added 0.043 parts of bismuth tris(2-ethylhexanoate) (NEOSTANN U-600, manufactured by NITTO KASEI CO., LTD.), followed by stirring. When heat generation was suppressed, the reaction temperature was set to 50°C, and the mixture was stirred for 3 hours to obtain an ethyl acetate solution (50% by mass) of the polyisocyanate compound (1).

[1112] [Chemical Formula 79]

[1113]

[1114] - Preparation of microgels -

[1115] The following oil phase components and aqueous phase components were mixed and emulsified using a homogenizer at 12,000 rpm for 10 minutes. The resulting emulsion was stirred at 45°C for 4 hours, followed by the addition of 5.20 g of a 10% by mass aqueous solution of 1,8-diazabicyclo[5.4.0]undec-7-ene-octanoate (U-CAT SA102, manufactured by San-Apro Ltd.). The mixture was stirred at room temperature for 30 minutes and allowed to stand at 45°C for 24 hours. The solids concentration was adjusted to 20% by mass with distilled water to obtain an aqueous dispersion of microgels. The average particle size, measured by light scattering, was 0.20 μm.

[1116] ~Oil phase ingredients~

[1117] (Component 1) Ethyl acetate: 12.0 parts

[1118] (Component 2) 3.76 parts of an adduct prepared by adding trimethylolpropane (6 mol equivalents) to xylene diisocyanate (18 mol equivalents) and adding mono-terminal methylated polyoxyethylene (1 mol equivalent, number of repeating oxyethylene units: 90) (50% by mass ethyl acetate solution, manufactured by Mitsui Chemicals, Inc.)

[1119] (Component 3) Polyisocyanate compound (1) (as a 50% by mass ethyl acetate solution): 15.0 parts

[1120] (Component 4) 65% by mass ethyl acetate solution of dipentaerythritol pentaacrylate (SR-399, manufactured by Sartomer Company, Inc.): 11.54 parts

[1121] (Component 5) 10% ethyl acetate solution of sulfonate surfactant (PIO NIN A-41-C, manufactured by Takemoto Oil & Fat Co., Ltd.): 4.42 parts

[1122] ~Aqueous phase components~

[1123] Distilled water: 46.87 parts

[1124] <Preparation of Polymer Particles R-2>

[1125] -Preparation of oil phase components-

[1126] A polyfunctional isocyanate compound (PM-200: manufactured by Wanhua Chemical Co.): 6.66 g; a 50% by mass ethyl acetate solution of "Takenate (registered trademark) D-116N (an adduct of trimethylolpropane (TMP), meta-xylylenediisocyanate (XDI), and polyethylene glycol monomethyl ether (EO90) (the following structure)" manufactured by Mitsui Chemicals, Inc.): 5.46 g; a 65% by mass ethyl acetate solution of dipentaerythritol pentaacrylate (SR-399, manufactured by Sartomer Company, Inc.): 11.24 g; ethyl acetate: 14.47 g; and PIONIN (registered trademark) A-41-C manufactured by Takemoto Oil & Fat Co., Ltd.: 0.45 g were mixed and stirred at room temperature (25°C) for 15 minutes to obtain an oil phase component.

[1127] [Chemical formula 80]

[1128]

[1129] -Preparation of aqueous phase components-

[1130] As the aqueous phase component, 47.2 g of distilled water was prepared.

[1131] -Microcapsule formation process-

[1132] The aqueous phase component was added to the oil phase component and mixed, and the obtained mixture was emulsified at 12,000 rpm for 16 minutes using a homogenizer to obtain an emulsion.

[1133] 16.8 g of distilled water was added to the obtained emulsion, and the obtained liquid was stirred at room temperature for 10 minutes.

[1134] The stirred liquid was then heated to 45°C and stirred for 4 hours while maintaining the liquid temperature at 45°C to distill off the ethyl acetate. Subsequently, 5.12 g of a 10% by 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 allowed to stand at 45°C for 24 hours. The solids concentration was adjusted to 20% by mass with distilled water to obtain an aqueous dispersion of polymer particles R-2. The volume average particle size of R-2, measured using a laser diffraction / scattering particle size distribution analyzer LA-920 (manufactured by HORIBA, Ltd.), was 165 nm.

[1135] <Preparation of Polymer Particles R-3>

[1136] A dispersion unit was placed in a four-necked flask: 10.0 parts of the following compound B-1 (n=45), 85.0 parts of distilled water, and 240.0 parts of n-propanol, and the mixture was heated and stirred at 70° C. under a nitrogen atmosphere.

[1137] Next, a mixture of 20.0 parts of the following compound A-1, 70.0 parts of the following compound A-2, and 0.7 parts of 2,2'-azobisisobutyronitrile, which had been mixed in advance, was added dropwise to the four-necked flask over 2 hours.

[1138] After the dropwise addition, the reaction was continued for 5 hours, and then 0.5 parts of 2,2'-azobisisobutyronitrile was added, and the temperature was raised to 80° C. 0.4 parts of 2,2'-azobisisobutyronitrile was added every 6 hours, and the reaction was allowed to proceed for a total of 19 hours.

[1139] The reaction solution was naturally cooled to room temperature (25° C.) to obtain a dispersion of polymer particles R-3 (solid content: 23%).

[1140] [Chemical Formula 81]

[1141]

[1142] The median particle size of polymer particles R-3 was 150 nm, and the coefficient of variation was 23%.

[1143] Furthermore, as a result of confirming the dispersibility of the polymer particles R-3 by the method described above, the polymer particles R-3 were particles that were dispersible in water and particles that were dispersible in an organic solvent.

[1144] <Preparation of Polymer Particles R-4>

[1145] A three-necked flask was charged with 350 parts of distilled water, 50 parts of compound A-1, 220 parts of compound A-2, 20 parts of compound A-3, and 10 parts of compound B-1 (n=45). The mixture was heated to 70°C under a nitrogen atmosphere. Subsequently, 1.0 part of potassium persulfate (KPS) was added, and the mixture was heated and stirred for 3 hours. The temperature was then raised to 95°C and the reaction was allowed to proceed for 4 hours. The reaction solution was allowed to cool naturally to room temperature (25°C), yielding an aqueous dispersion of polymer particles R-4 (solids content 22%). The average particle size of polymer particles R-4 was 142 nm.

[1146] [Chemical Formula 82]

[1147]

[1148] <Preparation of Polymer Particles R-5>

[1149] In a three-necked flask, 288 parts of ion-exchanged water, 1.6 parts of sodium dodecylbenzenesulfonate, 0.5 parts of A-1, and 0.2 parts of A-2 were added, and the mixture was stirred and emulsified at 200 rpm at 75° C. for 15 minutes under a nitrogen atmosphere.

[1150] 0.15 parts of potassium persulfate (KPS) and 7 parts of ion-exchanged water were added, and heating and stirring were performed at 80° C. for 30 minutes.

[1151] After 24.7 parts of A-1, 12.8 parts of A-2, and 6.7 parts of A-4 were added dropwise over 3 hours, heating and stirring were continued for 1 hour. The reaction solution was cooled naturally to room temperature (25°C) to obtain an aqueous dispersion of polymer particles R-5 (solids content: 13% by mass). The average particle size of polymer particles R-5 was 40 nm.

[1152] [Chemical Formula 83]

[1153]

[1154] [Chemical formula 84]

[1155]

[1156] <Formation of the Outermost Layer>

[1157] The outermost coating liquid having the composition described in Tables 4 to 6 (the outermost coating liquid contains the components described in Table 4 or Table 5 and is prepared with ion-exchanged water to a solid content of 6% by mass) was bar-coated on the image recording layer and dried at 120°C for 60 seconds to form a dry coating weight of 0.15 g / m 2 The outermost layer.

[1158] In Example 15, a dry coating amount of 0.50 g / m 2 In Example 17, a dry coating amount of 1.00 g / m 2 The outermost layer.

[1159] In addition, the preparation method of the inorganic layer compound dispersion (1) used in the outermost layer coating liquid is described below.

[1160] <<Preparation of Inorganic Layered Compound Dispersion (1)>>

[1161] 6.4 parts of synthetic mica (SOMASIF ME-100, manufactured by Co-op Chemical Co., Ltd.) was added to 193.6 parts of ion-exchanged water and dispersed using a homogenizer until the volume average particle size (laser scattering method) became 3 μm. The aspect ratio of the obtained dispersed particles was 100 or more.

[1162] 〔Color-changing compounds〕

[1163] wIR-1 to wIR-6: the following compounds, and TsO - represents the p-toluenesulfonate anion.

[1164] [Chemical Formula 85]

[1165]

[1166] 〔Hydrophilic polymer〕

[1167] WP-1: Polyvinyl alcohol, Mowiol 4-88 manufactured by Sigma-Aldrich Co. LLC.

[1168] WP-2: Polyvinyl alcohol, Mowiol 8-88 manufactured by Sigma-Aldrich Co. LLC.

[1169] WP-3: The following resin (Mw 52,000)

[1170] WP-4: Cellulose, METOLOSE 60SH-15 manufactured by Shin-Etsu Chemical Co., Ltd.

[1171] WP-5: Polyvinyl alcohol, Gohsenol L-3266 manufactured by Mitsubishi Chemical Corporation, with a saponification degree of 86 to 89% or more

[1172] WP-6: Cellulose, METOLOSE SM04 manufactured by Shin-Etsu Chemical Co., Ltd.

[1173] [Chemical Formula 86]

[1174]

[1175] 〔Hydrophobic polymer〕

[1176] L-1: Aqueous dispersion of polyvinylidene chloride, Diofan (registered trademark) A50 manufactured by Solvin

[1177] L-2: Styrene-acrylic resin, FS-201 manufactured by Nipponpaint Industrial Coatings Co., Ltd.

[1178] L-3: Styrene-acrylic resin, FS-102 manufactured by Nipponpaint Industrial Coatings Co., LTD.

[1179] <Production of Lithographic Printing Plate Originals>

[1180] As shown in Tables 4 to 6, lithographic printing plate precursors of Examples 1 to 18 and Comparative Examples 1 to 4 were produced according to the support and the method for forming each layer.

[1181] <Evaluation of the original lithographic printing plate>

[1182] [UV printing durability]

[1183] The lithographic printing plate precursor prepared in the above manner was exposed using a Kodak Magnus 800 Quantum equipped with an infrared semiconductor laser at an output of 27 W, an external drum rotation speed of 450 rpm, and a resolution of 2,400 dpi (dots per inch, 1 inch is 2.54 cm). 2 The exposure image includes a solid image and an Amplitude Modulation Screen 3% dot pattern.

[1184] The resulting exposed original plate was mounted on the cylinder of a Heidelberger Druckmaschinen AG SX-74 chrysanthemum-sized printing press without undergoing development. A 100-liter fountain solution circulation tank with a built-in non-woven filter and temperature control system was connected to the press. 80 liters of 2.0% fountain solution S-Z1 (Fujifilm Corporation) was placed in the circulation system. T&KUV OFS K-HS Ink GE-M (T&K TOKA Corporation) was used as the printing ink. After supplying the fountain solution and ink using a standard automatic print start method, printing was performed on Tokubishi Art paper (Mitsubishi Paper Mills Limited, continuous capacity 76.5 kg) at a printing speed of 10,000 sheets per hour.

[1185] As the number of printed sheets increases, the image area gradually wears away, causing the ink concentration on the printed material to decrease. Print durability was evaluated by measuring the dot area ratio of a 3% amplitude-modulated screen on the printed material using a Gretag densitometer (manufactured by GretagMacbeth) and determining the number of printed sheets at the end of printing, where the value decreased by 1% from the value measured after printing the 500th sheet. Evaluation was performed using relative print durability, with a value of 100 for a print count of 50,000 sheets. A larger value indicates better print durability.

[1186] Relative printing durability = (number of printed sheets of the target lithographic printing plate precursor) / 50,000 × 100

[1187] [UV plate wear inhibition]

[1188] The lithographic printing plate precursor prepared in the above manner was exposed using a Kodak Magnus 800 Quantum equipped with an infrared semiconductor laser at an output of 27 W, an external drum rotation speed of 450 rpm, and a resolution of 2,400 dpi (dots per inch, 1 inch is 2.54 cm). 2 The exposure image includes a solid image and an Amplitude Modulated Screening 3% dot pattern.

[1189] Piano wire (ESCO Co., Ltd.) with a diameter of 0.4 mm was applied to the halftone dots of the exposed original plate perpendicular to the rotational direction of the plate cylinder. Without undergoing development, the plate was mounted on the cylinder of a Heidelberger Druckmaschinen AG SX-74 printing press of chrysanthemum size. A 100-liter fountain solution circulation tank with a built-in non-woven filter and temperature control system was connected to the press. 80 L of 2.0% by weight fountain solution S-Z1 (Fujifilm Corporation) was loaded into the circulation tank. T&K UV OFS K-HS Ink GE-M (T&K TOKA Corporation) was used as the printing ink. After supplying the fountain solution and ink using a standard automatic print start method, printing was performed on Tokubishi Art (Mitsubishi Paper Mills Limited, continuous load: 76.5 kg) paper at a printing speed of 10,000 sheets per hour.

[1190] When the 2,000th print run was reached, the piano wire was removed from the plate, reinstalled on the press, and printing resumed. After resuming printing, the 100th print was inspected, and the image area corresponding to the piano wire position was checked visually using a 50x magnifying glass to check for ink misalignment. This inspection was repeated every 2,000 sheets, and evaluation was terminated at the point where ink misalignment occurred.

[1191] In addition, the greater the number of printed sheets until ink failure occurs, the more excellent the "UV plate abrasion suppression performance" is.

[1192] -Evaluation Criteria-

[1193] A: The number of printed sheets until ink failure occurred was 20,000 sheets or more.

[1194] B: The number of printed sheets until ink failure occurred was 4,000 or more and less than 20,000 sheets.

[1195] C: The number of printed sheets until ink failure occurred was less than 4,000 sheets.

[1196] 〔Visual recognition evaluation〕

[1197] The resulting lithographic printing plate precursor was exposed using a Creo Trendsetter 3244VX equipped with a water-cooled 40W infrared semiconductor laser at an output of 11.5W, an external drum rotation speed of 220 rpm, and a resolution of 2,400 dpi (dots per inch, 1 inch = 25.4 mm). Exposure was performed in an environment of 25°C and 50% RH.

[1198] The color development of the lithographic printing plate precursor immediately after exposure was measured. The measurement was performed using a spectrocolorimeter CM2600d manufactured by Konica Minolta, Inc. and operating software CM-S100W, using the SCE (Specular Reflection Elimination) method. * a * b * L in color system * Value (brightness), according to the L of the exposure part * The L value of the unexposed part * The difference in values ΔL was evaluated. The larger the ΔL value, the better the visibility.

[1199] [Table 4]

[1200]

[1201] [Table 5]

[1202]

[1203] [Table 6]

[1204]

[1205] In addition, ΔE2 represents the value of HOMO of the infrared absorber minus HOMO of the electron-donating polymerization initiator.

[1206] The results shown in Tables 4 and 5 indicate that the lithographic printing plate precursors of the Examples provide lithographic printing plate precursors that exhibit superior UV plate abrasion resistance compared to the lithographic printing plate precursors of the Comparative Examples. Furthermore, it is apparent that the lithographic printing plate precursors of the present invention provide lithographic printing plates that exhibit superior UV printing durability and visibility.

[1207] (Example 19 to Example 23)

[1208] <Production of Support Body Z>

[1209] In Examples 19 to 23, the support body Z was produced by the following steps.

[1210] -Alkali etching treatment-

[1211] The aluminum plate was etched by spraying a caustic soda aqueous solution with a caustic soda concentration of 26% by mass and an aluminum ion concentration of 6.5% by mass at a temperature of 55°C. The plate was then rinsed with water using a spray. The surface was then electrochemically roughened to a concentration of 3 g / m2 of aluminum dissolved therein. 2 .

[1212] - Decontamination treatment using an acidic aqueous solution (first decontamination treatment)-

[1213] Next, decontamination treatment was performed using an acidic aqueous solution. A 170 g / L sulfuric acid solution was used. The solution temperature was 30°C. The acidic aqueous solution was sprayed onto the aluminum plate using a sprayer for 3 seconds. The plate was then rinsed with water.

[1214] -Electrochemical roughening treatment-

[1215] Next, electrochemical roughening treatment was performed using an alternating current using a hydrochloric acid electrolyte solution. The electrolyte temperature was 40°C. The alternating current waveform was a symmetrical sine wave with positive and negative waveforms and a frequency of 50 Hz. The total amount of electricity used in the anodic reaction on the aluminum plate was 300 C / dm. 2 A carbon electrode was used as the counter electrode of the aluminum plate. The aluminum plate was then washed with water.

[1216] -Alkali etching treatment-

[1217] At a temperature of 35°C, a caustic soda aqueous solution having a caustic soda concentration of 5% by mass and an aluminum ion concentration of 0.5% by mass was sprayed onto the aluminum plate after electrochemical roughening treatment using a sprayer to obtain an etching amount of 0.1 g / m 2 The etching process was performed as follows. Then, a water washing process was performed.

[1218] - Decontamination treatment using an acidic aqueous solution-

[1219] Next, decontamination treatment was performed using an acidic aqueous solution. A 170 g / L sulfuric acid solution was used. The solution temperature was 30°C. The acidic aqueous solution was sprayed onto the aluminum plate using a sprayer for 3 seconds. The plate was then rinsed with water.

[1220] - Anodizing treatment -

[1221] Under the conditions of sulfuric acid solution of 170g / L and solution temperature of 40℃, direct current was used to make the anodic oxide film amount 3g / m 2 Anodizing treatment was performed.

[1222] <Method for Forming Primer Layer>

[1223] On the support described in Table 7, the dry coating amount was 20 mg / m 2 The primer coating liquid described in Table 7 was applied in a manner of , and dried in an oven at 100° C. for 30 seconds to form a primer layer.

[1224] <Formation of Image Recording Layer>

[1225] An image recording layer coating liquid having the composition described in Table 7 (the image recording layer coating liquid comprises the components described in Table 7 and is prepared with a mixed solvent of 1-methoxy-2-propanol (MFG): methyl ethyl ketone (MEK): methanol = 4:4:1 (mass ratio) to have a solid content of 6% by mass) was coated on the support or the undercoat layer with a rod and dried at 120°C for 40 seconds to form a dry coating weight of 1.0 g / m 2 image recording layer.

[1226] <Formation of the Outermost Layer>

[1227] The outermost coating liquid having the composition described in Table 7 (the outermost coating liquid contained the components described in Table 7 and was prepared with ion-exchanged water to a solid content of 6% by mass) was bar-coated on the image recording layer and dried at 120°C for 60 seconds to form a dry coating weight of 0.15 g / m 2 The outermost layer.

[1228] <Production of Lithographic Printing Plate Originals>

[1229] As shown in Table 7, lithographic printing plate precursors of Examples 19 to 23 were produced according to the support and the method for forming each layer.

[1230] Using the obtained lithographic printing plate precursor, various evaluations were performed in the same manner as in Example 1. The evaluation results are shown in Table 7.

[1231] [Table 7]

[1232]

[1233] The following shows the details of the abbreviations described in Table 7 other than the above.

[1234] <Infrared absorber>

[1235] IR-16 to IR-19: The following compounds

[1236] In addition, TsO - represents the p-toluenesulfonate anion.

[1237] [Chemical Formula 87]

[1238]

[1239] [Chemical Formula 88]

[1240]

[1241] <Surfactant>

[1242] U'-1 and U'-2: the following compounds

[1243] U'-3: Anionic surfactant, RAPISOL A-80, manufactured by NOF CORPORATION

[1244] [Chemical Formula 89]

[1245]

[1246] The results shown in Table 7 indicate that the lithographic printing plate precursors of Examples 19 to 23 provide lithographic printing plate precursors that exhibit superior UV plate abrasion resistance compared to the lithographic printing plate precursors of the comparative examples. Furthermore, it is shown that the lithographic printing plate precursors of the present invention provide lithographic printing plates that exhibit excellent UV printing durability and visibility.

[1247] Explanation of symbols

[1248] ta-anodic reaction time, tc-cathodic reaction time, tp-time from 0 to peak current, Ia-peak current on the anode circulation side, Ic-peak current on the cathode circulation side, AA-anodic reaction current of the aluminum plate, CA-cathodic reaction current of the aluminum plate, 1-aluminum plate, 2 and 4-roller brushes, 3-polishing slurry, 5, 6, 7 and 8-support rollers, 12a, 12b-aluminum support, 14-undercoat layer, 16-image recording layer, 18-aluminum plate, 20a, 20b-anodic oxide film, 22a, 22b-micropores, 24-large diameter pores, 26-small diameter pores Part, D-depth of large diameter hole, 50-main electrolytic cell, 51-AC power supply, 52-radial drum roller, 53a, 53b-main pole, 54-electrolyte supply port, 55-electrolyte, 56-auxiliary anode, 60-auxiliary anode tank, W-aluminum plate, S-liquid supply direction, Ex-electrolyte discharge direction, 610-anodic oxidation treatment device, 612-power supply tank, 614-electrolytic treatment tank, 616-aluminum plate, 618, 26-electrolyte, 620-power supply electrode, 622, 628-roller, 624-clamping roller, 630-electrolytic electrode, 632-tank wall, 634-DC power supply.

[1249] The disclosures of Japanese Patent Application No. 2020-095077 filed on May 29, 2020, and Japanese Patent Application No. 2020-124465 filed on July 21, 2020 are incorporated herein by reference in their entirety.

[1250] All documents, patent applications, and technical standards described in this specification are incorporated herein by reference to the same extent as if each document, patent application, or technical standard were specifically and individually set forth by reference.

Claims

1. An on-press developing type lithographic printing plate precursor comprising, in order, a support, an image recording layer, and an outermost layer, The image recording layer comprises an infrared absorber, an electron-donating polymerization initiator and a polymerizable compound. The value of the HOMO of the infrared absorber minus the HOMO of the electron-donating polymerization initiator is 0.60 eV or less, The infrared absorber includes a compound represented by the following formula 1, The outermost layer comprises a color-changing compound, In Formula 1, R1 and R2 each independently represent a hydrogen atom or an alkyl group, R1 and R2 are optionally linked to each other to form a ring, R3 to R6 each independently represent a hydrogen atom or an alkyl group, R7 and R8 each independently represent an alkyl group or an aryl group, Y1 and Y2 each independently represent an oxygen atom, a sulfur atom, -NR0- or a dialkylmethylene group, R0 represents a hydrogen atom, an alkyl group or an aryl group, Ar1 and Ar2 each independently represent a group forming a benzene ring or a naphthalene ring optionally having a group represented by Formula 2 described later, and A1 represents -NR9R 10 , -X1-L1 or a group represented by formula 2 described later, R9 and R 10 Each independently represents an alkyl group, an aryl group, an alkoxycarbonyl group or an arylsulfonyl group, X1 represents an oxygen atom or a sulfur atom, L1 represents a hydrocarbon group, a heteroaryl group or a group whose bond to X1 is cleaved by heat or infrared exposure, Za represents a counter ion for neutralizing the charge, and both Ar1 and Ar2 have a group represented by the following formula 2, -X Type 2 In Formula 2, X represents a chlorine atom or a bromine atom.

2. The on-press development type lithographic printing plate precursor according to claim 1, wherein The value of HOMO of the infrared absorber minus HOMO of the electron-donating polymerization initiator is 0.50 eV or less.

3. The on-press development type lithographic printing plate precursor according to claim 1 or 2, wherein The infrared absorber has a HOMO of -5.30 eV or less.

4. The on-press development type lithographic printing plate precursor according to claim 1, wherein At least one of Ar1 and Ar2 in Formula 1 has a bromine atom.

5. The on-press development type lithographic printing plate precursor according to claim 1 or 2, wherein The electron donating polymerization initiator has a HOMO greater than -5.90 eV.

6. The on-press development type lithographic printing plate precursor according to claim 1 or 2, wherein The polymerizable compound includes a polymerizable compound having two or fewer functional groups.

7. The on-press development type lithographic printing plate precursor according to claim 1 or 2, wherein The image-recording layer further comprises polyvinyl acetal.

8. The on-press development type lithographic printing plate precursor according to claim 1 or 2, wherein The outermost layer comprises a hydrophobic polymer.

9. The on-press development type lithographic printing plate precursor according to claim 8, wherein The hydrophobic polymer is hydrophobic polymer particles.

10. The on-press developing type lithographic printing plate precursor according to claim 1 or 2, which is subjected to a treatment at 110 mJ / cm 2 When exposure is performed with infrared rays having a wavelength of 830 nm at an energy density of , a brightness change ΔL before and after the exposure is 2.0 or more.

11. The on-press development type lithographic printing plate precursor according to claim 1 or 2, wherein The color-changing compound includes a compound that develops color upon exposure to infrared rays.

12. The on-press development type lithographic printing plate precursor according to claim 1 or 2, wherein The color-changing compound includes a decomposable compound that decomposes upon exposure to infrared rays.

13. The on-press development type lithographic printing plate precursor according to claim 1 or 2, wherein The color-changing compound is anthocyanin.

14. The on-press development type lithographic printing plate precursor according to claim 1 or 2, wherein The color-changing compound is a compound represented by the following formula 1-1, In formula 1-1, R 1 represents a group represented by any of the following formulas 2-1 to 4-1, R 11 ~R 18 Each independently represents a hydrogen atom, a halogen atom, -R a 、-OR b 、-SR c or -NR d R e , R a ~R e Each independently represents a hydrocarbon group, A1, A2 and multiple R 11 ~R 18 are optionally linked to form a monocyclic or polycyclic ring, A1 and A2 are independently an oxygen atom, a sulfur atom or a nitrogen atom, n 11 and n 12 Each independently represents an integer from 0 to 5, wherein n 11 and n 12 The total of n is 2 or more, 13 and n 14 Each independently represents 0 or 1, L represents an oxygen atom, a sulfur atom or -N(R 10 )-, R 10 represents a hydrogen atom, an alkyl group or an aryl group, Za represents a counter ion for neutralizing the charge, In formula 2-1 to formula 4-1, R 20 、R 30 、R 41 and R 42 Each independently represents an alkyl group or an aryl group, Zb represents a counter ion for neutralizing the charge, and the wavy line represents a bonding site with the group represented by L in the above formula 1-1.

15. The on-press development type lithographic printing plate precursor according to claim 14, wherein The color-changing compound is a compound represented by the following formula 1-2, In formula 1-2, R 1 represents a group represented by any of the above formulas 2-1 to 4-1, R 19 ~R 22 Each independently represents 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 represents -R a , R a ~R e Each independently represents a hydrocarbon group, R 19 With R 20 、R 21 With R 22 or R 23 With R 24 They are optionally linked to form a monocyclic or polycyclic ring, L represents an oxygen atom, a sulfur atom or -N(R 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 represents an alkyl group which may have a substituent, and Za represents a counter ion for neutralizing the charge.

16. The on-press development type lithographic printing plate precursor according to claim 14, wherein The color-changing compound is a compound represented by any of the following formulas 1-3 to 1-7, In formulas 1-3 to 1-7, R 1 represents a group represented by any of the above formulas 2-1 to 4-1, R 19 ~R 22 Each independently represents 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 represents a hydrogen atom, a halogen atom or -R a , R a ~R e Each independently represents a hydrocarbon group, R 19 With R 20 、R 21 With R 22 or R 25 With R 26 They are optionally linked to form a monocyclic or polycyclic ring, L represents an oxygen atom, a sulfur atom or -N(R 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 represents an alkyl group which may have a substituent, and Za represents a counter ion for neutralizing the charge.

17. The on-press development type lithographic printing plate precursor according to claim 15, wherein W in the above formulas 1-2 to 1-7 1 and W 2 Each independently represents an alkyl group having a substituent, and is a group having at least -OCH2CH2-, a sulfo group, a salt of a sulfo group, a carboxyl group, or a salt of a carboxyl group as the substituent.

18. The on-press development type lithographic printing plate precursor according to claim 1 or 2, wherein The image-recording layer further contains an electron-accepting polymerization initiator.

19. The on-press development type lithographic printing plate precursor according to claim 18, wherein The electron-accepting polymerization initiator is an onium salt compound.

20. The on-press development type lithographic printing plate precursor according to claim 18, wherein The electron-accepting polymerization initiator includes a compound represented by the following formula (II): In formula (II), X A Represents a halogen atom, R A Represents an aryl group.

21. The on-press development type lithographic printing plate precursor according to claim 18, wherein The value of LUMO of the electron-accepting polymerization initiator minus LUMO of the infrared absorber is 0.45 eV or more.

22. The on-press development type lithographic printing plate precursor according to claim 1 or 2, wherein The polymerizable compound includes a polymerizable compound having seven or more functional groups.

23. The on-press development type lithographic printing plate precursor according to claim 1 or 2, wherein The polymerizable compound includes a polymerizable compound having ten or more functional groups.

24. The on-press development type lithographic printing plate precursor according to claim 1 or 2, wherein The support body includes an aluminum plate and an aluminum anodic oxide 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 in the depth direction from the surface on the image recording layer side. The average diameter of the micropores on the surface of the anodic oxide film exceeds 10 nm and is 100 nm or less.

25. The on-press development type lithographic printing plate precursor according to claim 24, wherein The micropores are composed of a large-diameter pore portion and a small-diameter pore portion, wherein the large-diameter pore portion extends from the surface of the anodic oxide film to a depth of 10 nm to 1000 nm, and the small-diameter pore portion is connected to the bottom of the large-diameter pore portion and extends from the connected position to a depth of 20 nm to 2000 nm. The average diameter of the large-diameter pores on the surface of the anodic oxide film is 15 nm to 100 nm. The average diameter of the small-diameter pores at the communication positions is 13 nm or less.

26. A method for producing a lithographic printing plate, comprising: A step of exposing the on-press developed lithographic printing plate precursor according to any one of claims 1 to 25 in an image-like manner; and A step of supplying at least one selected from printing ink and fountain solution on a printing press to remove the image recording layer in non-image areas.

27. A lithographic printing method comprising: A step of exposing the on-press developed lithographic printing plate precursor according to any one of claims 1 to 25 in an image-like manner; A process of supplying at least one selected from printing ink and fountain solution on a printing press to remove the image recording layer in non-image areas to produce a lithographic printing plate; and The process of printing using the obtained planographic printing plate.

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