Lithographic printing plate master and method for producing lithographic printing plates

Abstract

The present invention provides a lithographic printing plate master that exhibits excellent transfer suppression of the image recording layer and good developability of the non-image areas, and a method for producing a lithographic printing plate using a lithographic printing plate master. [Solution] A lithographic printing plate and its application, comprising a support and an image recording layer on the support, wherein the image recording layer comprises a polymer A having a main chain containing two or more silicon atoms and a hydrophilic group.

Description

[Technical Field]

[0001] This disclosure relates to a lithographic printing plate master and a method for producing a lithographic printing plate. [Background technology]

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

[0003] The image recording layer includes a negative-type photosensitive image recording layer containing a polymerizable compound and a polymerization initiator, in which the exposed area polymerizes and hardens to form an image area, and a positive-type photosensitive image recording layer containing an alkali-soluble resin and an infrared absorbent (e.g., an infrared absorption dye, hereinafter also called an IR dye), in which the solubility of the exposed area is improved to form an image area. In the positive-type photosensitive image recording layer, the infrared absorbent, especially the IR dye, acts as a developer inhibitor in the unexposed area, substantially reducing the solubility of the resin in the developer solution through interaction with the resin, becoming the image area of ​​the lithographic printing plate. In the exposed area, the interaction between the IR dye and the resin weakens due to the heat generated from the IR dye, and it dissolves in the developer solution, becoming a non-image area.

[0004] The image recording layer in a lithographic printing plate is a photosensitive resin layer that forms image areas and non-image areas by applying energy to the image recording layer through exposure or other means. The characteristics required of lithographic printing plates have always been the ability to remove non-image areas after energy application and the durability of the formed image area. In negative-type photosensitive image recording layers, one form of image recording layer, improving the removal of non-image areas may reduce the film strength before exposure. Lowering the film strength before exposure can lead to the film being damaged by friction with various components that come into contact with the film surface during handling in the manufacturing, transportation, and plate-making processes of lithographic printing plates. This can result in the image recording layer being transferred to these components, and improvements are needed.

[0005] Furthermore, in recent years, in order to further reduce the environmental burden, there has been a trend towards simplifying or eliminating the processing of developing or platemaking processes, as these methods do not require the treatment of wastewater associated with wet processes such as developing. One such simplified method is called "on-press development" for negative-type photosensitive image recording layers. In this method, after exposing the lithographic printing plate, conventional developing is not performed, and the plate is directly mounted on the printing press, allowing the removal of unnecessary parts of the image recording layer to occur in the early stages of the normal printing process. In this disclosure, a lithographic printing plate that can be used for such on-press development, that is, a lithographic printing plate having an on-press development type negative-type photosensitive image recording layer, is referred to as an "on-press development type" lithographic printing plate. In press-developable negative-type photosensitive image recording layers, achieving both transfer suppression and developability becomes more difficult. This is because, in press-developable image recording layers, increasing the film strength tends to reduce the developability and dispersibility of the non-image areas of the image recording layer during development when ink and dampening solution come into contact with the image recording layer, due to the weak tack force of the ink during printing, making development defects more likely. On the other hand, lowering the film strength makes film damage and transfer during handling in the manufacturing, transportation, and plate-making processes of lithographic printing plates more likely compared to negative-type photosensitive image recording layers that require development.

[0006] Examples of conventional lithographic printing plates include those described in Patent Document 1, Patent Document 2, or Patent Document 3. Patent Document 1 discloses a lithographic printing plate having a support and an image recording layer on the support, wherein the image recording layer contains a (meth)acrylic polymer having substituents containing two or more silicon atoms in its side chains. Patent Document 2 discloses a lithographic printing plate master having a support, an image recording layer and a protective layer on the support, wherein the image recording layer contains a siloxane-based surfactant and the protective layer contains polyvinyl alcohol (hereinafter referred to as PVA) with a degree of saponification of 94% or more. Patent Document 3 discloses a support and a lithographic printing plate having a negative-type image recording layer on the support, wherein the image recording layer contains a siloxane-based surfactant and the arithmetic mean height of the outermost layer surface is defined. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] International Publication No. 2024 / 117242 [Patent Document 2] International Publication No. 2007 / 097302 [Patent Document 3] International Publication No. 2018 / 181993 [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] One embodiment of this disclosure aims to solve the problem of providing a lithographic printing plate with good transfer suppression properties for the image recording layer and good developability for non-image areas. Another embodiment of this disclosure aims to solve the problem of providing a method for producing a lithographic printing plate using the above-mentioned lithographic printing plate master. [Means for solving the problem]

[0009] The means for solving the above problems include the following embodiments. <1> A lithographic printing plate, comprising a support and an image recording layer on the support, wherein the image recording layer comprises a polymer A having a main chain containing two or more silicon atoms and a hydrophilic group. <2> The polymer A described above has hydrophilic groups in at least one of the side chains and the ends of the main chain. <1> The lithographic printing plate described above.

[0010] <3> The polymer A described above has hydrophilic groups in its side chains. <2> The lithographic printing plate described above. <4> The hydrophilic group of polymer A is at least one selected from the group consisting of a hydroxyl group, an amine group, a carboxyl group, a carbinol group, an alkylamino group, a (poly)ether group, a (poly)glycerol group, a (poly)ester group, and a (poly)amide group. <1> ~ <3> A lithographic printing plate original as described in one of the following.

[0011] <5> The polymer A mentioned above is a polymer represented by the following formula (A): <1> ~ <4> A lithographic printing plate original as described in one of the following.

[0012] [ka]

[0013] In formula (A) above, W represents a hydrophilic group, x represents the number of bonds in the dimethylsiloxane structural unit and is in the range of 0 or more, and y represents the number of bonds in the siloxane structural unit having a hydrophilic group in its side chain and is in the range of 1 or more. The bonding order between the dimethylsiloxane structural unit and the siloxane structural unit having a hydrophilic group in its side chain in formula (A) may be in a block or random order.

[0014] <6> The above image recording layer is a negative-type photosensitive image recording layer containing a polymerizable compound and a polymerization initiator. <1> ~ <5> A lithographic printing plate original as described in one of the following. <7> The above-mentioned negative-type photosensitive image recording layer contains an infrared absorber and an onium salt polymerization initiator as the polymerization initiator, and is of the on-pressure development type. <6> The lithographic printing plate described above. <8> The above-mentioned negative-type photosensitive image recording layer further contains polymer particles and is of the on-premise development type. <6> or <7> The lithographic printing plate described above. <9> The above-mentioned negative-type photosensitive image recording layer further contains a chromogenic precursor and is of the on-premise development type. <6> ~ <8> A lithographic printing plate original as described in one of the following. <10> The above-mentioned negative-type photosensitive image recording layer contains a polyfunctional polymerizable compound and is of the in-flight development type. <6> ~ <9> A lithographic printing plate original as described in one of the following. <11> The above negative-type photosensitive image recording layer contains a borate compound represented by the following formula (B1), and is of the in-machine development type. <6> ~ <10> A lithographic printing plate original as described in one of the following.

[0015] [ka]

[0016] In formula (B1), R B1 ~R B4 Each of these independently represents an unsubstituted or substituted alkyl group, an unsubstituted or substituted aryl group, an unsubstituted or substituted alkenyl group, or an unsubstituted or substituted alkynyl group, R B1 ~R B4 Each of them may independently have a ring structure. However, R B1 ~R B4 At least one of them is different from the others. + This represents a cation. <12> The above-mentioned lithographic printing plate has a protective layer on the image recording layer. <1> ~ <11> A lithographic printing plate original as described in one of the following. <13> The above-mentioned lithographic printing plate has an undercoat layer between the support and the image recording layer. <1> ~ <12> A lithographic printing plate original as described in one of the following.

[0017] <14> <1> ~ <13> A method for producing a lithographic printing plate, comprising the steps of: exposing a lithographic printing plate master described in any one of the above in an image-like manner; and supplying at least one selected from the group consisting of printing ink and dampening water on a printing press to remove the image recording layer in the non-image areas. [Effects of the Invention]

[0018] According to one embodiment of the present disclosure, it is possible to provide a lithographic printing plate that exhibits excellent transfer suppression of the image recording layer and good developability of the non-image areas. Furthermore, according to other embodiments of this disclosure, a method for producing a lithographic printing plate using the above-mentioned lithographic printing plate master can be provided. [Brief explanation of the drawing]

[0019] [Figure 1] This is a schematic cross-sectional view of one embodiment of a support. [Figure 2] This is a schematic cross-sectional view of another embodiment of the support. [Figure 3] This is a schematic diagram showing the cross-sectional shape of the edge of a lithographic printing plate. [Figure 4] This is a conceptual diagram showing an example of the cutting section of a slittering machine. [Figure 5] This is a schematic diagram of one embodiment of a mechanical surface roughening apparatus equipped with a rotating bundle of brushes. [Figure 6] This graph shows one embodiment of the AC power supply waveform in an electrochemical surface roughening treatment. [Figure 7] This is a schematic diagram of one embodiment of an electrolytic cell used for electrochemical roughening treatment of an aluminum support using an aqueous nitric acid solution. [Figure 8] This is a schematic diagram of one embodiment of an anodic oxidation apparatus used in the anodic oxidation process in a method for manufacturing a support having an anodic oxide film. [Modes for carrying out the invention]

[0020] The contents of this disclosure will be described in detail below. The descriptions of the constituent elements described below may be based on representative embodiments of this disclosure, but this disclosure is not limited to such embodiments. In this disclosure, the "~" symbol indicating a numerical range is used to mean that the numbers before and after it are included as the lower and upper limits, respectively. Furthermore, in the notation of groups (atomic groups) in this disclosure, notations that do not specify substitution or unsubstituted include both those with and without substituents. For example, "alkyl group" includes not only unsubstituted alkyl groups but also substituted alkyl groups. In this disclosure, "(meth)acrylic" is a term used to encompass both acrylic and methacrylic, and "(meth)acryloyl" is a term used to encompass both acryloyl and methacryloyl. The term "process" in this disclosure includes not only independent processes, but also processes that cannot be clearly distinguished from other processes, as long as their intended purpose is achieved. In this disclosure, "mass%" and "weight%" are synonymous, and "parts by mass" and "parts by weight" are synonymous. Unless otherwise specified, each component in the composition or each structural unit in the polymer in this disclosure may be included alone or in combination of two or more types. In this disclosure, the amount of each component in the composition, or each constituent unit in the polymer, means the total amount of the multiple substances or constituent units present in the composition, or the multiple constituent units present in the polymer, unless otherwise specified, if there are multiple substances or constituent units corresponding to each component or constituent unit in the composition. In this disclosure, a combination of two or more preferred embodiments is a more preferred embodiment. In this disclosure, unless otherwise specified, the weight-average molecular weight (Mw) and number-average molecular weight (Mn) are determined by gel permeation chromatography (GPC) analysis using TSKgel GMHxL, TSKgel G4000HxL, and TSKgel G2000HxL columns (all product names of Tosoh Corporation), detecting the molecular weight using THF (tetrahydrofuran) as the solvent and a differential refractometer, and converting it using polystyrene as the standard substance. In this disclosure, the term "lithographic printing plate" includes not only the lithographic printing plate but also the sacrificial plate. The term "lithographic printing plate" includes not only the lithographic printing plate produced from the lithographic printing plate through operations such as exposure and development as necessary, but also the sacrificial plate. In the case of a sacrificial plate, exposure and development operations are not necessarily required. A sacrificial plate is, for example, a lithographic printing plate used to attach to a printing cylinder that is not in use when printing some pages in single color or two colors in color newspaper printing. In this disclosure, the asterisk (*) in the chemical structural formula indicates a bonding position with other structures.

[0021] [Lithographic printing plate original plate] The lithographic printing plate according to this disclosure comprises a support and an image recording layer on the support, wherein the image recording layer comprises a polymer A having a main chain containing two or more silicon atoms and a hydrophilic group.

[0022] The following describes the details of each constituent element of the lithographic printing plate master related to this disclosure.

[0023] [Image recording layer] The image recording layer in the lithographic printing plate master according to this disclosure is not particularly limited, except that it contains polymer A (hereinafter also referred to as "polymer A") having a main chain containing two or more silicon atoms and a hydrophilic group, and may be a negative-type photosensitive image recording layer or a positive-type photosensitive image recording layer. In particular, from the viewpoint of achieving a better balance between the transfer suppression and developability of the image recording layer, the image recording layer in the lithographic printing plate master of this disclosure is preferably a negative-type photosensitive image recording layer (hereinafter also referred to as a negative-type image recording layer), and from the viewpoint of being easy to apply as an on-press developable type, it is preferably a water-soluble or water-dispersible negative-type image recording layer.

[0024] [Negative image recording layer] Furthermore, when applying the negative image recording layer of the lithographic printing plate master according to this disclosure to an on-press development type, it is preferable from the viewpoint of on-press development that the unexposed portion of the image recording layer can be removed by at least one of dampening solution and printing ink.

[0025] The following describes the details of each component contained in the image recording layer mentioned above.

[0026] <Polymer A> Polymer A has a main chain containing two or more silicon atoms and a hydrophilic group. The bonding position of the hydrophilic group in polymer A is arbitrary; it can be at the end of the main chain, between silicon atoms in the main chain, or on the side chains. In particular, from the viewpoint of having better transfer suppression properties of the image recording layer, polymer A preferably has hydrophilic groups in at least one of the side chains and the ends of the main chain, and more preferably has hydrophilic groups in the side chains.

[0027] (Main chain) Examples of main chains containing two or more silicon atoms include main chains containing two or more dimethylsiloxane structural units having the structure shown below.

[0028] [ka]

[0029] (hydrophilic group) From the viewpoint of easily removing non-image areas, the hydrophilic group of polymer A is preferably at least one selected from the group consisting of a hydroxyl group, an amine group, a carboxyl group, a carbinol group, an alkylamino group, a (poly)ether group, a (poly)glycerol group, a (poly)ester group, and a (poly)amide group, more preferably a carbinol group or a (poly)ether group, and even more preferably a (poly)ether group. A preferred hydrophilic polyether group is one in which multiple alkylene oxy groups are linked together, and it is preferable that the side chain consists of two or more linked alkylene oxy groups selected from methylene oxy groups and ethylene oxy groups. From the viewpoint of hydrophilicity, the number of linked alkylene oxy groups is preferably 3 to 100, more preferably 5 to 50, and even more preferably 8 to 20. Polymer A may have only one hydrophilic group or two or more, but from the viewpoint of suitability for synthesis, it is preferable to have only one.

[0030] Polymer A, for example, is a polymer represented by the following formula (A) that has hydrophilic groups in its side chains.

[0031] [ka]

[0032] In formula (A) above, W represents a hydrophilic group, x represents the number of bonds in the dimethylsiloxane structural unit and is in the range of 0 or more, and y represents the number of bonds in the siloxane structural unit having a hydrophilic group in its side chain and is in the range of 1 or more. The bonding order between the dimethylsiloxane structural unit and the siloxane structural unit having a hydrophilic group in its side chain in formula (A) is arbitrary and may be in a block or random order. In formula (A) above, the bonding order between the dimethylsiloxane structural unit and the siloxane structural unit having a hydrophilic group in its side chain is arbitrary, and it may be a random copolymer or a block copolymer. The copolymerization ratio between the dimethylsiloxane structural unit and the siloxane structural unit having a hydrophilic group in its side chain is also arbitrary, but from the viewpoint of having better coating surface properties of the image recording layer coating liquid used when forming the image recording layer and better transfer suppression properties of the formed image recording layer, x:y is preferably a molar ratio of 50:50 to 90:10 when x+y=100. The weight-average molecular weight of polymer A is preferably in the range of 500 to 50,000, and more preferably in the range of 2,000 to 20,000, from the viewpoint of inhibiting the transfer of the image recording layer.

[0033] Polymer A may be a polymer represented by the following formula (A2), for example, having hydrophilic groups at the ends of the main chain.

[0034] [ka]

[0035] In formula (A2), R1 and R2 each independently represent either a methyl group or a hydrophilic group, and at least one of R1 and R2 is a hydrophilic group. x represents the number of bonds in the dimethylsiloxane structural unit and is in the range of 0 or greater.

[0036] Below are examples of more specific structures of polymer A used in the lithographic printing plates related to this disclosure. The numbers accompanying the structures below indicate the number of bonds in the hydrophilic groups of the side chains (e.g., 9), meaning that there are 9 bonds, such as ethyleneoxy groups. Furthermore, the numerical values ​​in the main chain (e.g., 6, 10) indicate the number of repeating units, each having four dimethylsiloxane structural units and one siloxane structural unit with a hydrophilic group in its side chain, meaning that there are 6 and 10 repeating units linked together, respectively. It goes without saying that polymer A is not limited to the specific examples below.

[0037] [ka]

[0038] [ka]

[0039] [ka]

[0040] Among the specific examples above, compounds having a hydrophilic group in the side chain are preferred, and compounds having a polyether group as the hydrophilic group and compounds having a carbinol group are more preferred.

[0041] Polymer A may be a commercially available product, and specific examples of commercially available polymer A include the following: Please note that "DOWSIL," "XIAMETER," and "SYLGARD" are registered trademarks in the commercial product names listed below. The fact that "DOWSIL," "XIAMETER," and "SYLGARD" are registered trademarks will be omitted below.

[0042] Products manufactured by Dow Corning Toray Co., Ltd. include DOWSIL BY 16-205, DOWSIL BY 16-849 Fluid, DOWSIL FZ-3710 Fluid, DOWSIL FZ-3760, DOWSIL FZ-3785, DOWSIL SF 8417 Fluid, DOWSIL BY 16-891, DOWSIL FZ-3789, DOWSIL BY 16-839 Fluid, DOWSIL SF 8411 Fluid, DOWSIL SF 8413 Fluid, DOWSIL SF 8421 Fluid, DOWSIL BY 16-880 Fluid, DOWSIL BY 16-201, DOWSIL SF 8427 Fluid, DOWSIL SF 8428 Fluid, DOWSIL 580 WAX, DOWSIL BY 16-606, DOWSIL BY 16-846 Fluid, XIAMETER OFX-0203 Fluid, XIAMETER OFX-0230 Fluid, DOWSIL SF 8416 Fluid, DOWSIL SF 8419 Fluid, DOWSIL 501W Additive, DOWSIL FZ-2110, DOWSIL FZ-2123, DOWSIL L-7001, SYLGARD OFX-0309 Fluid, XIAMETER OFX-5211 Fluid, DOWSIL SF 8410 Fluid, DOWSIL SH 3746 Fluid, DOWSIL SH 8400 Fluid, DOWSIL SH 8700 Fluid, DOWSIL SH 510 Fluid (100 cSt, 500 cSt), DOWSIL SH 550 Fluid, DOWSIL SH 710 Fluid, DOWSIL FS 1265 Fluid, etc.

[0043] Shin-Etsu Silicone (registered trademark) products from Shin-Etsu Chemical Co., Ltd. include the KP series: KP-124, KP-109, KP-110, KP-121, KP-118, KP-341, KP-112, KP-125, KP-101, KP-106, KP-120, KP-105, KP-104, KP-611, KP-626, KP-327, KP-323, KP-322, KP-625, KP-623, KP-624, KP-620, KP-651, KP-652, KP-650, KP-310, KP-306, KP- 301, KP-621, KP-369, KP-368, KP-126 etc., KF series and FL series etc., KF-868, KF-865, KF-864, KF-859, KF-393, KF-860, KF-880, KF-8004, KF-8002, KF-8005, KF-867, KF-8021, KF-869, KF-861, KF-877, KF-101, KF-1001, KF-102, KF-1002, KF-1005, KF-2001, KF-2004, KF-99, KF-9901, P AM-E, KF-8010, KF-8012, KF-8008, KF-105, KF-6000, KF-6001, KF-6002, KF-6003, KF-6123, KF-9701, KF-2012, KF-857, KF-862, KF-858, KF -351A, KF-352A, KF-353, KF-354L, KF-355A, KF-615A, KF-945, KF-640, KF-642, KF-643, KF-644, KF-6020, KF-6204, KF-6011, KF-6012, KF- Examples include 6015, KF-6017, KF-410, FL-5, FL-100-100cs, FL-100-450cs, FL-100-1,000cs, FL-100-10,000cs, KF-412, KF-413, KF-414, KF-415, KF-4003, KF-4701, KF-4917, KF-7235B, KF-3935, KF-50-100cs, KF-50-300cs, KF-50-1,000cs, KF-50-3,000cs, KF-53, KF-54, KF-6004, etc.

[0044] BYK products include BYK-300, BYK-302, BYK-306, BYK-307, BYK-310, BYK-313, BYK-315 N, BYK-320, BYK-322, BYK-323, BYK-325 N, BYK-326*, BYK-327*, BYK-330, BYK-331, BYK-333, BYK-342, BYK-345 / 346, BYK-347, BYK-348, BYK-349 , BYK-370, BYK-375, BYK-377, BYK-378, BYK-3450*, BYK-3451*, BYK-3455, BYK-3456*, BYK-3760*, BYK-UV 3500, BYK-UV 3505*, BYK-UV 3510, BYK-UV 3530, BYK-UV 3535*, BYK-UV 3570, BYK-UV 3575*, BYK-UV 3576, BYK-350, BYK-354, BYK-355 / 356 Acrylic copolymer, BYK-358 N / 361 N, BYK-381 Acrylic copolymer, BYK-392 Acrylic copolymer, BYK-394 Acrylic copolymer, BYK-3441 Acrylic copolymer, BYK-399, BYK-3440*, BYK-3550, BYK-3560*, BYK-3565*, BYK-3566*, BYK-SILCLEAN Examples include 3700, BYK-SILCLEAN 3701*, BYK-SILCLEAN 3720, and BYK-DYNWET 800 N.

[0045] Evonik products include TEGO Glide 100, TEGO Glide 410, TEGO Glide 432, TEGO Glide 435, TEGO Glide 440, TEGO Glide 450, TEGO Glide 490, TEGO Glide 492, TEGO Glide 494, TEGO Glide 496, TEGO Glide A116, TEGO Glide B1484, TEGO Glide ZG400, TEGO Flow 425, TEGO wet 240, TEGO wet250, TEGO wet260, TEGO wet270, TEGO wet280, TEGO Twin 4000, TEGO Twin 4100, TEGO Twin 420, etc.

[0046] The image recording layer described above may contain only one type of polymer A, or it may contain two or more types. The content of polymer A in the image recording layer is preferably 0.001% to 5% by mass, and more preferably 0.01% to 2% by mass, based on the total solid content of the image recording layer coating solution.

[0047] The image recording layer described above is preferably a negative-type photosensitive image recording layer containing a polymerizable compound and a polymerization initiator. The following describes the case where the lithographic printing plate master related to this disclosure is a negative-type photosensitive image recording layer.

[0048] <Polymerizable compound> If the above-mentioned image recording layer is a negative-type photosensitive image recording layer, it is preferable that it contains a polymerizable compound. In this disclosure, "polymerizable compound" means a compound having a polymerizable group. The polymerizable group is not particularly limited and any known polymerizable group is acceptable, but it is preferably an ethylenically unsaturated group. Furthermore, the polymerizable group may be a radical polymerizable group or a cationic polymerizable group, but it is preferably a radical polymerizable group. Examples of radical polymerizable groups include (meth)acryloyl groups, allyl groups, vinylphenyl groups, and vinyl groups, with (meth)acryloyl groups being preferred from the viewpoint of reactivity. The molecular weight of the polymerizable compound (or weight-average molecular weight if it has a molecular weight distribution) is preferably 50 or more and less than 2,500.

[0049] The polymerizable compound may be, for example, a radical polymerizable compound or a cationic polymerizable compound, but it is preferable that it be an addition polymerizable compound (ethylenically unsaturated compound) having at least one ethylenically unsaturated bond. The ethylenically unsaturated compound is preferably a compound having at least one terminal ethylenically unsaturated bond, and more preferably a compound having two or more terminal ethylenically unsaturated bonds. The polymerizable compound may have chemical forms such as monomers, prepolymers, i.e., dimers, trimers or oligomers, or mixtures thereof. In particular, from the viewpoint of print resistance, the polymerizable compound preferably contains a polymerizable compound with two or more functions, more preferably a polymerizable compound with six or more functions, and even more preferably a polymerizable compound with ten or more functions. Furthermore, from the viewpoint of print resistance in the resulting lithographic printing plate, the polymerizable compound preferably contains a polyfunctional polymerizable compound with two or more functions (preferably six or more functions, more preferably ten or more functions), and as a polyfunctional polymerizable compound, it is even more preferable to include a polyfunctional (meth)acrylate compound.

[0050] Furthermore, from the viewpoint of on-pressure developability and stain suppression, the polymerizable compound preferably contains a polymerizable compound with two or fewer functions, more preferably a bifunctional polymerizable compound, and particularly preferably a bifunctional (meth)acrylate compound. The content of a bifunctional polymerizable compound (preferably a bifunctional polymerizable compound) is preferably 5% to 100% by mass, more preferably 10% to 100% by mass, and particularly preferably 15% to 100% by mass, relative to the total mass of polymerizable compounds in the image recording layer, from the viewpoint of print resistance, on-press developability, and stain suppression.

[0051] In polymerizable compounds, a smaller weight-average molecular weight is preferable from the viewpoint of on-pressure developability, and a larger weight-average molecular weight is preferable from the viewpoint of print durability. From the viewpoint of achieving both on-pressure developability and print durability, the weight-average molecular weight of polymerizable compounds is preferably 100 or more and less than 15,000, more preferably 500 or more and less than 13,000, and even more preferably 1,000 or more and less than 10,000.

[0052] From the viewpoint of suppressing poor development over time, polymerizable compounds preferably contain polymerizable compounds having aromatic rings. The proportion of aromatic rings in the molecule is preferably one or more per molecule, more preferably two or more, and even more preferably three or more.

[0053] It is preferable that the polymerizable compound contained in the image recording layer is an oligomeric polymerizable compound (hereinafter also simply referred to as "oligomer"). In this disclosure, "oligomer" refers to a polymerizable compound having a molecular weight (or weight-average molecular weight if it has a molecular weight distribution) of 600 or more and 15,000 or less, and containing at least one polymerizable group. From the viewpoint of excellent chemical resistance and print resistance, the molecular weight of the oligomer is preferably between 1,000 and 15,000.

[0054] Furthermore, from the viewpoint of improving print resistance, the number of polymerizable groups in one oligomer molecule is preferably 2 or more, more preferably 3 or more, even more preferably 6 or more, and particularly preferably 10 or more. Furthermore, there is no particular upper limit on the number of polymerizable groups in the oligomer, but it is preferable that the number of polymerizable groups be 20 or less.

[0055] From the viewpoints of scratch resistance and in-flight developability, as the oligomer, it is preferable that the number of polymerizable groups is 7 or more and the molecular weight is 1,000 or more and 15,000 or less, and it is more preferable that the number of polymerizable groups is 7 or more and 20 or less and the molecular weight is 1,000 or more and 15,000 or less. In addition, it may contain a polymer component that may occur in the process of manufacturing the oligomer.

[0056] From the viewpoints of scratch resistance, visibility, and in-flight developability, the oligomer preferably has at least one selected from the group consisting of a compound having a urethane bond, a compound having an ester bond, and a compound having an epoxy residue, and preferably has a compound having a urethane bond. In the present disclosure, the epoxy residue refers to a structure formed by an epoxy group, and means a structure similar to a structure obtained by a reaction of an acid group (such as a carboxylic acid group) and an epoxy group, for example.

[0057] As the compound having a urethane bond, which is an example of the oligomer, it 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).

[0058]

Chemical formula

[0059] In formula (Ac-1) and formula (Ac-2), L 1 ~L 4 each independently represents a divalent hydrocarbon group having 2 to 20 carbon atoms, and the wavy line portion represents the bonding position with other structures. L 1 ~L 4Each of these groups is preferably an alkylene group having 2 to 20 carbon atoms, more preferably an alkylene group having 2 to 10 carbon atoms, and even more preferably an alkylene group having 4 to 8 carbon atoms. The alkylene group may have a branched or cyclic structure, but it is preferably a linear alkylene group.

[0060] In formula (Ac-1) or formula (Ac-2), the dashed portion is preferably independently directly bonded to the dashed portion of the group represented by the following formula (Ae-1) or formula (Ae-2).

[0061] [ka]

[0062] In formulas (Ae-1) and (Ae-2), R independently represents either an acryloyloxy group or a methacryloyloxy group, and the wavy lines indicate the bonding positions with the wavy lines in formulas (Ac-1) and (Ac-2).

[0063] Furthermore, as a compound having a urethane bond, a compound obtained by introducing polymerizable groups through a polymer reaction into a polyurethane obtained by the reaction of a polyisocyanate compound and a polyol compound may be used. For example, a compound having a urethane bond may be obtained by reacting a polyurethane oligomer, which is obtained by reacting a polyol compound having an acid group with a polyisocyanate compound, with a compound having an epoxy group and a polymerizable group.

[0064] In a compound having an ester bond, which is an example of an oligomer, the number of polymerizable groups is preferably 3 or more, and more preferably 6 or more.

[0065] As examples of oligomers containing epoxy residues, compounds containing a hydroxyl group within the compound are preferred. Furthermore, the number of polymerizable groups in the compound having epoxy residues is preferably 2 to 6, and more preferably 2 to 3. Compounds having the above-mentioned epoxy residue can be obtained, for example, by reacting a compound having an epoxy group with acrylic acid.

[0066] Specific examples of oligomers are shown in the table below, but the oligomers used in this disclosure are not limited to these. Commercial oligomers may be used, including, but are not limited to, UA510H, UA-306H, UA-306I, UA-306T (all manufactured by Kyoeisha Chemical Co., Ltd.), UV-1700B, UV-6300B, UV7620EA (all manufactured by Nippon Synthetic Chemical Industry Co., Ltd.), U-15HA (manufactured by Shin Nakamura Chemical Industry Co., Ltd.), EBECRYL450, EBECRYL657, EBECRYL885, EBECRYL800, EBECRYL3416, EBECRYL860 (all manufactured by Daicel Ornex Co., Ltd.).

[0067] From the viewpoint of improving chemical resistance, print resistance, and suppression of on-press development residue, the oligomer content is preferably 30% to 100% by mass, more preferably 50% to 100% by mass, and even more preferably 80% to 100% by mass, based on the total mass of polymerizable compounds in the image recording layer.

[0068] The polymerizable compound may further contain polymerizable compounds other than the above-mentioned oligomer. From the viewpoint of chemical resistance, polymerizable compounds other than oligomers are preferably low-molecular-weight polymerizable compounds. Low-molecular-weight polymerizable compounds may be in chemical forms such as monomers, dimers, trimers, or mixtures thereof. Furthermore, from the viewpoint of chemical resistance, the low molecular weight polymerizable compound is preferably at least one polymerizable compound selected from the group consisting of polymerizable compounds having three or more ethylenically unsaturated groups and polymerizable compounds having an isocyanuric ring structure.

[0069] In the present disclosure, the low-molecular-weight polymerizable compound refers to a polymerizable compound having a molecular weight (in the case of having a molecular weight distribution, the weight-average molecular weight) of 50 or more and less than 600. From the viewpoints of chemical resistance, printing resistance, and suppression of in-flight development residues, 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 still more preferably 400 or more and less than 600.

[0070] When the polymerizable compound contains a low-molecular-weight polymerizable compound as a polymerizable compound other than an oligomer (in the case of containing two or more low-molecular-weight polymerizable compounds, the total amount thereof), from the viewpoints of chemical resistance, printing resistance, and suppression of in-flight development residues, 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, more preferably 10 / 1 to 3 / 7, and still more preferably 10 / 1 to 7 / 3 on a mass basis.

[0071] Also, as the low-molecular-weight polymerizable compound, the polymerizable compounds described in paragraphs 0082 to 0086 of International Publication No. 2019 / 013268 can also be preferably used.

[0072] Details of the structure of the polymerizable compound, whether it is used alone or in combination, and the usage method such as the addition amount can be arbitrarily set. Among them, from the viewpoint of printing resistance, the image recording layer preferably contains two or more polymerizable compounds. The content of the polymerizable compound (in the case of containing two or more polymerizable compounds, the total content of the polymerizable compounds) is preferably 5% by mass to 75% by mass, more preferably 10% by mass to 70% by mass, and still more preferably 15% by mass to 60% by mass with respect to the total mass of the image recording layer.

[0073] <Polymerization initiator> When the image recording layer is a negative-type photosensitive image recording layer, it preferably contains a polymerization initiator. The polymerization initiator is a compound that generates polymerization initiation species such as radicals by energy application, and the polymerizable compound is polymerized and cured by the generated polymerization initiation species to form an image portion. Polymerization initiators include electron-accepting polymerization initiators, such as onium compounds, and electron-donating polymerization initiators, such as borate compounds, and either may be included. Furthermore, the negative-type photosensitive image recording layer may contain both electron-accepting polymerization initiators and electron-donating polymerization initiators.

[0074] <<Onium Compounds>> The above-mentioned negative-type photosensitive image recording layer preferably contains an onium compound as an electron-accepting polymerization initiator. An electron-accepting polymerization initiator is, in one embodiment, a compound that, when electrons in an infrared absorber are excited by infrared exposure, accepts one electron through intermolecular electron transfer, thereby generating polymerization initiator species such as radicals. Furthermore, the onium compounds used in this disclosure are compounds that generate polymerization initiators such as radicals and cations in response to light, heat, or both of these energies, and known thermal polymerization initiators, compounds having bonds with low bond dissociation energy, photopolymerization initiators, etc., can be appropriately selected and used.

[0075] From the viewpoint of print resistance, iodonium compounds, sulfonium compounds, or azinium compounds are preferred as onium compounds, iodonium compounds or sulfonium compounds are more preferred, and iodonium compounds are particularly preferred. Specific examples of these compounds are given below, but this disclosure is not limited to them.

[0076] Examples of iodonium compounds include diaryliodonium compounds, more preferably diphenyliodonium compounds substituted with electron-donating groups, such as alkyl or alkoxy groups, and asymmetric diphenyliodonium compounds. Specific examples include diphenyliodonium = hexafluorophosphate, 4-methoxyphenyl-4-(2-methylpropyl)phenyliodonium = hexafluorophosphate, 4-(2-methylpropyl)phenyl-p-tolylliodonium = hexafluorophosphate, 4-hexyloxyphenyl-2,4,6-trimethoxyphenyliodonium = hexafluorophosphate, 4-hexyloxyphenyl-2,4-diethoxyphenyliodonium = tetrafluoroborate, 4-octyloxyphenyl-2,4,6-trimethoxyphenyliodonium = 1-perfluorobutanesulfonate, 4-octyloxyphenyl-2,4,6-trimethoxyphenyliodonium = hexafluorophosphate, and bis(4-t-butylphenyl)iodonium = hexafluorophosphate.

[0077] Furthermore, specific examples of onium compounds include those described in paragraphs 0044-0046 of International Publication No. 2020 / 262685.

[0078] The onium compound preferably comprises compound A represented by the following formula (Ia) and one or more compounds B selected from the group consisting of compounds represented by the following formula (Ib) or the following formula (Ic).

[0079] [ka]

[0080] In formulas (Ia) to (Ic), R1, R2, R3, R4, R5, and R6 are each independently a substituted or unsubstituted alkyl group or a substituted or unsubstituted alkoxy group having 2 to 9 carbon atoms, at least one of R3 and R4 is different from R1 or R2, the difference between the total number of carbon atoms in R1 and R2 and the total number of carbon atoms in R3 and R4 is between 0 and 4 (i.e., 0, 1, 2, 3, or 4), the difference between the total number of carbon atoms in R1 and R2 and the total number of carbon atoms in R5 and R6 is between 0 and 4, and X1, X2, and X3 are the same or different anions.

[0081] R1, R2, R3, R4, R5, and R6 are each preferably independently a substituted or unsubstituted C2-C9 alkyl group or a substituted or unsubstituted C2-C9 alkoxy group, more preferably a substituted or unsubstituted C3-C6 alkyl group or a substituted or unsubstituted C3-C6 alkoxy group, and even more preferably a substituted or unsubstituted C3-C6 alkyl group. The alkylalkoxy groups may be linear or branched, but are preferably branched. Examples of substituted or unsubstituted alkyl groups include ethyl group, n-propyl group, iso-propyl group, n-butyl group, iso-butyl group, sec-butyl group, t-butyl group, n-pentyl group, t-pentyl group, sec-pentyl group, neopentyl group, n-hexyl group, iso-hexyl group, sec-hexyl group, t-hexyl group, n-heptyl group, n-octyl group, iso-octyl group, 2-ethylhexyl group, and n-nonyl group. Examples of substituted or unsubstituted alkoxy groups include ethoxy, n-propoxy, iso-propoxy, t-butoxy, n-butoxy, and n-octyloxy groups.

[0082] As X1, X2, and X3 above, ClO4 - PF6 - BF4 - SbF6 - CH3SO3 - CF3SO3 -, C6H5SO3 - CH3C6H4SO3 - HOC6H4SO3 - ClC6H4SO3 - , and borate anions represented by the following structure (Id) are preferred.

[0083] B - (R 1 )(R 2 )(R 3 )(R 4 ) Formula (Id)

[0084] In formula (Id), R 1 , R 2 , R 3 and R 4 Each of these independently represents a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group (including halogen-substituted aryl groups), a substituted or unsubstituted alkenyl group, a substituted or unsubstituted alkynyl group, a substituted or unsubstituted cycloalkyl group, or a substituted or unsubstituted heterocyclic group. 1 , R 2 , R 3 and R 4 Two or more of these may be linked together to form a substituted or unsubstituted heterocycle containing a boron atom. The resulting heterocycle may have up to seven carbon atoms, nitrogen atoms, oxygen atoms, or nitrogen atoms. R 1 , R 2 , R 3 and R 4 Substituents in this compound include chlorine atoms, fluorine atoms, nitro groups, alkyl groups, alkoxy groups, and acetoxy groups.

[0085] The above R 1 , R 2 , R 3 and R 4 Preferably, all of these are substituted or unsubstituted aryl groups, and more preferably, all of them are unsubstituted phenyl groups.

[0086] It is preferable that at least one of X1, X2, and X3 is a tetraarylborate anion containing the same or different aryl groups, more preferably one or more of them is a tetraphenylborate anion, and even more preferably each of X1, X2, and X3 is a tetraphenylborate anion.

[0087] As a preferred embodiment, the onium compound includes a compound represented by formula (Ic), and examples include R1 being the same as R5 and R2 being the same as R6. In particular, R1 is the same as R2, and for example, it is preferable that both R1 and R2 are an iso-propyl group, an iso-butyl group, or a t-butyl group.

[0088] In another preferred embodiment, the onium compound includes a compound represented by formula (Ib), and examples include R1 being the same as R2 and R3 being the same as R4. At this time, it is preferable that both R1 and R2 are an iso-propyl group, an iso-butyl group, or a t-butyl group. Also, the difference in the number of carbon atoms between R1 and R3 is preferably 1 or 2.

[0089] The compounds represented by formula (Ia) to formula (Ic) may be obtained from Sigma-Aldrich or the like, or may be synthesized using known synthesis methods and easily available starting materials.

[0090] From the viewpoints of suppressing poor development over time and printing resistance, the onium compound is preferably a diaryliodonium compound represented by the following formula (5) or formula (6).

[0091]

Chemical formula

[0092] The diaryliodonium compound represented by formula (5) preferably has a symmetrical cation moiety. The diaryliodonium compound represented by formula (6) preferably has an asymmetric cation moiety. Also, R i5 ~R i9 At least one of them is preferably a substituted or unsubstituted alkyl group, R i10 ~R i14 Preferably, at least one of them is a substituted or unsubstituted alkyl group.

[0093] The above R i5 ~R i14 Each of these is preferably a hydrogen atom or a substituted or unsubstituted C1-C9 alkyl group, more preferably a hydrogen atom or a substituted or unsubstituted C3-C6 alkyl group, and even more preferably a substituted or unsubstituted C3-C6 alkyl group. The alkyl group may be linear or branched, but branched is preferred. Examples of substituted or unsubstituted alkyl groups include methyl group, ethyl group, n-propyl group, iso-propyl group, n-butyl group, iso-butyl group, sec-butyl group, t-butyl group, n-pentyl group, t-pentyl group, sec-pentyl group, neopentyl group, n-hexyl group, iso-hexyl group, sec-hexyl group, t-hexyl group, n-heptyl group, n-octyl group, iso-octyl group, 2-ethylhexyl group, and n-nonyl group.

[0094] The above X - As for, ClO4 -PF6 - BF4 - SbF6 - CH3SO3 - CF3SO3 - , C6H5SO3 - CH3C6H4SO3 - HOC6H4SO3 - ClC6H4SO3 - Alternatively, a borate anion represented by the above structure (Id) is preferred.

[0095] Furthermore, the onium compound may include a compound represented by formula (II) as described in paragraphs 0186-0197 of International Publication No. 2022 / 019217, from the viewpoint of developability and printfastness of the resulting lithographic printing plate.

[0096] The lowest unoccupied orbital (LUMO) of the onium compound is preferably -3.00 eV or less, and more preferably -3.02 eV or less, from the viewpoint of improving sensitivity and reducing the occurrence of plate skipping. Furthermore, the lower limit is preferably -3.80 eV or higher, and more preferably -3.60 eV or higher.

[0097] Onium compounds may be used individually or in combination of two or more. From the viewpoint of visibility, print resistance, and coating stability, the onium compound content is preferably 0.1% to 20% by mass, more preferably 0.5% to 10% by mass, and particularly preferably 0.5% to 7% by mass, relative to the total mass of the image recording layer.

[0098] <<Borate Compounds>> The image recording layer described above preferably contains an electron-donating borate compound. Borate compounds are used as electron-donating polymerization initiators in image recording layers. Borate compounds are compounds that generate polymerization initiators such as radicals and cations in response to light, heat, or both.

[0099] As the borate compound, tetraarylborate compounds or monoalkyltriarylborate compounds are preferred, and from the viewpoint of compound stability, tetraarylborate compounds are more preferred, and tetraphenylborate compounds are particularly preferred. The countercation of the borate compound is not particularly limited, but is preferably an alkali metal ion or a tetraalkylammonium ion, and more preferably a sodium ion, a potassium ion, or a tetrabutylammonium ion.

[0100] The borate compound is preferably a compound represented by formula (B1) from the viewpoint of visibility, print resistance, and suppression of development defects over time. That is, the negative-type photosensitive image recording layer preferably contains a borate compound represented by (B1) and is of the on-press development type.

[0101] [ka]

[0102] In formula (B1), R B1 ~R B4 Each of these independently represents an unsubstituted or substituted alkyl group, an unsubstituted or substituted aryl group, an unsubstituted or substituted alkenyl group, or an unsubstituted or substituted alkynyl group, R B1 ~R B4 Each of them may independently have a ring structure. However, R B1 ~R B4 At least one of them is different from the others. + This represents a cation.

[0103] R B1 ~R B4Examples of alkyl groups represented by include alkyl groups having 1 to 20 carbon atoms, such as methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, hexadecyl group, octadecyl group, eicosyl group, isopropyl group, isobutyl group, s-butyl group, t-butyl group, isopentyl group, neopentyl group, 1-methylbutyl group, isohexyl group, 2-ethylhexyl group, 2-methylhexyl group, cyclohexyl group, cyclopentyl group, and 2-norbornyl group. The alkyl groups may be linear, branched, or have a ring structure.

[0104] Also, R B1 ~R B4 The alkyl group represented by may have substituents. Examples of substituents on the alkyl group include halogen atoms, alkyl groups, aryl groups, alkenyl groups, alkoxy groups, ester groups, carbonyl groups, sulfonyl groups, amino groups, amide groups, and combinations thereof. R B1 ~R B4 The alkyl groups represented by are, independently, preferably unsubstituted linear or branched alkyl groups having 1 to 12 carbon atoms, more preferably unsubstituted linear or branched alkyl groups having 1 to 10 carbon atoms, and even more preferably unsubstituted linear or branched alkyl groups having 1 to 6 carbon atoms. Among these, branched unsubstituted alkyl groups are particularly preferred from the viewpoint of suppressing development defects over time.

[0105] R B1 ~R B4 Examples of aryl groups represented by this symbol include aryl groups having 6 to 20 carbon atoms, such as phenyl, naphthyl, anthryl, phenanthryl, indenyl, acenabutenyl, and fluorenyl groups. Examples of substituents on the aryl group include substituents on the alkyl group mentioned above. R B1 ~R B4As the aryl group represented by , each independently, an unsubstituted or substituted phenyl group is preferable.

[0106] R B1 ~R B4 Examples of the alkenyl group represented by include alkenyl groups having 2 to 20 carbon atoms, such as a vinyl group, a 1-propenyl group, a 1-butenyl group, a cinnamyl group, a 2-chloro-1-ethenyl group, and the like. R B1 ~R B4 The alkenyl group represented by may be linear, branched, or have a ring structure. Examples of the substituent of the alkenyl group include the substituents of the above alkyl group and the like. R B1 ~R B4 As the alkenyl group represented by , each independently, an unsubstituted alkenyl group having 2 to 20 carbon atoms is preferable.

[0107] R B1 ~R B4 Examples of the alkynyl group represented by include alkynyl groups having 2 to 20 carbon atoms, such as an ethynyl group, a 1-propynyl group, a 1-butynyl group, a trimethylsilylethynyl group, a phenylethynyl group, and the like. The above alkynyl group may be linear or branched.

[0108] Among the above functional groups, R B1 ~R B4 is preferably each independently a substituted or unsubstituted aryl group. R B1 ~R B4 When R~R are each independently a substituted or unsubstituted aryl group, the HOMO potential of the borate compound becomes lower, and the film stability of the image recording layer is improved. Thereby, the life of the lithographic printing plate can be extended.

[0109] In the present disclosure, at least one of R~R is different from the others. Among them, R B1 ~R B4 of which at least one is different from the others. Among them, RB1 ~R B4 Among them, R B1 ~R B3 is the same, and R B4 is preferably different from R B1 ~R B3 By this, a high-purity borate compound can be obtained. In addition, generation of radicals can be suppressed, and side reactions can be made difficult to occur. In the above case, R B1 ~R B3 is more preferably a phenyl group.

[0110] Also, among R B1 ~R B4 it is also preferable that at least two of them are phenyl groups and at least one is a substituted aryl group. Furthermore, among R B1 ~R B3 it is more preferable that at least two of them are phenyl groups and R B4 is an aryl group having a substituent (i.e., a substituted aryl group). It is particularly preferable that R B1 ~R B3 are phenyl groups and R B4 is an aryl group having a substituent.

[0111] R B1 ~R B3 are phenyl groups and R B4 is an aryl group having a substituent. In this case, the total number of carbon atoms and oxygen atoms of the substituent of the aryl group is preferably 2 or more, more preferably 3 or more. As the upper limit, for example, it is 8 or less.

[0112] The compound represented by the formula (B1) is preferably the compound represented by the following formula (B2).

[0113]

Chemical formula

[0114] In formula (B2), R represents an alkyl group having 2 or more carbon atoms, or an alkoxy group with a total of 2 or more carbon atoms and oxygen atoms. + This represents iodonium cation or infrared-absorbing dye cation.

[0115] In formula (B2), the alkyl group represented by R preferably has 2 to 8 carbon atoms, more preferably 2 to 6 carbon atoms, and even more preferably 2 to 4 carbon atoms. Examples of the alkyl groups mentioned above include ethyl group, propyl group, n-butyl group, tert-butyl group, isobutyl group, sec-butyl group, pentyl group, hexyl group, heptyl group, octyl group, neopentyl group, and isopropyl group. The alkyl group described above may be linear, branched, or have a ring structure.

[0116] In formula (B2), the alkoxy group R preferably has a total of 2 to 4 carbon atoms and oxygen atoms. Examples of the alkoxy groups mentioned above include methoxy, n-propoxy, isopropoxy, and n-butoxy groups. The alkoxy group described above may be linear or branched.

[0117] Also, in equation (B1), R B1 ~R B3 The phenyl group represented is preferably a phenyl group substituted with an electron-withdrawing group. Examples of the electron-withdrawing groups mentioned above include halogen atoms and fluoroalkyl groups. Among these, fluorine atoms, chlorine atoms, and fluoroalkyl groups having 1 to 3 carbon atoms are preferred.

[0118] In formula (B1), R B4The substituents on the aryl group represented by are preferably alkyl groups, aryl groups, alkenyl groups, alkoxy groups, ester groups, carbonyl groups, and amide groups, more preferably alkyl groups, alkenyl groups, and alkoxy groups, and even more preferably alkyl groups or alkoxy groups.

[0119] In this disclosure, the compound represented by formula (B1) above may be a compound represented by the following formula (B3).

[0120] [ka]

[0121] In formula (B3), R represents a group with a total of 2 or more carbon atoms and oxygen atoms, X represents a halogen atom, alkyl group, or alkoxy group, and the sum of the Hammett values ​​of R and X is between -0.09 and 0.09, M + Li + na + , K + iodonium cation, or This represents infrared-absorbing dye cations.

[0122] Examples of R in formula (B3) include alkyl groups, aryl groups, alkenyl groups, alkoxy groups, ester groups, carbonyl groups, sulfonyl groups, amide groups, and combinations thereof.

[0123] Examples of halogen atoms represented by X in formula (B3) include fluorine atoms, chlorine atoms, and bromine atoms. In formula (B3), the alkyl group and alkoxy group represented by X are the same as those in formula (II) above, and the preferred embodiment is also the same.

[0124] In particular, R in formula (B3) is preferably an alkyl group having 2 to 4 carbon atoms, or an alkoxy group with a total of 2 to 4 carbon atoms and 2 to 4 oxygen atoms, and more preferably an alkyl group having 2 to 4 carbon atoms. In the above case, X is preferably a halogen atom. Here, the halogen atoms may be different halogen atoms independently, but it is more preferable that they are all the same halogen atom.

[0125] In formula (B3), the sum of the Hammett σ values ​​of the substituents (R and X) introduced into the aryl skeleton is preferably in the range of -0.2 to 0.2, and more preferably in the range of -0.09 to 0.09. Being within this range allows the HOMO potential to be adjusted to the desired range, resulting in an excellent balance between the film stability and print resistance of the image recording layer. In this disclosure, the sum of the Hammett σ values ​​of substituents introduced to the aryl skeleton was calculated using the values ​​described in the reference "Chemistry Seminar 10: Hammett Side - Structure and Reactivity -" (by Naoki Inamoto, Maruzen Co., Ltd., June 1983).

[0126] M in equation (B1) + This represents a cation. That is, M + M is the countercation of the boron anion. In this disclosure, + The cation is not particularly limited as long as it can neutralize the boron anion, but from the viewpoint of suppressing staining during development, at least one selected from the group consisting of inorganic cations, iodonium cations, and infrared absorbing dye cations is preferred. The counter-cation may be used alone or in combination of two or more. In formula (B3), M + Li + na + , K + , represents an iodonium cation or an infrared absorbing dye cation. In formula (B2), M + This represents iodonium cation or infrared-absorbing dye cation.

[0127] When using two or more opposing cations, the combinations are not particularly limited, but inorganic cations together, iodonium cations together, or infrared absorbing dye cations together are preferred, and iodonium cations together or infrared absorbing dye cations together are more preferred. This further improves the suppression of development defects over time and print durability.

[0128] The iodonium cation described above may be the cationic portion of an electron-accepting polymerization initiator described later, and the infrared-absorbing dye cation may be the cationic portion of an infrared absorber described later. In the image recording layer, the cation portion of the electron-donating polymerization initiator and the cation portion of the infrared absorber can combine with the anionic portion of the borate compound represented by formula (B1) to form a salt.

[0129] Examples of inorganic cations include lithium cations, sodium cations, potassium cations, calcium cations, and magnesium cations. Among these, sodium cations, lithium cations, and potassium cations are preferred, with sodium cations being more preferred.

[0130] As the iodonium cation, the cation portion of the electron-accepting polymerization initiator described later can be used. A specific example is shown in the following structural formula. In the following structural formula, Me represents a methyl group. Note that the iodonium cation is not limited to the specific example shown below.

[0131] [ka]

[0132] As the infrared absorbing dye cation, the cation portion of the infrared absorber described later can be used. A specific example is shown in the following structural formula. In the following structural formula, Me represents a methyl group and Bu represents a butyl group. Note that the infrared absorbing dye cation is not limited to the specific example below.

[0133] [ka]

[0134] [ka]

[0135] The highest occupied orbital (HOMO) of the borate compound is preferably -6.0 eV or higher, more preferably -5.95 eV or higher, and even more preferably -5.93 eV or higher, from the viewpoint of chemical resistance and scratch resistance. Furthermore, the upper limit is preferably -5.00eV or less, more preferably -5.40eV or less, and particularly preferably between -5.93eV and -5.70eV.

[0136] In this disclosure, the highest occupied orbit (HOMO) and lowest unoccupied orbit (LUMO) are calculated by the following method. First, we ignore the counter anions in the compounds being calculated. Using the quantum chemistry calculation software Gaussian09, structural optimization is performed using DFT (B3LYP / 6-31G(d)). The MO (molecular orbital) energy calculation is performed using DFT (B3LYP / 6-31+G(d,p) / CPCM(solvent=methanol)) with the structure obtained from the above structure optimization. The MO energy Ebare (unit: hartree) obtained from the above MO energy calculation is converted to Escaled (unit: eV), which will be used as the HOMO and LUMO values ​​in this disclosure, using the following formula. Escaled=0.823168×27.2114×Ebare-1.07634 Note that 27.2114 is simply a coefficient for converting Hartree to eV, while 0.823168 and -1.07634 are adjustment coefficients used to determine the HOMO and LUMO of the compound being calculated so that the calculation matches the experimentally observed values.

[0137] The following are preferred examples of borate compounds represented by formula (B1), but are not limited to these. In the following structural formula, Me represents a methyl group.

[0138] [ka]

[0139] [ka]

[0140] [ka]

[0141] [ka]

[0142] [ka]

[0143] [ka]

[0144] If the above image recording layer contains a borate compound, it may contain only one type of borate compound or two or more types. From the viewpoint of visibility, print resistance, and coating stability, the content of the borate compound is preferably 0.01% to 30% by mass, more preferably 0.1% to 20% by mass, and even more preferably 0.5% to 15% by mass, relative to the total mass of the image recording layer.

[0145] [On-board developing type negative-type photosensitive image recording layer] When the above-mentioned negative-type photosensitive image recording layer is applied to an on-pressure developing type, it is preferable that the negative-type photosensitive image recording layer contains an external light absorber and an onium salt polymerization initiator.

[0146] <Infrared absorbent> When the above-mentioned negative-type photosensitive image recording layer is applied to an on-board developing type, it is preferable that the image recording layer contains an infrared absorber. There are no particular restrictions on the infrared absorber; for example, pigments and dyes can be used. Dyes used as infrared absorbers include commercially available dyes and known dyes listed in literature such as the "Dye Handbook" (edited by the Society of Synthetic Organic Chemistry, published in 1970). Specifically, examples of dyes include azo dyes, metal complex azo dyes, pyrazolone azo dyes, naphthoquinone dyes, anthraquinone dyes, phthalocyanine dyes, carbonium dyes, quinone imine dyes, methine dyes, cyanine dyes, squarylium dyes, pyryllium salts, and metal thiolate complexes.

[0147] Among these dyes, particularly preferred are cyanine dyes, squarylium dyes, pyryllium salts, nickel thiolate complexes, and indorenine-cyanine dyes. Furthermore, cyanine dyes and indorenine-cyanine dyes are also preferred. Of these, cyanine dyes are particularly preferred.

[0148] The infrared absorber is preferably a cationic polymethine dye having an oxygen or nitrogen atom at the meso position. Examples of cationic polymethine dyes include cyanine dyes, pyrylium dyes, thiopyrillium dyes, and azulenium dyes, with cyanine dyes being preferred from the viewpoint of ease of availability and solvent solubility during the introduction reaction.

[0149] Specific examples of cyanine dyes include the compounds described in paragraphs 0017 to 0019 of Japanese Patent Publication No. 2001-133969, the compounds described in paragraphs 0016 to 0021 of Japanese Patent Publication No. 2002-023360, the compounds described in paragraphs 0012 to 0037 of Japanese Patent Publication No. 2002-040638, preferably the compounds described in paragraphs 0034 to 0041 of Japanese Patent Publication No. 2002-278057, the compounds described in paragraphs 0080 to 0086 of Japanese Patent Publication No. 2008-195018, particularly preferably the compounds described in paragraphs 0035 to 0043 of Japanese Patent Publication No. 2007-90850, and the compounds described in paragraphs 0105 to 0113 of Japanese Patent Publication No. 2012-206495. Furthermore, the compounds described in paragraphs 0008 to 0009 of Japanese Patent Publication No. 5-5005 and paragraphs 0022 to 0025 of Japanese Patent Publication No. 2001-222101 can also be preferably used. As pigments, compounds described in paragraphs 0072 to 0076 of Japanese Patent Publication No. 2008-195018 are preferred.

[0150] Furthermore, the infrared absorber may also include an infrared absorber that decomposes upon infrared exposure (decomposable infrared absorber). It is presumed that by using a decomposition-type infrared absorbent as an infrared absorbent, the infrared absorbent or its decomposition products promote polymerization, and the interaction between the decomposition products of the infrared absorbent and polymerizable compounds results in excellent print resistance. The decomposition-type infrared absorber is preferably an infrared absorber that has the function of absorbing and decomposing infrared rays upon infrared exposure and producing color. Hereafter, the colored compounds formed when a decomposing infrared absorbent absorbs and decomposes infrared light due to infrared exposure will also be referred to as "colorants of decomposing infrared absorbents." Furthermore, it is preferable that the decomposition-type infrared absorber has the function of absorbing infrared rays through infrared exposure and converting the absorbed infrared rays into heat. A decomposition-type infrared absorber is acceptable as long as it absorbs and decomposes at least a portion of the light in the infrared wavelength range (wavelengths from 750 nm to 1 mm), but it is preferable that the infrared absorber has a maximum absorption wavelength in the wavelength range of 750 nm to 1,400 nm, and more preferably that the infrared absorber has a maximum absorption wavelength in the wavelength range of 760 nm to 900 nm. More specifically, the decomposition-type infrared absorber is preferably a compound that decomposes due to infrared exposure, producing a compound having a maximum absorption wavelength in the 500 nm to 600 nm wavelength range.

[0151] The decomposition-type infrared absorber is preferably an infrared absorber that decomposes due to heat, electron transfer, or both caused by infrared exposure, and more preferably an infrared absorber that decomposes due to electron transfer caused by infrared exposure. Here, "decomposition by electron transfer" means that electrons excited from the HOMO (highest occupied orbital) to the LUMO (lowest unoccupied orbital) of the decomposition-type infrared absorber by infrared exposure undergo intramolecular electron transfer to electron-accepting groups within the molecule (groups with a potential close to the LUMO), and decomposition occurs as a result.

[0152] From the viewpoint of visibility and print resistance, the infrared absorber is preferably a cyanine dye represented by the following formula (7).

[0153] [ka] In formula (7), R 1 R is obtained by infrared exposure. 1 -L represents the group that cleaves the bond, R 11 ~R 18 Each of these independently represents a hydrogen atom, a halogen atom, -Ra, -ORb, -SRc, or -NRdRe, and Ra~Re each independently represents a hydrocarbon group, with A1, A2 and multiple R 11 ~R 18 They may be linked together to form a monocycle or polycycle, and A1 and A2 each independently represent an oxygen atom, a sulfur atom, or a nitrogen atom, n 11 and n12 Each of these independently represents an integer from 0 to 5, where n 11 and n 12 The sum of n is 2 or more, 13 and n 14 Each of these independently represents either 0 or 1, and L represents an oxygen atom, a sulfur atom, or -NR 10 - represents R 10 represents a hydrogen atom, alkyl group, or aryl group, and Za represents a counterion that neutralizes the charge.

[0154] R 1 The group that cleaves the bond with -L is not particularly limited as long as it is cleavable, but from the viewpoint of visibility, it is preferable that it be a group represented by any of formulas 2-1 to 4-1.

[0155] [ka]

[0156] In formulas 2-1 to 4-1, R 20 , R 30 , R 41 and R 42 Each of the following independently represents an alkyl group or an aryl group, Zb represents a counterion that neutralizes the charge, and the dashed line represents the bonding site with the group represented by L in formula (7) above.

[0157] The compound represented by formula (7) reacts with R when exposed to infrared light. 1 - The L bond is cleaved, and L becomes =O, =S, or =NR 10 It becomes discolored, and so on.

[0158] In formula 2-1, R 20 The '' represents an alkyl or aryl group, and the wavy part represents the bonding site with the group represented by L in formula (7). R 20 The 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 even more preferably an alkyl group having 1 to 10 carbon atoms. The alkyl group described above may be linear, branched, or have a ring structure. 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 even more preferably an aryl group having 6 to 12 carbon atoms. R 20 From the viewpoint of visibility, alkyl groups are preferable.

[0159] Furthermore, from the standpoint of biodegradability and visibility, R 20 The alkyl group represented is preferably a secondary alkyl group or a tertiary alkyl group, and is preferably a tertiary alkyl group. Furthermore, from the standpoint of biodegradability and visibility, R 20 The alkyl group represented is preferably an alkyl group having 1 to 8 carbon atoms, more preferably a branched alkyl group having 3 to 10 carbon atoms, even more preferably a branched alkyl group having 3 to 6 carbon atoms, an isopropyl group or a tert-butyl group is particularly preferred, and a tert-butyl group is most preferred.

[0160] The following are specific examples of the group represented by formula 2-1 above, but this disclosure is not limited to these. In the following structural formulas, ● represents the bonding site with the group represented by L in formula (7).

[0161] [ka]

[0162] In formula 3-1, R 30 The '' represents an alkyl or aryl group, and the wavy part represents the bonding site with the group represented by L in formula (7). R 30 The alkyl and aryl groups represented by formula 2-1 are R 20 The alkyl and aryl groups represented by are the same, and the preferred embodiments are also the same.

[0163] From the standpoint of biodegradability and visibility, R 30 The alkyl group represented is preferably a secondary alkyl group or a tertiary alkyl group, and is preferably a tertiary alkyl group. Furthermore, from the standpoint of biodegradability and visibility, R 30 The alkyl group represented is preferably an alkyl group having 1 to 8 carbon atoms, more preferably a branched alkyl group having 3 to 10 carbon atoms, even more preferably a branched alkyl group having 3 to 6 carbon atoms, an isopropyl group or a tert-butyl group is particularly preferred, and a tert-butyl group is most preferred. Furthermore, from the standpoint of biodegradability and visibility, R 30 The alkyl group represented is preferably a substituted alkyl group, more preferably a fluorosubstituted alkyl group, even more preferably a perfluoroalkyl group, and particularly preferably a trifluoromethyl group.

[0164] From the standpoint of biodegradability and visibility, R 30 The aryl group represented is preferably a substituted aryl group, and examples of substituents include alkyl groups (preferably alkyl groups having 1 to 4 carbon atoms) and alkoxy groups (preferably alkoxy groups having 1 to 4 carbon atoms).

[0165] The following are specific examples of the group represented by formula 3-1, but this disclosure is not limited to these. In the following structural formulas, ● represents the bonding site with the group represented by L in formula (7).

[0166] [ka]

[0167] In formula 4-1, R 41 and R 42 Each of these independently represents an alkyl group or an aryl group, Zb represents a counterion that neutralizes the charge, and the dashed portion represents the bonding site with the group represented by L in formula (7). R 41 or R 42The alkyl and aryl groups represented by formula 2-1 are R 20 The alkyl and aryl groups represented by are the same, and the preferred embodiments are also the same. R 41 From the viewpoint of decomposability and visibility, alkyl groups are preferred. R 42 From the viewpoint of decomposability and visibility, alkyl groups are preferred.

[0168] From the standpoint of biodegradability and visibility, R 41 The alkyl group represented is preferably an alkyl group having 1 to 8 carbon atoms, more preferably an alkyl group having 1 to 4 carbon atoms, and particularly preferably a methyl group. From the standpoint of biodegradability and visibility, R 42 The alkyl group represented is preferably a secondary alkyl group or a tertiary alkyl group, and is preferably a tertiary alkyl group. Furthermore, from the standpoint of biodegradability and visibility, R 42 The alkyl group represented is preferably an alkyl group having 1 to 8 carbon atoms, more preferably a branched alkyl group having 3 to 10 carbon atoms, even more preferably a branched alkyl group having 3 to 6 carbon atoms, an isopropyl group or a tert-butyl group is particularly preferred, and the tert-butyl group is most preferred.

[0169] In equation 4-1, Zb can be any counterion that neutralizes the charge, and the compound as a whole may be included in Za in equation (7). Zb is preferably a sulfonate ion, carboxylate ion, tetrafluoroborate ion, hexafluorophosphate ion, p-toluenesulfonate ion, or perchlorate ion, with tetrafluoroborate ions or hexafluorophosphate ions being more preferred.

[0170] The following are specific examples of the group represented by formula 4-1, but this disclosure is not limited to these. In the following structural formulas, ● represents the bonding site with the group represented by L in formula (7).

[0171] [ka]

[0172] In formula (7), L is an oxygen atom, or -NR 10 - is preferred, and oxygen atoms are particularly preferred. Also, -NR 10 -R in 10 A alkyl group is preferred. 10 The alkyl group represented by is preferably an alkyl group having 1 to 10 carbon atoms. Also, R 10 The alkyl group represented by may be linear, branched, or have a ring structure. Among alkyl groups, methyl or cyclohexyl groups are preferred. -NR 10 -R in 10 If the group is an aryl group, an aryl group having 6 to 30 carbon atoms is preferred, an aryl group having 6 to 20 carbon atoms is more preferred, and an aryl group having 6 to 12 carbon atoms is even more preferred. These aryl groups may also have substituents.

[0173] In equation (7), R 11 ~R 18 These are, independently, a hydrogen atom and -R a , -OR b , -SR c , or -NR d R e It is preferable that this be the case. R a ~R e The hydrocarbon group represented is preferably a hydrocarbon group having 1 to 30 carbon atoms, more preferably a hydrocarbon group having 1 to 15 carbon atoms, and even more preferably a hydrocarbon group having 1 to 10 carbon atoms. The above hydrocarbon group may be linear, branched, or have a ring structure. Alkyl groups are particularly preferred among the hydrocarbon groups mentioned above.

[0174] The alkyl group described above is preferably an alkyl group having 1 to 30 carbon atoms, more preferably an alkyl group having 1 to 15 carbon atoms, and even more preferably an alkyl group having 1 to 10 carbon atoms. The alkyl group described above may be linear, branched, or have a ring structure. Specifically, examples include methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, hexadecyl group, octadecyl group, eicosyl group, isopropyl group, isobutyl group, s-butyl group, tert-butyl group, isopentyl group, neopentyl group, 1-methylbutyl group, isohexyl group, 2-ethylhexyl group, 2-methylhexyl group, cyclohexyl group, cyclopentyl group, and 2-norbornyl group. Among alkyl groups, methyl, ethyl, propyl, or butyl groups are preferred.

[0175] The alkyl group described above may have substituents. Examples of substituents include alkoxy groups, aryloxy groups, amino groups, alkylthio groups, arylthio groups, halogen atoms, carboxyl groups, carboxylate groups, sulfo groups, sulfonate groups, alkyloxycarbonyl groups, aryloxycarbonyl groups, and groups combining these.

[0176] R in equation (7) 11 ~R 14 Each of these is independently a hydrogen atom, or -R a It is preferably a hydrocarbon group (i.e., a hydrogen atom), more preferably an alkyl group, and even more preferably a hydrogen atom, except in the following cases. In particular, R bonded to the carbon atom to which L is bonded. 11 and R 13The alkyl group is preferred, and it is more preferable that the two are linked to form a ring. The ring formed may be a monocyclic or polycyclic ring. Specifically, examples of the ring formed include monocyclic rings such as cyclopentene rings, cyclopentadiene rings, cyclohexene rings, and cyclohexadiene rings, and polycyclic rings such as indene rings and indole rings. Also, A1 + R bonded to the carbon atom to which it is bonded. 12 is R 15 or R 16 (preferably R 16 It is preferable that R is bonded to the carbon atom to which A2 is bonded. 14 is R 17 or R 18 (preferably R 18 It is preferable to connect them to form a ring.

[0177] In equation (7), n 13 is 1, R 16 is, -R a (Ideally, a hydrocarbon group) Also, R 16 A1 + R bonded to the carbon atom to which it is bonded. 12 It is preferable to link with to form a ring. The formed ring is preferably an indolium ring, a pyrylium ring, a thiopyrillium ring, a benzoxazoline ring, or a benzimidazoline ring, with an indolium ring being more preferable from the viewpoint of improving the visibility of the exposed area. These rings may further have substituents. In equation (7), n 14 is 1, R 18 is, -R a (Ideally, a hydrocarbon group) Also, R 18 R is bonded to the carbon atom to which A2 is bonded. 14 It is preferable to link with to form a ring. The formed ring is preferably an indole ring, a pyran ring, a thiopyran ring, a benzoxazole ring, or a benzimidazole ring, with an indole ring being more preferable from the viewpoint of improving the visibility of the exposed area. These rings may further have substituents. R in equation (7) 16 and R 18 It is preferable that they are the same group, and if each forms a ring, A1 + Except for A2, it is preferable to form rings with the same structure.

[0178] R in equation (7) 15 and R 17 It is preferable that they are the same group. Also, R 15 and R 17 is, -R a It is preferably a hydrocarbon group, more preferably an alkyl group, and even more preferably a substituted alkyl group.

[0179] In the compound represented by formula (7), from the viewpoint of improving water solubility, R 15 and R 17 Preferably, the substituent is an alkyl group. R 15 or R 17 Examples of substituted alkyl groups represented by the following formulas (a1) to (a4) include groups represented by any of the following formulas.

[0180] [ka]

[0181] In formulas (a1) to (a4), R W0 represents an alkylene group with 2 to 6 carbon atoms, W represents a single bond or oxygen atom, and n W1 represents integers from 1 to 45, and R W1 C1-C12 alkyl group or -C(=O)-R W5 Represents R W5 R represents an alkyl group with 1 to 12 carbon atoms. W2 ~R W4 Each of these 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.

[0182] In equation (a1), R W0Specific examples of alkylene groups represented by include ethylene group, n-propylene group, isopropylene group, n-butylene group, isobutylene group, n-pentylene group, isopentylene group, n-hexyl group, isohexyl group, etc., with ethylene group, n-propylene group, isopropylene group, or n-butylene group being preferred, and n-propylene group being particularly preferred. n W1 A value of 1 to 10 is preferred, 1 to 5 is more preferred, and 1 to 3 is particularly preferred. R W1 Specific examples of alkyl groups represented by include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, tert-butyl group, n-pentyl group, isopentyl group, neopentyl group, n-hexyl group, n-octyl group, n-dodecyl group, etc. Methyl group, ethyl group, n-propyl group, isopropyl group, or n-butyl group, tert-butyl group are preferred, methyl group, or ethyl group are more preferred, and methyl group is particularly preferred. R W5 The alkyl group represented by R W1 Similar to alkyl groups represented by R, a preferred embodiment is also R W1 This is similar to a preferred embodiment of the alkyl group represented by .

[0183] Specific examples of the group represented by formula (a1) are shown below, but this disclosure is not limited to these. In the following structural formulas, Me represents a methyl group, Et represents an ethyl group, and * represents a bonding site.

[0184] [ka]

[0185] In equations (a2) to (a4), R W2 ~R W4Specific examples of alkylene groups represented by include methylene group, ethylene group, n-propylene group, isopropylene group, n-butylene group, isobutylene group, n-pentylene group, isopentylene group, n-hexyl group, isohexyl group, n-octylene group, n-dodecylene group, etc., with ethylene group, n-propylene group, isopropylene group, or n-butylene group being preferred, and ethylene group or n-propylene group being particularly preferred. In equation (a3), the two M's may be the same or different.

[0186] In formulas (a2) to (a4), the onium group represented by M can be an ammonium group, an iodonium group, a phosphonium group, a sulfonium group, or the like. CO2M in formula (a2), PO3M2 in formula (a2), and SO3M in formula (a4) may all have anionic structures in which M is dissociated. The countercation of the anionic structure is A1 + It may also be R in equation (7) 1 -L may contain any cations that can be included in L.

[0187] Among the groups represented by formulas (a1) to (a4), the group represented by formula (a1), formula (a2), or formula (a4) is preferred.

[0188] n in equation (7) 11 and n 12 It is preferable that they are the same, and both are preferably integers from 1 to 5, more preferably integers from 1 to 3, even more preferably 1 or 2, and particularly preferably 2.

[0189] In formula (7), A1 and A2 each independently represent an oxygen atom, a sulfur atom, or a nitrogen atom, with nitrogen atoms being preferred. In formula (7), it is preferable that A1 and A2 are the same atom.

[0190] In equation (7), Za represents the counterion that neutralizes the charge. R 11 ~R 18 and R 1-If all L groups are electrically neutral, then Za becomes a monovalent counteranion. However, R 11 ~R 18 and R 1 -L may have an anionic structure or a cationic structure, for example, R 11 ~R 18 and R 1 If -L has two or more anionic structures, Za can also act as a countercation. Furthermore, if the cyanine dye represented by formula (7) has a electrically neutral structure throughout the compound, excluding Za, then Za is not necessary. When Za is the counter anion, examples include sulfonate ions, carboxylate ions, tetrafluoroborate ions, hexafluorophosphate ions, p-toluenesulfonate ions, and perchlorate ions, with tetrafluoroborate ions being preferred. When Za is the countercation, examples include alkali metal ions, alkaline earth metal ions, ammonium ions, pyridinium ions, sulfonium ions, etc., with sodium ions, potassium ions, ammonium ions, pyridinium ions, or sulfonium ions being preferred, and sodium ions, potassium ions, or ammonium ions being more preferred.

[0191] From the viewpoint of visibility, the above infrared absorber is preferably a compound represented by the following formula (8).

[0192] [ka] In formula (8), R 1 R is obtained by infrared exposure. 1 -L represents the group that cleaves the bond, R 2 and R 3 Each of these independently represents a hydrogen atom or an alkyl group, and R 2 and R 3 They may be connected to each other to form a ring, Ar 1 and Ar 2Each of these independently represents a group that forms a benzene ring or a naphthalene ring, Y 1 and Y 2 These are, independently, an oxygen atom, a sulfur atom, and -NR. 0 - or represents a dialkylmethylene group, R 0 R represents a hydrogen atom, alkyl group, or aryl group. 4 and R 5 Each of these independently represents an aliphatic hydrocarbon group, a -CO2M group, or a -PO3M2 group, where M represents a hydrogen atom, a Na atom, a K atom, or an onium group, and R 6 ~R 9 Each of these independently represents a hydrogen atom or an alkyl group, and L represents an oxygen atom, a sulfur atom, or -NR 10 - represents R 10 represents a hydrogen atom, alkyl group, or aryl group, and Za represents a counterion that neutralizes the charge.

[0193] R in equation (8) 1 , L and Za are R in equation (7) 1 , is synonymous with L and Za, and the preferred embodiment is also similar.

[0194] Ar 1 and Ar 2 Each of these independently represents a group that forms a benzene ring or a naphthalene ring. The benzene ring and naphthalene ring may have substituents other than -X. Examples of substituents include alkyl groups, alkoxy groups, aryloxy groups, amino groups, alkylthio groups, arylthio groups, carboxyl groups, carboxylate groups, sulfo groups, sulfonate groups, and combinations thereof, but alkyl groups are preferred.

[0195] R 2 ~R 10 and R 0 The alkyl group in is preferably an alkyl group having 1 to 30 carbon atoms, more preferably an alkyl group having 1 to 15 carbon atoms, and even more preferably an alkyl group having 1 to 10 carbon atoms. The alkyl group may be linear, branched, or have a cyclic structure. Specifically, examples include methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, hexadecyl group, octadecyl group, eicosyl group, isopropyl group, isobutyl group, s-butyl group, t-butyl group, isopentyl group, neopentyl group, 1-methylbutyl group, isohexyl group, 2-ethylhexyl group, 2-methylhexyl group, cyclohexyl group, cyclopentyl group, and 2-norbornyl group. Among these alkyl groups, methyl, ethyl, propyl, or butyl groups are particularly preferred.

[0196] Furthermore, the alkyl group may have substituents. Examples of substituents include alkoxy groups, aryloxy groups, amino groups, alkylthio groups, arylthio groups, halogen atoms, carboxyl groups, carboxylate groups, sulfo groups, sulfonate groups, alkyloxycarbonyl groups, aryloxycarbonyl groups, and groups that combine these.

[0197] R 10 and R 0 The aryl group in is preferably an aryl group having 6 to 30 carbon atoms, more preferably an aryl group having 6 to 20 carbon atoms, and even more preferably an aryl group having 6 to 12 carbon atoms. Furthermore, the aryl group may have substituents. Examples of substituents include alkyl groups, alkoxy groups, aryloxy groups, amino groups, alkylthio groups, arylthio groups, halogen atoms, carboxyl groups, carboxylate groups, sulfo groups, sulfonate groups, alkyloxycarbonyl groups, aryloxycarbonyl groups, and groups that combine these. Examples of the above-mentioned aryl groups include, for example, phenyl group, naphthyl group, p-tolyl group, p-chlorophenyl group, p-fluorophenyl group, p-methoxyphenyl group, p-dimethylaminophenyl group, p-methylthiophenyl group, and p-phenylthiophenyl group. Among these aryl groups, phenyl, p-methoxyphenyl, p-dimethylaminophenyl, or naphthyl groups are preferred.

[0198] R 2 and R 3 It is preferable that they are connected to form a ring. R 2 and R 3 When linked to form a ring, a preferred number of ring members is a 5- or 6-membered ring, with a 6-membered ring being more preferred. Also, R 2 and R 3 The ring formed by the linking of these is preferably a hydrocarbon ring which may have ethylenically unsaturated bonds.

[0199] Y 1 and Y 2 These are, independently, an oxygen atom, a sulfur atom, and -NR. 0 - or represents a dialkylmethylene group, -NR 0 -A dialkylmethylene group is preferred, and a dialkylmethylene group is more preferred. R 0 represents a hydrogen atom, an alkyl group, or an aryl group, and is preferably an alkyl group.

[0200] R 4 and R 5 It is preferable that they are the same group. Also, R 4 and R 5 Each of these is preferably a linear alkyl group or an alkyl group having a sulfonate group at the terminal, and more preferably a methyl group, an ethyl group, or a butyl group having a sulfonate group at the terminal. Furthermore, the countercation of the sulfonate group may be the cation on the nitrogen atom in formula (8), or it may be an alkali metal cation or an alkaline earth metal cation. Furthermore, from the viewpoint of further improving the water solubility of the compound represented by formula (8), R 4 and R 5Each of these groups is preferably an alkyl group having an anionic structure, more preferably an alkyl group having a carboxylate group or a sulfonate group, and even more preferably an alkyl group with a sulfonate group attached to its terminus. Furthermore, the maximum absorption wavelength of the compound represented by formula (8) is increased to a longer wavelength, and from the viewpoint of visibility and print durability in lithographic printing plates, R 4 and R 5 Each of these groups is preferably an alkyl group having an aromatic ring, more preferably an alkyl group having an aromatic ring at its terminal end, and particularly preferably a 2-phenylethyl group, a 2-naphthalenylethyl group, or a 2-(9-anthracenyl)ethyl group.

[0201] R 6 ~R 9 Each of these independently represents either a hydrogen atom or an alkyl group, and a hydrogen atom is preferred.

[0202] Furthermore, the compound represented by formula (8) preferably has one or more halogen atoms from the viewpoint of long-term stability and print resistance, R 1 Ar 1 and Ar 2 It is more preferable that at least one selected from the group has one or more halogen atoms, A 1 Ar 1 and Ar 2 It is particularly preferable that each of them has one or more halogen atoms. Furthermore, from the viewpoint of long-term stability and print resistance, the compound represented by formula (8) is more preferably having two or more halogen atoms, even more preferably having three or more halogen atoms, and particularly preferably having three to six halogen atoms. Furthermore, chlorine atoms or bromine atoms are preferred as the halogen atoms. Furthermore, the compound represented by formula 1 is Ar from the viewpoint of long-term stability and print resistance. 1 and Ar 2 Preferably, at least one of them has a halogen atom, Ar 1 and Ar2 It is more preferable that at least one of them has a chlorine atom or a bromine atom, and Ar 1 and Ar 2 It is particularly preferable that at least one of them has a bromine atom.

[0203] Furthermore, as the infrared absorber and the infrared absorber that decomposes upon infrared exposure, those described in International Publication No. 2020 / 262692 can be suitably used. Furthermore, as infrared absorbers that are decomposed by infrared exposure, those described in Japanese Patent Publication No. 2008-544322 or International Publication No. 2016 / 027886 can be suitably used. Furthermore, as the cyanine dye, which is a decomposition-type infrared absorber, the infrared-absorbing compounds described in International Publication No. 2019 / 219560 can be suitably used.

[0204] Infrared absorbers may be used individually or in combination of two or more types. The total content of the infrared absorber in the image recording layer is preferably 0.1% to 10.0% by mass, and more preferably 0.5% to 5.0% by mass, relative to the total mass of the image recording layer.

[0205] Furthermore, regarding the relationship between the borate compound (electron-donating polymerization initiator), the onium compound (electron-accepting polymerization initiator), and the infrared absorber, the HOMO and LUMO relationships of each compound described in paragraphs 0081 to 0083 of International Publication No. 2023 / 023681 are preferred.

[0206] <Chromogenic precursor> The above-mentioned negative-type photosensitive image recording layer preferably contains a chromogenic precursor and is an on-pressure developed negative-type photosensitive image recording layer. The above-mentioned chromogenic precursor preferably contains an acid chromogen from the viewpoint of color development. Furthermore, the chromogenic precursor preferably contains a leuco compound from the viewpoint of color development. As used in this disclosure, "chromogenic precursor" means a compound that develops color in response to stimuli such as light or acid, thereby changing the color of the image recording layer, and "acid chromogen" means a compound that develops color when heated while accepting an electron-accepting compound (e.g., a proton such as an acid), thereby changing the color of the image recording layer. As acid colorants, colorless compounds having partial skeletons such as lactones, lactams, saltons, spiropyrans, esters, and amides, which rapidly undergo ring-opening or cleavage upon contact with electron-accepting compounds, are particularly preferred.

[0207] Examples of acid chromogens that are preferred embodiments of the chromogen precursor include, for example, the acid chromogens described in paragraphs 0229-0236 of International Publication No. 2020 / 262685.

[0208] In particular, the colorant used in this disclosure is preferably at least one compound selected from the group consisting of spiropyran compounds, spirooxazine compounds, spirolactone compounds, and spirolactam compounds, from the viewpoint of color development. From the viewpoint of visibility, the hue of the pigment after color development is preferably green, blue, or black.

[0209] Furthermore, the above-mentioned acid colorant is preferably a leuco dye from the viewpoint of color development and visibility of the exposed area. The above-mentioned leuco dye is not particularly limited as long as it has a leuco structure, but it is preferable that it has a spiro structure, and more preferably that it has a spirolactone ring structure. Furthermore, from the viewpoint of color development and visibility of the exposed area, the leuco dye is preferably a leuco dye having a phthalide structure or a fluorane structure. Furthermore, the leuco dye having the phthalide structure or fluorane structure described above is preferably a compound represented by any of the following formulas (Le-1) to (Le-3), and more preferably a compound represented by the following formula (Le-2), from the viewpoint of color development and visibility of the exposed area.

[0210] [ka]

[0211] In formulas (Le-1) to (Le-3), ERG each independently represents an electron-donating group, X1 to X4 each independently represents a hydrogen atom, a halogen atom, or a dialkylanilino group, and X5 to X 10 Each of the following independently represents a hydrogen atom, a halogen atom, or a monovalent organic group; Y1 and Y2 independently represent C or N; if Y1 is N, X1 is absent; if Y2 is N, X4 is absent; Ra1 represents a hydrogen atom, an alkyl group, or an alkoxy group; and Rb1 to Rb4 independently represent a hydrogen atom, an alkyl group, an aryl group, or a heteroaryl group.

[0212] In the ERG of formulas (Le-1) to (Le-3), the electron-donating group is preferably an amino group, alkylamino group, arylamino group, heteroarylamino group, dialkylamino group, monoalkylmonoarylamino group, monoalkylmonoheteroarylamino group, diarylamino group, diheteroarylamino group, monoarylmonoheteroarylamino group, alkoxy group, allyloxy group, heteroaryloxy group, or alkyl group, more preferably an amino group, alkylamino group, arylamino group, heteroarylamino group, dialkylamino group, monoalkylmonoarylamino group, monoalkylmonoheteroarylamino group, diarylamino group, diheteroarylamino group, monoarylmonoheteroarylamino group, alkoxy group, or allyloxy group, even more preferably a monoalkylmonoarylamino group, diarylamino group, diheteroarylamino group, or monoarylmonoheteroarylamino group, and particularly preferably a monoalkylmonoarylamino group. Furthermore, as the electron-donating group in the above ERG, from the viewpoint of color development and visibility of the exposed area, it is preferable that the disubstituted amino group has an aryl group having a substituent at least one ortho position or a heteroaryl group having a substituent at least one ortho position, more preferably that the disubstituted amino group has a substituent at least one ortho position and a phenyl group having an electron-donating group at the para position, even more preferably that the amino group has a substituent at least one ortho position and a phenyl group having an electron-donating group at the para position and an aryl group or heteroaryl group, and particularly preferably that the amino group has a substituent at least one ortho position and a phenyl group having an electron-donating group at the para position and an aryl group having an electron-donating group or a heteroaryl group having an electron-donating group. In this disclosure, the ortho position in an aryl group or heteroaryl group other than a phenyl group refers to the bond position adjacent to position 1 (for example, position 2) when the bond position to another structure of the aryl group or heteroaryl group is considered position 1. Furthermore, from the viewpoint of color development and visibility of the exposed area, the electron-donating group of the aryl group or heteroaryl group is preferably an amino group, alkylamino group, arylamino group, heteroarylamino group, dialkylamino group, monoalkylmonoarylamino group, monoalkylmonoheteroarylamino group, diarylamino group, diheteroarylamino group, monoarylmonoheteroarylamino group, alkoxy group, allyloxy group, heteroaryloxy group, or alkyl group, more preferably an alkoxy group, allyloxy group, heteroaryloxy group, or alkyl group, and particularly preferably an alkoxy group.

[0213] In formulas (Le-1) to (Le-3), X1 to X4 are each independently preferably hydrogen atoms or chlorine atoms, and more preferably hydrogen atoms, from the viewpoint of color development and visibility of the exposed area. X5~X in equation (Le-2) or equation (Le-3) 10Each of these groups is preferably, from the viewpoint of color development and visibility of the exposed area, a hydrogen atom, halogen atom, alkyl group, aryl group, amino group, alkylamino group, arylamino group, heteroarylamino group, dialkylamino group, monoalkylmonoarylamino group, monoalkylmonoheteroarylamino group, diarylamino group, diheteroarylamino group, monoarylmonoheteroarylamino group, hydroxyl group, alkoxy group, allyloxy group, heteroallyloxy group, acyl group, alkoxycarbonyl group, allyloxycarbonyl group, heteroallyloxycarbonyl group, or cyano group; more preferably a hydrogen atom, halogen atom, alkyl group, aryl group, alkoxy group, or allyloxy group; even more preferably a hydrogen atom, halogen atom, alkyl group, or aryl group; and particularly preferably a hydrogen atom. In formulas (Le-1) to (Le-3), Y1 and Y2 are preferably C at least one of them, and more preferably both Y1 and Y2 are C, from the viewpoint of color development and visibility of the exposed area. In formulas (Le-1) to (Le-3), Ra1 is preferably an alkyl group or an alkoxy group, more preferably an alkoxy group, and particularly preferably a methoxy group, from the viewpoint of color development and visibility of the exposed area. In formulas (Le-1) to (Le-3), Rb1 to Rb4 are each independently preferably a hydrogen atom or an alkyl group, more preferably an alkyl group, and particularly preferably a methyl group, from the viewpoint of color development and visibility of the exposed area.

[0214] Furthermore, the leuco dye having the phthalide structure or fluorane structure described above is more preferably a compound represented by any of the following formulas (Le-4) to (Le-6), and even more preferably a compound represented by the following formula (Le-5), from the viewpoint of color development and visibility of the exposed area.

[0215] [ka] In formulas (Le-4) to (Le-6), ERG independently represents an electron-donating group, X1 to X4 independently represent a hydrogen atom, a halogen atom, or a dialkylanilino group, Y1 and Y2 independently represent C or N, if Y1 is N, then X1 is absent, if Y2 is N, then X4 is absent, Ra1 represents a hydrogen atom, an alkyl group, or an alkoxy group, and Rb1 to Rb4 independently represent a hydrogen atom, an alkyl group, an aryl group, or a heteroaryl group.

[0216] In equations (Le-4) to (Le-6), ERG, X1 to X4, Y1, Y2, Ra1, and Rb1 to Rb4 are equivalent to ERG, X1 to X4, Y1, Y2, Ra1, and Rb1 to Rb4 in equations (Le-1) to (Le-3), and the same applies to the preferred embodiment.

[0217] Furthermore, the leuco dye having the phthalide structure or fluorane structure described above is more preferably a compound represented by any of the following formulas (Le-7) to (Le-9), and is particularly preferably a compound represented by the following formula (Le-8), from the viewpoint of color development and visibility of the exposed area.

[0218] [ka]

[0219] In formulas (Le-7) to (Le-9), X1 to X4 each independently represent a hydrogen atom, a halogen atom, or a dialkylanilino group; Y1 and Y2 each independently represent C or N; if Y1 is N, X1 is absent; if Y2 is N, X4 is absent; Ra1 to Ra4 each independently represent a hydrogen atom, an alkyl group, or an alkoxy group; Rb1 to Rb4 each independently represent a hydrogen atom, an alkyl group, an aryl group, or a heteroaryl group; and Rc1 and Rc2 each independently represent an aryl group or a heteroaryl group.

[0220] In equations (Le-7) to (Le-9), X1 to X4, Y1 and Y2 are equivalent to X1 to X4, Y1 and Y2 in equations (Le-1) to (Le-3), and the preferred embodiment is also equivalent. In formula (Le-7) or formula (Le-9), Ra1 to Ra4 are each independently preferably alkyl groups or alkoxy groups, more preferably alkoxy groups, and particularly preferably methoxy groups, from the viewpoint of color development and visibility of the exposed area. In formulas (Le-7) to (Le-9), Rb1 to Rb4 are each independently preferably substituted with a hydrogen atom, an alkyl group, or an alkoxy group, more preferably an alkyl group, and particularly preferably a methyl group, from the viewpoint of color development and visibility of the exposed area. In formula (Le-8), Rc1 and Rc2 are each preferably a phenyl group or an alkylphenyl group, and more preferably a phenyl group, from the viewpoint of color development and visibility of the exposed area. Furthermore, Rc1 and Rc2 in formula (Le-8) are each preferably, from the viewpoint of color development and visibility of the exposed area, an aryl group having a substituent at least one ortho position, or a heteroaryl group having a substituent at least one ortho position, more preferably an aryl group having a substituent at least one ortho position, even more preferably a phenyl group having a substituent at least one ortho position, and particularly preferably a phenyl group having a substituent at least one ortho position and an electron-donating group at the para position. Examples of substituents in Rc1 and Rc2 are those described later. Furthermore, in formula (Le-8), from the viewpoint of color development and visibility of the exposed area, it is preferable that X1 to X4 are hydrogen atoms and Y1 and Y2 are carbon. Furthermore, in formula (Le-8), from the viewpoint of color development and visibility of the exposed area, it is preferable that Rb1 and Rb2 are each independently substituted with an alkyl group or an alkoxy group aryl group. Furthermore, in formula (Le-8), from the viewpoint of color development and visibility of the exposed area, it is preferable that Rb1 and Rb2 are each independently an aryl group or a heteroaryl group, more preferably an aryl group, even more preferably an aryl group having an electron-donating group, and particularly preferably a phenyl group having an electron-donating group at the para position. Furthermore, the electron-donating groups in Rb1, Rb2, Rc1, and Rc2 are preferably amino groups, alkylamino groups, arylamino groups, heteroarylamino groups, dialkylamino groups, monoalkylmonoarylamino groups, monoalkylmonoheteroarylamino groups, diarylamino groups, diheteroarylamino groups, monoarylmonoheteroarylamino groups, alkoxy groups, allyloxy groups, heteroaryloxy groups, or alkyl groups, more preferably alkoxy groups, allyloxy groups, heteroaryloxy groups, or alkyl groups, and particularly preferably alkoxy groups.

[0221] Furthermore, from the viewpoint of color development and visibility of the exposed area, it is also preferable that the acid colorant includes one or more compounds selected from the group consisting of compounds represented by the following formula (Le-10) and compounds represented by the following formula (Z-4). In other words, the image recording layer in the lithographic printing plate according to this disclosure preferably further contains one or more compounds selected from the group consisting of compounds represented by the following formula (Le-10) and compounds represented by the following formula (Z-4).

[0222] [ka]

[0223] In formula (Le-10), each Ar1 independently represents an aryl group or a heteroaryl group, and each Ar2 independently represents an aryl group having a substituent at least one ortho position, or a heteroaryl group having a substituent at least one ortho position.

[0224] In equation (Le-10), Ar1 is equivalent to Rb1 and Rb2 in equations (Le-7) to (Le-9), and the same applies to the preferred embodiment. In equation (Le-10), Ar2 is synonymous with Rc1 and Rc2 in equations (Le-7) to (Le-9), and the preferred embodiment is similar.

[0225] The alkyl groups in formulas (Le-1) to (Le-9) may be linear, branched, or have a ring structure. Furthermore, the number of carbon atoms in the alkyl group in formulas (Le-1) to (Le-9) is preferably 1 to 20, more preferably 1 to 8, even more preferably 1 to 4, and particularly preferably 1 or 2. In formulas (Le-1) to (Le-10), the number of carbon atoms in the aryl group is preferably 6 to 20, more preferably 6 to 10, and particularly preferably 6 to 8. Specific examples of aryl groups in formulas (Le-1) to (Le-10) include phenyl, naphthyl, anthracenyl, and phenantrenyl groups, which may have substituents. Specific examples of heteroaryl groups in formulas (Le-1) to (Le-10) include furyl groups, pyridyl groups, pyrimidyl groups, pyrazoyl groups, and thiophenyl groups, which may have substituents.

[0226] Furthermore, each of the monovalent organic groups, alkyl groups, aryl groups, heteroaryl groups, dialkylanilino groups, alkylamino groups, alkoxy groups, etc. in formulas (Le-1) to (Le-10) may have substituents. Examples of substituents include alkyl groups, aryl groups, heteroaryl groups, halogen atoms, amino groups, alkylamino groups, arylamino groups, heteroarylamino groups, dialkylamino groups, monoalkylmonoarylamino groups, monoalkylmonoheteroarylamino groups, diarylamino groups, diheteroarylamino groups, monoarylmonoheteroarylamino groups, hydroxyl groups, alkoxy groups, allyloxy groups, heteroallyloxy groups, acyl groups, alkoxycarbonyl groups, allyloxycarbonyl groups, heteroallyloxycarbonyl groups, cyano groups, etc. Moreover, these substituents may be further substituted with other substituents.

[0227] [ka]

[0228] In formula (Z-4), Rza1 represents a hydrogen atom, an alkyl group, or an alkoxy group; Rzb1 to Rb4 each independently represent a hydrogen atom, an alkyl group, or an aryl group, and Rzb1 and Rzb2, and Rzb3 and Rzb4 may be linked to form a ring structure; X represents O or NR; R represents a hydrogen atom, an alkyl group, an aryl group, or a heteroaryl group; and Y1 and Y2 each independently represent CH or N.

[0229] In formula (Z-4), Rza1 is preferably an alkyl group or an alkoxy group. In formula (Z-4), Rzb1 and Rzb2 are preferably each independently an alkyl group. In formula (Z-4), Rzb3 and Rzb4 are each independently a hydrogen atom, an alkyl group, or an aryl group, and it is preferable that one of them is an aryl group. In formula (Z-4), X is preferably O, and Y1 and Y2 are preferably CH.

[0230] The alkyl group in formula (Z-4) may be linear, branched, or have a ring structure. The number of carbon atoms in the alkyl group in formula (Z-4) is preferably 1 to 20, more preferably 1 to 8, and even more preferably 1 to 5. In formula (Z-4), the number of carbon atoms in the aryl group is preferably 6 to 20, more preferably 6 to 10, and particularly preferably 6 to 8. Each group in formula (Z-4), such as an alkyl group or aryl group, may have substituents. Examples of substituents include alkyl groups, aryl groups, halogen atoms, amino groups, alkylamino groups, arylamino groups, dialkylamino groups, monoalkylmonoarylamino groups, diarylamino groups, hydroxy groups, alkoxy groups, allyloxy groups, acyl groups, alkoxycarbonyl groups, allyloxycarbonyl groups, and cyano groups. Furthermore, these substituents may be further substituted with other substituents.

[0231] Furthermore, examples of leuco dyes having the phthalide structure or fluorane structure that can be preferably used include the acid colorants described in paragraphs 0160-0168 of International Publication No. 2023 / 032681.

[0232] Furthermore, the following compounds are also preferred as acid colorants.

[0233] [ka]

[0234] It is also possible to use commercially available colorants, such as ETAC, RED500, RED520, CVL, S-205, BLACK305, BLACK400, BLACK100, BLACK500, H-7001, GREEN300, NIRBLACK78, BLUE220, H-3035, BLUE203, ATP, H-1046, H-2114 (all manufactured by Fukui Yamada Chemical Industry Co., Ltd.), ORANGE-DCF, and Vermilio. Examples include n-DCF, PINK-DCF, RED-DCF, BLMB, CVL, GREEN-DCF, TH-107 (all manufactured by Hodogaya Chemical Co., Ltd.), ODB, ODB-2, ODB-4, ODB-250, ODB-BlackXV, Blue-63, Blue-502, GN-169, GN-2, Green-118, Red-40, Red-8 (all manufactured by Yamamoto Kasei Co., Ltd.), and Crystal Violet Lactone (manufactured by Tokyo Chemical Industry Co., Ltd.). Among these commercially available products, ETAC, S-205, BLACK305, BLACK400, BLACK100, BLACK500, H-7001, GREEN300, NIRBLACK78, H-3035, ATP, H-1046, H-2114, GREEN-DCF, Blue-63, GN-169, and Crystal Violet Lactone are preferred because the resulting film has good visible light absorption.

[0235] These colorants may be used individually or in combination of two or more components. The content of the colorant is preferably 0.5% to 10% by mass, and more preferably 1% to 5% by mass, relative to the total mass of the image recording layer.

[0236] <Polymer particles> The above-mentioned negative-type photosensitive image recording layer preferably contains polymer particles and is an on-pressure developed image recording layer. The inclusion of polymer particles in the image recording layer is expected to improve print durability and enhance on-press development performance.

[0237] Polymer particles (hereinafter also referred to as polymer particles) are preferably selected from the group consisting of thermoplastic resin particles, heat-reactive resin particles, polymer particles having polymerizable groups, microcapsules containing hydrophobic compounds, and microgels (crosslinked polymer particles). Among these, polymer particles having polymerizable groups or microgels are preferred. In a particularly preferred embodiment, the polymer particles contain at least one ethylenically unsaturated polymerizable group. The presence of such polymer particles provides the effect of improving the print resistance of the exposed areas and the on-press developability of the unexposed areas. Furthermore, from the viewpoint of print resistance and on-press developability, the polymer particles are preferably thermoplastic resin particles.

[0238] As thermoplastic resin particles, thermoplastic polymer particles described in Research Disclosure No. 33303 of January 1992, Japanese Patent Publication No. 9-123387, 9-131850, 9-171249, 9-171250, and European Patent No. 931647 are preferred. Specific examples of polymers constituting thermoplastic resin particles include homopolymers or copolymers of monomers such as ethylene, styrene, vinyl chloride, methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate, vinylidene chloride, acrylonitrile, vinylcarbazole, and acrylates or methacrylates having a polyalkylene structure, or mixtures thereof. Preferably, copolymers containing polystyrene, styrene, and acrylonitrile, or polymethyl methacrylate are used. The average particle size of the thermoplastic resin particles is preferably 0.01 μm to 3.0 μm.

[0239] Examples of heat-reactive resin particles include polymer particles having heat-reactive groups. Heat-reactive polymer particles form hydrophobic regions through crosslinking due to thermal reactions and the resulting changes in functional groups.

[0240] In polymer particles having a heat-reactive group, any functional group that undergoes any reaction as long as a chemical bond is formed may be used as the heat-reactive group, but it is preferably a polymerizable group. Examples of such groups include ethylenically unsaturated groups that undergo radical polymerization (e.g., acryloyl group, methacryloyl group, vinyl group, allyl group, etc.), cationic polymerizable groups (e.g., vinyl group, vinyloxy group, epoxy group, oxetanyl group, etc.), isocyanate groups or their blocks, epoxy groups, vinyloxy groups and functional groups having active hydrogen atoms that react with these groups (e.g., amino group, hydroxyl group, carboxyl group, etc.), carboxyl groups and their hydroxyl or amino groups that undergo condensation reactions, and acid anhydrides and their amino or hydroxyl groups that undergo ring-opening addition reactions.

[0241] As microcapsules, for example, as described in Japanese Patent Publication No. 2001-277740 and Japanese Patent Publication No. 2001-277742, at least a portion of the constituent components of the image recording layer are encapsulated within the microcapsules. The constituent components of the image recording layer can also be contained outside the microcapsules. In the image recording layer containing microcapsules, a preferred configuration is one in which hydrophobic constituent components are encapsulated within the microcapsules and hydrophilic constituent components are contained outside the microcapsules.

[0242] Microgels (crosslinked polymer particles) may contain a portion of the components of the image recording layer on at least one of their surface or interior. In particular, reactive microgels having radical polymerizable groups on their surface are preferred from the viewpoint of the sensitivity of the resulting lithographic printing plate and the print resistance of the resulting lithographic printing plate.

[0243] Known methods can be applied to microencapsulate or microgel the components of the image recording layer.

[0244] Furthermore, as polymer particles, those obtained by the reaction of a polyhydric isocyanate compound, which is an adduct of a polyhydric phenol compound having two or more hydroxyl groups in its molecule with isophorone diisocyanate, and a compound having active hydrogen are preferred from the viewpoint of print resistance, stain resistance, and storage stability of the resulting lithographic printing plate. As the above-mentioned polyhydric phenol compound, a compound having multiple benzene rings with phenolic hydroxyl groups is preferred. The compound having the active hydrogen described above is preferably a polyol compound or a polyamine compound, more preferably a polyol compound, and even more preferably at least one compound selected from the group consisting of propylene glycol, glycerin, and trimethylolpropane. As resin particles obtained by the reaction of a polyvalent isocyanate compound, which is an adduct of a polyvalent phenol compound having two or more hydroxyl groups in its molecule with isophorone diisocyanate, and a compound having active hydrogen, polymer particles described in paragraphs 0032 to 0095 of Japanese Patent Application Publication No. 2012-206495 are preferred.

[0245] Furthermore, from the viewpoint of print resistance and solvent resistance of the resulting lithographic printing plate, it is preferable that the polymer particles include both i) constituent units having a hydrophobic main chain and a pendant cyano group directly bonded to the hydrophobic main chain, and ii) constituent units having a pendant group containing a hydrophilic polyalkylene oxide segment. As the hydrophobic main chain mentioned above, an acrylic resin chain is preferred. Preferred examples of the pendant cyano group mentioned above include -[CH2CH(C≡N)]- or -[CH2C(CH3)(C≡N)]-. Furthermore, the constituent units having the pendant cyano group can be easily derived from ethylene-based unsaturated monomers, such as acrylonitrile or methacrylonitrile, or combinations thereof. Furthermore, as the alkylene oxide in the hydrophilic polyalkylene oxide segment described above, ethylene oxide or propylene oxide is preferred, and ethylene oxide is more preferred. The number of repeating alkylene oxide structures in the hydrophilic polyalkylene oxide segment described above is preferably 10 to 100, more preferably 25 to 75, and even more preferably 40 to 50. Particles of a resin having a hydrophobic main chain and comprising both i) a constituent unit having a pendant cyano group directly bonded to the hydrophobic main chain, and ii) a constituent unit having a pendant group containing a hydrophilic polyalkylene oxide segment, are preferably those described in paragraphs 0039 to 0068 of Japanese Patent Publication No. 2008-503365.

[0246] Furthermore, the polymer particles described above preferably have hydrophilic groups from the viewpoint of print resistance and on-press developability. The hydrophilic groups mentioned above are not particularly limited as long as they have a hydrophilic structure, but examples include acidic groups such as carboxyl groups, hydroxyl groups, amino groups, cyano groups, and polyalkylene oxide structures. In particular, from the viewpoint of on-press developability and print durability, the polyalkylene oxide structure is preferred, and the polyethylene oxide structure, polypropylene oxide structure, or polyethylene / propylene oxide structure is more preferred. Furthermore, from the viewpoint of on-pressure development and suppression of developing residue during on-pressure development, it is preferable that the polyalkylene oxide structure has a polypropylene oxide structure, and it is more preferable that it has both a polyethylene oxide structure and a polypropylene oxide structure. Furthermore, the hydrophilic group preferably includes a constituent unit having a cyano group or a group represented by the following formula Z, more preferably a constituent unit represented by the following formula (AN) or a group represented by the following formula Z, and particularly preferably a group represented by the following formula Z, from the viewpoint of print resistance, ink transfer, and on-press developability. *-QWY formula Z In formula Z, Q represents a divalent linking group, W represents a divalent group having a hydrophilic structure or a divalent group having a hydrophobic structure, Y represents a monovalent group having a hydrophilic structure or a monovalent group having a hydrophobic structure, either W or Y has a hydrophilic structure, and * represents a bonding site with another structure.

[0247] [ka]

[0248] In formula (AN), R AN represents a hydrogen atom or a methyl group.

[0249] From the viewpoint of print resistance, it is preferable that the polymer contained in the above polymer particles includes structural units formed by compounds having cyano groups. The cyano group is usually introduced into the resin as a constituent unit containing a cyano group, using a compound (monomer) that has a cyano group. Examples of compounds having a cyano group include acrylonitrile compounds, with (meth)acrylonitrile being a preferred example. The constituent unit having a cyano group is preferably a constituent unit formed by an acrylonitrile compound, and more preferably a constituent unit formed by (meth)acrylonitrile, i.e., a constituent unit represented by the above formula (AN). If the above polymer includes a polymer having a cyano group, the content of the cyano group in the polymer having a cyano group, preferably the component represented by the above formula (AN), is preferably 5% to 90% by mass, more preferably 20% to 80% by mass, and particularly preferably 30% to 60% by mass, based on the total mass of the polymer having a cyano group, from the viewpoint of print resistance.

[0250] Furthermore, from the viewpoint of print resistance, ink transfer properties, and on-press developability, it is preferable that the polymer particles include polymer particles having a group represented by the above formula Z.

[0251] In the above formula Z, Q is preferably a divalent linking group having 1 to 20 carbon atoms, and more preferably a divalent linking group having 1 to 10 carbon atoms. Furthermore, Q in the above formula Z is preferably an alkylene group, an arylene group, an ester bond, an amide bond, or a group formed by combining two or more of these, and more preferably a phenylene group, an ester bond, or an amide bond.

[0252] The hydrophilic divalent group in W of the above formula Z is a polyalkylene oxy group, or a polyalkylene oxy group with -CH2CH2NR at one end. W It is preferable that the group is bonded to -. Note that R W represents a hydrogen atom or an alkyl group. The divalent group having a hydrophobic structure in W of the above formula Z is -R WA -, -OR WA -O-, -R W NR WA -NR W -, -OC(=O)-R WA -O-, or -OC(=O)-R WA It is preferable that it be -O-. WA Each of these independently represents a linear, branched, or cyclic alkylene group having 6 to 120 carbon atoms, a haloalkylene group having 6 to 120 carbon atoms, an arylene group having 6 to 120 carbon atoms, an alkalinelene group having 6 to 120 carbon atoms (a divalent group obtained by removing one hydrogen atom from an alkylaryl group), or an aralkylene group having 6 to 120 carbon atoms.

[0253] The monovalent group having a hydrophilic structure in Y of the above formula Z is -OH, -C(=O)OH, a polyalkylene oxy group having a hydrogen atom or alkyl group at one end, or a polyalkylene oxy group having a hydrogen atom or alkyl group at the other end with -CH2CH2N(R W It is preferable that the group is bonded to a )- The monovalent group having a hydrophobic structure in Y of the above formula Z is a linear, branched, or cyclic alkyl group having 6 to 120 carbon atoms, a haloalkyl group having 6 to 120 carbon atoms, an aryl group having 6 to 120 carbon atoms, an alcaryl group (alkylaryl group) having 7 to 120 carbon atoms, an aralkyl group having 7 to 120 carbon atoms, or -OR WB , -C(=O)OR WB , or -OC(=O)R WB It is preferable that this is the case. WB This represents an alkyl group having 6 to 20 carbon atoms.

[0254] In polymer particles having the group represented by the above formula Z, it is more preferable that W is a divalent group having a hydrophilic structure, Q is a phenylene group, an ester bond, or an amide bond, W is a polyalkylene oxy group, and Y is a polyalkylene oxy group whose terminal end is a hydrogen atom or an alkyl group, from the viewpoint of print resistance, ink transfer, and on-press developability.

[0255] Furthermore, from the viewpoint of print resistance and on-press developability, the above polymer particles preferably include polymer particles having polymerizable groups, and more preferably include polymer particles having polymerizable groups on the particle surface. Furthermore, from the viewpoint of print resistance, it is preferable that the polymer particles include polymer particles having hydrophilic groups and polymerizable groups. The polymerizable group described above may be a cationic polymerizable group or a radical polymerizable group, but from the viewpoint of reactivity, a radical polymerizable group is preferable. The polymerizable group is not particularly limited as long as it is polymerizable, but from the viewpoint of reactivity, an ethylenically unsaturated group is preferred, a vinylphenyl group (styryl group), a (meth)acryloxy group, or a (meth)acrylamide group is more preferred, and a (meth)acryloxy group is particularly preferred. Furthermore, it is preferable that the polymer in polymer particles having polymerizable groups has constituent units having polymerizable groups. Furthermore, polymerizable groups may be introduced to the surface of polymer particles by polymer reaction.

[0256] Furthermore, from the viewpoint of print resistance and on-press developability, the image recording layer preferably contains addition polymerization resin particles having a dispersible group as the polymer particles, and more preferably the dispersible group contains a group represented by the formula Z.

[0257] Furthermore, the polymer particles preferably contain a resin having a urea bond, from the viewpoint of print resistance, ink transfer properties, on-press developability, and suppression of developing residue during on-press development. More preferably, the polymer particles contain a resin having a structure obtained by reacting at least an isocyanate compound represented by the following formula (Iso) with water. Particularly preferably, the polymer particles contain a 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. In addition, the particles containing the resin having a urea bond are preferably microgels.

[0258] [ka]

[0259] In equation (Iso), n represents an integer between 0 and 10.

[0260] An example of a reaction between the isocyanate compound represented by the above formula (Iso) and water is shown below. Note that the following example uses n=0 and the 4,4-isomer. As shown below, when an isocyanate compound represented by the above formula (Iso) is reacted with water, some of the isocyanate groups are hydrolyzed by the water, generating amino groups. These amino groups then react with the isocyanate groups to form a urea bond, resulting in the formation of a dimer. Furthermore, the following reaction is repeated to form a resin containing a urea bond. Furthermore, in the reaction described below, by adding compounds that are reactive with isocyanate groups (compounds containing active hydrogen), such as alcohol compounds and amine compounds, the structures of alcohol compounds, amine compounds, etc., can be introduced into resins containing urea bonds. As for the compounds having the active hydrogen described above, those described in the microgel section above are preferred.

[0261] [ka]

[0262] Furthermore, the resin having the above-mentioned urea bond preferably has an ethylenically unsaturated group, and more preferably has a group represented by the following formula (PETA).

[0263] [ka]

[0264] In formula (PETA), the wavy lines indicate the bonding locations with other structures.

[0265] Furthermore, when the above image recording layer is applied to other applications for on-press development, it is preferable to include thermoplastic resin particles from the viewpoint of print resistance and on-press development properties. The thermoplastic resin contained in the thermoplastic resin particles is not particularly limited and includes, for example, polyethylene, polystyrene, polyvinyl chloride, polyvinylidene chloride, methyl poly(meth)acrylate, ethyl poly(meth)acrylate, butyl poly(meth)acrylate, polyacrylonitrile, polyvinyl acetate, and copolymers thereof. The thermoplastic resin may also be in latex form. The thermoplastic resin according to this disclosure is preferably a resin that melts or softens due to the heat generated in the exposure process described later, thereby forming part or all of the hydrophobic film that forms the recording layer.

[0266] The thermoplastic resin described above preferably includes resin A, which has constituent units formed from aromatic vinyl compounds and constituent units having cyano groups, from the viewpoint of ink adhesion and print resistance.

[0267] The resin A contained in the thermoplastic resin preferably has structural units formed by aromatic vinyl compounds. The aromatic vinyl compound can be any compound having a structure in which a vinyl group is bonded to an aromatic ring, but examples include styrene compounds and vinylnaphthalene compounds, with styrene compounds being preferred, and styrene being more preferred. Examples of styrene compounds include styrene, p-methylstyrene, p-methoxystyrene, β-methylstyrene, p-methyl-β-methylstyrene, α-methylstyrene, and p-methoxy-β-methylstyrene, with styrene being preferred. Examples of vinylnaphthalene compounds include 1-vinylnaphthalene, methyl-1-vinylnaphthalene, β-methyl-1-vinylnaphthalene, 4-methyl-1-vinylnaphthalene, and 4-methoxy-1-vinylnaphthalene, with 1-vinylnaphthalene being preferred.

[0268] Furthermore, preferred structural units formed from aromatic vinyl compounds are those represented by the following formula A1.

[0269] [ka]

[0270] In formula A1, R A1 and R A2 Each of these independently represents a hydrogen atom or an alkyl group, Ar represents an aromatic ring group, and R A3 represents a substituent, and n is an integer between 0 and the maximum number of substituents for Ar, inclusive. In formula A1, R A1 and R A2 Each of these is preferably independently a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, more preferably a hydrogen atom or a methyl group, and even more preferably both are hydrogen atoms. In formula A1, Ar is preferably a benzene ring or a naphthalene ring, and more preferably a benzene ring. In formula A1, R A3The group is preferably an alkyl group or an alkoxy group, more preferably an alkyl group having 1 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms, and even more preferably a methyl group or a methoxy group. In formula A1, R A3 If multiple R A3 They may be the same, or they may be different. In formula A1, n is preferably an integer between 0 and 2, more preferably 0 or 1, and even more preferably 0.

[0271] In resin A contained in the thermoplastic resin, the content of structural units formed by aromatic vinyl compounds is preferably greater than the content of structural units having cyano groups, as described later, from the viewpoint of ink adhesion. It is more preferably 15% to 85% by mass, and even more preferably 30% to 70% by mass, based on the total mass of the thermoplastic resin.

[0272] The resin A contained in the thermoplastic resin particles preferably contains constituent units having cyano groups. The cyano group is usually introduced into resin A as a constituent unit containing a cyano group, using a compound (monomer) that has a cyano group. Examples of compounds that have a cyano group include acrylonitrile compounds, with (meth)acrylonitrile being a preferred example. The constituent units having a cyano group are preferably formed from acrylonitrile compounds, and more preferably from (meth)acrylonitrile.

[0273] Furthermore, as a structural unit formed by a compound having a cyano group, the structural unit represented by the following formula B1 is preferred.

[0274] [ka]

[0275] In formula B1, R B1represents a hydrogen atom or an alkyl group. In formula B1, R B1 It is preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, more preferably a hydrogen atom or a methyl group, and even more preferably a hydrogen atom.

[0276] From the viewpoint of ink transferability, the content of structural units having cyano groups in resin A is preferably less than the content of structural units formed by the aromatic vinyl compound, and is more preferably 55% to 90% by mass, and more preferably 60% to 85% by mass, based on the total mass of resin A.

[0277] Furthermore, when resin A contained in the thermoplastic resin includes structural units formed by aromatic vinyl compounds and structural units having cyano groups, the content ratio of structural units formed by aromatic vinyl compounds and structural units having cyano groups (structural units formed by aromatic vinyl compounds: structural units having cyano groups) is preferably 5:5 to 9:1 by mass, and more preferably 6:4 to 8:2.

[0278] From the viewpoint of print resistance and chemical resistance, it is preferable that resin A contained in thermoplastic resin particles further has constituent units formed by N-vinyl heterocyclic compounds. Examples of N-vinyl heterocyclic compounds include N-vinylpyrrolidone, N-vinylcarbazole, N-vinylpyrrole, N-vinylphenothiazine, N-vinylsuccinimide, N-vinylphthalimide, N-vinylcaprolactam, and N-vinylimidazole, with N-vinylpyrrolidone being preferred.

[0279] Furthermore, preferred structural units formed by N-vinyl heterocyclic compounds are those represented by the following formula C1.

[0280] [ka]

[0281] In formula C1, Ar N This represents a heterocyclic structure containing a nitrogen atom, Ar N The nitrogen atom inside bonds with the carbon atom indicated by the asterisk (*). In formula C1, Ar N The heterocyclic structure represented by is preferably a pyrrolidone ring, carbazole ring, pyrrole ring, phenothiazine ring, succinimide ring, phthalimide ring, caprolactam ring, and imidazole ring, and more preferably a pyrrolidone ring. Also, Ar N The heterocyclic structure represented by may have known substituents.

[0282] The content of structural units formed by N-vinyl heterocyclic compounds in resin A is preferably 5% to 50% by mass, and more preferably 10% to 40% by mass, based on the total mass of resin A.

[0283] The resin A contained in the thermoplastic resin particles may contain constituent units having acidic groups, but from the viewpoint of on-press developability and ink transfer properties, it is preferable that it does not contain constituent units having acidic groups. Specifically, the content of constituent units having acidic groups 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 above content is not particularly limited and may be 0% by mass. Furthermore, 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 above acid value is not particularly limited and may be 0 mgKOH / g. In this disclosure, the acid value is determined by a measurement method in accordance with JIS K0070:1992.

[0284] The resin A contained in the thermoplastic resin particles may contain constituent units that include hydrophobic groups, from the viewpoint of ink adhesion. Examples of the hydrophobic groups mentioned above include alkyl groups, aryl groups, and aralkyl groups. Preferably, the constituent units containing hydrophobic groups are those formed from alkyl (meth)acrylate compounds, aryl (meth)acrylate compounds, or aralkyl (meth)acrylate compounds, with constituent units formed from alkyl (meth)acrylate compounds being more preferable. The alkyl group in the alkyl (meth)acrylate compound described above preferably has 1 to 10 carbon atoms. The alkyl group may be linear, branched, or have a cyclic structure. Examples of alkyl (meth)acrylate compounds include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, cyclohexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and dicyclopentanyl (meth)acrylate. The aryl group in the above aryl (meth)acrylate compound preferably has 6 to 20 carbon atoms, and more preferably a phenyl group. The aryl group may also have known substituents. Phenyl (meth)acrylate is a preferred example of the aryl (meth)acrylate compound. The alkyl group in the above aralkyl (meth)acrylate compound preferably has 1 to 10 carbon atoms. The alkyl group may be linear, branched, or have a cyclic structure. Furthermore, the aryl group in the above aralkyl (meth)acrylate compound preferably has 6 to 20 carbon atoms, and more preferably a phenyl group. Benzyl (meth)acrylate is a preferred example of the aralkyl (meth)acrylate compound.

[0285] The content of hydrophobic structural units in resin A contained in thermoplastic resin particles is preferably 5% to 50% by mass, and more preferably 10% to 30% by mass, based on the total mass of resin A.

[0286] The thermoplastic resin contained in the above-mentioned thermoplastic resin particles preferably has hydrophilic groups from the viewpoint of print resistance and on-press developability. There are no particular restrictions on hydrophilic groups as long as they have a hydrophilic structure, but examples include acidic groups such as carboxyl groups, hydroxyl groups, amino groups, cyano groups, and polyalkylene oxide structures. The hydrophilic group is preferably a group having a polyalkylene oxide structure, a group having a polyester structure, or a sulfonic acid group, from the viewpoint of print resistance and on-press developability, more preferably a group having a polyalkylene oxide structure or a sulfonic acid group, and even more preferably a group having a polyalkylene oxide structure.

[0287] From the viewpoint of on-air developability, the above polyalkylene oxide structure is preferably a polyethylene oxide structure, a polypropylene oxide structure, or a poly(ethylene oxide / propylene oxide) structure. Furthermore, from the viewpoint of on-air developability, among the hydrophilic groups mentioned above, it is preferable that the polyalkylene oxide structure has a polypropylene oxide structure, and it is more preferable that it has both a polyethylene oxide structure and a polypropylene oxide structure. From the viewpoint of on-preparability, the number of alkylene oxide structures in the above polyalkylene oxide structure is preferably 2 or more, more preferably 5 or more, even more preferably 5 to 200, and particularly preferably 8 to 150.

[0288] Furthermore, from the viewpoint of on-pressure development, the hydrophilic group is preferably the group represented by the formula Z.

[0289] From the viewpoint of improving print resistance, chemical resistance, and on-press developability, it is preferable that the resin A contained in the thermoplastic resin particles contains constituent units having hydrophilic groups. The above hydrophilic groups include -OH, -CN, and -CONR. 1 R 2 , -NR 2 COR 1 (R 1 and R 2 Each of these independently represents a hydrogen atom, an alkyl group, an alkenyl group, or an aryl group. 1 and R2 It may also bond with it to form a ring. )-NR 3 R 4 , -N + R 3 R 4 R 5 X - (R 3 ~R 5 Each of these independently represents an alkyl group having 1 to 8 carbon atoms, X - Examples include groups represented by the following formula PO (where represents a counteranion), hydrophilic groups preferably present in the thermoplastic resin contained in the above thermoplastic resin particles, etc. Among these hydrophilic groups, -CONR 1 R 2 Alternatively, a group represented by formula PO is preferred, and a group represented by formula PO is more preferred.

[0290] [ka]

[0291] During the expression PO, L P Each of these independently represents an alkylene group, R P represents a hydrogen atom or an alkyl group, and n represents an integer between 1 and 100. During the expression PO, L P Each of these is preferably an ethylene group, a 1-methylethylene group, or a 2-methylethylene group, and more preferably an ethylene group. 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, even more preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and particularly preferably a hydrogen atom or a methyl group. In formula PO, n is preferably an integer between 1 and 10, and more preferably an integer between 1 and 4.

[0292] The content of hydrophilic structural units in resin A is preferably 5% to 60% by mass, and more preferably 10% to 30% by mass, based on the total mass of resin A.

[0293] The resin A contained in the thermoplastic resin particles may further contain other constituent units. These other constituent units may include any constituent units other than those described above, and examples include constituent units formed from acrylamide compounds, vinyl ether compounds, and the like. Examples of acrylamide compounds include (meth)acrylamide, N-methyl(meth)acrylamide, N-ethyl(meth)acrylamide, N-propyl(meth)acrylamide, N-butyl(meth)acrylamide, N,N'-dimethyl(meth)acrylamide, N,N'-diethyl(meth)acrylamide, N-hydroxyethyl(meth)acrylamide, N-hydroxypropyl(meth)acrylamide, and N-hydroxybutyl(meth)acrylamide. Examples of vinyl ether compounds include methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether, n-butyl vinyl ether, tert-butyl vinyl ether, 2-ethylhexyl vinyl ether, n-nonyl vinyl ether, lauryl vinyl ether, cyclohexyl vinyl ether, cyclohexylmethyl vinyl ether, 4-methylcyclohexylmethyl vinyl ether, benzyl vinyl ether, dicyclopentenyl vinyl ether, 2-dicyclopentenoxyethyl vinyl ether, methoxyethyl vinyl ether, ethoxyethyl vinyl ether, butoxyethyl vinyl ether, methoxyethoxyethyl vinyl ether, ethoxyethoxyethyl vinyl ether, methoxypolyethylene glycol vinyl ether, tetrahydrofurfuryl vinyl ether, 2-hydroxyethyl vinyl ether, 2-hydroxypropyl vinyl ether, 4-hydroxybutyl vinyl ether, 4-hydroxymethylcyclohexylmethyl vinyl ether, diethylene glycol monovinyl ether, polyethylene glycol vinyl ether, chloroethyl vinyl ether, chlorobutyl vinyl ether, chloroethoxyethyl vinyl ether, phenylethyl vinyl ether, and phenoxypolyethylene glycol vinyl ether.

[0294] The content of other constituent units in the thermoplastic resin is preferably 5% to 50% by mass, and more preferably 10% to 30% by mass, based on the total mass of the thermoplastic resin.

[0295] The glass transition temperature (Tg) of the thermoplastic resin is preferably 60°C to 150°C, more preferably 80°C to 140°C, and even more preferably 90°C to 130°C, from the viewpoint of print resistance and ink adhesion. When thermoplastic resin particles contain two or more types of thermoplastic resins, the value obtained by the FOX formula described later is called the glass transition temperature of the thermoplastic resin.

[0296] In this disclosure, the glass transition temperature of the resin can be measured using differential scanning calorimetry (DSC). The specific measurement method shall be carried out in accordance with the methods described in JIS K 7121 (1987) or JIS K 6240 (2011). In this specification, the glass transition temperature used is the extrapolation glass transition onset temperature (hereinafter sometimes referred to as Tig). The method for measuring the glass transition temperature will be explained in more detail. To determine the glass transition temperature, the apparatus is held at a temperature approximately 50°C lower than the expected Tg of the resin until it stabilizes. Then, the temperature is heated at a heating rate of 20°C / min to a temperature approximately 30°C higher than the temperature at which the glass transition is completed, and a differential thermal analysis (DTA) curve or digital sensor cell (DSC) curve is created. The extrapolation glass transition onset temperature (Tig), i.e., the glass transition temperature Tg as defined herein, is determined as the temperature at the intersection of a straight line drawn by extending the low-temperature baseline of the DTA curve or DSC curve toward the high-temperature side, and a tangent line drawn at the point where the slope of the curve representing the stepwise transition portion of the glass transition is maximum.

[0297] When thermoplastic resin particles contain two types of thermoplastic resins, the Tg of the thermoplastic resins contained in the thermoplastic resin particles can be determined as follows. When the Tg of the first thermoplastic resin is denoted as Tg1(K), and the mass fraction of the first thermoplastic resin relative to the total mass of thermoplastic resin components in the thermoplastic resin particle is denoted as W1, and the Tg of the second resin is denoted as Tg2(K), and the mass fraction of the second resin relative to the total mass of thermoplastic resin components in the thermoplastic resin particle is denoted as W2, the Tg0(K) of the thermoplastic resin particle can be estimated according to the following FOX formula. FOX formula: 1 / Tg0=(W1 / Tg1)+(W2 / Tg2) Furthermore, if the thermoplastic resin particles contain three or more types of resin, or if the pretreatment solution contains three or more types of thermoplastic resin particles with different types of resin, the Tg0(K) of the thermoplastic resin particles can be estimated according to the following formula, similar to the above, where Tgn(K) is the Tg of the nth resin and Wn is the mass fraction of the nth resin relative to the total mass of the resin components in the thermoplastic resin particles. FOX formula: 1 / Tg0=(W1 / Tg1)+(W2 / Tg2)+(W3 / Tg3)...+(Wn / Tgn)

[0298] In this disclosure, Tg is a value measured by a differential scanning calorimetry (DSC). For example, the EXSTAR6220 from SII Nanotechnology can be used as a differential scanning calorimetry (DSC).

[0299] From the viewpoint of print resistance, the arithmetic mean particle size of the thermoplastic resin particles is preferably 1 nm or more and 200 nm or less, more preferably 3 nm or more and less than 80 nm, and even more preferably 10 nm or more and 49 nm or less.

[0300] In this disclosure, the arithmetic mean particle size of thermoplastic resin particles refers to the value measured by dynamic light scattering (DLS), unless otherwise specified. The measurement of the arithmetic mean particle size of thermoplastic resin particles by DLS is performed using a Brookhaven BI-90 (manufactured by Brookhaven Instrument Company) in accordance with the manual for the above-mentioned instrument.

[0301] The weight-average molecular weight of the thermoplastic resin contained in the thermoplastic resin particles is preferably 3,000 to 300,000, and more preferably 5,000 to 100,000.

[0302] The method for producing the thermoplastic resin contained in the thermoplastic resin particles is not particularly limited and can be produced by known methods. For example, it can be obtained by polymerizing a styrene compound, an acrylonitrile compound, and, if necessary, at least one compound selected from the group consisting of the above N-vinyl heterocyclic compound, a compound used to form a structural unit having an ethylenically unsaturated group, a compound used to form a structural unit having an acidic group, a compound used to form a structural unit having a hydrophobic group, and a compound used to form other structural units, by a known method.

[0303] Specific examples of thermoplastic resins contained in thermoplastic resin particles are shown in the table below, but the thermoplastic resins used in this disclosure are not limited to these.

[0304] [ka]

[0305] [ka]

[0306] Furthermore, in the above specific examples, the content ratio of each constituent unit can be appropriately changed according to the preferred range of content of each constituent unit as described above. Furthermore, the weight-average molecular weight of each compound shown in the above specific examples can be appropriately changed according to the preferred range of weight-average molecular weight of the thermoplastic resin described above.

[0307] The average particle size of the above particles is preferably 0.01 μm to 3.0 μm, more preferably 0.03 μm to 2.0 μm, and even more preferably 0.10 μm to 1.0 μm. Good resolution and stability over time can be obtained within this range. In this disclosure, the average primary particle size of the above particles shall be measured by light scattering, or by taking electron microscope images of the particles, measuring the particle size of a total of 5,000 particles on the image, and calculating the average value. For non-spherical particles, the particle size shall be the particle size of a spherical particle having the same particle area as the particle on the image. Furthermore, unless otherwise specified, the average particle size in this disclosure refers to the volume-average particle size.

[0308] If the above image recording layer contains polymer particles, it may contain one type of polymer particle alone or two or more types. Furthermore, the content of particles, particularly polymer particles, in the image recording layer is preferably 5% to 90% by mass, more preferably 10% to 90% by mass, even more preferably 20% to 90% by mass, and particularly preferably 50% to 90% by mass, based on the total mass of the image recording layer, from the viewpoint of on-press developability and print durability. Furthermore, from the viewpoint of on-press developability and print durability, the polymer particle content in the image recording layer is preferably 20% to 100% by mass, more preferably 35% to 100% by mass, even more preferably 50% to 100% by mass, and particularly preferably 80% to 100% by mass, based on the total mass of components with a molecular weight of 3,000 or more in the image recording layer.

[0309] <Binder Polymer> The image recording layer may contain a binder polymer. As the binder polymer, a binder polymer used in the image recording layer of a lithographic printing plate can be used. Specifically, as the binder polymer, the binder polymer described in paragraphs 0288 to 0317 of International Publication No. 2022 / 019217 can be preferably used.

[0310] The image recording layer may use one type of binder polymer alone or two or more types in combination. The binder polymer can be included in the image recording layer in any amount, but the binder polymer content is preferably 1% to 90% by mass, and more preferably 5% to 80% by mass, relative to the total mass of the image recording layer. Furthermore, if the image recording layer in this disclosure contains other binder polymers, the content of the other binder polymers relative to the total mass of the thermoplastic resin particles and the other binder polymers is preferably greater than 0% by mass and 99% by mass or less, more preferably between 20% by mass and 95% by mass, and even more preferably between 40% by mass and 90% by mass.

[0311] <Oil-based agent> The image recording layer may also preferably contain an oil. In this disclosure, the term "oil agent" refers to a hydrophobic compound that is in a liquid state at 80°C and does not misculate and separates when mixed with the same mass of water. Furthermore, when using two or more types of oil agents, even if they contain compounds with a melting point of 80°C or higher, it is sufficient that the two or more oil agents remain in a liquid state at 80°C when mixed together. Furthermore, from the viewpoint of on-air developability and dampening solution turbidity suppression, the oil agent is preferably a compound with a molecular weight of less than 1,000, more preferably a compound with a molecular weight of 200 to 800, and particularly preferably a compound with a molecular weight of 300 to 500. Furthermore, from the viewpoint of in-flight developability and dampening solution turbidity suppression, the oil agent is preferably a compound with a boiling point of 200°C or higher at 1 atm, more preferably a compound with a boiling point of 250°C or higher at 1 atm, even more preferably a compound with a boiling point of 300°C or higher at 1 atm, and particularly preferably a compound with a boiling point of 400°C or higher and 500°C or lower at 1 atm. In this disclosure, unless otherwise specified, the term "boiling point" refers to the boiling point at 1 atmosphere. Furthermore, the melting point of the oil agent at 1 atmosphere is preferably 50°C or lower, more preferably 30°C or lower, and particularly preferably -200°C or higher and 25°C or lower, from the viewpoint of on-pressure developingability and dampening solution turbidity suppression. In this disclosure, unless otherwise specified, the term "melting point" refers to the melting point at 1 atmosphere.

[0312] Examples of oil-based additives include phosphate ester compounds, aromatic hydrocarbon compounds, glyceride compounds, fatty acid compounds, and aromatic ester compounds. In particular, from the viewpoint of print resistance, ink transfer, on-press developability, and dampening solution turbidity suppression, at least one compound selected from the group consisting of phosphate ester compounds, aromatic hydrocarbon compounds, glyceride compounds, and aromatic ester compounds is preferred, at least one compound selected from the group consisting of phosphate ester compounds, aromatic hydrocarbon compounds, and glyceride compounds is more preferred, at least one compound selected from the group consisting of phosphate ester compounds and aromatic hydrocarbon compounds is even more preferred, and phosphate ester compounds are particularly preferred.

[0313] As for the phosphate ester compound, from the viewpoint of print resistance, ink transfer properties, on-press developability, and dampening solution turbidity suppression, triester phosphate compounds are preferred, triaryl phosphate compounds are more preferred, tricresil phosphate is even more preferred, and a mixture of two or more of the ortho, meta, and para isomers of tricresil phosphate is particularly preferred. As for aromatic hydrocarbon compounds, compounds having two or more aromatic rings are preferred from the viewpoint of on-engine developability and dampening solution turbidity suppression, and compounds having two or more unfused benzene rings are more preferred. As for the glyceride compound, triglyceride compounds are preferred from the viewpoint of on-in-flight developability and dampening solution turbidity suppression, fatty oils are more preferred, and fatty oils that are liquid at 25°C, such as castor oil, are particularly preferred. As for the fatty acid compound, unsaturated fatty acids are preferred from the viewpoint of on-air developability and dampening solution turbidity suppression, unsaturated fatty acids with 8 to 30 carbon atoms are more preferred, and unsaturated fatty acids with 12 to 24 carbon atoms are particularly preferred. As aromatic ester compounds, aromatic diester compounds are preferred from the viewpoint of on-air developability and dampening solution turbidity suppression, and aromatic diester compounds having an aliphatic ring are more preferred. As for aliphatic ester compounds, from the viewpoint of in-flight developability and dampening solution turbidity suppression, aliphatic ester compounds having a branched alkyl group are preferred, and aliphatic ester compounds having a branched alkyl group and having 10 to 24 carbon atoms are more preferred.

[0314] As for the oiling agent, it is preferable to include an oiling agent having phosphorus atoms, and more preferably an oiling agent having phosphorus atoms, from the viewpoint of print resistance, ink transfer properties, on-press developability, and dampening solution turbidity suppression. Furthermore, from the viewpoint of on-engine developability and dampening solution turbidity suppression, it is preferable that the oil agent contains an oil agent having an aromatic ring, more preferably an oil agent having two or more aromatic rings, and particularly preferably an oil agent having two or more non-fused benzene rings.

[0315] The clogP value of the oil agent is preferably 5.0 or higher, more preferably 5.50 or higher, even more preferably 5.50 or higher, even more preferably 5.50 to 10.0, and particularly preferably 5.60 to 7.00, from the viewpoint of print resistance, ink transfer, on-press developability, and dampening solution turbidity suppression. The clogP value is the value obtained by calculating the common logarithm logP of the partition coefficient P between 1-octanol and water. While publicly known methods and software can be used to calculate the clogP value, unless otherwise specified, this disclosure uses the ClogP program integrated into Cambridge Soft's ChemBioDraw Ultra 12.0.

[0316] Examples of oils include tricresyl phosphate, dimethyl(1-phenylethyl)benzene, 2,4-diphenyl-4-methyl-1-pentene, dicyclohexyl phthalate, castor oil, alpha-linolenic acid, and tri(2-ethylhexyl) phosphate.

[0317] The oil agent may be used alone or in combination of two or more types, but the image recording layer preferably contains two or more oil agents having different structures from the viewpoint of on-pressure developmentability and dampening solution turbidity suppression. The oil content is preferably 0.0001% to 10.0% by mass, more preferably 0.0002% to 1.0% by mass, even more preferably 0.0005% to 0.5% by mass, and particularly preferably 0.001% to 0.05% by mass, relative to the total mass of the image recording layer.

[0318] <Chain movement agent> The image recording layer may contain a chain transfer agent. As the chain transfer agent, a chain transfer agent used in the image recording layer of a lithographic printing plate can be used. Specifically, as the chain transfer agent, the chain transfer agent described in paragraphs 0388 to 0393 of International Publication No. 2022 / 019217 can be preferably used.

[0319] One type of chain transfer agent may be used, or two or more types may be used in combination. The content of the chain transfer agent is preferably 0.01% to 50% by mass, more preferably 0.05% to 40% by mass, and even more preferably 0.1% to 30% by mass, relative to the total mass of the image recording layer.

[0320] <Lipidifying agent> The image recording layer may contain a grease-sensitive agent to improve ink adhesion. As the grease-sensitive agent, a grease-sensitive agent used in the image recording layer of a lithographic printing plate can be used. Specifically, as the grease-sensitive agent, the grease-sensitive agents described in paragraphs 0395 to 0404 of International Publication No. 2022 / 019217 can be preferably used.

[0321] The amount of the lipid-sensitive agent is preferably 1% to 40.0% by mass, more preferably 2% to 25.0% by mass, and even more preferably 3% to 20.0% by mass, relative to the total mass of the image recording layer.

[0322] The image recording layer may contain one type of lipid-sensitive agent alone, or two or more types in combination. One preferred embodiment of the image recording layer used in this disclosure is an embodiment that contains two or more compounds as an oil-sensitive agent. Specifically, in order to achieve both on-pressure developability and ink-bearing properties, the image recording layer used in this disclosure preferably uses a combination of a phosphonium compound, a nitrogen-containing low molecular weight compound, and an ammonium group-containing polymer as an oil-sensitive agent, and more preferably uses a combination of a phosphonium compound, a quaternary ammonium salt, and an ammonium group-containing polymer.

[0323] <Developing accelerator> The image recording layer preferably further contains a development accelerator. The development accelerator preferably has a polarity term value of SP of 6.0 to 26.0, more preferably 6.2 to 24.0, even more preferably 6.3 to 23.5, and particularly preferably 6.4 to 22.0.

[0324] SP values ​​(solubility parameters, unit: cal / cm³) in this disclosure 3 ) 1 / 2 The value of the polarity term in ) shall be the value of the polarity term δp in the Hansen solubility parameter. The Hansen solubility parameter is a representation in three dimensions of the solubility parameter introduced by Hildebrand, divided into three components: dispersion term δd, polarity term δp, and hydrogen bonding term δh. In this disclosure, the above polarity term δp is used. δp[cal / cm 3 ] is the Hansen solubility parameter, dipole force term, V [cal / cm 3] is the molar volume, and μ[D] is the dipole moment. For δp, the following simplified formula by Hansen and Beerbower is generally used.

[0325]

number

[0326] The development accelerator is preferably a hydrophilic polymer compound or a hydrophilic low-molecular-weight compound. In this disclosure, hydrophilicity means that the polarity term of the SP value is between 6.0 and 26.0, a hydrophilic polymer compound means a compound with a molecular weight (or weight-average molecular weight if it has a molecular weight distribution) of 3,000 or more, and a hydrophilic low molecular weight compound means a compound with a molecular weight (or weight-average molecular weight if it has a molecular weight distribution) of less than 3,000.

[0327] Examples of hydrophilic polymer compounds include cellulose compounds, with cellulose compounds being preferred. Examples of cellulose compounds include cellulose, or compounds in which at least a portion of cellulose has been modified (modified cellulose compounds), with modified cellulose compounds being preferred. Preferred modified cellulose compounds include compounds in which at least a portion of the hydroxyl groups of cellulose are substituted with at least one group selected from the group consisting of alkyl groups and hydroxyalkyl groups. The degree of substitution in a compound in which at least a portion of the hydroxyl groups of the cellulose described above is substituted with at least one group selected from the group consisting of alkyl groups and hydroxyalkyl groups is preferably 0.1 to 6.0, and more preferably 1 to 4. As the modified cellulose compound, alkylcellulose compounds or hydroxyalkylcellulose compounds are preferred, and hydroxyalkylcellulose compounds are more preferred. Methylcellulose is a preferred example of an alkylcellulose compound. Hydroxypropylcellulose is a preferred example of a hydroxyalkylcellulose compound.

[0328] The molecular weight (or weight-average molecular weight if it has a molecular weight distribution) of the hydrophilic polymer compound is preferably 3,000 to 5,000,000, and more preferably 5,000 to 200,000.

[0329] Examples of hydrophilic low molecular weight compounds include glycol compounds, polyol compounds, organic amine compounds, organic sulfonic acid compounds, organic sulfamine compounds, organic sulfuric acid compounds, organic phosphonic acid compounds, organic carboxylic acid compounds, and betaine compounds, with polyol compounds, organic sulfonic acid compounds, or betaine compounds being preferred.

[0330] Examples of glycol compounds include glycols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, and tripropylene glycol, as well as ether or ester derivatives of these compounds. Examples of polyol compounds include glycerin, pentaerythritol, and tris(2-hydroxyethyl) isocyanurate. Examples of organic amine compounds include triethanolamine, diethanolamine, monoethanolamine, and their salts. Examples of organic sulfonic acid compounds include alkyl sulfonic acid, toluene sulfonic acid, benzene sulfonic acid, and their salts, with alkyl sulfonic acid having 1 to 10 carbon atoms in the alkyl group being preferred. Examples of organic sulfamine compounds include alkyl sulfamic acids and their salts. Examples of organic sulfuric acid compounds include alkyl sulfuric acid, alkyl ether sulfuric acid, and their salts. Examples of organic phosphonic acid compounds include phenylphosphonic acid and its salts. Examples of organic carboxylic acid compounds include tartaric acid, oxalic acid, citric acid, malic acid, lactic acid, gluconic acid, and their salts. Examples of betaine compounds include phosphobetaine compounds, sulfobetaine compounds, and carboxybetaine compounds, with trimethylglycine being a preferred example.

[0331] The molecular weight (or weight-average molecular weight if a molecular weight distribution exists) of the hydrophilic low molecular weight compound is preferably 100 or more and less than 3,000, and more preferably 300 to 2,500.

[0332] The development accelerator is preferably a compound having a cyclic structure. The cyclic structure is not particularly limited, but examples include glucose rings, isocyanuric rings, aromatic rings, and aliphatic rings, in which at least some of the hydroxyl groups may be substituted, with glucose rings or isocyanuric rings being preferred. Examples of compounds containing a glucose ring include the cellulose compounds mentioned above. Examples of compounds having an isocyanuric ring include the aforementioned tris(2-hydroxyethyl)isocyanurate. Examples of compounds having an aromatic ring include the aforementioned toluenesulfonic acid and benzenesulfonic acid. Examples of compounds having an aliphatic ring include the alkyl sulfates mentioned above, in which the alkyl group has a ring structure.

[0333] Furthermore, the compound having the above cyclic structure preferably has a hydroxyl group. Preferred examples of compounds having a hydroxyl group and a cyclic structure include the cellulose compounds mentioned above and the tris(2-hydroxyethyl) isocyanurate mentioned above.

[0334] Furthermore, the development accelerator is preferably an onium salt compound. Examples of onium salt compounds include ammonium compounds and sulfonium compounds, with ammonium compounds being preferred. Examples of onium salt compounds used as development accelerators include trimethylglycine. Furthermore, the onium salt compounds in the above-mentioned electron-accepting polymerization initiators are compounds whose SP value polarity term is not between 6.0 and 26.0, and are therefore not included in the development accelerators.

[0335] The image recording layer may contain one type of development accelerator alone, or two or more types in combination. In this disclosure, one preferred embodiment of the image recording layer is one which contains two or more compounds as a development accelerator. Specifically, the image recording layer preferably contains, from the viewpoint of on-pressure developmentability and ink transfer, the above polyol compound and the above betaine compound, the above betaine compound and the above organic sulfonic acid compound, or the above polyol compound and the above organic sulfonic acid compound as a development accelerator.

[0336] The content of the development accelerator relative to the total mass of the image recording layer is preferably 0.1% by mass or more and 20% by mass or less, more preferably 0.5% by mass or more and 15% by mass or less, and even more preferably 1% by mass or more and 10% by mass or less.

[0337] <Other ingredients> The image recording layer may contain other components such as surfactants, polymerization inhibitors, higher fatty acid derivatives, plasticizers, inorganic particles, and inorganic layered compounds. Specifically, refer to paragraphs 0114 to 0159 of Japanese Patent Application Publication No. 2008-284817.

[0338] <<Formation of the image recording layer>> If the image recording layer in the lithographic printing plate master according to this disclosure is a negative-type image recording layer, it can be formed by, for example, dispersing or dissolving the necessary components in a known solvent to prepare a coating solution, as described in paragraphs 0142 to 0143 of Japanese Patent Application Publication No. 2008-195018, applying the coating solution onto a support by a known method such as bar coating, and drying. The amount of the image recording layer coated (solid content) after coating and drying varies depending on the application, but is approximately 0.3 g / m². 2 ~3.0g / m 2This is preferable. Within this range, good sensitivity and good coating characteristics for the image recording layer can be obtained. Any known solvent can be used as the solvent. Specifically, examples include water, acetone, methyl ethyl ketone (2-butanone), cyclohexane, ethyl acetate, ethylene dichloride, tetrahydrofuran, toluene, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol dimethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, acetylacetone, cyclohexanone, diacetone alcohol, ethylene glycol monomethyl ether acetate, ethylene glycol ethyl ether acetate, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether acetate, 1-methoxy-2-propanol, 3-methoxy-1-propanol, methoxymethoxyethanol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, 3-methoxypropyl acetate, N,N-dimethylformamide, dimethyl sulfoxide, γ-butyrolactone, methyl lactate, ethyl lactate, etc. The solvent may be used alone or in combination of two or more types. The solid content concentration in the coating solution is preferably 1% to 50% by mass. The amount of coating (solid content) of the image recording layer after coating and drying varies depending on the application, but from the viewpoint of obtaining good sensitivity and good film characteristics of the image recording layer, 0.3 g / m² is recommended. 2 ~3.0g / m 2 It is preferable. Furthermore, the thickness of the image recording layer in the lithographic printing plate master according to this disclosure is preferably 0.1 μm to 3.0 μm, and more preferably 0.3 μm to 2.0 μm. In this disclosure, the film thickness of each layer in a lithographic printing plate is determined by preparing a section cut perpendicular to the surface of the lithographic printing plate and observing the cross-section of the section using a scanning microscope (SEM).

[0339] [Positive-type image recording layer] The image recording layer in the lithographic printing plate master according to this disclosure may be a positive-type image recording layer. The positive image recording layer contains at least a water-insoluble and alkali-soluble resin and an infrared absorber (e.g., an IR dye) that absorbs light and generates heat.

[0340] <Alkali-soluble resin> The positive image recording layer contains an alkali-soluble resin. In this disclosure, "alkali-soluble" means that 0.01 g of the resin dissolves in 5 g of a sodium hydroxide aqueous solution at 30°C and pH 13.0 within 200 seconds. Dissolution refers to a state in which no residual dissolved material can be visually confirmed. Examples of alkali-soluble resins include acrylic resins, novolac resins, polyureas, polyurethanes, or polycarbonates. From the viewpoint of further improving development discrimination and print durability, acrylic resin or novolac resin is preferred. The following describes preferred embodiments of the alkali-soluble resin relating to this disclosure.

[0341] [Acrylic resin] As the alkali-soluble resin, for example, any compound known in the field of positive-type lithographic printing plates can be used without particular limitation, but the water-insoluble and alkali-soluble resin described in paragraphs 0025 to 0062 of Japanese Patent Application Publication No. 2008-151929 is preferred. Among these, acrylic resins having sulfonamide groups in the side chain, or acrylic resins having phenolic hydroxyl groups in the side chain, are preferred.

[0342] [Polyurea, polyurethane, polycarbonate] Furthermore, polyurea, polyurethane, or polycarbonate can also be suitably used as alkali-soluble resins. Polyurea, polyurethane, or polycarbonate is preferably found to have acidic groups, and more preferably to have sulfonamide groups in its main chain from the viewpoint of print resistance and developability. Polyurea, polyurethane, or polycarbonate is preferably provided with other acidic groups in its side chains. Preferred acidic groups in the side chains are phenolic hydroxyl groups, sulfonamide groups, or carboxyl groups. Examples of these alkali-soluble resins include the compounds described in paragraphs 0083 to 0114 of Japanese Patent Publication No. 2018-165797, and these descriptions can be referenced in this disclosure.

[0343] [Novolac resin] Novolac resins are also preferred as alkali-soluble resins. Preferred novolac resins that can be used in the positive-type photosensitive resin composition according to this disclosure include phenol-formaldehyde resin, m-cresol-formaldehyde resin, p-cresol-formaldehyde resin, m- / p-mixed cresol-formaldehyde resin, phenol / cresol (m-, p-, or m- / p-mixed) mixed formaldehyde resin, and pyrogallolacetone resin. Furthermore, as described in U.S. Patent No. 4,123,279, examples include condensed polymers of phenol and formaldehyde having C3-C8 alkyl groups as substituents, such as t-butylphenolformaldehyde resin and octylphenolformaldehyde resin.

[0344] As for the alkali-soluble resin, there are no particular restrictions as long as it has the property of dissolving when it comes into contact with an alkaline developer. However, it is preferable that at least one of the main chain and side chains in the polymer has an acidic functional group such as a sulfonic acid group, a phosphate group, a sulfonamide group, or an active imide group. Examples include resins containing 10 mol% or more of a monomer having such an acidic functional group that imparts alkali solubility, and resins containing 20 mol% or more are more preferable. If the copolymer component of the monomer that imparts alkali solubility is 10 mol% or more, sufficient alkali solubility can be obtained, and the developability is also excellent.

[0345] As for the alkali-soluble resin, there are no particular restrictions as long as it has the property of dissolving when it comes into contact with an alkaline developer. However, it is preferable that at least one of the main chain and side chains in the polymer has an acidic functional group such as a sulfonic acid group, a phosphate group, a sulfonamide group, or an active imide group. Examples include resins containing 10 mol% or more of a monomer having such an acidic functional group that imparts alkali solubility, and resins containing 20 mol% or more are more preferable. If the copolymer component of the monomer that imparts alkali solubility is 10 mol% or more, sufficient alkali solubility can be obtained, and the developability is also excellent.

[0346] <Infrared absorbent> The positive-type photosensitive resin composition contains an infrared absorbent. As for the infrared absorber, there are no particular restrictions as long as it is a dye that absorbs infrared light and generates heat, and various dyes known as infrared absorbers can be used. Specific examples of infrared absorbers include those similar to those used in the negative-type image recording layer described above.

[0347] <Configuration of the positive image recording layer> When the lithographic printing plate master according to this disclosure has a positive-type image recording layer, it can be formed by applying a positive-type photosensitive resin composition onto a support having a hydrophilic surface. The image recording layer may be a single layer, or it may be a multilayered image recording layer having a lower layer and an upper layer near the support. Furthermore, the image recording layer has an image recording layer having a lower layer and an upper layer in that order from the support side, and it is preferable that at least one of the lower and upper layers is made of a positive-type photosensitive resin composition, and it is more preferable that either the lower or upper layer is made of a positive-type photosensitive resin composition.

[0348] The image recording layer of the positive-type lithographic printing plate master according to this disclosure can be formed by dissolving each component of the positive-type photosensitive resin composition described above in a solvent, applying it to a suitable support, and curing it. Examples of solvents used here include, but are not limited to, ethylene dichloride, cyclohexanone, methyl ethyl ketone, methanol, ethanol, propanol, ethylene glycol monomethyl ether, 1-methoxy-2-propanol, 2-methoxyethyl acetate, 1-methoxy-2-propyl acetate, dimethoxyethane, methyl lactate, ethyl lactate, N,N-dimethylacetamide, N,N-dimethylformamide, tetramethylurea, N-methylpyrrolidone, dimethyl sulfoxide, sulfolane, γ-butyrolactone, and toluene. These solvents may be used individually or in combination.

[0349] (Formation of lower and upper layers) When forming a positive-type image recording layer, it is preferable to have an image recording layer on a support having a lower layer and an upper layer in that order. For example, a composition for forming the upper layer that provides good ink receptivity and print resistance can be used, while a composition for forming the lower layer that provides good alkali solubility can be used. In principle, it is preferable to form the lower and upper layers as two separate layers. Methods for separating and forming the two layers include, for example, utilizing the difference in solvent solubility between the components in the lower layer and the components in the upper layer, or applying the upper layer and then rapidly drying and removing the solvent.

[0350] [Support] The lithographic printing plate master relating to this disclosure has a support. As the support material, it can be appropriately selected and used from known supports for lithographic printing plates. As the support, a support having a hydrophilic surface (hereinafter also referred to as "hydrophilic support") is preferred.

[0351] In this disclosure, an aluminum plate that has been roughened and anodized by a known method is preferred as the support. That is, the support in this disclosure preferably has an aluminum plate and an anodized aluminum film disposed on the aluminum plate.

[0352] Furthermore, the support comprises an aluminum plate and an anodic oxide film of aluminum disposed on the aluminum plate, wherein the anodic oxide film is located on the image recording layer side of the aluminum plate, and the anodic oxide film has micropores extending in the depth direction from the surface on the image recording layer side, and preferably the average diameter of the micropores on the surface of the anodic oxide film is greater than 10 nm and less than or equal to 100 nm. Furthermore, it is preferable that the micropore is composed of a large-diameter pore extending from the surface of the anodic oxide film to a depth of 10 nm to 1,000 nm, and a small-diameter pore communicating with the bottom of the large-diameter pore and extending from the communication point to a depth of 20 nm to 2,000 nm, with the average diameter of the large-diameter pore on the surface of the anodic oxide film being 15 nm to 100 nm, and the average diameter of the small-diameter pore at the communication point being 15 nm or less. Furthermore, it is preferable that the support has an anodic oxide film, and that the micropores in the anodic oxide film consist of small-diameter pores extending from the surface of the anodic oxide film to a depth of 10 nm to 1,000 nm, and large-diameter pores communicating with the bottom of the small-diameter pores and extending from the communication point to a depth of 20 nm to 2,000 nm, and that the average diameter of the small-diameter pores on the surface of the anodic oxide film is 35 nm or less, and the average maximum diameter of the large-diameter pores is 40 nm to 300 nm or less. Furthermore, it is preferable that the support has an anodic oxide film, and that the anodic oxide film has, in order from the surface of the anodic oxide film in the depth direction, an upper layer with a thickness of 30 nm to 500 nm having micropores with an average diameter of 20 nm to 100 nm, an intermediate layer with a thickness of 100 nm to 300 nm having micropores with an average diameter of 1 / 2 to 5 times the average diameter of the micropores in the upper layer, and a lower layer with a thickness of 300 nm to 2,000 nm having micropores with an average diameter of 15 nm or less.

[0353] Figure 1 is a schematic cross-sectional view of one embodiment of the aluminum support 12a. The aluminum support 12a has a laminated structure in which an aluminum plate 18 and an aluminum anodic oxide film 20a (hereinafter also simply referred to as "anodic oxide film 20a") are laminated in this order. The anodic oxide film 20a in the aluminum support 12a is located on the image recording layer side of the aluminum plate 18. In other words, it is preferable that the lithographic printing plate master according to this disclosure has at least an anodic oxide film, an image recording layer, and a water-soluble resin layer on the aluminum plate in this order.

[0354] -Anodized coating- The following describes preferred embodiments of the anodic oxide film 20a. The anodic oxide film 20a is a film produced on the surface of the aluminum plate 18 by an anodizing treatment, and this film has extremely fine micropores 22a that are substantially perpendicular to the film surface and uniformly distributed. The micropores 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 opposite to the aluminum plate 18 side) along the thickness direction (towards the aluminum plate 18 side).

[0355] The average diameter (average aperture diameter) of the micropores 22a in the anodic oxide film 20a on the anodic oxide film surface is preferably greater than 10 nm and less than or equal to 100 nm. In particular, from the viewpoint of balancing print resistance, stain resistance, and image visibility, 15 nm to 60 nm is more preferable, 20 nm to 50 nm is even more preferable, and 25 nm to 40 nm is particularly preferable. The diameter inside the pore may be wider or narrower than that of the surface layer. When the average diameter exceeds 10 nm, it exhibits excellent print resistance and image visibility. Furthermore, when the average diameter is 100 nm or less, it also exhibits excellent print resistance. The average diameter of micropores 22a was obtained by observing the surface of the anodic oxide film 20a with a field emission scanning electron microscope (FE-SEM) at a magnification of 150,000x (N=4 images), measuring the diameter of micropores (diameter) at 50 locations within a 400nm × 600nm range in the resulting 4 images, and averaging the result. If the shape of the micropore 22a is not circular, the equivalent diameter of a circle is used. The "equivalent diameter of a circle" is the diameter of a circle that is assumed to have the same projected area as the projected area of ​​the opening.

[0356] The shape of the micropore 22a is not particularly limited; in Figure 1, it is roughly tubular (roughly cylindrical), but it may also be conical, with the diameter decreasing towards the depth (thickness) direction. Furthermore, the shape of the bottom of the micropore 22a is not particularly limited; it may be curved (convex) or flat.

[0357] In the support, the micropore may consist of a large-diameter pore extending to a certain depth from the surface of the anodic oxide film, and a small-diameter pore communicating with the bottom of the large-diameter pore and extending to a certain depth from the communication point. For example, as shown in Figure 2, the aluminum support 12b may include an aluminum plate 18 and an anodic oxide film 20b having micropores 22b composed of large-diameter holes 24 and small-diameter holes 26. For example, the micropores 22b in the anodic oxide film 20b consist of a large-diameter pore portion 24 extending from the surface of the anodic oxide film to a depth of 10 nm to 1,000 nm (depth D: see Figure 2), and a small-diameter pore portion 26 communicating with the bottom of the large-diameter pore portion 24 and extending from the communication point to a depth of 20 nm to 2,000 nm. Specifically, for example, the embodiment described in paragraphs 0107 to 0114 of Japanese Patent Application Publication No. 2019-162855 can be used.

[0358] The depth of the micropore is not particularly limited, but from the viewpoint of achieving both on-press development and print durability, 0.01 μm to 1 μm is preferred, 0.05 μm to 0.6 μm is more preferred, and 0.07 μm to 0.25 μm is even more preferred. Note that the depth of the micropore refers to the distance in the depth direction from the surface of the micropore film to the deepest part of the bottom of the micropore.

[0359] The density of micropores on the film surface is not particularly limited, but from the viewpoint of balancing on-press development and print durability, 200 pores / μm is preferred. 2 ~2,000 pieces / μm 2 Preferably, 400 particles / μm 2 ~1,500 pieces / μm 2 This is preferable. The density of micropores is obtained by observing the film surface using a field emission scanning electron microscope (FE-SEM) at a magnification of 150,000x, and selecting a measurement area of ​​400nm × 600nm from four images obtained from four different locations. The number of micropores present in the measurement area is measured, the number of micropores per unit area of ​​the measurement area is calculated for each image, and the calculated values ​​are then taken as an arithmetic mean.

[0360] From the viewpoint of achieving both on-press developability and print durability, the aperture ratio due to micropores on the film surface is preferably 10% to 90%, and more preferably 30% to 85%. The above-mentioned aperture ratio is calculated by multiplying the average area of ​​the openings created by the large-diameter pores of micropores, which is calculated using the average radius obtained by dividing the average diameter of the large-diameter pores of micropores on the film surface by 2, by the density (number density) of micropores on the film surface, and converting this value to a percentage.

[0361] <<Method for manufacturing the support>> A preferred method for manufacturing the support used in this disclosure is, for example, a manufacturing method that involves performing the following steps in order. • Surface roughening process: A process of roughening the surface of an aluminum plate. • Anodizing process: A process of anodizing an aluminum plate that has undergone surface roughening treatment. • Pore widening process: A process in which an aluminum plate having an anodic oxide film obtained in the anodizing process is brought into contact with an acidic aqueous solution or an alkaline aqueous solution to enlarge the diameter of micropores in the anodic oxide film. The following details the procedures for each step.

[0362] <<Surface roughening treatment process>> The surface roughening process involves applying a surface roughening treatment, including electrochemical surface roughening, to the surface of the aluminum plate. This process is preferably carried out before the anodic oxidation process described later, but it may not be necessary if the surface of the aluminum plate already has a desirable surface shape. This process can be carried out by the method described in paragraphs 0086 to 0101 of Japanese Patent Application Publication No. 2019-162855.

[0363] <<Anodizing Process>> The procedure for the anodic oxidation process is not particularly limited as long as the above-described micropores are obtained, and known methods can be used. In the anodizing process, aqueous solutions of sulfuric acid, phosphoric acid, and oxalic acid can be used as the electrolytic bath. For example, the concentration of sulfuric acid can range from 100 g / L to 300 g / L. The conditions for the anodizing process are set appropriately depending on the electrolyte used, but for example, the electrolyte temperature is 5°C to 70°C (preferably 10°C to 60°C) and the current density is 0.5 A / dm². 2 ~60A / dm 2 (preferably 1 A / dm 2 ~60A / dm 2 ), voltage 1V to 100V (preferably 5V to 50V), electrolysis time 1 second to 100 seconds (preferably 5 seconds to 60 seconds), and film thickness 0.1g / m² 2 ~5g / m 2 (Preferably 0.2 g / m 2 ~3g / m 2 ) are some examples.

[0364] <<Pore-wide treatment>> Pore ​​widening is a process (pore diameter enlargement process) that enlarges the diameter of micropores (pore diameter) present in the anodic oxide film formed by the anodic oxidation process described above. Pore ​​widening can be performed by contacting the aluminum plate obtained by the anodic oxidation process described above with an acidic aqueous solution or an alkaline aqueous solution. The method of contact is not particularly limited, and examples include immersion and spraying methods.

[0365] <<Silicate treatment process>> The method for manufacturing the support preferably includes a silicate treatment step in which an anodic oxide film is formed on an aluminum plate by the above-mentioned anodic oxidation treatment and pore-widening treatment, etc. This is because the silicate treatment step makes it possible to easily manufacture a support in which the specific Si atomic amount described later is within a predetermined range. Silication treatment is a process in which an aqueous solution containing alkali metal silicates such as sodium silicate and potassium silicate (hereinafter also referred to as "treatment solution") is brought into contact with the anodic oxide film formed on an aluminum plate. In silicate treatment, it is preferable to immerse the aluminum plate having the anodic oxide film in the treatment solution. For silicate treatment, refer to the methods and procedures described in U.S. Patent No. 2,714,066 and U.S. Patent No. 3,181,461, which are incorporated herein by reference.

[0366] Examples of alkali metal silicates used in silicate treatment include sodium silicate, potassium silicate, and lithium silicate. In addition to alkali metal silicates, the treatment solution may further contain appropriate amounts of alkali metal hydroxides such as sodium hydroxide, potassium hydroxide, and lithium hydroxide. Furthermore, the treatment solution may further contain alkaline earth metal salts or Group IVA metal salts. Examples of alkaline earth metal salts include nitrates, sulfates, hydrochlorides, phosphates, acetates, oxalates, and borates such as calcium nitrate, strontium nitrate, magnesium nitrate, and barium nitrate. Examples of Group IVA metal salts include titanium tetrachloride, titanium trichloride, potassium titanium fluoride, potassium titanium oxalate, titanium sulfate, titanium tetraiodide, zirconium oxide chloride, zirconium dioxide, zirconium oxychloride, and zirconium tetrachloride. These alkaline earth metal salts and Group IVA metal salts may be used individually or in combination of two or more.

[0367] The silicate treatment conditions and the concentration of the treatment solution are adjusted as appropriate depending on the size of the aluminum plate and the anodized film to be treated, as well as the structure (specific structure) and density of the micropores. The alkali metal silicate content in the treatment solution is, for example, 3% to 30% by mass relative to the total mass of the treatment solution, and preferably 3% to 10% by mass. The temperature of the treatment solution used in silicate treatment is, for example, 30°C to 80°C, with 40°C to 70°C being more preferable. The silicate processing time is, for example, 1 to 15 seconds, with 3 to 10 seconds being more preferable. The amount of silicate adsorbed onto the support surface by silicate treatment can be expressed by the average value of the Si atomic weight (hereinafter also referred to as "specific Si atomic weight") calculated when a circular area with a diameter of 30 mm is measured by X-ray fluorescence analysis. The Si atomic weight is obtained by performing X-ray fluorescence analysis on a circular area with a diameter of 30 mm on the support surface, measuring the Kα-ray intensity of the Si element, and then quantifying the Si atomic weight present on the film surface using a calibration curve. Here, "average value of Si atomic weight" means a value obtained by selecting three or more non-overlapping circular areas on the image recording layer side surface of the anodized film, obtaining the Si atomic weight for each area, and then taking the arithmetic mean of the Si atomic weights obtained for each area.

[0368] <<Method for Measuring Atomic Weight of Si>> The atomic weight of Si in the anodic oxide film was measured based on the fluorescent X-ray analysis method and the calibration curve method. As the standard sample for creating the calibration curve, an aqueous solution containing a known amount of silicon atoms was uniformly dropped within an area of 30 mmφ on an aluminum plate and then dried before use. The measurement conditions for the fluorescent X-ray analysis are shown below.

[0369] Fluorescent X-ray analyzer: RIX3000 manufactured by Rigaku Corporation, X-ray tube: Rh, measurement spectrum: Si-Kα, tube voltage: 50 kV, tube current: 50 mA, slit: COARSE, spectroscopic crystal: RX4, detector: F-PC, analysis area: 30 mmφ, peak position (2θ): 144.75 deg., background (2θ): 140.70 deg. and 146.85 deg., integration time: 80 seconds / sample From the viewpoints of on-machine developability over time, printing resistance, and stain resistance, the atomic weight of Si is 0.001 g / m 2 ~0.2 g / m 2 is preferable, and 0.05 g / m 2 ~0.1 g / m 2 is more preferable.

[0370] The support may have, if necessary, a backcoat layer containing an organic polymer compound described in JP-A-5-45885 or a silicon alkoxy compound described in JP-A-6-35174 on the surface opposite to the image recording layer.

[0371] 〔Undercoat layer〕 The lithographic printing plate original according to the present disclosure preferably has an undercoat layer (sometimes referred to as an intermediate layer) between the image recording layer and the support. The undercoat layer contributes to improving the developability while suppressing a decrease in printing resistance by strengthening the adhesion between the support and the image recording layer in the exposed area and making it easier for the image recording layer to peel off from the support in the unexposed area. In addition, in the case of infrared laser exposure, the undercoat layer functions as a heat insulating layer, and thus has an effect of preventing the heat generated by the exposure from diffusing to the support and reducing the sensitivity.

[0372] Examples of compounds used in the undercoat layer include polymers having adsorbent groups and hydrophilic groups that can be adsorbed onto the support surface. Polymers having adsorbent groups and hydrophilic groups, and further having crosslinkable groups, are preferred to improve adhesion with the image recording layer. The compounds used in the undercoat layer may be low-molecular-weight compounds or polymers. Two or more compounds may be mixed and used as needed.

[0373] When the compound used in the undercoat layer is a polymer, copolymers of monomers having adsorbent groups, monomers having hydrophilic groups, and monomers having crosslinkable groups are preferred. Preferred adsorbent groups that can be adsorbed onto the support surface are phenolic hydroxyl groups, carboxyl groups, -PO3H2, -OPO3H2, -CONHSO2-, -SO2NHSO2-, and -COCH2COCH3. Preferred hydrophilic groups are sulfo groups or their salts, and carboxyl groups. Preferred crosslinking groups are acrylic groups, methacrylic groups, acrylamide groups, methacrylamide groups, and allyl groups. The polymer may have crosslinkable groups introduced by salt formation between the polar substituent of the polymer and a compound having a substituent oppositely charged to the polar substituent and an ethylenically unsaturated bond, or it may be further copolymerized with other monomers, preferably hydrophilic monomers.

[0374] Specifically, suitable examples include silane coupling agents having an ethylenically double bond reactive group that can be added and polymerized as described in Japanese Patent Publication No. 10-282679, and phosphorus compounds having an ethylenically double bond reactive group as described in Japanese Patent Publication No. 2-304441. Low molecular weight or high molecular weight compounds having a crosslinkable group (preferably an ethylenically unsaturated bond group), a functional group that interacts with the support surface, and a hydrophilic group as described in Japanese Patent Publication Nos. 2005-238816, 2005-125749, 2006-239867, and 2006-215263 are also preferably used. More preferable examples include polymers having adsorbent groups, hydrophilic groups, and crosslinkable groups that can be adsorbed onto the surface of a support, as described in Japanese Patent Publication No. 2005-125749 and Japanese Patent Publication No. 2006-188038.

[0375] The content of ethylenically unsaturated bonding groups in the polymer used for the undercoat layer is preferably 0.1 mmol to 10.0 mmol, more preferably 0.2 mmol to 5.5 mmol per gram of polymer. The weight-average molecular weight (Mw) of the polymer used in the undercoat layer is preferably 5,000 or more, and more preferably between 10,000 and 300,000.

[0376] In addition to the above-mentioned undercoat compound, the undercoat layer may also contain, to prevent soiling over time, a chelating agent, a secondary or tertiary amine, a polymerization inhibitor, or a compound having an amino group or a functional group having polymerization-inhibiting ability that interacts with the support surface (for example, 1,4-diazabicyclo[2.2.2]octane (DABCO), 2,3,5,6-tetrahydroxy-p-quinone, chloranil, sulfophthalic acid, hydroxyethylethylenediaminetriacetic acid, dihydroxyethylethylenediaminediacetic acid, hydroxyethyliminodiacetic acid, etc.).

[0377] The primer layer is applied by a known method. The amount of primer layer applied (solid content) is 0.1 mg / m². 2 ~100mg / m 2 Preferably, 1 mg / m² 2 ~30mg / m 2 This is preferable.

[0378] [Outermost layer] The lithographic printing plate according to this disclosure may have an outermost layer (sometimes called a "protective layer" or "overcoat layer") on the side of the image recording layer opposite to the support side. Furthermore, it is preferable that the lithographic printing plate according to this disclosure has a support, an image recording layer, and an outermost layer in this order. The outermost layer may have functions to suppress image formation inhibition reactions by blocking oxygen, as well as to prevent damage to the image recording layer and prevent ablation during high-intensity laser exposure.

[0379] The outermost layer can be a known outermost layer ("protective layer" or "overcoat layer") in a lithographic printing plate. Specifically, the outermost layer described in paragraphs 0444-0462 of International Publication No. 2022 / 019217 can be preferably used as the outermost layer.

[0380] The lithographic printing plate master relating to this disclosure may have other layers besides those described above. Other layers are not particularly limited and may include known layers. For example, a backcoat layer may be provided on the side of the support opposite to the image recording layer, if necessary.

[0381] The lithographic printing plate master according to this disclosure may have a drooped shape at its edges.

[0382] Figure 3 is a schematic diagram showing the cross-sectional shape of the edge of a lithographic printing plate. In Figure 3, the lithographic printing plate 100 has a sag 102 at its edge. The distance X from the upper end of the end face 100c of the lithographic printing plate 100 (the boundary point between the sag 102 and the end face 100c) to the intersection of the extension of the end face 100c and the extension of the image recording layer surface (protective layer surface if a protective layer is formed) 100a is called the "sag amount X," and the distance Y from the point where the image recording layer surface 100a of the lithographic printing plate 100 begins to sag to the above intersection is called the "sag width Y."

[0383] Regarding the edge sag shape, the sag amount X is preferably 25 μm or more, more preferably 35 μm or more, and even more preferably 40 μm or more. The upper limit of the sag amount X is preferably 150 μm from the viewpoint of preventing deterioration of on-press developability due to deterioration of the edge surface condition. If on-press developability deteriorates, ink may adhere to the remaining image recording layer, which can cause edge staining. If the sag amount X is too small, the ink adhering to the edge is more likely to transfer to the blanket, which can cause edge staining. When the sag amount X is in the range of 25 μm to 150 μm, if the sag width Y is small, the occurrence of cracks at the edge increases, and printing ink may accumulate there, which can cause edge staining. From this viewpoint, the sag width Y is preferably in the range of 70 μm to 300 μm, and more preferably in the range of 80 μm to 250 μm. Note that the above range of sag amount and sag width is independent of the edge shape of the support surface 100b of the lithographic printing plate original 100. Typically, at the edges of the lithographic printing plate 100, sagging occurs at the boundary B between the image recording layer and the support, and also at the support surface 100b, similar to the image recording layer surface 100a.

[0384] The formation of the end portion having the aforementioned sagging shape can be achieved, for example, by adjusting the cutting conditions of the lithographic printing plate. Specifically, this can be done by adjusting the gap between the upper and lower cutting blades, the amount of cutting action, and the blade angle in a slitter device used for cutting lithographic printing plates. Figure 4 is a conceptual diagram showing an example of the cutting section of a slitter device. The slitter device has a pair of upper and lower cutting blades 110 and 120 arranged vertically. The cutting blades 110 and 120 are circular blades on a disc, and the upper cutting blades 110a and 110b are supported coaxially on a rotation axis 111, and the lower cutting blades 120a and 120b are supported coaxially on a rotation axis 121. The upper cutting blades 110a and 110b and the lower cutting blades 120a and 120b are rotated in opposite directions. The lithographic printing plate 130 is passed between the upper cutting blades 110a and 110b and the lower cutting blades 120a and 120b and cut to a predetermined width. By adjusting the gap between the upper cutting blade 110a and the lower cutting blade 120a, and the gap between the upper cutting blade 110b and the lower cutting blade 120b in the cutting section of the slitter device, it is possible to form an end with a drooping shape.

[0385] (Method for preparing lithographic printing plates, and lithographic printing method) A lithographic printing plate can be produced by image exposure and development processing of the lithographic printing plate master according to this disclosure. There are no particular restrictions on the method of producing a lithographic printing plate using the lithographic printing plate master according to this disclosure, and known methods for producing lithographic printing plates can be applied. In particular, the method for producing a lithographic printing plate according to this disclosure, as described below, is preferred.

[0386] The method for producing a lithographic printing plate according to this disclosure preferably includes a step of exposing a lithographic printing plate according to this disclosure to an image (hereinafter also referred to as the "exposure step") and a step of removing the image recording layer of the non-image portion by supplying at least one selected from the group consisting of printing ink and dampening water on a printing press (hereinafter also referred to as the "on-press development step"). The lithographic printing method according to this disclosure preferably includes the steps of: exposing a lithographic printing plate according to this disclosure in an image-like manner (exposure step); supplying at least one selected from the group consisting of printing ink and dampening water to remove the image recording layer of non-image areas on a printing press to produce a lithographic printing plate (on-press development step); and printing using the obtained lithographic printing plate (printing step).

[0387] The preferred embodiments of each step in the method for producing the lithographic printing plate and the lithographic printing method relating to this disclosure will be described in order below. As previously stated, there are no particular restrictions on the method for producing a lithographic printing plate using the lithographic printing plate master plate related to this disclosure, and the development process is not limited to an on-press development process; a development process using a developing solution is also applicable.

[0388] The exposure process and on-press development process in the method for producing lithographic printing plates will be described below. The exposure process in the method for producing lithographic printing plates according to this disclosure is the same as the exposure process in the lithographic printing method described later, and the on-press development process in the method for producing lithographic printing plates according to this disclosure is the same as the on-press development process in the lithographic printing method described later.

[0389] <Exposure process> The method for producing a lithographic printing plate according to this disclosure preferably includes an exposure step in which a lithographic printing plate according to this disclosure is exposed in an image-like manner to form exposed and unexposed areas. The lithographic printing plate according to this disclosure is preferably exposed in an image-like manner by laser exposure through a transparent original image having a line image, a halftone image, etc., or by laser light scanning using digital data. The wavelength of the light source is preferably 750 nm to 1,400 nm. Suitable light sources with a wavelength of 750 nm to 1,400 nm include solid-state lasers and semiconductor lasers that emit infrared light. For infrared lasers, the output is preferably 100 mW or more, the exposure time per pixel is preferably 20 microseconds or less, and the irradiation energy is preferably 10 mJ / cm². 2 ~300 mJ / cm 2 It is preferable that this be the case. Furthermore, it is preferable to use a multi-beam laser device in order to shorten the exposure time. The exposure mechanism may be any of the following: an internal drum system, an external drum system, or a flatbed system. Image exposure can be performed using conventional methods, such as with a platesetter. In the case of on-press development, the lithographic printing plate can be mounted on the printing press, and then the image exposure may be performed on the press.

[0390] <Developing process> <<On-press development process>> When the lithographic printing plate according to this disclosure is a press-developed negative-type image recording layer, the method for producing the lithographic printing plate preferably includes a press-developing step in which at least one selected from the group consisting of printing ink and dampening water is supplied on the printing press to remove the image recording layer in the non-image areas. The onboard film processing method is described below.

[0391] [On-press development method] In the on-press development method, it is preferable that the exposed lithographic printing plate is supplied with oil-based ink and water-based components on the printing press, and the image recording layer in the non-image areas is removed to produce the lithographic printing plate. In other words, when a lithographic printing plate is exposed to image light and then mounted on a printing press without any development process, or when the lithographic printing plate is mounted on a printing press, exposed to image light on the press, and then printed with oil-based ink and aqueous components, in the early stages of printing, in the non-image areas, the uncured image recording layer is dissolved or dispersed and removed by either or both of the supplied oil-based ink and aqueous components, exposing a hydrophilic surface in those areas. On the other hand, in the exposed areas, the image recording layer cured by exposure forms an oil-based ink receiving area with a lipophilic surface. Initially, either oil-based ink or aqueous components may be supplied to the plate surface, but it is preferable to supply oil-based ink first to prevent contamination of the aqueous components by the components of the removed image recording layer. In this way, the lithographic printing plate is developed on the printing press and used as is for printing many copies. As the oil-based ink and aqueous components, ordinary lithographic printing ink and dampening solution are preferably used.

[0392] For the laser used to image-expose the lithographic printing plate according to the above disclosure, the wavelength of the light source is preferably 300 nm to 450 nm or 750 nm to 1,400 nm. In the case of a 300 nm to 450 nm light source, a lithographic printing plate containing a sensitizing dye having an absorption maximum in this wavelength range in the image recording layer is preferably used, and for a 750 nm to 1,400 nm light source, the above-mentioned type is preferably used. A semiconductor laser is preferred as the 300 nm to 450 nm light source.

[0393] <<Developing process using developer>> [Developer development method] The lithographic printing plate according to this disclosure can also be subjected to a developing process, which involves supplying a developer solution to remove unexposed areas in the exposure process, following the exposure process described above in which the lithographic printing plate is exposed to an image; in other words, a developing solution developing method. In the developer-development method, the unexposed areas are dissolved and removed using an alkaline developer or organic solvent, exposing the hydrophilic support surface and forming the non-image area. The developing solution processing method can be a known method of developing using a known developing solution, tailored to the lithographic printing plate to which it is applied.

[0394] By supplying printing ink to the lithographic printing plate obtained by the above-described method for producing a lithographic printing plate, a recording medium can be printed (printing process).

[0395] <Printing process> The lithographic printing method includes a printing step of supplying printing ink to a lithographic printing plate prepared from a lithographic printing plate master according to this disclosure and printing on a recording medium. There are no particular restrictions on the printing ink, and various known inks can be used as desired. Oil-based inks or UV-curing inks are preferred as printing inks. Furthermore, dampening solution may be supplied during the printing process as needed. Furthermore, the above printing process may be carried out continuously with the on-press development process or the development process using a developing solution without stopping the printing press. There are no particular restrictions on the recording medium; any known recording medium can be used as desired.

[0396] In the method for preparing a lithographic printing plate from a lithographic printing plate master and the lithographic printing method according to this disclosure, the entire surface of the lithographic printing plate master may be heated before exposure, during exposure, and between exposure and development, if necessary. Such heating promotes the image formation reaction in the image recording layer, which can result in advantages such as improved sensitivity and print durability, and stabilized sensitivity. Pre-development heating is preferably carried out under mild conditions of 150°C or less. This configuration prevents problems such as hardening of non-image areas. For post-development heating, it is preferable to use very strong conditions, preferably in the range of 100°C to 500°C. This range provides sufficient image enhancement and suppresses problems such as deterioration of the support and thermal decomposition of the image area.

[0397] (Laminated structure) The lithographic printing plate master relating to this disclosure may be in the form of a laminate.

[0398] <Protective material> The laminate of lithographic printing plates according to this disclosure preferably has a protective material positioned at least on top of the laminated lithographic printing plates to protect the lithographic printing plates. The (YX) / Y value of the protective material is preferably 0.06 or less, more preferably 0.03 or less, and particularly preferably 0.01 or less, from the viewpoint of suppressing development defects over time. The lower limit of the (YX) / Y value is 0.

[0399] The (YX) / Y value of the protective material is measured as follows: The protective material was cut into 10cm x 20cm pieces and dried in a 100°C oven for 1 hour. The dried protective material is humidified in an environment of 25°C and 30% RH, and its saturated mass X is determined. Specifically, the mass is measured every hour, and the mass X at each measurement is determined. n and the mass X from one hour ago n-1 We determine that the saturation mass has been reached when the relationship shown in the following equation is met. X n -X n-1 ≤0.005g Saturation mass X(g / m 2 ) is calculated using the following formula. X=X n / 0.02 The above protective material was conditioned at 25°C and 80% RH, and its saturated mass Y was determined. Specifically, the mass was measured every hour, and the mass Y at each measurement was determined. n and the mass Y from one hour ago n-1 We determine that the saturation mass has been reached when the relationship shown in the following equation is met. Y n -Y n-1 ≤0.005g Saturation mass Y (g / m 2 ) is calculated using the following formula. Y=Y n / 0.02 Based on the values ​​of X and Y obtained above, the water absorption rate of the protective material is calculated as follows. Water absorption rate=(YX) / Y

[0400] Examples of materials for the protective material include cardboard, corrugated cardboard, plastic, foamed plastic, and rubber. In particular, from the viewpoint of suppressing deterioration over time, it is preferable that the protective material be at least one selected from the group consisting of cardboard, corrugated cardboard, laminated paper, plastic sheets, foamed plastic sheets, and rubber sheets, with corrugated cardboard or plastic sheets being more preferable, and plastic sheets being especially preferable. As the plastic, known polymers can be used, but examples include polyester, polycardate, and polyolefin, with polyester being preferred. Cardboard may have one or more surfaces coated with a plastic material, such as polypropylene or low-density polyethylene. The cardboard surface may also be metal-coated, with aluminum being preferred from the standpoint of processability and cost. There are no particular restrictions on the size (length x width) of the protective material; it can be appropriately selected according to the lithographic printing plate used. For example, it can be the same size as the lithographic printing plate, or slightly larger. Furthermore, while there are no particular restrictions on the thickness of the protective material, it is preferably 10 μm to 10 mm, and more preferably 100 μm to 5 mm, from the viewpoint of strength, moisture permeability, and suppression of development defects over time. Furthermore, the thickness of the protective material is preferably 100 μm or more, from the viewpoint of strength, moisture permeability, and suppression of development defects over time. Furthermore, it is preferable to place protective material not only at the top of the laminate but also at the bottom.

[0401] <Interleaf paper> The laminate of lithographic printing plates according to this disclosure may have a sheet of paper between the two laminated lithographic printing plates. Furthermore, a sheet of interleaving paper may be placed between the lithographic printing plate and the protective material. Furthermore, the bottom of the laminate may have a lamination sheet.

[0402] In order to suppress material costs, it is preferable to select low-cost raw materials for the laminated paper used in this disclosure. For example, paper made using 100% by mass of wood pulp, paper made by mixing wood pulp with synthetic pulp, and paper having a low-density or high-density polyethylene layer on its surface can be used. Specifically, an example of acidic paper is produced using a pulp made by beating bleached kraft pulp, diluting it to a concentration of 4% by mass, adding a sizing agent at 0.1% by mass of the base paper mass, a paper strength agent at 0.2% by mass, and further adding aluminum sulfate until the pH reaches 5.0. However, a neutral paper with a pH of 7-8 is preferably used, employing a neutral sizing agent such as alkyl ketene dimer (AKD) or alkenyl succinic anhydride (ASA) as the sizing agent, and using calcium carbonate as a filler instead of aluminum sulfate. In particular, the laminated paper is preferably paper, more preferably paper containing aluminum sulfate or calcium carbonate, and especially preferably paper containing calcium carbonate. Furthermore, the material of the laminated paper is preferably paper containing 50% by mass or more of pulp, more preferably paper containing 70% by mass or more of pulp, and particularly preferably paper containing 80% by mass or more of pulp.

[0403] The laminated paper preferably has a calcium content of 0.15% to 0.5% by mass, more preferably 0.2% to 0.45% by mass, and particularly preferably 0.25% to 0.4% by mass, relative to the total mass of the laminated paper. The calcium content of the laminating paper can be determined by measuring the laminating paper using X-ray fluorescence. The calcium contained in paper is mainly calcium carbonate, which is widely used as a filler in neutral paper and has the effect of increasing the whiteness of the paper.

[0404] There are no particular restrictions on the basis weight of the lamination paper (measured according to the measurement method specified in JIS P8124 (2011)), but from the viewpoint of print durability and on-press developability, 29 g / m² is recommended. 2 ~80g / m 2 Preferably, it is 35 g / m 2 ~70g / m 2 It is more preferable that it be 51 g / m 2 ~65g / m 2 It is particularly preferable that this be the case. Furthermore, the basis weight of the above-mentioned laminated paper was set at 51 g / m² from the viewpoint of print durability and on-press developability. 2 It is preferable that the above conditions are met. The thickness of the laminated paper (according to the measurement method specified in JIS P8118 (2014)) is not particularly limited, but is preferably 20 μm to 100 μm, more preferably 42 μm to 80 μm, even more preferably 45 μm to 65 μm, and particularly preferably 45 μm to 55 μm.

[0405] Furthermore, from the viewpoint of suppressing spot-like color defects, the moisture content of the laminated paper (the moisture content when the laminated paper is stored at 25°C / 50%RH and its moisture content stabilizes) is preferably 0% to 20% by mass, more preferably 0% to 15% by mass, and particularly preferably 0% to 10% by mass, relative to the total mass of the laminated paper.

[0406] Furthermore, as the interlining paper, the interlining paper described in Japanese Patent Publication No. 2010-76336 can be suitably used.

[0407] There are no particular restrictions on the shape of the interleaving sheets, but they should be the same shape as, or larger than, the shape of the lithographic printing plate in the planar direction.

[0408] Furthermore, the laminate of lithographic printing plates may be packaged as a whole by a known method. [Examples]

[0409] The present disclosure will be described in detail below with reference to examples, but the disclosure is not limited to these examples. In these examples, unless otherwise specified, "%" and "parts" mean "mass%" and "parts by mass," respectively. In the following compositional or structural formulas, Me represents a methyl group, and the Me3SiO group (or Me3Si group) may be denoted as "M", the Me2SiO group as "D", and the MeHSiO group as "DH". In polymer compounds, unless otherwise specified, molecular weight is the weight-average molecular weight (Mw), and the ratio of constituent repeating units is expressed as a mole percentage. Furthermore, the weight-average molecular weight (Mw) is the value measured as a polystyrene equivalent by gel permeation chromatography (GPC).

[0410] (Examples 1 to 9, and Comparative Examples 1 to 4) Each lithographic printing plate was obtained by forming the undercoat layer described in Table 1 on the support described in Table 1, forming the image recording layer described in Table 1 on the undercoat layer, and forming or not forming the protective layer described in Table 1 on the image recording layer. In Example 9, as described in Table 1 below, the undercoat layer was not provided and the image recording layer was formed on the support. Details of the formation method for each layer will be described later.

[0411] <Preparation of support A> Support material A was manufactured by subjecting a 0.3 mm thick aluminum plate (aluminum alloy plate) of material 1S to the following treatment. Water washing was performed between all treatment steps, and after water washing, liquid was removed using a nip roller.

[0412] -Alkaline etching treatment (1)- An aluminum plate was etched by spraying it with a caustic soda aqueous solution containing 26% by mass of caustic soda and 6.5% by mass of aluminum ions at a temperature of 70°C. Afterward, it was rinsed with water by spraying. The amount of aluminum dissolved in the surface to be subsequently subjected to electrochemical roughening treatment was 5 g / m². 2 That was the case.

[0413] -Desmat treatment using acidic aqueous solution (1)- Next, a desmatt treatment was performed using an acidic aqueous solution. Specifically, the acidic aqueous solution was sprayed onto the aluminum plate and desmatt treatment was performed for 3 seconds. The acidic aqueous solution used for the desmatt treatment was a 150 g / L sulfuric acid solution. The temperature of the solution was 30°C.

[0414] -Electrochemical surface roughening treatment- Next, an electrolyte solution with a hydrochloric acid concentration of 13 g / L and an aluminum ion concentration of 15 g / L was used, and hydrochloric acid electrolysis was performed using alternating current. The electrolyte solution temperature was 25°C. The aluminum ion concentration was adjusted by adding aluminum chloride. The waveform of an alternating current is a sine wave with symmetrical positive and negative waveforms, with a frequency of 50 Hz, anode reaction time and cathode reaction time in one cycle of the alternating current at a ratio of 1:1, and current density at the peak current value of the alternating current waveform is 35 A / dm².2 The amount of electric charge was 320 C / dm², which is the sum of the electric charges that the aluminum plate participates in the anode reaction. 2 The electrolytic treatment is 80C / dm 2 The procedure was carried out in four stages, with a 2.5-second interval between applications. A carbon electrode was used as the counter electrode for the aluminum plate. Afterwards, the plate was rinsed with water.

[0415] -Alkaline etching treatment (2)- An aluminum plate that had undergone electrochemical roughening treatment was etched by spraying it with a caustic soda aqueous solution containing 5% by mass of caustic soda and 0.5% by mass of aluminum ions at a temperature of 45°C. The amount of aluminum dissolved on the surface treated with hydrochloric acid electrolysis was 0.2 g / m². 2 That was the case. Afterwards, it was washed with water.

[0416] -Desmat treatment using acidic aqueous solution (2)- Next, a desmatt treatment was performed using an acidic aqueous solution. Specifically, the acidic aqueous solution was sprayed onto the aluminum plate and desmatt treatment was performed for 3 seconds. The acidic aqueous solution used for the desmatt treatment had a sulfuric acid concentration of 170 g / L and an aluminum ion concentration of 5 g / L. The temperature of the solution was 35°C.

[0417] <First stage: Anodizing treatment> The first stage of anodic oxidation was performed using a DC electrolytic anodic oxidation apparatus with the structure shown in Figure 6. A 150 g / L sulfuric acid aqueous solution was used as the electrolyte, with a liquid temperature of 50°C and a current density of 15 A / dm². 2 Anodizing treatment was performed under the following conditions, resulting in a film thickness of 0.25 g / m². 2 An anodic oxide film was formed. In the anodic oxidation treatment apparatus 610 shown in Figure 6, the aluminum plate 616 is transported as indicated by the arrows in Figure 6. In the power supply tank 612 where the electrolyte 618 is stored, the aluminum plate 616 is charged positively by the power supply electrode 620. Then, in the power supply tank 612, the aluminum plate 616 is transported upward by the roller 622, its direction is changed downward by the nip roller 624, and then it is transported toward the electrolytic treatment tank 614 where the electrolyte 626 is stored, and its direction is changed horizontally by the roller 628. Next, the aluminum plate 616 is charged negatively by the electrolytic electrode 630, so that an anodic oxide film is formed on its surface, and the aluminum plate 616 that has left the electrolytic treatment tank 614 is transported to the next process. In the anodic oxidation treatment apparatus 610, a direction changing mechanism is formed by rollers 622, nip rollers 624, and rollers 628, and the aluminum plate 616 is conveyed in a mountain shape and an inverted U shape 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 power supply electrode 620 and the electrolytic electrode 630 are connected to a DC power supply 634. A tank wall 632 is positioned between the power supply tank 612 and the electrolytic treatment tank 614.

[0418] -Pore-wide processing- An anodized aluminum plate was immersed in a caustic soda aqueous solution with a liquid temperature of 40°C, a caustic soda concentration of 5% by mass, and an aluminum ion concentration of 0.5% by mass, and subjected to pore widening treatment. After that, it was rinsed with water by spraying.

[0419] -Second stage: Anodizing treatment- The second stage of anodic oxidation was performed using a DC electrolytic anodic oxidation apparatus with the structure shown in Figure 6. A 150 g / L sulfuric acid aqueous solution was used as the electrolyte, with a liquid temperature of 50°C and a current density of 30 A / dm². 2 Anodizing treatment was performed under the following conditions, resulting in a film thickness of 3.5 g / m². 2 An anodic oxide film was formed.

[0420] -Backcoat formation- The back surface of the support, which has been surface-treated as described above, is coated with the following back coat solution using a bar coater, dried at 100°C for 1 minute, and the coating amount after drying is 50 mg / m². 2 A back coat was provided to obtain an aluminum support A.

[0421] (Sol-gel reaction solution) Tetraethyl silicate: 50.0 parts ·Wednesday: 86.4 parts · Methanol: 10.8 parts • Phosphoric acid (85% by mass aqueous solution): 0.08 parts When the components listed in the sol-gel reaction solution above were mixed and stirred, heat was generated in approximately 35 minutes. After stirring for 40 minutes to allow the reaction to proceed, the mixture was further mixed with the following dilution to prepare the back coat coating solution. (Diluted solution) Pyrogallolacetone condensation resin: 15.0 parts • Dibutyl maleate: 5.0 parts Methanol silica sol, manufactured by Nissan Chemical Industries, Ltd.: 70.0 parts DOWSIL FZ-2123, manufactured by Dow Toray Industries, Inc.: 0.1 part • Methanol: 650 parts 1-Methoxy-2-propanol: 200 parts

[0422] <Preparation of undercoat layer A> Apply primer coating liquid A with the following composition to the support at a dry coating rate of 0.1 g / m². 2 The coat was applied in this manner to form a base coat layer. -Primer coating liquid A- • Undercoat compound (see U-1 below, 11% aqueous solution): 0.0788 parts • Kirest 400 (chelating agent; manufactured by Kirest Co., Ltd.): 0.0280 parts • Kirest 3EAF (chelating agent; manufactured by Kirest Co., Ltd.): 0.0499 parts • Surfactant (Emarex® 710, manufactured by Nippon Emulsion Co., Ltd.): 0.00159 parts • Preservative (Biohope L, K.I. Chemicals Co., Ltd.): 0.00149 parts ·Wed: 2.8219 copies

[0423] [ka]

[0424] <Fabrication of Image Recording Layer A> Apply the image recording layer coating liquid A shown below to the undercoat layer using a bar, and dry in an oven at 120°C for 40 seconds, resulting in a dry coating amount of 1.0 g / m². 2 An image recording layer was formed, and a lithographic printing plate was prepared. -Image recording layer coating solution A- Infrared absorber (IR-1 below): 0.0207 parts Infrared absorber (IR-2 below): 0.0069 parts Colorant (see S-1 below): 0.0300 parts Colorant (see S-2 below): 0.0120 parts Onium-based polymerization initiator (see I-1 below): 0.0981 parts Borate compound (see B-1 below): 0.0270 parts Polymerizable compound (see M-4 below): 0.3536 parts Anionic surfactant (see A-1 below): 0.0162 parts Polymer A or comparative polymer CA (compounds listed in Table 1): 0.0042 parts 2-Butanone: 5.3155 parts 1-Methoxy-2-propanol: 2.9361 parts Methanol: 2.3212 parts The following microgel solution: 1:2.8000 parts

[0425] The structures of each compound contained in the image recording layer coating solution are described below.

[0426] [ka]

[0427] [ka]

[0428] [ka]

[0429] [ka]

[0430] [ka] (B-1)

[0431] The details of polymer A and comparative polymer CA, listed in Table 1 and used in the above image recording layer coating solution, are as follows.

[0432] <<Synthesis of Polymer (A-1)>> The average composition formula MD is used in the reactor. 24 380.43 g of methylhydrogenpolysiloxane represented as DH6M, 468.29 g of allyl polyether represented by the average structural formula CH2=CH-CH2-O(C2H4O)9CH3, 278 g of isopropyl alcohol (hereinafter abbreviated as IPA), and 1.88 g of a 1.5% by mass sodium acetate / methanol solution were charged and heated to 60°C while stirring under a nitrogen flow. 3.25 g of a 1% by mass IPA solution of chloroplatinic acid was added and the reaction was carried out at 80°C for 3 hours. Next, 2 g of the reaction solution was taken and the completion of the reaction was confirmed by the alkaline decomposition gas generation method (decomposing the remaining Si-H groups with an ethanol / aqueous solution of KOH and calculating the reaction rate from the volume of hydrogen gas generated). Furthermore, by heating this under reduced pressure and distilling off the low-boiling components, A-1 with the following structure was obtained. As is clear from the structure below, (A-1) is a compound included in polymer A.

[0433] [ka]

[0434] <<Synthesis of Polymer (A-6)>> The average composition formula of the methylhydrogenpolysiloxane used in the synthesis of the above polymer (A-1) is given by MD. 40 DH 10 Except for replacing M with 370.69g of the initial charge and 468.29g of the allyl polyether, polymer (A-6) was obtained by synthesizing under the same conditions as the synthesis of polymer (A-1). As is clear from the structure below, (A-6) is a compound included in polymer A.

[0435] [ka]

[0436] <Commercial polymer A> The polymers (A-2), (A-3), (A-4), (A-5), and (A-7) shown below are all compounds included in polymer A. • Polymer (A-2): DOWSIL® SF-8427 Fluid, manufactured by Dow Toray Industries, Ltd., modified dimethylpolysiloxane with carbinols at both ends. • Polymer (A-3): DOWSIL (registered trademark) FZ-2123, manufactured by Dow Toray Industries, Ltd., side-chain polyether modified dimethylpolysiloxane • Polymer (A-4): KF-6104, manufactured by Shin-Etsu Chemical Co., Ltd., side-chain polyglycerin-modified dimethylpolysiloxane • Polymer (A-5): BYK-3760, manufactured by BYK, polyester-modified polydimethylsiloxane • Polymer (A-7): KF-6123, manufactured by Shin-Etsu Chemical Co., Ltd., polyether-modified dimethylpolysiloxane at both ends.

[0437] <Comparative polymer CA-1, CA-2)> As is clear from the structure below, the polymers (CA-1) and (CA-2) below are comparative polymers that do not have a main chain containing two or more silicon atoms. • Comparative polymer CA-1 (structure shown below)

[0438] [ka]

[0439] • Comparative polymer CA-2 (structure shown below)

[0440] [ka]

[0441] <Synthesis of polymerizable compound (M-4)> A mixed solution of Takenate D-160N (polyisocyanate trimethylolpropane adduct, manufactured by Mitsui Chemicals, Inc., 4.7 parts), Arronix M-403 (manufactured by Toagosei Co., Ltd., in an amount that results in a 1:1 ratio between the NCO value of Takenate D-160N and the hydroxyl value of Arronix M-403), t-butylbenzoquinone (0.02 parts), and methyl ethyl ketone (11.5 parts) was heated to 65°C. Neostan U-600 (bismuth-based polycondensation catalyst, manufactured by Nitto Kasei Co., Ltd., 0.11 parts) was added to the reaction solution and heated at 65°C for 4 hours. The reaction solution was cooled to room temperature (25°C), and methyl ethyl ketone was added to synthesize a urethane acrylate (M-4) solution with a solid content of 50% by mass. Molecular weight fractionation of a urethane acrylate solution was performed using a recycled GPC (instrument: LC908-C60, columns: JAIGEL-1H-40 and 2H-40 (manufactured by Nippon Analytical Industry Co., Ltd.)) with tetrahydrofuran (THF) as the eluent. The weight-average molecular weight of the obtained urethane acrylate (M-4) was 20,000.

[0442] <Synthesis of Microgel Solution 1> -Preparation of polyvalent isocyanate compound (1)- To a suspension of 17.78 g (80 mmol) of isophorone diisocyanate and 7.35 g (20 mmol) of the following polyhydric phenol compound (1) in ethyl acetate (25.31 g), 43 mg of bismastris (2-ethylhexanoate) (Neostan U-600, manufactured by Nitto Kasei Co., Ltd.) was added and the mixture was stirred. Once the exothermic reaction subsided, the reaction temperature was set to 50°C and the mixture was stirred for 3 hours to obtain an ethyl acetate solution (50% by mass) of polyhydric isocyanate compound (1).

[0443] [ka]

[0444] -Preparation of Microgel Solution 1- The oil phase and aqueous phase components listed below were mixed and emulsified using a homogenizer at 12,000 rpm for 10 minutes. The resulting emulsion was stirred at 45°C for 4 hours, then 5.20 g of a 10% by mass aqueous solution of 1,8-diazabicyclo[5.4.0]undec-7-en-octylate (U-CAT SA102, manufactured by Sunapro Co., Ltd.) was added, stirred at room temperature for 30 minutes, and allowed to stand at 45°C for 24 hours. The solid content concentration was adjusted to 20% by mass with distilled water to obtain an aqueous dispersion of microgel (1). The average particle size was measured by light scattering and found to be 0.28 μm.

[0445] (Oil phase components) (Ingredient 1) Ethyl acetate: 12.0g (Component 2) An adduct obtained by adding trimethylolpropane (6 mol) and xylene diisocyanate (18 mol), to which methyl end-terminal polyoxyethylene (1 mol, number of oxyethylene units repeated: 90) was added (50% by mass ethyl acetate solution, manufactured by Mitsui Chemicals, Inc.): 3.76 g (Component 3) Polyhydric isocyanate compound (1) (as a 50% by mass ethyl acetate solution): 15.0 g (Component 4) 65% by mass ethyl acetate solution of dipentaerythritol pentaacrylate (SR-399, manufactured by Sartomer): 11.54 g (Component 5) 10% ethyl acetate solution of sulfonate-type surfactant (Pionin A-41-C, manufactured by Takemoto Oil Co., Ltd.): 4.42g

[0446] (Aqueous phase component) Distilled water: 46.87g

[0447] <Preparation of protective layer A> The protective layer coating solution A described below was applied in a bar onto the image recording layer A, and then oven-dried at 120°C for 60 seconds, resulting in a dry coating amount of 0.41 g / m². 2 A protective layer A was formed, and a lithographic printing plate was prepared. As shown in Table 1, the lithographic printing plate of Example 8 does not have protective layer A.

[0448] -Protective coating liquid A- The following components were mixed to prepare protective coating solution A. Wednesday: 1.0161 copies Metroze SM04 (methylcellulose, manufactured by Shin-Etsu Chemical Co., Ltd., degree of methoxy substitution = 1.8): 0.0600 parts FS-102 (Styrene-acrylic resin, manufactured by Nippon Paint Industrial Coatings Co., Ltd., Tg=103℃, 17% aqueous dispersion): 0.1177 parts Rapizole A-80 (anionic surfactant, manufactured by NOF Corporation, 80% aqueous solution): 0.0063 parts

[0449] (Example 10) The lithographic printing plate of Example 10 has the following undercoat layer B, image recording layer B, and protective layer B on the support B described below.

[0450] <Preparation of support B> Support material B was manufactured by subjecting a 0.3 mm thick aluminum plate (aluminum alloy plate) made of material 1050 to the following treatment. Water washing was performed between all treatment steps, and after water washing, liquid was removed using a nip roller.

[0451] <<Alkaline etching treatment>> The aluminum plate obtained above was etched by spraying it with a caustic soda aqueous solution containing 26% by mass of caustic soda and 6.5% by mass of aluminum ions at a temperature of 70°C. Afterward, it was rinsed with water by spraying. The amount of aluminum dissolved was 5 g / m². 2 That was the case.

[0452] <<Desmatt treatment using acidic aqueous solution>> Next, a desmatt treatment was performed using an aqueous nitric acid solution. Specifically, the aqueous nitric acid solution was sprayed onto the aluminum plate and desmatt treatment was performed for 3 seconds. The aqueous nitric acid solution used for the desmatt treatment was the waste liquid of nitric acid used in the subsequent electrochemical surface roughening treatment. The temperature of the solution was 35°C.

[0453] <<Electrochemical surface roughening treatment>> Electrochemical surface roughening was continuously performed using a 60 Hz AC voltage with nitric acid electrolysis. The electrolyte used was an aqueous solution of 10.4 g / L nitric acid to which aluminum nitrate was added to adjust the aluminum ion concentration to 4.5 g / L, at a liquid temperature of 50°C. The AC power waveform is shown in Figure 6, with a current value tp of 0.8 msec from zero to peak, a duty cycle of 1:1, and a trapezoidal rectangular wave AC. Electrochemical surface roughening was performed using a carbon electrode as the counter electrode. Ferrite was used as the auxiliary anode. The electrolytic cell shown in Figure 5 was used. The current density was 71 A / dm², measured at the peak current value of the AC current waveform. 2 The auxiliary anode received 5% of the current flowing from the power supply. (C / dm 2 ) is the total amount of electricity when the aluminum plate is at anode, which is 205 C / dm 2 That was the case. Afterwards, it was rinsed with water using a spray bottle.

[0454] <<Alkaline etching treatment>> The aluminum plate obtained above was etched by spraying it with a caustic soda aqueous solution containing 5% by mass of caustic soda and 0.5% by mass of aluminum ions at a temperature of 35°C. Afterward, it was rinsed with water by spraying. The amount of aluminum dissolved was 0.2 g / m².2 That was the case.

[0455] <<Desmatt treatment using acidic aqueous solution>> Next, a desmatt treatment was performed using an aqueous sulfuric acid solution. Specifically, the aqueous sulfuric acid solution was sprayed onto an aluminum plate and desmatt treatment was performed for 3 seconds. The aqueous sulfuric acid solution used for the desmatt treatment had a sulfuric acid concentration of 170 g / L and an aluminum ion concentration of 5 g / L. The temperature of the solution was 30°C.

[0456] <<Electrochemical surface roughening treatment>> Electrochemical surface roughening was performed continuously using a 60 Hz AC voltage for hydrochloric acid electrolysis. The electrolyte was prepared by adding aluminum chloride to a 5.0 g / L aqueous solution of hydrochloric acid to adjust the aluminum ion concentration to 4.5 g / L, and the electrolyte was maintained at a liquid temperature of 35°C. The AC power waveform is shown in Figure 6, with a current value tp of 0.8 msec from zero to peak, a duty cycle of 1:1, and a trapezoidal rectangular wave AC. Electrochemical surface roughening was performed using a carbon electrode as the counter electrode. Ferrite was used as the auxiliary anode. The electrolytic cell shown in Figure 7 was used. The current density was 71 A / dm², measured at the peak current value of the AC current waveform. 2 The auxiliary anode received 5% of the current flowing from the power supply. The amount of electricity in hydrochloric acid electrolysis (C / dm 2 ) is the total amount of electricity when the aluminum plate is at anode, which is 75 C / dm 2 That was the case. Afterwards, it was rinsed with water using a spray bottle.

[0457] <<Alkaline etching treatment>> The aluminum plate obtained above was etched by spraying it with a caustic soda aqueous solution containing 5% by mass of caustic soda and 0.5% by mass of aluminum ions at a temperature of 35°C. Afterward, it was rinsed with water by spraying. The amount of aluminum dissolved was 0.05 g / m². 2 That was the case.

[0458] <<Desmatt treatment using acidic aqueous solution>> Next, a desmatt treatment was performed using an aqueous sulfuric acid solution. Specifically, the aqueous sulfuric acid solution was sprayed onto an aluminum plate and desmatt treatment was performed for 3 seconds. The aqueous sulfuric acid solution used for the desmatt treatment was specifically waste liquid generated in the anodizing process (an aqueous solution with a sulfuric acid concentration of 170 g / L and an aluminum ion concentration of 5 g / L). The temperature of the solution was 35°C.

[0459] <<First stage: Anodizing treatment>> The first stage of anodic oxidation was performed using a DC electrolytic anodic oxidation apparatus with the structure shown in Figure 6. The electrolyte used was a solution prepared with 170 g / L sulfuric acid and an aluminum ion concentration of 7.5 g / L, at a liquid temperature of 43°C. The current density was 30 A / dm². 2 The treatment was carried out, resulting in a film thickness of 0.2 g / m². 2 An anodic oxide film was formed.

[0460] <Pore-wide processing> The anodized aluminum plate described above was immersed in a caustic soda aqueous solution at a temperature of 35°C, with a caustic soda concentration of 5% by mass and an aluminum ion concentration of 0.5% by mass, and subjected to a pore-widening treatment. After that, it was rinsed with water using a spray.

[0461] <Second stage: Anodizing treatment> The second stage of anodic oxidation was performed using a DC electrolytic anodic oxidation apparatus with the structure shown in Figure 6. The electrolyte used was a solution prepared with 170 g / L sulfuric acid and an aluminum ion concentration of 7.5 g / L, at a liquid temperature of 52°C. The current density was 13 A / dm². 2 The treatment was carried out, resulting in a coating weight of 2.3 g / m². 2 An anodic oxide film was formed.

[0462] -Backcoat formation- The back surface of the support, which has been surface-treated as described above, is coated with the following back coat solution using a bar coater, dried at 100°C for 1 minute, and the coating amount after drying is 50 mg / m². 2 A back coat was provided to obtain an aluminum support B.

[0463] (Sol-gel reaction solution) Tetraethyl silicate: 50.0 parts ·Wednesday: 86.4 parts · Methanol: 10.8 parts • Phosphoric acid (85% by mass aqueous solution): 0.08 parts When the components listed in the sol-gel reaction solution above were mixed and stirred, heat was generated in approximately 35 minutes. After stirring for 40 minutes to allow the reaction to proceed, the mixture was further mixed with the following dilution to prepare the back coat coating solution. (Diluted solution) Pyrogallolacetone condensation resin: 15.0 parts • Dibutyl maleate: 5.0 parts Methanol silica sol, manufactured by Nissan Chemical Industries, Ltd.: 70.0 parts DOWSIL FZ-2123, manufactured by Dow Toray Industries, Inc.: 0.1 part • Methanol: 650 parts 1-Methoxy-2-propanol: 200 parts

[0464] <Preparation of undercoat layer B> On the support B described above, apply the primer layer solution with the following composition at a dry coating rate of 0.1 g / m². 2 The coat was applied in this manner to form a base coat layer. -Primer coating liquid B- • Undercoat compound (see U-1 below, 11% aqueous solution): 0.10502 parts Sodium gluconate: 0.0700 parts • Surfactant (Emarex® 710, manufactured by Nippon Emulsion Co., Ltd.): 0.00159 parts • Preservative (Biohope L, K.I. Chemicals Co., Ltd.): 0.00149 parts ·Wednesday: 2.8719 copies

[0465] [ka]

[0466] <Formation of Image Recording Layer B> The image recording layer coating solution described below was applied in a bar onto the above-mentioned undercoat layer B, and then oven-dried at 120°C for 40 seconds, resulting in a dry coating amount of 1.0 g / m².2 An image recording layer B was formed, and a lithographic printing plate was prepared. -Image recording layer coating solution B- Infrared absorber (IR-1, structure as described above): 0.0270 parts Infrared absorber (IR-2, structure as described above): 0.0080 parts Colorant (S-1, structure as described above): 0.0300 parts Colorant (S-2, structure as described above): 0.0120 parts Onium-based polymerization initiator (I-1, structure shown above): 0.0981 parts Borate compound (sodium tetraphenylborate (TPB)): 0.0200 parts Polymerizable compound (M-4, 70%): 0.2726 parts Polymer (A-3): 0.0042 parts Anionic surfactant (A-1, structure shown above, 30%): 0.0200 parts 2-Butanone: 5.6432 parts 1-Methoxy-2-propanol: 3.100g Methanol: 2.4645 parts The aforementioned microgel solution in a 1:2.3256 part ratio.

[0467] <Preparation of protective layer B> The protective layer coating solution B described below is applied in a bar onto the image recording layer B, and then oven-dried at 120°C for 60 seconds until the dry coating amount is 0.1 g / m². 2 A protective layer B was formed, and the lithographic printing plate master for Example 9 was prepared. -Image recording layer coating solution B- Inorganic layered compound dispersion (1): 0.5625 parts Hydrophilic polymer (1) (20% aqueous solution of the following compound): 0.0825 parts Metroze SM04 (methylcellulose, manufactured by Shin-Etsu Chemical Co., Ltd., degree of methoxy substitution = 1.8): 0.0250 parts Rapisol A-80 (anionic surfactant, manufactured by NOF Corporation, 80% aqueous solution): 0.0007 parts Ion-exchanged water: 43,300 units

[0468] [ka]

[0469] (Example 11) The lithographic printing plate of Example 11 has the following undercoat layer C, the following image recording layer C, and the following protective layer C on the following support C.

[0470] <Preparation of support C> A support C was manufactured by subjecting a 0.3 mm thick aluminum plate (aluminum alloy plate) of material 1S to the following process. Water washing was performed between all processing steps, and after the water washing, liquid was removed using a nip roller.

[0471] (Mechanical surface roughening treatment (brush grain method)) Using the apparatus shown in Figure 6, a pumice suspension (specific gravity 1.1 g / cm³) was prepared. 3 While supplying the polishing slurry liquid to the surface of the aluminum plate, mechanical surface roughening treatment was performed using a rotating bundled brush. In Figure 6, 1 is the aluminum plate, 2 and 4 are roller-shaped brushes (bundled brushes in this embodiment), 3 is the polishing slurry liquid, and 5, 6, 7 and 8 are support rollers. In the mechanical surface roughening treatment, the median diameter (μm) of the abrasive material was set to 30 μm, the number of brushes to 4, and the brush rotation speed (rpm: revolutions / minute, the same applies hereafter) to 250 rpm. The material of the bundled brush was 6-10 nylon, with a bristle diameter of 0.3 mm and a bristle length of 50 mm. The brush was densely packed into a φ300 mm stainless steel cylinder with holes drilled in it. The distance between the two support rollers (φ200 mm) at the bottom of the bundled brush was 300 mm. The bundled brush was pressed against the aluminum plate until the load on the drive motor that rotated the brush was 10 kW more than the load before the bundled brush was pressed against the aluminum plate. The direction of brush rotation was the same as the direction of movement of the aluminum plate.

[0472] (Alkaline etching treatment) An aluminum plate was etched by spraying it with an aqueous solution of caustic soda containing 26% by mass of caustic soda and 6.5% by mass of aluminum ions at a temperature of 70°C. The amount of aluminum dissolved in the surface to be subsequently subjected to electrochemical roughening treatment was 10 g / m². 2 That was the case.

[0473] (Desmat treatment using acidic aqueous solution) As an acidic aqueous solution, waste nitric acid used in the subsequent electrochemical surface roughening treatment was sprayed onto an aluminum plate for 3 seconds at a liquid temperature of 35°C to perform the desmatt treatment.

[0474] (Electrochemical surface roughening treatment using nitric acid aqueous solution) A continuous electrochemical surface roughening treatment was performed using a 60 Hz AC voltage. The electrolyte used was an aqueous solution of 10.4 g / L nitric acid to which aluminum nitrate was added to adjust the aluminum ion concentration to 4.5 g / L, at a liquid temperature of 35°C. The AC power waveform is shown in Figure 6, with a current value tp of 0.8 msec from zero to peak, a duty cycle of 1:1, and a trapezoidal rectangular wave AC. Electrochemical surface roughening was performed using a carbon electrode as the counter electrode. A ferrite was used as the auxiliary anode. The electrolytic cell shown in Figure 7 was used. The current density was 30 A / dm² at the peak current value. 2 5% of the current flowing from the power supply was diverted to the auxiliary anode. Electrical quantity (C / dm 2 ) is the total amount of electric charge when the aluminum plate is at anode, which is 185 C / dm 2 That was the case.

[0475] (Alkaline etching treatment) An aluminum plate was etched by spraying it with an aqueous solution of caustic soda containing 27% by mass of caustic soda and 2.5% by mass of aluminum ions at a temperature of 50°C. The amount of aluminum dissolved was 3.5 g / m². 2 That was the case.

[0476] (Desmat treatment using acidic aqueous solution) As an acidic aqueous solution, a solution with a sulfuric acid concentration of 170 g / L and an aluminum ion concentration of 5 g / L at a liquid temperature of 30°C was sprayed onto an aluminum plate for 3 seconds to perform the desmatt treatment.

[0477] (Electrochemical surface roughening treatment using hydrochloric acid solution) A continuous electrochemical surface roughening treatment was performed using a 60 Hz AC voltage. The electrolyte used was a 6.2 g / L aqueous solution of hydrochloric acid to which aluminum chloride was added to adjust the aluminum ion concentration to 4.5 g / L, at a liquid temperature of 35°C. The AC power waveform is shown in Figure 6, with a current value travel time tp of 0.8 msec, a duty cycle of 1:1, and a trapezoidal rectangular wave AC. Electrochemical surface roughening was performed using a carbon electrode as the counter electrode. A ferrite anode was used as the auxiliary anode. The electrolytic cell shown in Figure 7 was used. The current density was 25 A / dm² at the peak current value. 2 Therefore, the amount of electricity in hydrochloric acid electrolysis (C / dm 2 ) is the total amount of electricity when the aluminum plate is at anode, which is 63C / dm 2 That was the case.

[0478] (Alkaline etching treatment) An aluminum plate was etched by spraying it with an aqueous solution of caustic soda containing 5% by mass of caustic soda and 0.5% by mass of aluminum ions at a temperature of 60°C. The amount of aluminum dissolved was 0.2 g / m². 2 That was the case.

[0479] (Desmat treatment using acidic aqueous solution) As an acidic aqueous solution, a solution of waste liquid (sulfuric acid concentration 170 g / L and aluminum ion concentration 5 g / L) generated in an anodizing process at a liquid temperature of 35°C was sprayed onto an aluminum plate for 4 seconds to perform the desmatt treatment.

[0480] (First stage: anodic oxidation treatment) The first stage of anodic oxidation was performed using a DC electrolytic anodic oxidation apparatus with the structure shown in Figure 6. A 170 g / L sulfuric acid aqueous solution was used as the electrolyte, with a liquid temperature of 50°C and a current density of 30 A / dm².2 Anodizing treatment was performed under the following conditions, resulting in a film thickness of 0.3 g / m². 2 An anodic oxide film was formed.

[0481] (Pore-wide processing) An anodized aluminum plate was immersed in a caustic soda aqueous solution with a caustic soda concentration of 5% by mass and an aluminum ion concentration of 0.5% by mass for 3 seconds at 40°C to perform a pore widening treatment.

[0482] (Second stage: Anodizing treatment) The second stage of anodic oxidation was performed using a DC electrolytic anodic oxidation apparatus with the structure shown in Figure 6. A 170 g / L sulfuric acid aqueous solution was used as the electrolyte, with a liquid temperature of 50°C and a current density of 13 A / dm². 2 Anodizing treatment was performed under the following conditions, resulting in a film thickness of 2.6 g / m². 2 An anodic oxide film was formed.

[0483] (Hydrophilic treatment) To ensure hydrophilicity in the non-image areas, the aluminum plate was silicate-treated by immersing it in a 2.5% by mass sodium silicate aqueous solution at 50°C for 7 seconds. The amount of Si deposited was 8.5 mg / m². 2 The average diameter of the micropores was 30 nm.

[0484] -Backcoat formation- The back surface of the support, which has been surface-treated as described above, is coated with the following back coat solution using a bar coater, dried at 100°C for 1 minute, and the coating amount after drying is 50 mg / m². 2 A back coat was provided to obtain an aluminum support C.

[0485] (Sol-gel reaction solution) Tetraethyl silicate: 50.0 parts ·Wednesday: 86.4 parts · Methanol: 10.8 parts • Phosphoric acid (85% by mass aqueous solution): 0.08 parts When the components listed in the sol-gel reaction solution above were mixed and stirred, heat was generated in approximately 35 minutes. After stirring for 40 minutes to allow the reaction to proceed, the mixture was further mixed with the following dilution to prepare the back coat coating solution. (Diluted solution) Pyrogallolacetone condensation resin: 15.0 parts • Dibutyl maleate: 5.0 parts Methanol silica sol, manufactured by Nissan Chemical Industries, Ltd.: 70.0 parts DOWSIL FZ-2123, manufactured by Dow Toray Industries, Inc.: 0.1 part • Methanol: 650 parts 1-Methoxy-2-propanol: 200 parts

[0486] <Preparation of undercoat layer C> On the support C obtained above, a primer coating liquid C with the following composition is applied at a dry coating rate of 26 mg / m². 2 The coat was applied in such a manner to form the base coat layer C. -Primer coating liquid C- • Undercoat compound (2) (structure shown below): 0.13 parts Hydroxyethyliminodiacetic acid: 0.05 parts • Ethylenediaminetetraacetate tetrasodium: 0.05 parts • Polyoxyethylene lauryl ether: 0.03 parts ·Wednesday: 61.39 parts

[0487] [ka]

[0488] <Fabrication of Image Recording Layer C> An image recording layer coating solution C with the following composition was applied in a bar onto the undercoat layer C, and then oven-dried at 100°C for 60 seconds to form an image recording layer C with a thickness of 1.2 μm. -Image recording layer coating liquid C- • Binder polymer (1) (structure shown below) 23% by mass of 1-methoxy-2-propanol solution: 0.3750 parts • Binder polymer (2) (structure shown below) 23% by mass of 1-methoxy-2-propanol solution: 0.3834 parts • Infrared absorber (1) (structure shown below): 0.0185 parts • Borate compound (1) (sodium tetraphenylborate): 0.0040 parts • Polymerization initiator (1) (structure shown below): 0.1250 parts • Polymerizable compound (1) (Tris(acryloyloxyethyl) isocyanurate, NK Ester A-9300 40% 2-butanone solution, manufactured by Shin-Nakamura Chemical Industry Co., Ltd.): 0.2050 parts • Low molecular weight hydrophilic compound (1) (tris(2-hydroxyethyl) isocyanurate): 0.0287 parts • Low molecular weight hydrophilic compound (2) (trimethylglycine): 0.0147 parts • 30% by mass aqueous solution of anionic surfactant 1 (structure shown below): 0.240 parts • UV absorber (1) (TINUVIN405, manufactured by BASF Ltd.) (structure shown below): 0.040 parts ·Polymer (A-3): 0.0042 parts • Phosphonium compound (1) (structure shown below): 0.025 parts • Ammonium group-containing polymer (1) (structure shown below, reduced viscosity 44 ml / g): 0.030 parts Benzyldimethyloctylammonium PF6 salt: 0.023 parts 2-Butanone: 5,391 parts • 1-Methoxy-2-propanol: 3.154 parts Methanol: 1.117 parts • Microgel solution 1:2.843 parts

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[0490] [ka]

[0491] [ka]

[0492] <Synthesis of Binder Polymer (1)> 78.0 g of 1-methoxy-2-propanol was weighed into a three-necked flask and heated to 70°C under a nitrogen stream. A mixed solution consisting of 52.1 g of Bremmer PME-100 (methoxydiethylene glycol monomethacrylate, manufactured by NOF Corporation), 21.8 g of methyl methacrylate, 14.2 g of methacrylic acid, 2.15 g of hexakis(3-mercaptopropionic acid) dipentaerythritol, 0.38 g of V-601 (2,2'-azobis(isobutyrate)dimethyl, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), and 54 g of 1-methoxy-2-propanol was added dropwise over 2 hours and 30 minutes. After the addition was complete, the temperature was raised to 80°C and the reaction was continued for another 2 hours. A mixed solution consisting of 0.04 g of V-601 and 4 g of 1-methoxy-2-propanol was added, and the reaction was continued at 90°C for 2.5 hours. After the reaction was complete, the reaction solution was cooled to room temperature. To the above reaction solution, 137.2g of 1-methoxy-2-propanol, 0.24g of 4-hydroxytetramethylpiperidine-N-oxide, 26.0g of glycidyl methacrylate, and 3.0g of tetraethylammonium bromide were added and the mixture was thoroughly stirred, then heated at 90°C. After 18 hours, the reaction solution was cooled to room temperature (25°C) and then diluted with 99.4 g of 1-methoxy-2-propanol. The binder polymer (1) obtained in this way had a solid content concentration of 23% by mass, and a polystyrene-equivalent weight-average molecular weight measured by GPC was 35,000.

[0493] [ka]

[0494] <Synthesis of Binder Polymer (2)> 78.00 g of 1-methoxy-2-propanol was weighed into a three-necked flask and heated to 70°C under a nitrogen stream. A mixed solution consisting of 65.8 g of Bremmer PME-100 (methoxydiethylene glycol monomethacrylate, manufactured by NOF Corporation), 28.4 g of methyl methacrylate, 2.8 g of methacrylic acid, 6.4 g of hexakis(3-mercaptopropionic acid) dipentaerythritol, 1.1 g of V-601 (2,2'-azobis(isobutyrate)dimethyl, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), and 55 g of 1-methoxy-2-propanol was added dropwise to this reaction vessel over 2 hours and 30 minutes. After the addition was complete, the temperature was raised to 80°C and the reaction was continued for another 2 hours. After 2 hours, a mixed solution consisting of V-601:0.11g and 1-methoxy-2-propanol:1g was added, and the temperature was raised to 90°C and the reaction was continued for 2.5 hours. After the reaction was complete, the reaction solution was cooled to room temperature. To the above reaction solution, 177.2g of 1-methoxy-2-propanol, 0.28g of 4-hydroxytetramethylpiperidine-N-oxide, 46.0g of glycidyl methacrylate, and 3.4g of tetrabutylammonium bromide were added and the mixture was thoroughly stirred, then heated at 90°C. After 18 hours, the reaction solution was cooled to room temperature (25°C), and then diluted with 0.06 g of 4-methoxyphenol and 114.5 g of 1-methoxy-2-propanol. The binder polymer (2) thus obtained had a solid content concentration of 23% by mass, and a polystyrene-equivalent weight-average molecular weight measured by GPC was 50,000.

[0495] [ka]

[0496] <Fabrication of protective layer C> A protective layer coating solution C with the following composition was applied in a bar onto the image recording layer C, and the mixture was oven-dried at 120°C for 60 seconds to form a protective layer C with a thickness of 0.15 μm. -Coating liquid C for protective layer- Inorganic layered compound dispersion (1): 1.799 parts Hydrophilic polymer (1) (20% aqueous solution of the following compound): 0.264 parts Polyvinyl alcohol (CKS50, manufactured by Nippon Synthetic Chemical Industry Co., Ltd., sulfonic acid modified, saponification degree 99 mol% or higher, degree of polymerization 300) 6% by mass aqueous solution: 0.012 parts Polyvinyl alcohol (PVA-405, manufactured by Kuraray Co., Ltd., degree of saponification 81.5 mol%, degree of polymerization 500) 6% by mass aqueous solution: 0.001 parts Rapizole A-80 (anionic surfactant, manufactured by NOF Corporation, 80% aqueous solution): 0.145 parts Ion-exchanged water: 5.3379 parts

[0497] [ka]

[0498] (Preparation of inorganic layered compound dispersion (1)) A dispersion of inorganic layered compounds (1) was prepared by adding 6.4 parts of synthetic mica Somasif ME-100 (manufactured by Coop Chemical Co., Ltd.) to 193.6 parts of deionized water and dispersing the mixture using a homogenizer until the volume-average particle size (laser scattering method) was 3 μm. The aspect ratio of the dispersed particles was 100 or greater.

[0499] (Example 12) The lithographic printing plate of Example 12 has the following image recording layer D and the following protective layer D on the surface of the support C and undercoat layer C, similar to Example 11.

[0500] <Fabrication of Image Recording Layer D> As in Example 10, a coating liquid D for the image recording layer with the following composition was applied in a bar onto the above-mentioned undercoat layer C, and the mixture was oven-dried at 100°C for 60 seconds to form an image recording layer D with a thickness of 1.2 μm. -Coating solution D for image recording layer- • 23% by mass of binder polymer (1) (the structure described above) in 1-methoxy-2-propanol solution: 0.2891 parts • 23% by mass of binder polymer (3) (structure shown below) in 1-methoxy-2-propanol solution: 0.4574 parts • Infrared absorber (1) (structure shown below): 0.0278 parts • Borate compound (1) (sodium tetraphenylborate): 0.015 parts • Polymerization initiator (1) (structure shown below): 0.2348 parts • Polymerizable compound (1) (Tris(acryloyloxyethyl) isocyanurate, NK ester A-9300 40% 2-butanone solution, manufactured by Shin-Nakamura Chemical Industry Co., Ltd.): 0.2875 parts • Low molecular weight hydrophilic compound (1) (tris(2-hydroxyethyl) isocyanurate): 0.0287 parts • Low molecular weight hydrophilic compound (2) (trimethylglycine): 0.0147 parts • Anionic surfactant 1 30% by mass aqueous solution (structure shown below): 0.25 parts • UV absorber (1) (TINUVIN405, manufactured by BASF Ltd.) (structure shown below): 0.04 parts ·Polymer (A-3): 0.0042 parts • Phosphonium compound (1) (structure shown below): 0.020 parts 2-Butanone: 5,346 parts • 1-Methoxy-2-propanol: 3.128 parts · Methanol: 0.964 parts ·Pure water: 0.036 part • 1:2.8000 parts of the above microgel solution

[0501] <Synthesis of Binder Polymer (3)> 78.00 g of 1-methoxy-2-propanol was weighed into a three-necked flask and heated to 70°C under a nitrogen stream. A mixed solution consisting of 52.8 g of Bremmer PME-100 (methoxydiethylene glycol monomethacrylate, manufactured by Nippon Oil & Fats Co., Ltd.), 2.8 g of methyl methacrylate, 25.0 g of methacrylic acid, 6.4 g of hexakis(3-mercaptopropionic acid) dipentaerythritol, 1.1 g of V-601 (2,2'-azobis(isobutyrate)dimethyl, manufactured by Wako Pure Chemical Industries, Ltd.), and 55 g of 1-methoxy-2-propanol was added dropwise to this reaction vessel over 2 hours and 30 minutes. After the addition was complete, the temperature was raised to 80°C and the reaction was continued for another 2 hours. After 2 hours, a mixed solution consisting of V-601:0.11g and 1-methoxy-2-propanol:1g was added, and the temperature was raised to 90°C and the reaction was continued for 2.5 hours. After the reaction was complete, the reaction solution was cooled to room temperature. To the above reaction solution, 177.2g of 1-methoxy-2-propanol, 0.28g of 4-hydroxytetramethylpiperidine-N-oxide, 46.0g of glycidyl methacrylate, and 3.4g of tetrabutylammonium bromide were added and the mixture was thoroughly stirred, then heated at 90°C. After 18 hours, the reaction solution was cooled to room temperature (25°C), and then diluted with 0.06 g of 4-methoxyphenol and 114.5 g of 1-methoxy-2-propanol. The binder polymer (3) thus obtained had a solid content concentration of 23% by mass, and a polystyrene-equivalent weight-average molecular weight measured by GPC was 15,000.

[0502] [ka]

[0503] <Formation of protective layer D> A protective layer coating solution D with the following composition was applied in a bar onto the image recording layer D, and the layer was oven-dried at 120°C for 60 seconds to form a protective layer D with a thickness of 0.18 μm. -Protective coating liquid D- • Inorganic layered compound dispersion (1) (the above dispersion): 2.212 parts • Polyvinyl alcohol (Goselan® L-3266, manufactured by Nippon Synthetic Chemical Industry Co., Ltd., sulfonic acid modified, saponification degree 85 mol%) 6% by mass aqueous solution: 1,440 parts • Phosphoric acid: 0.020 parts • Diammonium phosphate: 0.032 parts • Surfactant (Pionin A-32-B (see below), manufactured by Takemoto Oil Co., Ltd.) 40% by mass aqueous solution: 0.014 parts • Surfactant (Surfinol 465®, manufactured by Nisshin Chemical Co., Ltd.): 0.006 parts • Pure water: 3.955 parts

[0504] (Example 18) The lithographic printing plate of Example 18 has, on the support J described below, an undercoat layer C, the image recording layer J described below, and a protective layer D, the same as in Example 12.

[0505] <Preparation of support J> A support C was manufactured by subjecting a 0.3 mm thick aluminum plate (aluminum alloy plate) of material 1S to the following process. Water washing was performed between all processing steps, and after the water washing, liquid was removed using a nip roller.

[0506] (Mechanical surface roughening treatment (brush grain method)) Using the apparatus shown in Figure 5, a pumice suspension (specific gravity 1.1 g / cm³) was prepared. 3 While supplying the polishing slurry liquid to the surface of the aluminum plate, mechanical surface roughening treatment was performed using a rotating bundled brush. In Figure 5, 1 is the aluminum plate, 2 and 4 are roller-shaped brushes (bundled brushes in this embodiment), 3 is the polishing slurry liquid, and 5, 6, 7 and 8 are support rollers. In the mechanical surface roughening treatment, the median diameter (μm) of the abrasive material was set to 30 μm, the number of brushes to 4, and the brush rotation speed (rpm: revolutions / minute, the same applies hereafter) to 250 rpm. The material of the bundled brush was 6-10 nylon, with a bristle diameter of 0.3 mm and a bristle length of 50 mm. The brush was densely packed into a φ300 mm stainless steel cylinder with holes drilled in it. The distance between the two support rollers (φ200 mm) at the bottom of the bundled brush was 300 mm. The bundled brush was pressed against the aluminum plate until the load on the drive motor that rotated the brush was 10 kW more than the load before the bundled brush was pressed against the aluminum plate. The direction of brush rotation was the same as the direction of movement of the aluminum plate.

[0507] (Alkaline etching treatment) An aluminum plate was etched by spraying it with an aqueous solution of caustic soda containing 26% by mass of caustic soda and 6.5% by mass of aluminum ions at a temperature of 70°C. The amount of aluminum dissolved in the surface to be subsequently subjected to electrochemical roughening treatment was 10 g / m². 2 That was the case.

[0508] (Desmat treatment using acidic aqueous solution) As an acidic aqueous solution, waste nitric acid used in the subsequent electrochemical surface roughening treatment was sprayed onto an aluminum plate for 3 seconds at a liquid temperature of 35°C to perform the desmatt treatment.

[0509] (Electrochemical surface roughening treatment using nitric acid aqueous solution) A continuous electrochemical surface roughening treatment was performed using a 60 Hz AC voltage. The electrolyte used was an aqueous solution of 10.4 g / L nitric acid to which aluminum nitrate was added to adjust the aluminum ion concentration to 4.5 g / L, at a liquid temperature of 35°C. The AC power waveform is shown in Figure 6, with a current value travel time tp of 0.8 msec, a duty cycle of 1:1, and a trapezoidal rectangular wave AC. Electrochemical surface roughening was performed using a carbon electrode as the counter electrode. A ferrite anode was used as the auxiliary anode. The electrolytic cell shown in Figure 5 was used. The current density was 30 A / dm² at the peak current value. 25% of the current flowing from the power supply was diverted to the auxiliary anode. Electrical quantity (C / dm 2 ) is the total amount of electric charge when the aluminum plate is at anode, which is 185 C / dm 2 That was the case.

[0510] (Alkaline etching treatment) An aluminum plate was etched by spraying it with an aqueous solution of caustic soda containing 27% by mass of caustic soda and 2.5% by mass of aluminum ions at a temperature of 50°C. The amount of aluminum dissolved was 3.5 g / m². 2 That was the case.

[0511] (Desmat treatment using acidic aqueous solution) As an acidic aqueous solution, a solution with a sulfuric acid concentration of 170 g / L and an aluminum ion concentration of 5 g / L at a liquid temperature of 30°C was sprayed onto an aluminum plate for 3 seconds to perform the desmatt treatment.

[0512] (Electrochemical surface roughening treatment using hydrochloric acid solution) A continuous electrochemical surface roughening treatment was performed using a 60 Hz AC voltage. The electrolyte used was a 6.2 g / L aqueous solution of hydrochloric acid to which aluminum chloride was added to adjust the aluminum ion concentration to 4.5 g / L, at a liquid temperature of 35°C. The AC power waveform is shown in Figure 6, with a current value travel time tp of 0.8 msec, a duty cycle of 1:1, and a trapezoidal rectangular wave AC. Electrochemical surface roughening was performed using a carbon electrode as the counter electrode. A ferrite anode was used as the auxiliary anode. The electrolytic cell shown in Figure 7 was used. The current density was 25 A / dm² at the peak current value. 2 Therefore, the amount of electricity in hydrochloric acid electrolysis (C / dm 2 ) is the total amount of electricity when the aluminum plate is at anode, which is 63C / dm 2 That was the case.

[0513] (Alkaline etching treatment) An aluminum plate was etched by spraying it with an aqueous solution of caustic soda containing 5% by mass of caustic soda and 0.5% by mass of aluminum ions at a temperature of 60°C. The amount of aluminum dissolved was 0.2 g / m². 2 That was the case.

[0514] (Desmat treatment using acidic aqueous solution) As an acidic aqueous solution, a solution of waste liquid (sulfuric acid concentration 170 g / L and aluminum ion concentration 5 g / L) generated in an anodizing process at a liquid temperature of 35°C was sprayed onto an aluminum plate for 4 seconds to perform the desmatt treatment.

[0515] (First stage: anodic oxidation treatment) The first stage of anodic oxidation was performed using a DC electrolytic anodic oxidation apparatus with the structure shown in Figure 6. A 170 g / L sulfuric acid aqueous solution was used as the electrolyte, with a liquid temperature of 50°C and a current density of 30 A / dm². 2 Anodizing treatment was performed under the following conditions, resulting in a film thickness of 0.3 g / m². 2 An anodic oxide film was formed.

[0516] (Pore-wide processing) An anodized aluminum plate was immersed in a caustic soda aqueous solution with a caustic soda concentration of 5% by mass and an aluminum ion concentration of 0.5% by mass for 3 seconds at 40°C to perform a pore widening treatment.

[0517] (Second stage: Anodizing treatment) The second stage of anodic oxidation was performed using a DC electrolytic anodic oxidation apparatus with the structure shown in Figure 6. A 170 g / L sulfuric acid aqueous solution was used as the electrolyte, with a liquid temperature of 50°C and a current density of 13 A / dm². 2 Anodizing treatment was performed under the following conditions, resulting in a film thickness of 2.6 g / m². 2 An anodic oxide film was formed.

[0518] (Hydrophilic treatment) To ensure hydrophilicity in the non-image areas, the aluminum plate was silicate-treated by immersing it in a 2.5% by mass sodium silicate aqueous solution at 50°C for 7 seconds. The amount of Si deposited was 8.5 mg / m². 2The average diameter of the micropores was 30 nm.

[0519] (Formation of backcourt B) As described above, the back surface of the support (the side opposite to the side with the image recording layer) was coated with the back coat coating liquid B shown below using a bar coater, dried at 100°C for 120 seconds, and a back coat with a thickness of 1.2 μm was obtained to obtain an aluminum support J.

[0520] (Back coat application solution B) • Mitsubishi Chemical BR-605 (acrylic resin) 11.072 units • 0.500 parts of Smecton-SEN (flat particle), manufactured by Kunimine Industries Co., Ltd. • Manufactured by Negami Kogyo, acrylic particles Art Pearl J-6PF, 0.975 parts • Kao Corporation's Leodol TW-S106V (Polyoxyethylene (6) Sorbitan) Monostearate) 0.250 units 2-Butanone 74.123 units 1-Methoxy-2-propanol 8,720 parts • Methanol 4,360 parts The above components were mixed and stirred to prepare backcoat coating solution B.

[0521] <Fabrication of Image Recording Layer J> As in Example 10, an image recording layer coating liquid J with the following composition was applied in a bar onto the above-mentioned undercoat layer C, and the mixture was oven-dried at 100°C for 60 seconds to form an image recording layer J with a thickness of 1.1 μm.

[0522] -Image recording layer coating liquid J- • Binder polymer (2) (the above structure) 23% by mass of 1-methoxy-2-propanol solution: 1.5185 parts • Infrared absorbent (Dye-5) (structure shown below): 0.0322 parts • Borate compound (1) (sodium tetraphenylborate): 0.0375 parts · • Polymerizable compound (1) (Tris(acryloyloxyethyl) isocyanurate, NK Ester A-9300 40% 2-butanone solution, manufactured by Shin-Nakamura Chemical Industry Co., Ltd.): 0.6721 parts ·Polymerizable compound (M-4, 70%): 0.1280 parts • 30% by mass aqueous solution of anionic surfactant 1 (structure shown below): 0.25 parts • Hydrogen donor (P-1) (structure shown below): 0.0477 parts ·Polymer (A-3): 0.0020 part 2-Butanone: 5,579 parts • 1-Methoxy-2-propanol: 2,600 parts Methanol: 1.283 parts ·Pure water: 0.681 part • Microgel solution 2:1.22 parts

[0523] [ka]

[0524] [ka]

[0525] -Preparation of Microgel Solution 2- 1-methoxy-2-propanol was added to the aforementioned microgel solution 1 to adjust the solid content concentration to 17.2%, thereby obtaining microgel solution 2.

[0526] <Formation of protective layer D> A protective layer coating liquid D of the above composition was applied to the image recording layer J using a bar coating method, and the mixture was oven-dried at 120°C for 60 seconds to form a protective layer D with a thickness of 0.18 μm. A lithographic printing plate of Example 18 was obtained, having the same undercoat layer C as in Example 11, the image recording layer J, and the same protective layer D as in Example 12, on the support J.

[0527] The lithographic printing plate original of Example 18 was cut using a rotary blade as shown in Figure 4, adjusting the gap between the upper and lower cutting blades, the amount of engagement, and the blade tip angle to form a droop shape at the end. In Figure 3, the sag shape was defined as follows: the sag amount X, which is the distance from the upper end of the end face 100c of the lithographic printing plate 100 to the intersection of the extension line of the end face 100c and the extension line of the image recording layer surface 100a, was set to 50; and the sag width Y, which is the distance from the point where the image recording layer surface 100a of the lithographic printing plate 100 begins to sag to the aforementioned intersection, was set to 180.

[0528] <Evaluation of lithographic printing plates> 1. Evaluation of the transfer suppression properties of the image recording layer. The created lithographic printing plate was processed to 5cm x 30cm. A 7cm x 30cm stainless steel plate was brought into contact with the surface of the image recording layer of a lithographic printing plate. The plate was then passed through a metal nip roll, which had been plated with hard chromium and polished to a smooth finish, under a pressure of 40 MPa. After repeating this operation five times, the components adhering to the contact surface between the image recording layer and the stainless steel plate were extracted with a 1 / 1 acetone / methanol mixture, and the amount of adhering components was quantified by high-performance liquid chromatography (extraction area: 60cm²). 2 (Extraction solution volume: 5 mL). The column used was Mightysil RP-18GP 250-3.0 (5 μm) manufactured by Kanto Chemical Co., Ltd., the detector was SPD-M20A manufactured by Shimadzu Corporation, and the eluent was a mixture of pure water and methanol. 0.1% acetic acid and 0.1% triethylamine were added to the eluent as buffers. The analysis was performed under conditions of column temperature 40°C and flow rate 0.5 mL / min. -Evaluation Criteria- 5: The total amount of adhering components is 0.5 mg / m². 2 less than 4: The total amount of adhering components is 0.5 mg / m². 2 More than 1.0mg / m 2 less than 3: The total amount of adhering components is 1.0 mg / m² 2 More than 2.0mg / m 2 less than 2: The total amount of adhering components is 2.0 mg / m² 2 More than 5.0mg / m 2 less than 1: The total amount of adhering components is 5.0 mg / m². 2 That's all. The results are shown in Table 1 below. According to the above evaluation criteria, a score of 3 or higher is considered acceptable for practical use, while a score of 4 or 5 is preferred. Note that in Table 1, the item name will be written as "Recording Layer Transfer Inhibition."

[0529] 2. Evaluation of on-board development capabilities The prepared lithographic printing plates were exposed to a Kodak Magnus 800 Quantum equipped with an infrared semiconductor laser under the following conditions: output power of 27W, external drum rotation speed of 450rpm, and resolution of 2,400dpi (dots per inch, 1 inch = 2.54cm) (irradiation energy equivalent to 110mJ / cm2). The exposed images included both solid images and a chart with 50% AM screen (Amplitude Modulation Screen) halftone dots. The resulting exposed master plate was mounted on the cylinder of a Heidelberg SX-74 printing press (Kikuban size) without any development process. A 100L dampening solution circulation tank with a built-in nonwoven fabric filter and temperature control device was connected to the press. 80L of 2.0% dampening solution S-Z1 (manufactured by Fujifilm Corporation) was placed in the circulation system, and T&K UV OFS K-HS Sumi GE-M (manufactured by T&K TOKA Corporation) was used as the printing ink. After supplying the dampening solution and ink using the standard automatic printing start method, 200 sheets were printed on Tokubishi Art Paper (basis weight: 76.5kg, manufactured by Mitsubishi Paper Mills Ltd.) at a printing speed of 10,000 sheets per hour. In the above-mentioned on-press development process, the number of sheets of printing paper required to reach a state where ink no longer transfers to the non-image areas (hereinafter also referred to as the number of sheets to be developed on press) was determined. A lower number of sheets to be developed indicates better on-press development performance. In the above-mentioned on-press development process, the number of sheets of printing paper required to reach a state where ink no longer transfers to the non-image areas was determined as the on-press development performance. A lower number of sheets indicates better on-press development performance. -Evaluation Criteria- 5: Less than 10 photos developed on board. 4: Number of prints to be developed on board: 10 or more but less than 15 3: Number of prints to be developed on board: 15 or more but less than 20 2: Number of photos to be developed on board: 20 or more but less than 30 1: More than 30 prints to be developed on board. The results are shown in Table 1 below. In the above evaluation criteria, a level of 4 or 5 indicates a level that poses no practical problems.

[0530] The layer configuration of each lithographic printing plate and the evaluation results described above are shown in Table 1 below.

[0531] [Table 1]

[0532] As is clear from Table 1, the lithographic printing plates of the examples showed better transfer suppression of the image recording layer and better on-press development compared to the lithographic printing plates of the comparative examples.

[0533] (Examples 13 to 15, and Comparative Examples 5 and 6) The lithographic printing plates for Examples 13 to 15, as well as Comparative Examples 5 and 6, were prepared with the layer configurations shown in Table 2.

[0534] <Preparation of support E> A support for lithographic printing plates was manufactured by subjecting a 0.3 mm thick aluminum alloy plate of material 1S to the processes described below (Ea) to (Ek). Water washing was performed between all processing steps, and after water washing, the liquid was removed using a nip roller.

[0535] (Ea) Mechanical surface roughening treatment (brush grain method) Pumice suspension (specific gravity 1.1 g / cm³) 3 While supplying the polishing slurry to the surface of the aluminum plate, mechanical surface roughening treatment was performed using a rotating bundled brush. The median diameter (μm) of the abrasive material was set to 30 μm, the number of brushes to 4, and the brush rotation speed (rpm: revolutions / minute) to 250 rpm. The material of the bundled brush was 6,10 nylon, with a bristle diameter of 0.3 mm and a bristle length of 50 mm. The brush was densely planted in a φ300 mm stainless steel cylinder with holes drilled in it. The distance between the two support rollers (φ200 mm) at the bottom of the bundled brush was 300 mm. The bundled brush was pressed against the aluminum plate until the load on the drive motor that rotates the brush was 10 kW more than the load before the bundled brush was pressed against the aluminum plate. The direction of brush rotation was the same as the direction of movement of the aluminum plate.

[0536] (Eb) Alkaline etching treatment The aluminum plate obtained above was etched by spraying an aqueous solution of caustic soda with a concentration of 26% by mass of caustic soda and an aluminum ion concentration of 6.5% by mass onto it using a spray tube at a temperature of 70°C. Afterward, it was rinsed with water using a spray. The amount of aluminum dissolved was 10 g / m². 2 That was the case.

[0537] (Ec) Desmat treatment in acidic aqueous solution Next, a desmatt treatment was performed in an aqueous nitric acid solution. The aqueous nitric acid solution used for the desmatt treatment was the waste liquid from the electrochemical surface roughening process in the next step. The temperature of the solution was 35°C. The desmatt solution was sprayed onto the surface and the treatment was performed for 3 seconds.

[0538] (Ed) Electrochemical roughening treatment Electrochemical surface roughening was continuously performed using a 60Hz AC voltage with nitric acid electrolysis. The electrolyte used was an aqueous solution of 10.4g / L nitric acid at 35°C, to which aluminum nitrate was added to adjust the aluminum ion concentration to 4.5g / L. The AC power supply waveform used was a trapezoidal rectangular wave AC with a current peak time tp of 0.8msec, a duty cycle of 1:1, and a carbon electrode as the counter electrode. Ferrite was used as the auxiliary anode. The current density was 30A / dm2 at the peak current value, and 5% of the current flowing from the power supply was diverted to the auxiliary anode. 2 The total amount of electric charge on the aluminum plate at anode was 185 C / dm2. Afterward, it was washed with water using a spray.

[0539] (Ee) Alkali etching treatment The aluminum plate obtained above was etched by spraying an aqueous solution of caustic soda with a concentration of 5% by mass of caustic soda and an aluminum ion concentration of 0.5% by mass onto it using a spray tube at a temperature of 50°C. Afterward, it was rinsed with water using a spray. The amount of aluminum dissolved was 0.5 g / m2.

[0540] (Ef) Desmat treatment in acidic aqueous solution Next, a desmatt treatment was performed in an aqueous sulfuric acid solution. The aqueous sulfuric acid solution used for the desmatt treatment had a sulfuric acid concentration of 170 g / L and an aluminum ion concentration of 5 g / L. The temperature of the solution was 30°C. The desmatt solution was sprayed and the desmatt treatment was performed for 3 seconds.

[0541] (Eg) Electrochemical surface roughening treatment Electrochemical surface roughening was continuously performed using hydrochloric acid electrolysis with a 60 Hz AC voltage. The electrolyte used was an aqueous solution of 6.2 g / L hydrochloric acid at a liquid temperature of 35°C, to which aluminum chloride was added to adjust the aluminum ion concentration to 4.5 g / L. Electrochemical surface roughening was performed using a trapezoidal rectangular wave AC current with a current value of 0.8 msec (tp) from zero to peak, a duty cycle of 1:1, and a carbon electrode as the counter electrode. Ferrite was used as the auxiliary anode. The current density is 25 A / dm² at the peak current value. 2 Therefore, the amount of electricity (C / dm2) in hydrochloric acid electrolysis is 63 C / dm2, which is the sum of the amounts of electricity when the aluminum plate is the anode. 2 That was the case. Afterwards, it was rinsed with water using a spray bottle.

[0542] (Eh) Alkali etching treatment The aluminum plate obtained above was etched by spraying an aqueous solution of caustic soda with a concentration of 5% by mass of caustic soda and an aluminum ion concentration of 0.5% by mass onto it using a spray tube at a temperature of 50°C. Afterward, it was rinsed with water using a spray. The amount of aluminum dissolved was 0.1 g / m². 2 That was the case.

[0543] (Ei) Desmat treatment in acidic aqueous solution Next, a desmatt treatment was performed in an aqueous sulfuric acid solution. Specifically, waste liquid generated in the anodizing process (5 g / L of aluminum ions dissolved in 170 g / L aqueous sulfuric acid solution) was used, and the desmatt treatment was performed at a liquid temperature of 35°C for 4 seconds. The desmatt solution was sprayed and the desmatt treatment was performed for 3 seconds.

[0544] (Ej) Anodizing treatment Anodizing was performed using a two-stage electrolytic anodizing apparatus (6m each for the first and second electrolytic sections, 3m each for the first and second power supply sections, and 2.4m each for the first and second supply electrode sections). Sulfuric acid was used as the electrolyte supplied to the first and second electrolytic sections. Both electrolytes had a sulfuric acid concentration of 50g / L (containing 0.5% by mass of aluminum ions) and were heated to 20°C. Afterwards, the samples were rinsed with water using a spray.

[0545] (Ek) Silicate treatment To ensure hydrophilicity in the non-image areas, silicate treatment was performed by dipping the sample in a 2.5% by mass aqueous solution of sodium silicate no. 3 at 50°C for 7 seconds. The amount of Si deposited was 10 mg / m². 2 That was the case. Afterwards, it was rinsed with water using a spray bottle.

[0546] <Preparation of undercoat layer E> As described above, the primer coating liquid E shown below was applied to the support E, which was then dried at 80°C for 15 seconds to form a primer layer and complete the support. The coating amount after drying was 15 mg / m2. -Undercoat coating liquid E- • The following copolymer with a weight-average molecular weight of 28,000: 0.3 parts · Methanol: 100 parts ·Wed: 1 part

[0547] [ka]

[0548] <Fabrication of the image recording layer E> Apply the undercoat forming liquid composition E, with the following composition, onto the undercoat layer E using a wire bar, and dry i...

Claims

1. A support, and an image recording layer having been placed on the support. The image recording layer comprises polymer A having a main chain containing two or more silicon atoms and a hydrophilic group. Planographic printing plate original plate.

2. The lithographic printing plate according to claim 1, wherein the polymer A has hydrophilic groups in at least one of the side chains and the ends of the main chain.

3. The lithographic printing plate according to claim 2, wherein the polymer A has hydrophilic groups in its side chains.

4. The lithographic printing plate according to claim 2, wherein the hydrophilic group of polymer A is at least one selected from the group consisting of a hydroxyl group, an amine group, a carboxyl group, a carbinol group, an alkylamino group, a (poly)ether group, a (poly)glycerol group, a (poly)ester group, and a (poly)amide group.

5. The lithographic printing plate according to claim 1, wherein the polymer A is a polymer represented by the following formula (A). 【Chemistry 1】 In formula (A), W represents a hydrophilic group, x represents the number of bonds in the dimethylsiloxane structural unit and is in the range of 0 or more, and y represents the number of bonds in the siloxane structural unit having a hydrophilic group in its side chain and is in the range of 1 or more. The bonding order between the dimethylsiloxane structural unit and the siloxane structural unit having a hydrophilic group in its side chain in formula (A) may be in a block or random order.

6. The lithographic printing plate according to claim 1, wherein the image recording layer is a negative-type photosensitive image recording layer containing a polymerizable compound and a polymerization initiator.

7. The lithographic printing plate according to claim 6, wherein the negative-type photosensitive image recording layer comprises an infrared absorber and an onium salt polymerization initiator as the polymerization initiator, and is of the on-press development type.

8. The lithographic printing plate according to claim 6, wherein the negative-type photosensitive image recording layer further comprises polymer particles and is of the on-press development type.

9. The lithographic printing plate according to claim 6, wherein the negative-type photosensitive image recording layer further comprises a chromogenic precursor and is of the on-press development type.

10. The lithographic printing plate according to claim 6, wherein the negative-type photosensitive image recording layer contains a polyfunctional polymerizable compound and is of the on-press development type.

11. The lithographic printing plate according to claim 6, wherein the negative-type photosensitive image recording layer contains a borate compound represented by the following formula (B1) and is of the on-press development type. 【Chemistry 2】 In formula (B1), R Ｂ１ ~R Ｂ４ Each of these independently represents an unsubstituted or substituted alkyl group, an unsubstituted or substituted aryl group, an unsubstituted or substituted alkenyl group, or an unsubstituted or substituted alkynyl group, R Ｂ１ ~R Ｂ４ Each of them may independently have a ring structure. However, R Ｂ１ ~R Ｂ４ At least one of them is different from the others. M ＋ This represents a cation.

12. The lithographic printing plate according to claim 1, wherein the lithographic printing plate has a protective layer on the image recording layer.

13. The lithographic printing plate according to claim 1, wherein the lithographic printing plate has an undercoat layer between the support and the image recording layer.

14. A step of exposing the lithographic printing plate according to claim 1 in the manner of an image, The process includes a step of supplying at least one selected from the group consisting of printing ink and dampening water on a printing press to remove the image recording layer in the non-image area. Method for producing lithographic printing plates.

Images