JP2020179567A - Original plate for lithographic printing plate, method of making lithographic printing plate, and lithographic printing method - Google Patents

Abstract

To provide an original plate for a lithographic printing plate that is excellent in the printing durability and scratch and stain resistance of a resultant lithographic printing plate, and a method of making a lithographic printing plate or a lithographic printing method using the original plate for a lithographic printing plate.SOLUTION: An original plate for a lithographic printing plate has a support, an image recording layer, and an outermost layer in the stated order, the image recording layer has an infrared absorber and a polymer, and the outermost layer is a continuous or non-continuous water-insoluble layer. There are also provided a method of making a lithographic printing plate or a lithographic printing method using the original plate for a lithographic printing plate.SELECTED DRAWING: None

Description

The present disclosure relates to a lithographic printing plate original plate, a method for producing a lithographic printing plate, and a lithographic printing method.

In general, a lithographic printing plate comprises a lipophilic image portion that receives ink in the printing process and a hydrophilic non-image portion that receives dampening water. In flat plate printing, utilizing the property that water and oil-based ink repel each other, the oil-based image part of the flat plate printing plate is the ink receiving part, and the hydrophilic non-image part is the dampening water receiving part (ink non-receptive part). This is a method in which a difference in the adhesiveness of ink is generated on the surface of a flat plate printing plate, the ink is inlaid only on the image portion, and then the ink is transferred to an object to be printed such as paper for printing.
In order to produce this lithographic printing plate, a lithographic printing plate original plate (PS plate) in which a lipophilic photosensitive resin layer (image recording layer) is provided on a hydrophilic support has been widely used. Normally, after the lithographic printing plate original plate is exposed through an original image such as a squirrel film, the part that becomes the image part of the image recording layer remains, and the other unnecessary image recording layer is an alkaline developer or organic. A lithographic printing plate is obtained by performing plate making by a method of dissolving and removing with a solvent to expose the surface of a hydrophilic support to form a non-image portion.

In addition, due to growing interest in the global environment, environmental issues related to waste liquids associated with wet treatments such as development treatments have been highlighted.
In response to the above environmental issues, simplification and non-processing of development or plate making are aimed at. As one of the simple manufacturing methods, a method called "on-machine development" is performed. That is, it is a method in which the lithographic printing plate original plate is exposed and then mounted on the printing machine as it is without the conventional development, and the unnecessary portion of the image recording layer is removed at the initial stage of the normal printing process.

Examples of the conventional planographic printing plate original plate include those described in Patent Document 1.
Patent Document 1 has a heat-sensitive layer containing a fine particle polymer on a support and a water-soluble overcoat layer on the heat-sensitive layer, and dynamic friction when one surface slides on another surface. An original plate for lithographic printing plates, characterized in that the coefficient is 2.5 or less, is described.

Japanese Unexamined Patent Publication No. 2001-347766

An object to be solved by the embodiment of the present invention is to provide a lithographic printing plate original plate having excellent printing resistance and scratch stain suppression of the obtained lithographic printing plate.
An object to be solved by another embodiment of the present invention is to provide a method for producing a lithographic printing plate or a lithographic printing method using the lithographic printing plate original plate.

The means for solving the above problems include the following aspects.
<1> The support, the image recording layer, and the outermost layer are provided in this order, the image recording layer contains an infrared absorber and a polymer, and the outermost layer is continuous or discontinuous. A lithographic printing plate original plate that is a water-soluble layer.
<2> The planographic printing plate original plate according to <1>, wherein the coefficient of dynamic friction of the outermost layer surface measured by a sapphire needle having a tip diameter of 0.1 mm is 0.01 to 0.05.
<3> The planographic printing plate original plate according to <1> or <2>, wherein the contact angle of water on the outermost layer surface by the aerial water droplet method is 50 ° or less.
<4> The planographic printing plate original plate according to any one of <1> to <3>, wherein the polymer is polymer particles.
<5> The planographic printing plate original plate according to any one of <1> to <4>, wherein the outermost layer contains a compound having a melting point of 50 ° C. to 150 ° C.
<6> The planographic printing plate original plate according to <5>, wherein the compound having a melting point of 50 ° C. to 150 ° C. has a molecular weight of 300 to 1,000.
<7> The planographic printing plate original plate according to any one of <1> to <6>, wherein the outermost layer contains a compound having 12 to 22 carbon atoms.
<8> The planographic printing plate original plate according to <7>, wherein the compound having 12 to 22 carbon atoms has a molecular weight of 300 to 1,000.
<9> The planographic printing plate original plate according to any one of <1> to <8>, wherein the outermost layer contains a compound having two or more hydroxy groups.
<10> The support is an aluminum support having an anodized film on the surface on the image recording layer side, and the average thickness of the anodized film is 0.5 μm to 3.0 μm <1>. The planographic printing plate original plate according to any one of <9>.
<11> The planographic printing plate original plate according to any one of <1> to <10>, wherein the polymer contains a polymer having a hydrophilic structure.
<12> The planographic printing plate original plate according to <11>, wherein the hydrophilic structure contains a structural unit represented by the following formula (AN) or a group represented by the following formula Z.
* -Q-W-Y 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, and Y represents a monovalent group having a hydrophilic structure. Represented, either W or Y has a hydrophilic structure, and * represents a binding site with another structure.

In formula (AN), ^RAN represents a hydrogen atom or a methyl group.

<13> The lithographic printing plate original plate according to any one of <1> to <12>, wherein the polymer contains polymer particles having a polymerizable group.
<14> The lithographic printing plate original plate according to any one of <1> to <13>, which is an on-machine development type lithographic printing plate original plate.
<15> The step of exposing the lithographic printing plate original plate according to any one of <1> to <14> like an image, and at least one selected from the group consisting of printing ink and dampening water on a printing machine. A method for producing a lithographic printing plate, which includes a step of removing an image recording layer of a non-image portion by supplying a lithographic printing plate.
<16> A step of exposing the planographic printing plate original plate according to any one of <1> to <14> to an image, and supplying at least one selected from the group consisting of printing ink and dampening water are supplied. A lithographic printing method including a step of removing an image recording layer of a non-image portion on a printing machine to produce a lithographic printing plate, and a step of printing with the obtained lithographic printing plate.

According to the embodiment of the present invention, it is possible to provide a lithographic printing plate original plate having excellent printing resistance and scratch stain suppressing property of the obtained lithographic printing plate.
Further, according to another embodiment of the present invention, it is possible to provide a method for producing a lithographic printing plate or a lithographic printing method using the lithographic printing plate original plate.

The contents of the present disclosure will be described in detail below. The description of the constituents described below may be based on the representative embodiments of the present disclosure, but the present disclosure is not limited to such embodiments.
In addition, in this specification, "~" indicating a numerical range is used in the meaning of including numerical values described before and after it as a lower limit value and an upper limit value.
In the numerical range described stepwise in the present disclosure, the upper limit value or the lower limit value described in one numerical range may be replaced with the upper limit value or the lower limit value of another numerical range described stepwise. .. Further, in the numerical range described in the present disclosure, the upper limit value or the lower limit value of the numerical range may be replaced with the value shown in the examples.
Further, in the notation of a group (atomic group) in the present specification, the notation that does not describe substitution and non-substitution includes those having no substituent as well as those having a substituent. For example, the "alkyl group" includes not only an alkyl group having no substituent (unsubstituted alkyl group) but also an alkyl group having a substituent (substituted alkyl group).
In the present specification, "(meth) acrylic" is a term used in a concept that includes both acrylic and methacrylic, and "(meth) acryloyl" is a term that is used as a concept that includes both acryloyl and methacryloyl. Is.
Further, the term "process" in the present specification is not limited to an independent process, and even if it cannot be clearly distinguished from other processes, the term "process" will be used as long as the intended purpose of the process is achieved. included. Further, in the present disclosure, "% by mass" and "% by weight" are synonymous, and "parts by mass" and "parts by weight" are synonymous.
Further, in the present disclosure, a combination of two or more preferred embodiments is a more preferred embodiment.
Unless otherwise specified, the weight average molecular weight (Mw) and the number average molecular weight (Mn) in the present disclosure use columns of TSKgel GMHxL, TSKgel G4000HxL, and TSKgel G2000HxL (all trade names manufactured by Toso Co., Ltd.). It is a molecular weight converted by detecting with a solvent THF (tetrahydrofuran) and a differential refractometer by a gel permeation chromatography (GPC) analyzer and using polystyrene as a standard substance.
In the present specification, the term "lithographic printing plate original plate" includes not only a lithographic printing plate original plate but also a discarded plate original plate. Further, the term "lithographic printing plate" includes not only a lithographic printing plate produced by subjecting a lithographic printing plate original plate through operations such as exposure and development as necessary, but also a discarded plate. In the case of a discarded original plate, exposure and development operations are not always necessary. The discard plate is a planographic printing plate original plate for attaching to an unused plate cylinder when printing a part of the paper surface in a single color or two colors in, for example, color newspaper printing.
Hereinafter, the present disclosure will be described in detail.

(Planographic printing plate original)
The planographic printing plate original plate according to the present disclosure has a support, an image recording layer, and an outermost layer in this order, the image recording layer contains an infrared absorber and a polymer, and the outermost layer is continuous. , Or a discontinuous, water-insoluble layer.
The lithographic printing plate original plate according to the present disclosure may be a negative type lithographic printing plate original plate or a positive type lithographic printing plate original plate, but is preferably a negative type lithographic printing plate original plate.
Further, the lithographic printing plate original plate according to the present disclosure can be suitably used as a lithographic printing plate original plate for on-machine development.

As a result of diligent studies by the present inventors, it has been found that by adopting the above configuration, it is possible to provide a lithographic printing plate original plate having excellent printing resistance and scratch / stain suppressing property of the obtained lithographic printing plate.
The detailed mechanism for obtaining the above effect is unknown, but it is presumed as follows.
By having a continuous or discontinuous water-insoluble layer as the outermost layer on the image recording layer side, the external force that causes scratches is dispersed and the deformation of the image recording layer is suppressed, so that the scratches and stains are suppressed. In addition to being excellent in suppressing properties, wear resistance in the image area is also improved, and printing resistance, particularly even when ultraviolet curable ink (UV ink) is used, is also referred to as "UV printing resistance". ) Is presumed to be excellent.

Further, since the outermost layer is a water-insoluble layer, the lipophilicity in the image portion is improved, the meat-forming property is excellent, and the influence on the development of the outermost layer is small, so that the on-machine developability is improved. Is also estimated to be excellent.

<Outermost layer>
The planographic printing plate original plate according to the present disclosure has a support, an image recording layer, and an outermost layer in this order, and the outermost layer is a continuous or discontinuous water-insoluble layer.
In the present disclosure, "water-soluble" means that the solubility in 100 g of water having a pH of 7.0 at 22 ° C. is 0.1 g or more, and "water-insoluble" means water having a pH of 7.0 at 22 ° C. It means that the solubility in 100 g is less than 0.1 g, the solubility is preferably less than 0.05 g, and the solubility is more preferably less than 0.01 g.

The outermost layer may be a continuous layer or a discontinuous layer, but from the viewpoint of scratch suppression, it is preferable that the outermost layer is a continuous layer, and has print resistance, fillability, and on-machine development. From the viewpoint of property and developer developability, a discontinuous layer is preferable.
Further, the discontinuous layer is preferably a sea structure in a sea island structure from the viewpoint of suppressing scratches and stains.
Further, from the viewpoint of suppressing scratches and stains, the outermost layer preferably covers the surface of the lithographic printing plate original plate on the image recording layer side by 10 area% or more and 100 area% or less, and 30 area% or more and 100 area% or less. It is more preferable to cover it, and it is particularly preferable to cover it by 50 area% or more and 100 area% or less.

In the planographic printing plate original plate according to the present disclosure, the dynamic friction coefficient of the outermost layer surface measured by a sapphire needle having a tip diameter of 0.1 mm is set to 0. It is preferably 005 to 0.06, more preferably 0.01 to 0.05, and particularly preferably 0.015 to 0.045.
The method for measuring the dynamic friction coefficient of the outermost layer surface in the present disclosure shall be the following method.
A surface measuring machine TRIBOGEAR TYPE: 18LFW (manufactured by Shinto Kagaku Co., Ltd.) scans the outermost surface of the lithographic printing plate original plate with a load of 40 g / m ² and a scanning speed of 20 mm / s using a sapphire needle 0.1 mm. , The dynamic friction coefficient at the time of scratching is calculated from the resistance force at the time of scanning.

The contact angle of water on the outermost layer surface by the aerial water droplet method is preferably 60 ° or less, more preferably 50 ° or less, and more preferably 15 °, from the viewpoint of printing resistance and scratch suppression. It is more preferably 40 ° or more, and particularly preferably 20 ° or more and 30 ° or less.
The method for measuring the contact angle of water by the aerial water droplet method on the outermost layer surface in the present disclosure shall be measured by the following method.
Using DMo-701 (manufactured by Kyowa Interface Science Co., Ltd.), the contact angle of water with respect to the outermost layer surface in the lithographic printing plate original plate is determined by the aerial water droplet method. The volume of water droplets used for the measurement is 1 μL.

The outermost layer is a water-insoluble layer, and preferably contains a water-insoluble compound (hereinafter, also referred to as “specific compound”).
The specific compound is preferably a compound having a molecular weight of 1,500 or less, and more preferably a compound having a molecular weight of 300 to 1,000, from the viewpoint of scratch-stain suppressing property, on-machine developability, and developer developability. A compound having a molecular weight of 300 to 830 is more preferable, and a compound having a molecular weight of 300 to 500 is particularly preferable.

The outermost layer preferably contains, as a specific compound, a compound having a melting point of 40 ° C. to 150 ° C. from the viewpoints of printing resistance, scratch suppression property, carving property, and on-machine developability.
The melting point of the compound having a melting point of 40 ° C. to 150 ° C. is preferably 50 ° C. to 150 ° C. from the viewpoints of printing resistance, scratch-staining inhibitory property, meat-forming property, and on-machine developability. The temperature is more preferably ° C. to 120 ° C., further preferably 60 ° C. to 100 ° C., and particularly preferably 60 ° C. to 80 ° C.
The molecular weight of the compound having a melting point of 40 ° C. to 150 ° C. is preferably 300 to 1,000 from the viewpoints of printing resistance, scratch-staining inhibitory property, meat-forming property, and on-machine developability. , 300 to 830, and particularly preferably 300 to 500.

Further, the outermost layer preferably contains a compound having 10 to 60 carbon atoms as a specific compound from the viewpoints of printing resistance, scratch suppression property, carving property, and on-machine developability, and has a carbon number of 10 to 60. It is more preferable to contain a compound having 11 to 40, and particularly preferably to contain a compound having 12 to 22 carbon atoms.
Further, the molecular weight of the compound having 12 to 22 carbon atoms is preferably 300 to 1,000 from the viewpoints of printing resistance, scratch suppression property, incarnation property, and on-machine developability. It is more preferably 300 to 830, and particularly preferably 300 to 500.

Further, the outermost layer has a melting point of 40 ° C. to 150 ° C. and a carbon number of 12 to 2 as a specific compound from the viewpoints of printing resistance, scratch suppression property, incarnation property, and on-machine developability. It is preferable to contain a compound having a melting point of 22, and more preferably to contain a compound having a melting point of 60 ° C. to 100 ° C. and a carbon number of 12 to 22, a melting point of 60 ° C. to 80 ° C. and a carbon number of carbon. It is particularly preferable to include a compound having a value of 12 to 22.

The specific compound preferably contains a compound having a hydrophilic group from the viewpoints of printing resistance, scratch suppression property, incarnation property, and on-machine developability.
As the hydrophilic group, a hydroxy group, a phosphite ester structure, a borate ester structure, or an amide group is preferable, a hydroxy group or an amide group is more preferable, and a hydroxy group is particularly preferable.
Above all, the outermost layer preferably contains, as a specific compound, a compound having two or more hydroxy groups, from the viewpoints of printing resistance, scratch suppressing property, carving property, and on-machine developability.
The compound having two or more hydroxy groups is not particularly limited, but a glyceryl monocarboxylic acid compound described later is preferably mentioned.

Specifically, as specific compounds, monocarboxylic acid glyceryl compounds, amide compounds, phosphite triester compounds, and borocarbonate compounds, from the viewpoints of printing resistance, scratch suppression property, carving property, and on-machine developability. It preferably contains at least one compound selected from the group consisting of acid triester compounds, and preferably contains at least one compound selected from the group consisting of glyceryl monocarboxylic acid compounds, amide compounds, and boric acid triester compounds. It is more preferable to contain at least one compound selected from the group consisting of a glyceryl monocarboxylic acid compound and an amide compound, and it is particularly preferable to contain a glyceryl monocarboxylic acid compound. When a glyceryl monocarboxylic acid compound is contained, it is a water-insoluble compound but has an appropriate hydrophilicity, so that it is excellent in on-machine developability, and also has excellent printing resistance, scratch-staining property, and meat-forming property. Better.
Preferable examples of the glyceryl monocarboxylic acid compound include glyceryl monostearate, glyceryl mono (hydroxystearic acid), glyceryl monolaurate, and glyceryl monocaprylate.
As the amide compound, for example, behenic acid amide, arachidic acid amide, stearic acid amide and the like are preferably mentioned.
Examples of the phosphorous acid triester compound include tristearyl phosphite, trilauryl phosphite, and tridecyl phosphite.
Examples of the boric acid triester compound include tristearyl borate, trilauryl borate, and tridecyl borate.
In addition, the monocarboxylic acid glyceryl compound, the amide compound, the phosphite triester compound, or the borate triester compound are independently of printing resistance, scratch suppression property, carving property, and on-machine developability. From the viewpoint, it is preferable to have an alkyl group having 8 to 24 carbon atoms, more preferably to have a linear alkyl group having 8 to 24 carbon atoms, and further preferably to have a linear alkyl group having 10 to 21 carbon atoms. It is particularly preferable to have a linear alkyl group having 12 to 18 carbon atoms.

The outermost layer may contain one specific compound alone or may contain two or more specific compounds.
The content of the specific compound in the outermost layer is preferably 50% by mass or more, more preferably 80% by mass or more, and particularly preferably 90% by mass or more, based on the total mass of the outermost layer. preferable.

Further, the outermost layer may contain other compounds other than the specific compound. The other compounds are not particularly limited, and examples thereof include components used for the image recording layer described later.

The amount per unit area of the outermost layer in the lithographic printing plate original plate according to the present disclosure is 5 mg / m ^{2 to} 500 mg / m from the viewpoints of printing resistance, scratch / stain suppressing property, meat-forming property, and on-machine developability. it is preferably m ^{2, and} more preferably from ^{10mg / m 2 ~200mg / m 2} , and particularly preferably ^{15mg / m 2 ~100mg / m 2} .

The maximum thickness of the outermost layer in the lithographic printing plate original plate according to the present disclosure shall be 0.5 μm or less from the viewpoints of printing resistance, scratch stain suppressing property, inking property, and on-machine developability. Is more preferable, 0.2 μm or less is more preferable, and 0.01 μm or more and 0.1 μm or less is particularly preferable.

The method for forming the outermost layer in the lithographic printing plate original plate according to the present disclosure is not particularly limited, and may be formed, for example, by applying and drying a composition containing a specific compound on the image recording layer. It is also possible to prepare a composition for forming an image recording layer containing a specific compound, apply the above composition to unevenly distribute the specific compound on the surface, and dry and form the specific compound.
Among them, a method of preparing a composition for forming an image recording layer containing a specific compound, applying the above composition, unevenly distributing the specific compound on the surface, and drying the composition to form the outermost layer is preferable.
The composition for forming an image recording layer preferably contains an organic solvent described later.
Further, the specific compound is preferably a compound having surface uneven distribution from the viewpoints of ease of formation of the outermost layer, printing resistance, scratch-staining suppressing property, meat-forming property, and on-machine developability.
When the specific compound is unevenly distributed on the surface, the specific compound is mixed with the composition for forming the image recording layer immediately before application at the time of preparing the composition for forming the image recording layer from the viewpoint of the uniformity of the outermost layer. Is preferable.

<Image recording layer>
The planographic printing plate original plate according to the present disclosure has a support, an image recording layer, and an outermost layer in this order, and the image recording layer contains an infrared absorber and a polymer.
The image recording layer used in the present disclosure is preferably a negative type image recording layer, and more preferably a water-soluble or water-dispersible negative type image recording layer.
Further, the image recording layer used in the present disclosure preferably further contains a polymerization initiator and a polymerizable compound from the viewpoint of printing resistance and photosensitivity, and is preferably an electron-accepting polymerization initiator and polymerization. It is preferable to further contain a sex compound.
Further, the image recording layer used in the present disclosure is preferably an on-board development type image recording layer.
Hereinafter, details of each component contained in the image recording layer will be described.

-Infrared absorber-
The image recording layer preferably further contains an infrared absorber. Examples of the infrared absorber include pigments and dyes.
As the dye used as the infrared absorber, commercially available dyes and known dyes described in documents such as "Dye Handbook" (edited by the Society of Synthetic Organic Chemistry, published in 1970) can be used. Specifically, dyes such as azo dyes, metal complex salt azo dyes, pyrazolone azo dyes, naphthoquinone dyes, anthraquinone dyes, phthalocyanine dyes, carbonium dyes, quinoneimine dyes, methine dyes, cyanine dyes, squarylium dyes, pyrylium salts, and metal thiolate complexes. Can be mentioned.
Particularly preferable of these dyes are cyanine pigments, squarylium pigments, pyrylium salts, nickel thiolate complexes, and indrenin cyanine pigments. Further, cyanine pigment and indorenin cyanine pigment can be mentioned. Of these, the cyanine pigment is particularly preferable.

Specific examples of the cyanine dye include the compounds described in paragraphs 0017 to 0019 of JP 2001-133939, paragraphs 0016 to 0021 of JP 2002-0233360, and paragraphs 0012 to 0037 of JP 2002-040638. , Preferably the compounds described in paragraphs 0034 to 0041 of JP-A-2002-278057, paragraphs 0080 to 0083 of JP-A-2008-195018, and particularly preferably paragraphs 0035 of JP-A-2007-90850. The compounds described in ~ 0043, the compounds described in paragraphs 0105 to 0113 of JP2012-206495A can be mentioned.
Further, the compounds described in paragraphs 0008 to 0009 of JP-A-5-5005 and paragraphs 0022 to 0025 of JP-A-2001-222101 can also be preferably used.
As the pigment, the compounds described in paragraphs 0072 to 0076 of JP-A-2008-195018 are preferable.
Further, an infrared absorber that decomposes by infrared exposure (also referred to as "degradable infrared absorber") can be preferably used.
As the infrared absorber that decomposes by infrared exposure, those described in Japanese Patent Publication No. 2008-544322, International Publication No. 2016/027886, International Publication No. 2017/141882, or International Publication No. 2018/0432559 are preferable. Can be used for.

Only one type of infrared absorber may be used, or two or more types may be used in combination. Further, a pigment and a dye may be used in combination as an infrared absorber.
The content of the infrared absorber in the image recording layer is preferably 0.1% by mass to 10.0% by mass, more preferably 0.5% by mass to 5.0% by mass, based on the total mass of the image recording layer. preferable.

-Polymer-
The image recording layer contains a polymer.
The polymer preferably contains a binder polymer.
As the polymer, a (meth) acrylic resin, a polyvinyl acetal resin, or a polyurethane resin is preferable.

Above all, as the polymer, a known binder polymer used for the image recording layer of the lithographic printing plate original plate can be preferably used. As an example, a binder polymer (hereinafter, also referred to as a binder polymer for on-machine development) used in a machine-developed planographic printing plate original plate will be described in detail.
As the binder polymer for on-machine development, a binder polymer having an alkylene oxide chain is preferable. The binder polymer having an alkylene oxide chain may have a poly (alkylene oxide) moiety in the main chain or the side chain. Further, it may be a graft polymer having a poly (alkylene oxide) in a side chain, or a block copolymer of a block composed of a poly (alkylene oxide) -containing repeating unit and a block composed of a (alkylene oxide) -free repeating unit.
When the main chain has a poly (alkylene oxide) moiety, a polyurethane resin is preferable. When the main chain polymer has a poly (alkylene oxide) moiety in the side chain, the polymer of the main chain includes (meth) acrylic resin, polyvinyl acetal resin, polyurethane resin, polyurea resin, polyimide resin, polyamide resin, epoxy resin, polystyrene resin, and novolak type. Examples thereof include phenol resin, polyester resin, synthetic rubber and natural rubber, and (meth) acrylic resin is particularly preferable.

Further, as another preferable example of the binder polymer, a high molecular weight polymer chain having a polyfunctional thiol having 6 or more functionalities or 10 functionalities as a nucleus and being bonded to the nucleus by a sulfide bond, and the polymer chain having a polymerizable group. Examples thereof include molecular compounds (hereinafter, also referred to as star-shaped polymer compounds). As the star-shaped polymer compound, for example, the compound described in JP2012-148555 can be preferably used.

The star-shaped polymer compound contains a polymerizable group such as an ethylenically unsaturated bond for improving the film strength of the image portion as described in JP-A-2008-195018, with a main chain or a side chain, preferably a side chain. Examples include those held in the chain. The polymerizable group forms crosslinks between the polymer molecules to promote curing.
The polymerizable group is preferably an ethylenically unsaturated group such as a (meth) acrylic group, a vinyl group, an allyl group or a styryl group, an epoxy group or the like, and the (meth) acrylic group, the vinyl group or the styryl group is polymerizable. From the viewpoint, it is more preferable, and a (meth) acrylic group is particularly preferable. These groups can be introduced into the polymer by polymer reaction or copolymerization. For example, a reaction between a polymer having a carboxy group in the side chain and glycidyl methacrylate, or a reaction between a polymer having an epoxy group and an ethylenically unsaturated group-containing carboxylic acid such as methacrylic acid can be used. These groups may be used together.

The molecular weight of the binder polymer is preferably such that the weight average molecular weight (Mw) is 2,000 or more, more preferably 5,000 or more, and is 10,000 to 300,000 in terms of polystyrene by the GPC method. It is more preferable to have.

If necessary, hydrophilic polymers such as polyacrylic acid and polyvinyl alcohol described in JP-A-2008-195018 can be used in combination. In addition, a lipophilic polymer and a hydrophilic polymer can be used in combination.

Further, the polymer preferably contains a polymer having a hydrophilic structure from the viewpoints of printing resistance, inking property, and on-machine developability.
The hydrophilic structure is not particularly limited as long as it has hydrophilicity, but from the viewpoint of printing resistance, meat-forming property, and on-machine developability, a structural unit having a cyano group, or the following. It is preferable to include a group represented by the following formula Z, and more preferably to include a structural unit represented by the following formula (AN) or a group represented by the following formula Z, and a group represented by the following formula Z. Is particularly preferable.
* -Q-W-Y 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, and Y represents a monovalent group having a hydrophilic structure. Represented, either W or Y has a hydrophilic structure, and * represents a binding site with another structure.

In formula (AN), ^RAN represents a hydrogen atom or a methyl group.

From the viewpoint of UV print resistance, the polymer preferably contains a structural unit formed of a compound having a cyano group.
The cyano group is usually preferably introduced into the resin A as a structural unit containing a cyano group by using a compound (monomer) having a cyano group. Examples of the compound having a cyano group include acrylonitrile compounds, and (meth) acrylonitrile is preferable.
The structural unit having a cyano group is preferably a structural unit formed of an acrylonitrile compound, and more preferably a structural unit formed of (meth) acrylonitrile, that is, a structural unit represented by the above formula (AN). ..
When the polymer contains a polymer having a structural unit having a cyano group, the content of the structural unit having a cyano group, preferably the structural unit represented by the above formula (AN), in the polymer having a structural unit having a cyano group. Is preferably 5% by mass to 90% by mass, more preferably 20% by mass to 80% by mass, based on the total mass of the polymer having a structural unit having a cyano group, from the viewpoint of UV printing resistance. It is preferably 30% by mass to 60% by mass, and particularly preferably 30% by mass.

Further, the polymer preferably contains a polymer having a group represented by the above formula Z from the viewpoints of print resistance, fillability, and on-machine developability.

Q in the above formula Z is preferably a divalent linking group having 1 to 20 carbon atoms, and more preferably a divalent linking group having 1 to 10 carbon atoms.
Further, Q in the above formula Z is preferably an alkylene group, an arylene group, an ester bond, an amide bond, or a group in which two or more of these are combined, and may be a phenylene group, an ester bond, or an amide bond. More preferred.

The divalent group having a hydrophilic structure in W of the above formula Z is preferably a polyalkyleneoxy group or a group in which −CH ₂ CH ₂ NR ^W − is bonded to one end of a polyalkyleneoxy group. .. Incidentally, R ^W represents a hydrogen atom or an alkyl group.
The divalent groups having a hydrophobic structure in W of the above formula Z are -R ^WA- , -O-R ^WA -O-, -R ^W N-R ^WA- NR ^W- , -OC (= O)-. It is preferably R ^WA- O- or -OC (= O) -R ^WA- O-. ^Note that each ^{R WA} independently, linear 6-120 carbon atoms, branched or cyclic alkylene group, haloalkylene group of 6 to 120 carbon atoms, an arylene group having 6 to 120 carbon atoms, Arukariren of 6 to 120 carbon atoms It represents a group (a divalent group obtained by removing one hydrogen atom from an alkylaryl group) or an aralkylene group having 6 to 120 carbon atoms.

The monovalent group having a hydrophilic structure in Y of the above formula Z is -OH, -C (= O) OH, a polyalkyleneoxy group having a hydrogen atom or an alkyl group at the end, or a hydrogen atom or alkyl at the end. it is preferably bound group - at the other end of the polyalkyleneoxy group is a group ^{_{-CH 2 CH 2 N (R W}} ).
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, and the like. It may be an alcoholyl group (alkylaryl group) having 6 to 120 carbon atoms, an aralkyl group having 6 to 120 carbon atoms, -OR ^WB , -C (= O) OR ^WB , or -OC (= O) R ^WB. preferable. R ^WB represents an alkyl group having 6 to 20 carbon atoms.

The polymer having a group represented by the above formula Z is more preferably a divalent group in which W has a hydrophilic structure from the viewpoints of print resistance, fillability, and on-machine developability. Is a phenylene group, an ester bond, or an amide bond, W is a polyalkyleneoxy group, and Y is a polyalkyleneoxy group having a hydrogen atom or an alkyl group at the end.

Further, the polymer preferably contains polymer particles, and more preferably polymer particles, from the viewpoints of print resistance, fillability, and on-machine developability.
The polymer particles may be selected from the group consisting of thermoplastic polymer particles, heat-reactive polymer particles, polymer particles having a polymerizable group, microcapsules containing a hydrophobic compound, and microgels (crosslinked polymer particles). preferable. Of these, polymer particles or microgels having a polymerizable group are preferable. In a particularly preferred embodiment, the polymer particles contain at least one ethylenically unsaturated polymerizable group. The presence of such polymer particles has the effect of enhancing the print resistance of the exposed portion and the on-machine developability of the unexposed portion.
Further, the polymer particles are preferably thermoplastic polymer particles.

As the thermoplastic polymer particles, Research Disclosure No. 1 of January 1992. The thermoplastic polymer particles described in 33303, JP-A-9-123387, JP-A-9-131850, JP-A-9-171249, JP-A-9-171250, and European Patent No. 931647 are preferable.
Specific examples of the polymer constituting the thermoplastic polymer particles include ethylene, styrene, vinyl chloride, methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate, vinylidene chloride, acrylonitrile, vinylcarbazole, and a polyalkylene structure. Examples include homopolymers or copolymers of monomers such as acrylates or methacrylates or mixtures thereof. Preferably, a copolymer containing polystyrene, styrene and acrylonitrile, or polymethylmethacrylate can be mentioned. The average particle size of the thermoplastic polymer particles is preferably 0.01 μm to 3.0 μm.

Examples of the heat-reactive polymer particles include polymer particles having a heat-reactive group. The heat-reactive polymer particles form a hydrophobic region by cross-linking due to a heat reaction and the change of functional groups at that time.

The thermally reactive group in the polymer particles having a thermally reactive group may be a functional group that undergoes any reaction as long as a chemical bond is formed, but is preferably a polymerizable group, and as an example, Eethylene unsaturated groups (eg, acryloyl group, methacryloyl group, vinyl group, allyl group, etc.), cationically polymerizable groups (eg, vinyl group, vinyloxy group, epoxy group, oxetanyl group, etc.) that carry out a radical polymerization reaction, addition reaction Isocyanato group or a block thereof, an epoxy group, a vinyloxy group, a functional group having an active hydrogen atom which is a reaction partner thereof (for example, an amino group, a hydroxy group, a carboxy group, etc.), a carboxy group for performing a condensation reaction, and a Preferred examples thereof include a hydroxy group or an amino group as a reaction partner, an acid anhydride for carrying out a ring-opening addition reaction, and an amino group or a hydroxy group as a reaction partner.

As the microcapsules, for example, as described in JP-A-2001-277740 and JP-A-2001-277742, at least a part of the constituent components of the image recording layer is encapsulated in the microcapsules. The components of the image recording layer can also be contained outside the microcapsules. The image recording layer containing the microcapsules is preferably configured in which the hydrophobic constituents are encapsulated in the microcapsules and the hydrophilic constituents are contained outside the microcapsules.

The microgel (crosslinked polymer particles) can contain a part of the constituent components of the image recording layer on at least one of the surface or the inside thereof. In particular, a reactive microgel having a radically polymerizable group on its surface is preferable from the viewpoint of the sensitivity of the obtained lithographic printing plate original plate and the printing durability of the obtained lithographic printing plate.

Known methods can be applied to microencapsulate or microgelify the constituents of the image recording layer.

Further, as the polymer particles, an adduct of a polyhydric phenol compound having two or more hydroxy groups in the molecule and isophorone diisocyanate from the viewpoint of printing resistance, stain resistance and storage stability of the obtained flat plate printing plate. The one obtained by the reaction of the polyhydric isocyanate compound and the compound having active hydrogen is preferable.
As the multivalent phenol compound, a compound having a plurality of benzene rings having a phenolic hydroxy group is preferable.
As the compound having the above-mentioned compound having active hydrogen, a polyol compound or a polyamine compound is preferable, a polyol compound is more preferable, and at least one compound selected from the group consisting of propylene glycol, glycerin and trimethylolpropane is further preferable. preferable.
Examples of the resin particles obtained by the reaction of the polyhydric phenol compound having two or more hydroxy groups in the molecule, the polyhydric isocyanate compound which is an adduct of isophorone diisocyanate, and the compound having active hydrogen include JP2012. The polymer particles described in paragraphs 0032 to 0905 of JP-206495 are preferably mentioned.

Further, the polymer particles have a hydrophobic main chain from the viewpoint of printing resistance and solvent resistance of the obtained lithographic printing plate, and i) a pendant cyano group directly bonded to the hydrophobic main chain. It is preferable to include both a constituent unit having and ii) a constituent unit having a pendant group containing a hydrophilic polyalkylene oxide segment.
Acrylic resin chains are preferably mentioned as the hydrophobic main chain.
As an example of the pendant cyano group, − [CH ₂ CH (C≡N) −] or − [CH ₂ C (CH ₃ ) (C≡N) −] is preferably mentioned.
In addition, the constituent unit having the pendant cyano group can be easily derived from an ethylene-based unsaturated monomer, for example, acrylonitrile or methacrylonitrile, or a combination thereof.
Further, as the alkylene oxide in the hydrophilic polyalkylene oxide segment, ethylene oxide or propylene oxide is preferable, and ethylene oxide is more preferable.
The number of repetitions of the alkylene oxide structure in the hydrophilic polyalkylene oxide segment is preferably 10 to 100, more preferably 25 to 75, and even more preferably 40 to 50.
Both a constituent unit having a hydrophobic backbone and i) having a pendant cyano group directly attached to the hydrophobic backbone and ii) a constituent unit having a pendant group containing a hydrophilic polyalkylene oxide segment. As the resin particles containing the above, those described in paragraphs 0039 to 0068 of JP-A-2008-503365 are preferably mentioned.

Further, from the viewpoint of printing resistance, the polymer preferably contains polymer particles having a polymerizable group, and more preferably contains polymer particles having a polymerizable group on the particle surface.
The polymerizable group may be a cationically polymerizable group or a radically polymerizable group, but from the viewpoint of reactivity, it is preferably a radically polymerizable group.
The polymerizable group is not particularly limited as long as it is a polymerizable group, but from the viewpoint of reactivity, an ethylenically unsaturated group is preferable, and a vinylphenyl group (styryl group), a (meth) acryloxy group, or a (meth) acryloxy group, or A (meth) acrylamide group is more preferred, and a (meth) acryloxy group is particularly preferred.
Further, the polymer in the polymer particles having a polymerizable group preferably has a structural unit having a polymerizable group.
Further, a polymerizable group may be introduced on the surface of the polymer particles by a polymer reaction.

The average particle size of the polymer 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 in this range.
The average primary particle size of the polymer particles in the present disclosure is measured by a light scattering method, or an electron micrograph of the particles is taken, and a total of 5,000 particle size particles are measured on the photograph and averaged. The value shall be calculated. For non-spherical particles, the particle size value of spherical particles having the same particle area as the particle area on the photograph is used as the particle size.
Further, the average particle size in the present disclosure shall be the volume average particle size unless otherwise specified.
From the viewpoint of developability, the content of the polymer particles is preferably 5% by mass to 90% by mass with respect to the total mass of the image recording layer.

In the image recording layer used in the present disclosure, one type of polymer may be used alone, or two or more types may be used in combination.
The polymer can be contained in the image recording layer in an arbitrary amount, but the content of the polymer is preferably 1% by mass to 90% by mass with respect to the total mass of the image recording layer. More preferably, it is 5% by mass to 80% by mass.

-Polymerization initiator-
The image recording layer in the lithographic printing plate original plate according to the present disclosure preferably further contains a polymerization initiator, and more preferably further contains a polymerization initiator and a polymerizable compound.
Further, the polymerization initiator preferably contains an electron-accepting polymerization initiator.

<< Electron-accepting polymerization initiator >>
The image recording layer preferably contains an electron-accepting polymerization initiator (also referred to as a "polymerization aid") as a polymerization initiator.
The electron-accepting polymerization initiator is a compound that generates a polymerization initiator such as a radical by accepting one electron by electron transfer between molecules when the electrons of the infrared absorber are excited by infrared exposure.
The electron-accepting polymerization initiator used in the present disclosure is a compound that generates a polymerization initiator such as a radical or a cation by energy of light, heat, or both, and is a known thermal polymerization initiator and has a small bond dissociation energy. A compound having a bond, a photopolymerization initiator and the like can be appropriately selected and used.
As the electron-accepting polymerization initiator, a radical polymerization initiator is preferable, and an onium salt compound is more preferable.
The electron-accepting polymerization initiator is preferably an infrared photosensitive polymerization initiator.
Examples of the electron-accepting radical polymerization initiator include (a) organic halides, (b) carbonyl compounds, (c) azo compounds, (d) organic peroxides, (e) metallocene compounds, and (f) azide compounds. , (G) Hexaarylbiimidazole compound, (i) Disulfone compound, (j) Oxim ester compound, (k) Onium salt compound.

As the (a) organic halide, for example, the compounds described in paragraphs 0022 to 0023 of JP-A-2008-195018 are preferable.
(B) As the carbonyl compound, for example, the compound described in paragraph 0024 of JP-A-2008-195018 is preferable.
(C) As the azo compound, for example, the azo compound described in JP-A-8-108621 can be used.
(D) As the organic peroxide, for example, the compound described in paragraph 0025 of JP-A-2008-195018 is preferable.
(E) As the metallocene compound, for example, the compound described in paragraph 0026 of JP-A-2008-195018 is preferable.
Examples of the (f) azide compound include compounds such as 2,6-bis (4-azidobenzylidene) -4-methylcyclohexanone.
(G) As the hexaarylbiimidazole compound, for example, the compound described in paragraph 0027 of JP-A-2008-195018 is preferable.
(I) Examples of the disulfon compound include the compounds described in JP-A-61-166544 and JP-A-2002-328465.
As the (j) oxime ester compound, for example, the compounds described in paragraphs 0028 to 0030 of JP-A-2008-195018 are preferable.

Among the above-mentioned electron-accepting polymerization initiators, oxime ester compounds and onium salt compounds are preferable from the viewpoint of curability. Among them, from the viewpoint of printing resistance, an iodonium salt compound, a sulfonium salt compound or an azinium salt compound is preferable, an iodonium salt compound or a sulfonium salt compound is more preferable, and an iodonium salt compound is particularly preferable.
Specific examples of these compounds are shown below, but the present disclosure is not limited thereto.

As an example of the iodonium salt compound, a diaryl iodonium salt compound is preferable, a diphenyl iodonium salt compound substituted with an electron donating group such as an alkyl group or an alkoxyl group is more preferable, and an asymmetric diphenyl iodonium salt compound is preferable. .. Specific examples include diphenyliodonium = hexafluorophosphate, 4-methoxyphenyl-4- (2-methylpropyl) phenyliodonium = hexafluorophosphate, 4- (2-methylpropyl) phenyl-p-tolyliodonium = hexa. Fluorophosphate, 4-hexyloxyphenyl-2,4,6-trimethoxyphenyliodonium = hexafluorophosphate, 4-hexyloxyphenyl-2,4-diethoxyphenyliodonium = tetrafluoroborate, 4-octyloxy Phenyl-2,4,6-trimethoxyphenyliodonium = 1-perfluorobutane sulfonate, 4-octyloxyphenyl-2,4,6-trimethoxyphenyliodonium = hexafluorophosphate, bis (4-t-butylphenyl) ) Iodonium = hexafluorophosphate can be mentioned.

As an example of the sulfonium salt compound, a triarylsulfonium salt compound is preferable, and in particular, an electron-attracting group, for example, a triarylsulfonium salt compound in which at least a part of a group on the aromatic ring is substituted with a halogen atom is preferable, and aromatic. A triarylsulfonium salt compound having a total number of halogen atoms substituted on the ring of 4 or more is more preferable. Specific examples include triphenylsulfonium = hexafluorophosphate, triphenylsulfonium = benzoylformate, bis (4-chlorophenyl) phenylsulfonium = benzoylformate, and bis (4-chlorophenyl) -4-methylphenylsulfonium = tetrafluoro. Borate, Tris (4-chlorophenyl) Sulfonium = 3,5-bis (methoxycarbonyl) Benzene Sulfonium, Tris (4-chlorophenyl) Sulfonium = Hexafluorophosphate, Tris (2,4-Dichlorophenyl) Sulfonium = Hexafluorophos Fert can be mentioned.

Further, as the counter anion of the iodonium salt compound and the sulfonium salt compound, a sulfonamide anion or a sulfonimide anion is preferable, and a sulfonimide anion is more preferable.
As the sulfonamide anion, an aryl sulfonamide anion is preferable.
Further, as the sulfonimide anion, a bisaryl sulfonimide anion is preferable.
Specific examples of sulfonamide anions or sulfonamide anions are shown below, but the present disclosure is not limited thereto. In the specific examples below, Ph represents a phenyl group, Me represents a methyl group, and Et represents an ethyl group.

The electron-accepting polymerization initiator may be used alone or in combination of two or more.
The content of the electron-accepting polymerization initiator is preferably 0.1% by mass to 50% by mass, more preferably 0.5% by mass to 30% by mass, based on the total mass of the image recording layer. It is preferably 0.8% by mass to 20% by mass, and particularly preferably 0.8% by mass.

<< Electron-donated polymerization initiator (polymerization aid) >>
The image recording layer preferably contains an electron donating type polymerization initiator (also referred to as "polymerization aid") as a polymerization initiator, and more preferably contains an electron accepting type polymerization initiator and a polymerization aid. preferable.
The electron donating type polymerization initiator in the present disclosure donates one electron by intermolecular electron transfer to an orbit where one electron is missing from the infrared absorber when the electron of the infrared absorber is excited or moved intramolecularly by infrared exposure. This is a compound that generates a polymerization-initiated species such as a radical.
The electron-donating type polymerization initiator is preferably an electron-donating radical polymerization initiator.
From the viewpoint of improving the printing durability of the lithographic printing plate, the image recording layer more preferably contains the electron donating type polymerization initiator described below, and examples thereof include the following five types.
(I) Alkyl or aryl ate complex: It is considered that the carbon-heterobond is oxidatively cleaved to generate an active radical. Specifically, a borate compound is preferable.
(Ii) N-arylalkylamine compound: It is considered that the CX bond on the carbon adjacent to nitrogen is cleaved by oxidation to generate an active radical. As X, a hydrogen atom, a carboxyl group, a trimethylsilyl group or a benzyl group is preferable. Specifically, for example, N-phenylglycines (which may or may not have a substituent on the phenyl group) and N-phenyliminodiacetic acid (which may or may not have a substituent on the phenyl group). May be mentioned.)
(Iii) Sulfur-containing compound: The above-mentioned amines in which the nitrogen atom is replaced with a sulfur atom can generate an active radical by the same action. For example, phenylthioacetic acid (which may or may not have a substituent on the phenyl group) can be mentioned.
(Iv) Tin-containing compounds: The above-mentioned amines in which the nitrogen atom is replaced with a tin atom can generate active radicals by the same action.
(V) Sulfinates: Oxidation can generate active radicals. Specific examples thereof include arylsulfinic sodium.

Among these, the image recording layer preferably contains a borate compound from the viewpoint of printing resistance.
The borate compound is preferably a tetraaryl borate compound or a monoalkyl triaryl borate compound, and more preferably a tetraaryl borate compound from the viewpoint of print resistance and color development.
The counter cation contained in 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.

Specific examples of the borate compound include sodium tetraphenylborate.

B-1 to B-9 are shown below as preferable specific examples of the electron donating type polymerization initiator, but it goes without saying that the present invention is not limited to these. Further, in the following chemical formula, Ph represents a phenyl group and Bu represents an n-butyl group.

As the electron donating type polymerization initiator, only one kind may be added, or two or more kinds may be used in combination.
The content of the electron donating type polymerization initiator is preferably 0.01% by mass to 30% by mass, preferably 0.05% by mass, based on the total mass of the image recording layer from the viewpoint of sensitivity and printing resistance. It is more preferably ~ 25% by mass, and even more preferably 0.1% by mass to 20% by mass.

-Polymerizable compound-
The image recording layer preferably contains a polymerizable compound.
The polymerizable compound used in the present disclosure may be, for example, a radical-polymerizable compound or a cationically polymerizable compound, but is an addition-polymerizable compound having at least one ethylenically unsaturated bond (ethyleney). It is preferably an unsaturated compound). The ethylenically unsaturated compound is preferably a compound having at least one terminal ethylenically unsaturated bond, and more preferably a compound having two or more terminal ethylenically unsaturated bonds. The polymerizable compound has a chemical form such as a monomer, a prepolymer, that is, a dimer, a trimer or an oligomer, or a mixture thereof.

Examples of the monomer include unsaturated carboxylic acids (for example, acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid, maleic acid, etc.), esters thereof, and amides, and unsaturated carboxylic acids are preferable. Esters of acids and polyhydric alcohol compounds and amides of unsaturated carboxylic acids and polyhydric amine compounds are used. Further, an addition reaction product of an unsaturated carboxylic acid ester or amide having a nucleophilic substituent such as a hydroxy group, an amino group or a mercapto group with a monofunctional or polyfunctional isocyanate or an epoxy, and a monofunctional or polyfunctional group. A dehydration condensation reaction product with a functional carboxylic acid is also preferably used. Further, an addition reaction product of unsaturated carboxylic acid esters or amides having an electrophilic substituent such as an isocyanate group or an epoxy group with monofunctional or polyfunctional alcohols, amines and thiols, and a halogen atom, Substituents of unsaturated carboxylic acid esters or amides having a releasable substituent such as a tosyloxy group with monofunctional or polyfunctional alcohols, amines and thiols are also suitable. Further, as another example, it is also possible to use a compound group in which the above unsaturated carboxylic acid is replaced with unsaturated phosphonic acid, styrene, vinyl ether or the like. These are JP-A-2006-508380, JP-A-2002-287344, JP-A-2008-256850, JP-A-2001-342222, JP-A-9-179296, JP-A-9-179297. , JP-A-9-179298, JP-A-2004-294935, JP-A-2006-243493, JP-A-2002-275129, JP-A-2003-64130, JP-A-2003-280187, It is described in Kaihei 10-333321.

Specific examples of the monomer of the ester of the polyhydric alcohol compound and the unsaturated carboxylic acid include ethylene glycol diacrylate, 1,3-butanediol diacrylate, tetramethylene glycol diacrylate, and propylene glycol diacrylate as acrylic acid esters. Trimethylol propan triacrylate, hexanediol diacrylate, tetraethylene glycol diacrylate, pentaerythritol tetraacrylate, sorbitol triacrylate, isocyanurate ethylene oxide (EO) modified triacrylate, polyester acrylate oligomer and the like. As methacrylic acid ester, tetramethylene glycol dimethacrylate, neopentyl glycol dimethacrylate, trimethylolpropantrimethacrylate, ethylene glycol dimethacrylate, pentaerythritol trimethacrylate, bis [p- (3-methacryloxy-2-hydroxypropoxy) phenyl] There are dimethylmethane, bis [p- (methacrylicoxyethoxy) phenyl] dimethylmethane and the like. Specific examples of the amide monomer of the polyvalent amine compound and the unsaturated carboxylic acid include methylenebisacrylamide, methylenebismethacrylamide, 1,6-hexamethylenebisacrylamide, and 1,6-hexamethylenebismethacrylamide. Diethylenetriaminetrisacrylamide, xylylenebisacrylamide, xylylenebismethacrylamide and the like.

Further, a urethane-based addition-polymerizable compound produced by using an addition reaction of isocyanate and a hydroxy group is also suitable, and specific examples thereof include 2 per molecule described in JP-A-48-41708. A vinyl urethane compound containing two or more polymerizable vinyl groups in one molecule obtained by adding a vinyl monomer containing a hydroxy group represented by the following formula (M) to a polyisocyanate compound having two or more isocyanate groups. And so on.
^{_{CH 2 = C (R M4)}} COOCH 2 CH (R M5) OH (M)
In formula (M), ^RM4 and ^RM5 each independently represent a hydrogen atom or a methyl group.

Further, the urethane acrylates described in JP-A-51-37193, JP-A-2-32293, JP-A-2-16765, JP-A-2003-344997, and JP-A-2006-65210, Ethylenes described in Japanese Patent Application Laid-Open No. 58-49860, Japanese Patent Publication No. 56-17654, Japanese Patent Publication No. 62-39417, Japanese Patent Application Laid-Open No. 62-39418, Japanese Patent Application Laid-Open No. 2000-250211 and Japanese Patent Application Laid-Open No. 2007-94138. Urethane compounds having an oxide-based skeleton, urethane compounds having a hydrophilic group described in US Pat. No. 7,153,632, JP-A-8-505598, JP-A-2007-293221, JP-A-2007-293223. Kind is also suitable.

The details of the method of use such as the structure of the polymerizable compound, whether it is used alone or in combination, and the amount of addition can be arbitrarily set.
The content of the polymerizable compound is preferably 5% by mass to 75% by mass, more preferably 10% by mass to 70% by mass, and 15% by mass to 60% by mass with respect to the total mass of the image recording layer. It is particularly preferably by mass%.

-Acid color former
The image recording layer preferably contains an acid color former (hereinafter, also simply referred to as "acid color former").
The "acid color former" used in the present disclosure means a compound having a property of developing a color by heating in a state of receiving an electron-accepting compound (for example, a proton such as an acid). The acid color former has a partial skeleton such as lactone, lactam, salton, spiropyrane, ester, and amide, and when it comes into contact with an electron-accepting compound, these partial skeletons are rapidly ring-opened or cleaved. Compounds are preferred.

Examples of such acid color formers are 3,3-bis (4-dimethylaminophenyl) -6-dimethylaminophthalide (referred to as "crystal violet lactone") and 3,3-bis (4). -Dimethylaminophenyl) phthalide, 3- (4-dimethylaminophenyl) -3- (4-diethylamino-2-methylphenyl) -6-dimethylaminophthalide, 3- (4-dimethylaminophenyl) -3- ( 1,2-dimethylindole-3-yl) phthalide, 3- (4-dimethylaminophenyl) -3- (2-methylindole-3-yl) phthalide, 3,3-bis (1,2-dimethylindole-) 3-yl) -5-dimethylaminophthalide, 3,3-bis (1,2-dimethylindole-3-yl) -6-dimethylaminophthalide, 3,3-bis (9-ethylcarbazole-3-3) Il) -6-dimethylaminophthalide, 3,3-bis (2-phenylindole-3-yl) -6-dimethylaminophthalide, 3- (4-dimethylaminophenyl) -3- (1-methylpyrrole) -3-yl) -6-dimethylaminophthalide,

3,3-bis [1,1-bis (4-dimethylaminophenyl) ethylene-2-yl] -4,5,6,7-tetrachlorophthalide, 3,3-bis [1,1-bis (1,1-bis) 4-Pyrrolidinophenyl) ethylene-2-yl] -4,5,6,7-tetrabromophthalide, 3,3-bis [1- (4-dimethylaminophenyl) -1- (4-methoxyphenyl) Ethylene-2-yl] -4,5,6,7-tetrachlorophthalide, 3,3-bis [1- (4-pyrrolidinophenyl) -1- (4-methoxyphenyl) ethylene-2-yl] -4,5,6,7-tetrachlorophthalide, 3- [1,1-di (1-ethyl-2-methylindole-3-yl) ethylene-2-yl] -3- (4-diethylaminophenyl) ) Phenylide, 3- [1,1-di (1-ethyl-2-methylindole-3-yl) ethylene-2-yl] -3- (4-N-ethyl-N-phenylaminophenyl) phthalide, 3 -(2-ethoxy-4-diethylaminophenyl) -3- (1-n-octyl-2-methylindol-3-yl) -phthalide, 3,3-bis (1-n-octyl-2-methylindol-) Phenylides such as 3-yl) -phthalide, 3- (2-methyl-4-diethylaminophenyl) -3- (1-n-octyl-2-methylindole-3-yl) -phthalide,

4,4-Bis-dimethylaminobenzhydrinbenzyl ether, N-halophenyl-leucoauramine, N-2,4,5-trichlorophenyl leucooramine, rhodamine-B-anilinolactam, rhodamine- (4-nitroanilino) ) Lactam, Rhodamine-B- (4-chloroanilino) lactam, 3,7-bis (diethylamino) -10-benzoylphenoxazine, benzoyl leucomethylene blue, 4-nitrobenzoyl methylene blue,

3,6-dimethoxyfluorane, 3-dimethylamino-7-methoxyfluorane, 3-diethylamino-6-methoxyfluorane, 3-diethylamino-7-methoxyfluorane, 3-diethylamino-7-chlorofluorine, 3 -Diethylamino-6-methyl-7-chlorofluorine, 3-diethylamino-6,7-dimethylfluorane, 3-N-cyclohexyl-Nn-butylamino-7-methylfluorane, 3-diethylamino-7- Dibenzylaminofluorane, 3-diethylamino-7-octylaminofluorane, 3-diethylamino-7-di-n-hexylaminofluorane, 3-diethylamino-7-anilinofluorane, 3-diethylamino-7- ( 2'-fluorophenylamino) fluorane, 3-diethylamino-7- (2'-chlorophenylamino) fluorane, 3-diethylamino-7- (3'-chlorophenylamino) fluorane, 3-diethylamino-7- (2', 3) '-Dichlorophenylamino) fluorane, 3-diethylamino-7- (3'-trifluoromethylphenylamino) fluorane, 3-di-n-butylamino-7- (2'-fluorophenylamino) fluorane, 3-di- n-Butylamino-7- (2'-chlorophenylamino) fluorane, 3-N-isopentyl-N-ethylamino-7- (2'-chlorophenylamino) fluorane,

3-Nn-hexyl-N-ethylamino-7- (2'-chlorophenylamino) fluorane, 3-diethylamino-6-chloro-7-anilinofluorane, 3-di-n-butylamino-6- Chloro-7-anilinofluorane, 3-diethylamino-6-methoxy-7-anilinofluorane, 3-di-n-butylamino-6-ethoxy-7-anilinofluorane, 3-pyrrolidino-6- Methyl-7-anilinofluorane, 3-piperidino-6-methyl-7-anilinofluoran, 3-morpholino-6-methyl-7-anilinofluorane, 3-dimethylamino-6-methyl-7- Anilinofluorane, 3-diethylamino-6-methyl-7-anilinofluorane, 3-di-n-butylamino-6-methyl-7-anilinofluorane, 3-di-n-pentylamino-6 -Methyl-7-anilinofluorane, 3-N-ethyl-N-methylamino-6-methyl-7-anilinofluorane, 3-Nn-propyl-N-methylamino-6-methyl-7 -Anilinofluorane, 3-Nn-propyl-N-ethylamino-6-methyl-7-anilinofluorane, 3-Nn-butyl-N-methylamino-6-methyl-7-ani Renofluorane, 3-N-n-butyl-N-ethylamino-6-methyl-7-anilinofluorane, 3-N-isobutyl-N-methylamino-6-methyl-7-anilinofluorane, 3-N-isobutyl-N-ethylamino-6-methyl-7-anilinofluorane, 3-N-isopentyl-N-ethylamino-6-methyl-7-anilinofluorane, 3-N-n- Hexyl-N-methylamino-6-methyl-7-anilinofluorane, 3-N-cyclohexyl-N-ethylamino-6-methyl-7-anilinofluorane, 3-N-cyclohexyl-Nn- Propylamino-6-methyl-7-anilinofluorane, 3-N-cyclohexyl-Nn-butylamino-6-methyl-7-anilinofluorane, 3-N-cyclohexyl-Nn-hexylamino -6-Methyl-7-anilinofluorane, 3-N-cyclohexyl-Nn-octylamino-6-methyl-7-anilinofluorane,

3-N- (2'-methoxyethyl) -N-methylamino-6-methyl-7-anilinofluorane, 3-N- (2'-methoxyethyl) -N-ethylamino-6-methyl-7 -Anilinofluorane, 3-N- (2'-methoxyethyl) -N-isobutylamino-6-methyl-7-anilinofluorane, 3-N- (2'-ethoxyethyl) -N-methylamino -6-Methyl-7-anilinofluorane, 3-N- (2'-ethoxyethyl) -N-ethylamino-6-methyl-7-anilinofluorane, 3-N- (3'-methoxypropyl) ) -N-Methylamino-6-methyl-7-anilinofluorane, 3-N- (3'-methoxypropyl) -N-ethylamino-6-methyl-7-anilinofluorane, 3-N- (3'-ethoxypropyl) -N-methylamino-6-methyl-7-anilinofluorane, 3-N- (3'-ethoxypropyl) -N-ethylamino-6-methyl-7-anilinoflu Oran, 3-N- (2'-tetrahydrofurfuryl) -N-ethylamino-6-methyl-7-anilinofluoran, 3-N- (4'-methylphenyl) -N-ethylamino-6- Methyl-7-anilinofluorane, 3-diethylamino-6-ethyl-7-anilinofluorane, 3-diethylamino-6-methyl-7- (3'-methylphenylamino) fluorane, 3-diethylamino-6- Methyl-7- (2', 6'-dimethylphenylamino) fluorane, 3-di-n-butylamino-6-methyl-7- (2', 6'-dimethylphenylamino) fluorane, 3-di-n -Butylamino-7- (2', 6'-dimethylphenylamino) fluorane, 2,2-bis [4'-(3-N-cyclohexyl-N-methylamino-6-methylfluorane) -7-yl Aminophenyl] Propane, 3- [4'-(4-phenylaminophenyl) Aminophenyl] Amino-6-Methyl-7-Chlorofluorane, 3- [4'-(Dimethylaminophenyl)] Amino-5,7 -Fluorans such as dimethylfluorane,

3- (2-Methyl-4-diethylaminophenyl) -3- (1-ethyl-2-methylindol-3-yl) -4-azaphthalide, 3- (2-n-propoxycarbonylamino-4-di-n) -Propylaminophenyl) -3- (1-ethyl-2-methylindole-3-yl) -4-azaphthalide, 3- (2-methylamino-4-di-n-propylaminophenyl) -3- (1) -Ethyl-2-methylindol-3-yl) -4-azaphthalide, 3- (2-methyl-4-din-hexylaminophenyl) -3- (1-n-octyl-2-methylindol-3-) Il) -4,7-diazaphthalide, 3,3-bis (2-ethoxy-4-diethylaminophenyl) -4-azaphthalide, 3,3-bis (1-n-octyl-2-methylindole-3-yl) -4-azaphthalide, 3- (2-ethoxy-4-diethylaminophenyl) -3- (1-ethyl-2-methylindole-3-yl) -4-azaphthalide, 3- (2-ethoxy-4-diethylaminophenyl) ) -3- (1-octyl-2-methylindole-3-yl) -4 or 7-azaphthalide, 3- (2-ethoxy-4-diethylaminophenyl) -3- (1-ethyl-2-methylindole-) 3-Il) -4 or 7-azaphthalide, 3- (2-hexyloxy-4-diethylaminophenyl) -3- (1-ethyl-2-methylindole-3-yl) -4 or 7-azaphthalide, 3- (2-Ethyl-4-diethylaminophenyl) -3- (1-ethyl-2-phenylindole-3-yl) -4 or 7-azaphthalide, 3- (2-butoxy-4-diethylaminophenyl) -3- ( 1-Ethyl-2-phenylindole-3-yl) -4 or 7-azaphthalide 3-methyl-spiro-dinaphthopylane, 3-ethyl-spiro-dinaftopylan, 3-phenyl-spiro-dinaftopylan, 3-benzyl-spiro-dinaftpyran , 3-Methyl-naphtho- (3-methoxybenzo) spiropyrane, 3-propyl-spiro-dibenzopyran-3,6-bis (dimethylamino) fluorene-9-spiryl-3'-(6'-dimethylamino) phthalide , 3,6-Bis (diethylamino) fluorene-9-spiro-3'-(6'-dimethylamino) phthalides and other phthalides,

In addition, 2'-anilino-6'-(N-ethyl-N-isopentyl) amino-3'-methylspiro [isobenzofuran-1 (3H), 9'-(9H) xanthen-3-one, 2'-anilino -6'-(N-ethyl-N- (4-methylphenyl)) amino-3'-methylspiro [isobenzofuran-1 (3H), 9'-(9H) xanthene] -3-one, 3'-N , N-Dibenzylamino-6'-N, N-diethylaminospiro [isobenzofuran-1 (3H), 9'-(9H) xanthene] -3-one, 2'-(N-methyl-N-phenyl) Amino-6'-(N-ethyl-N- (4-methylphenyl)) aminospiro [isobenzofuran-1 (3H), 9'-(9H) xanthene] -3-one and the like can be mentioned.

Among them, the acid color former used in the present disclosure is at least one compound selected from the group consisting of a spiropyran compound, a spirooxazine compound, a spirololactone compound, and a spirolactam compound from the viewpoint of color development. preferable.
From the viewpoint of visibility, the hue of the dye after color development is preferably green, blue or black.

It is also possible to use commercially available products as the acid color former, 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, Vermilion-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.), crystal violet lactone (manufactured by Tokyo Kasei Kogyo Co., Ltd.) and the like. 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 preferable because the film to be formed has a good visible light absorption rate.

These acid color formers may be used alone or in combination of two or more kinds of components.
The content of the acid color former is preferably 0.5% by mass to 10% by mass and more preferably 1% by mass to 5% by mass with respect to the total mass of the image recording layer.

-Chain transfer agent-
The image recording layer used in the present disclosure may contain a chain transfer agent. The chain transfer agent contributes to the improvement of printing durability in the lithographic printing plate.
As the chain transfer agent, a thiol compound is preferable, a thiol having 7 or more carbon atoms is more preferable from the viewpoint of boiling point (difficulty in volatilization), and a compound having a mercapto group on the aromatic ring (aromatic thiol compound) is further preferable. The thiol compound is preferably a monofunctional thiol compound.

Specific examples of the chain transfer agent include the following compounds.

Only one type of chain transfer agent may be added, or two or more types may be used in combination.
The content of the chain transfer agent is preferably 0.01% by mass to 50% by mass, more preferably 0.05% by mass to 40% by mass, and 0.1% by mass to 30% by mass with respect to the total mass of the image recording layer. % Is more preferable.

-Low molecular weight hydrophilic compound-
The image recording layer may contain a low molecular weight hydrophilic compound in order to improve on-machine developability while suppressing a decrease in printing resistance. The low molecular weight hydrophilic compound is preferably a compound having a molecular weight of less than 1,000, more preferably a compound having a molecular weight of less than 800, and further preferably a compound having a molecular weight of less than 500.
Examples of the low molecular weight hydrophilic compound include, as water-soluble organic compounds, glycols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, and tripropylene glycol, ethers or ester derivatives thereof, and glycerin. Polyols such as pentaerythritol and tris (2-hydroxyethyl) isocyanurate, organic amines such as triethanolamine, diethanolamine and monoethanolamine and salts thereof, organic sulfates such as alkyl sulfonic acid, toluene sulfonic acid and benzene sulfonic acid. Acids and salts thereof, organic sulfamic acids such as alkylsulfamic acid and salts thereof, organic sulfates such as alkylsulfuric acid and alkylether sulfuric acid and salts thereof, organic phosphonic acids such as phenylphosphonic acid and salts thereof, tartrate acid, oxalic acid, quench Examples thereof include organic carboxylic acids such as acids, malic acids, lactic acids, gluconic acids and amino acids, salts thereof, and betaines.

As the low molecular weight hydrophilic compound, it is preferable to contain at least one selected from polyols, organic sulfates, organic sulfonates and betaines.

Specific examples of organic sulfonates include alkyl sulfonates such as sodium n-butyl sulfonate, sodium n-hexyl sulfonate, sodium 2-ethylhexyl sulfonate, sodium cyclohexyl sulfonate, and sodium n-octyl sulfonate; 5 , 8,11-Trioxapentadecane-1-sulfonate, 5,8,11-trioxaheptadecane-1-sulfonate, 13-ethyl-5,8,11-trioxaheptadecane-1-sulfon Alkyl sulfonates containing ethylene oxide chains such as sodium acid, sodium 5,8,11,14-tetraoxatetracosan-1-sulfonate; sodium benzenesulfonate, sodium p-toluenesulfonate, p-hydroxybenzenesulfonic acid Sodium, sodium p-styrene sulfonate, sodium dimethyl-5-sulfonate isophthalate, sodium 1-naphthyl sulfonate, sodium 4-hydroxynaphthyl sulfonate, disodium 1,5-naphthalenedi sulfonate, 1,3,6- Examples thereof include aryl sulfonates such as trisodium naphthalene trisulfonate, and compounds described in paragraphs 0026 to 0031 of JP-A-2007-276454 and paragraphs 0020-0047 of JP-A-2009-154525. The salt may be a potassium salt or a lithium salt.

Examples of organic sulfates include sulfates of alkyl, alkenyl, alkynyl, aryl or heterocyclic monoethers of polyethylene oxide. The number of ethylene oxide units is preferably 1 to 4, and the salt is preferably a sodium salt, a potassium salt or a lithium salt. Specific examples include the compounds described in paragraphs 0034 to 0038 of JP-A-2007-276454.

As betaines, compounds having 1 to 5 carbon atoms of the hydrocarbon substituent on the nitrogen atom are preferable, and specific examples thereof include trimethylammonium acetate, dimethylpropylammonium acetate, and 3-hydroxy-4-trimethylammonium. Obutyrate, 4- (1-pyridinio) butyrate, 1-hydroxyethyl-1-imidazolioacetate, trimethylammonium methanesulfonate, dimethylpropylammonium methanesulfonate, 3-trimethylammonio-1-propanesulfonate, 3 -(1-Pyridinio) -1-propanesulfonate and the like can be mentioned.

Since the low-molecular-weight hydrophilic compound has a small structure of the hydrophobic part and has almost no surface-active action, dampening water permeates the exposed part (image part) of the image recording layer and reduces the hydrophobicity and film strength of the image part. It is possible to maintain good ink acceptability and print resistance of the image recording layer.

The content of the low molecular weight hydrophilic compound is preferably 0.5% by mass to 20% by mass, more preferably 1% by mass to 15% by mass, and 2% by mass to 10% by mass with respect to the total mass of the image recording layer. Is more preferable. Good on-machine developability and print resistance can be obtained in this range.
The low molecular weight hydrophilic compound may be used alone or in combination of two or more.

-Fat sensitive agent-
The image recording layer may contain a fat-sensing agent such as a phosphonium compound, a nitrogen-containing low molecular weight compound, and an ammonium group-containing polymer in order to improve the meat-forming property. In particular, when the protective layer contains an inorganic layered compound, these compounds function as a surface coating agent for the inorganic layered compound, and it is possible to suppress a decrease in inking property during printing due to the inorganic layered compound.
As the fat sensitive agent, it is preferable to use a phosphonium compound, a nitrogen-containing low molecular weight compound, and an ammonium group-containing polymer in combination, and the phosphonium compound, a quaternary ammonium salt, and an ammonium group-containing polymer are used in combination. Is more preferable.

Examples of the phosphonium compound include the phosphonium compounds described in JP-A-2006-297907 and JP-A-2007-50660. Specific examples include tetrabutylphosphonium iodide, butyltriphenylphosphonium bromide, tetraphenylphosphonium bromide, 1,4-bis (triphenylphosphonio) butane-di (hexafluorophosphine), and 1,7-bis (tri). Examples thereof include phenylphosphonio) heptane-sulfate and 1,9-bis (triphenylphosphonio) nonane-naphthalen-2,7-disulfonate.

Examples of nitrogen-containing low molecular weight compounds include amine salts and quaternary ammonium salts. In addition, imidazolinium salts, benzoimidazolinium salts, pyridinium salts, quinolinium salts and the like can also be mentioned. Of these, quaternary ammonium salts and pyridinium salts are preferable. Specific examples include tetramethylammonium = hexafluorophosphate, tetrabutylammonium = hexafluorophosphate, dodecyltrimethylammonium = p-toluenesulfonate, benzyltriethylammonium = hexafluorophosphate, and benzyldimethyloctylammonium = hexafluorophos. Examples thereof include fert, benzyldimethyldodecylammonium = hexafluorophosphate, compounds described in paragraphs 0021 to 0037 of JP-A-2008-284858 and paragraphs 0030 to 0057 of JP-A-2009-90645.

The ammonium group-containing polymer may have an ammonium group in its structure, and a polymer containing 5 mol% to 80 mol% of a (meth) acrylate having an ammonium group in the side chain as a copolymerization component is preferable. Specific examples thereof include the polymers described in paragraphs 0008-0105 of JP2009-208458A.

The ammonium salt-containing polymer preferably has a reduced specific viscosity (unit: ml / g) value in the range of 5 to 120, and is in the range of 10 to 110, as determined according to the measurement method described in JP-A-2009-208458. Is more preferable, and those in the range of 15 to 100 are particularly preferable. When the reduced specific viscosity is converted into a weight average molecular weight (Mw), it is preferably 10,000 to 150,000, more preferably 17,000 to 140,000, and particularly preferably 20,000 to 130,000.

Specific examples of the ammonium group-containing polymer are shown below.
(1) 2- (trimethylammonio) ethyl methacrylate = p-toluenesulfonate / 3,6-dioxaheptyl methacrylate copolymer (molar ratio 10/90, Mw 45,000)
(2) 2- (trimethylammonio) ethyl methacrylate = hexafluorophosphate / 3,6-dioxaheptyl methacrylate copolymer (molar ratio 20/80, Mw 60,000)
(3) 2- (Ethyldimethylammonio) Ethyl Methacrylate = p-Toluene Sulfonate / Hexyl Methacrylate Copolymer (Mole Ratio 30/70, Mw 45,000)
(4) 2- (trimethylammonio) ethyl methacrylate = hexafluorophosphate / 2-ethylhexyl methacrylate copolymer (molar ratio 20/80, Mw 60,000)
(5) 2- (trimethylammonio) ethyl methacrylate = methyl sulfate / hexyl methacrylate copolymer (molar ratio 40/60, Mw 7,000,000)
(6) 2- (Butyldimethylammonio) ethyl methacrylate = hexafluorophosphate / 3,6-dioxaheptyl methacrylate copolymer (molar ratio 25/75, Mw 65,000)
(7) 2- (Butyldimethylammonio) ethyl acrylate = hexafluorophosphate / 3,6-dioxaheptyl methacrylate copolymer (molar ratio 20/80, Mw 65,000)
(8) 2- (Butyldimethylammonio) ethyl methacrylate = 13-ethyl-5,8,11-trioxa-1-heptadecanesulfonate / 3,6-dioxaheptyl methacrylate copolymer (molar ratio 20/80) , Mw 75,000)
(9) 2- (Butyldimethylammonio) ethyl methacrylate = hexafluorophosphate / 3,6-dioxaheptyl methacrylate / 2-hydroxy-3-methacloyloxypropyl methacrylate copolymer (molar ratio 15/80/5) , Mw 65,000)

The content of the oil-sensitive agent is preferably 0.01% by mass to 30.0% by mass, more preferably 0.1% by mass to 15.0% by mass, and 1% by mass with respect to the total mass of the image recording layer. % To 10% by mass is more preferable.

-Other ingredients-
The image recording layer may contain a surfactant, a polymerization inhibitor, a higher fatty acid derivative, a plasticizer, inorganic particles, an inorganic layered compound and the like as other components. Specifically, the description in paragraphs 0114 to 0159 of JP-A-2008-284817 can be referred to.

-Formation of image recording layer-
The image recording layer in the lithographic printing plate original plate according to the present disclosure is coated by dispersing or dissolving each of the necessary components in a known solvent, for example, as described in paragraphs 0142 to 0143 of JP-A-2008-195018. It can be formed by preparing a liquid, applying the coating liquid on the support by a known method such as coating with a bar coater, and drying.
As the solvent, a known solvent can be used. Specifically, for example, 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-dimethyl Examples thereof include formamide, dimethylsulfoxide, γ-butyrolactone, methyl lactate and ethyl lactate. The solvent may be used alone or in combination of two or more. The solid content concentration in the coating liquid is preferably about 1 to 50% by mass.
The coating amount (solid content) of the image recording layer after coating and drying varies depending on the application, but from the viewpoint of obtaining good sensitivity and good film characteristics of the image recording layer, 0.3 g / m ^{2 to} 3.0 g /. m ² is preferred.

<Support>
The support in the lithographic printing plate original plate according to the present disclosure can be appropriately selected from known hydrophilic supports for lithographic printing plate original plates and used. As the support, a hydrophilic support is preferably mentioned. As the hydrophilic support, an aluminum plate which has been roughened by a known method and has an anodized film is preferable.

-Aluminum plate-
The aluminum plate (aluminum support) is made of a metal whose main component is aluminum, which is dimensionally stable, that is, aluminum or an aluminum alloy. The aluminum plate is composed of a pure aluminum plate or an alloy plate containing aluminum as a main component and a trace amount of foreign elements.

Foreign elements contained in aluminum alloys include silicon, iron, manganese, copper, magnesium, chromium, zinc, bismuth, nickel and titanium. The content of foreign elements in the alloy is 10% by mass or less. As the aluminum plate, a pure aluminum plate is preferable, but completely pure aluminum may contain a slight amount of different elements because it is difficult to manufacture completely pure aluminum due to smelting technology. The composition of the aluminum plate 18 is not limited, and publicly known materials (for example, JIS A 1050, JIS A 1100, JIS A 3103, and JIS A 3005) can be appropriately used.

The width of the aluminum plate is preferably about 400 mm to 2,000 mm, and the thickness is preferably about 0.1 mm to 0.6 mm. This width or thickness can be appropriately changed according to the size of the printing machine, the size of the printing plate, and the user's wishes.

-Anodized film-
The support used in the lithographic printing plate original plate according to the present disclosure is preferably an aluminum support having an anodic oxide film on the surface on the image recording layer side from the viewpoint of more exerting the effect in the present disclosure, and the image recording layer. It is an aluminum support having an anodic oxide film on the side surface, and the average thickness of the anodic oxide film is more preferably 0.5 μm to 3.0 μm.
The anodized film refers to an aluminum oxide film generally formed on the surface of an aluminum plate by anodizing treatment, which is substantially perpendicular to the surface of the film and has ultrafine micropores in which each is uniformly distributed.
The average thickness of the anodized film is preferably 0.2 μm to 3.0 μm, more preferably 0.5 μm to 3.0 μm, from the viewpoint of printing resistance and scratch suppression. It is more preferably 0.5 μm to 2.0 μm, and particularly preferably 0.75 μm to 1.5 μm.
Further, as a method for treating a support such as an anodized film and micropores, the method described in International Publication No. 2019/044431 is preferably mentioned.

Further, if necessary, the aluminum plate can be subjected to micropore enlargement treatment and pore sealing treatment of the anodized film described in JP-A-2001-253181 and JP-A-2001-322365, US Pat. Surface hydrophilization with alkali metal silicates as described in 066, 3,181,461, 3,280,734 and 3,902,734, USA. A surface hydrophilization treatment with polyvinylphosphonic acid or the like as described in each of Patents No. 3,276,868, No. 4,153,461 and No. 4,689,272 is appropriately selected. You may go there.
The support preferably has a centerline average roughness of 0.10 μm to 1.2 μm.

If necessary, the support may be 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. It may have a backcoat layer containing.

<Undercoat layer>
The planographic printing plate original plate 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 strengthens the adhesion between the support and the image recording layer in the exposed portion, and makes it easy for the image recording layer to peel off from the support in the unexposed portion, so that the developability is not impaired. Contributes to improving. Further, in the case of infrared laser exposure, the undercoat layer functions as a heat insulating layer, so that the heat generated by the exposure is diffused to the support to prevent the sensitivity from being lowered.

Examples of the compound used for the undercoat layer include polymers having an adsorptive group and a hydrophilic group that can be adsorbed on the surface of the support. A polymer having an adsorptive group and a hydrophilic group and further having a crosslinkable group is preferable in order to improve the adhesion to the image recording layer. The compound used for the undercoat layer may be a low molecular weight compound or a polymer. As the compound used for the undercoat layer, two or more kinds may be mixed and used as needed.

When the compound used for the undercoat layer is a polymer, a copolymer of a monomer having an adsorptive group, a monomer having a hydrophilic group and a monomer having a crosslinkable group is preferable.
The adsorbable adsorptive group to the surface of the support, a phenolic hydroxy group, a carboxy _{group, -PO 3 H 2, -OPO 3} H 2, -CONHSO 2 -, - SO 2 NHSO 2 -, - COCH 2 COCH 3 Is preferable. As the hydrophilic group, a sulfo group or a salt thereof, or a salt of a carboxy group is preferable. As the crosslinkable group, an acrylic group, a methacryl group, an acrylamide group, a methacrylicamide group, an allyl group and the like are preferable.
The polymer may have a crosslinkable group introduced by salt formation of the polar substituent of the polymer, a substituent having a pair charge with the polar substituent and a compound having an ethylenically unsaturated bond, and the above. A monomer other than the above, preferably a hydrophilic monomer, may be further copolymerized.

Specifically, a silane coupling agent having an addition-polymerizable ethylenic double bond reactive group described in JP-A No. 10-282679, and an ethylenic di-ethylene compound described in JP-A-2-304441. A phosphorus compound having a double bond reactive group is preferably used. Crosslinkable groups (preferably ethylenically unsaturated bonding groups) and supports described in JP-A-2005-238816, JP-A-2005-125479, JP-A-2006-239867, and JP-A-2006-215263. Low molecular weight or high molecular weight compounds having functional and hydrophilic groups that interact with the surface are also preferably used.
More preferred are polymer polymers having an adsorptive group, a hydrophilic group and a crosslinkable group that can be adsorbed on the surface of the support described in JP-A-2005-125479 and JP-A-2006-188038.

The content of the ethylenically unsaturated bond group 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 1 g of the polymer.
The weight average molecular weight (Mw) of the polymer used in the undercoat layer is preferably 5,000 or more, and more preferably 10,000 to 300,000.

In addition to the above-mentioned compound for the undercoat layer, the undercoat layer includes a chelating agent, a secondary or tertiary amine, a polymerization inhibitor, an amino group, or a functional group having a polymerization inhibitory ability and a support surface to prevent stains over time. Compounds with groups that interact with (eg, 1,4-diazabicyclo [2.2.2] octane (DABCO), 2,3,5,6-tetrahydroxy-p-quinone, chloranyl, sulfophthalic acid, hydroxy Ethylethylenediamine triacetic acid, dihydroxyethylethylenediaminediacetic acid, hydroxyethyliminodiacetic acid, etc.) may be contained.

The undercoat layer is applied by a known method. The coating amount (solid content) of the undercoat layer is ^preferably from ^{0.1mg / m 2 ~100mg / m 2} , 1mg / m 2 ~30mg / m 2 is more preferable.

<Protective layer>
The planographic printing plate original plate according to the present disclosure may have a protective layer (sometimes referred to as an overcoat layer) between the image recording layer and the outermost layer. The protective layer has a function of suppressing an image formation inhibition reaction by blocking oxygen, a function of preventing scratches on the image recording layer, and a function of preventing ablation during high-intensity laser exposure.

Protective layers with such properties are described, for example, in US Pat. Nos. 3,458,311 and JP-A-55-49729. As the oxygen low-permeability polymer used for the protective layer, either a water-soluble polymer or a water-insoluble polymer can be appropriately selected and used, and if necessary, two or more kinds may be mixed and used. it can. Specific examples thereof include polyvinyl alcohol, modified polyvinyl alcohol, polyvinylpyrrolidone, water-soluble cellulose derivatives, poly (meth) acrylonitrile, and the like.
As the modified polyvinyl alcohol, an acid-modified polyvinyl alcohol having a carboxy group or a sulfo group is preferably used. Specific examples thereof include the modified polyvinyl alcohols described in JP-A-2005-250216 and JP-A-2006-259137.

The protective layer preferably contains an inorganic layered compound in order to enhance oxygen blocking property. Inorganic laminar compound is a particle having a thin tabular shape, for example, natural mica, micas such as synthetic mica, wherein: talc represented by 3MgO · 4SiO · H 2 _O, teniolite, montmorillonite, saponite, hectorite Examples include light, zirconium phosphate and the like.
The inorganic layered compound preferably used is a mica compound. Examples of the mica compound include formulas: A (B, C) _2-5 D ₄ O ₁₀ (OH, F, O) ₂ [However, A is any of K, Na, Ca, and B and C are It is any of Fe (II), Fe (III), Mn, Al, Mg, and V, and D is Si or Al. ] Can be mentioned as a group of mica such as natural mica and synthetic mica.

In the mica group, natural mica includes muscovite, paragonite, phlogopite, biotite and lepidolite. As synthetic mica, non-swelling mica such as fluorine gold mica KMg ₃ (AlSi ₃ O ₁₀ ) F ₂ , potassium tetrasilicon mica KMg _2.5 Si ₄ O ₁₀ ) F ₂ , and Na tetrasilic mica Namg _{2. 5} (Si ₄ O ₁₀ ) F ₂ , Na or Li teniolite (Na, Li) Mg ₂ Li (Si ₄ O ₁₀ ) F ₂ , montmorillonite-based Na or Li hectrite (Na, Li) _1/8 Mg _{2 /} Examples thereof include swelling mica such as ₅ Li _1/8 (Si ₄ O ₁₀ ) F ₂ . In addition, synthetic smectites are also useful.

Among the above mica compounds, fluorine-based swelling mica is particularly useful. That is, the swellable synthetic mica has a laminated structure composed of a unit crystal lattice layer having a thickness of about 10 Å to 15 Å (1 Å = 0.1 nm), and the metal atom substitution in the lattice is significantly larger than that of other clay minerals. As a result, the lattice layer causes a positive charge shortage, and in order to compensate for this, cations such as Li ⁺ , Na ⁺ , Ca ²⁺ , and Mg ²⁺ are adsorbed between the layers. The cations intervening between these layers are called exchangeable cations and can be exchanged with various cations. In particular, when the cations between layers are Li ⁺ and Na ⁺ , the bond between the layered crystal lattices is weak because the ionic radius is small, and the cations swell greatly with water. When the share is applied in that state, it easily cleaves and forms a stable sol in water. Swellable synthetic mica has a strong tendency to do so and is particularly preferably used.

As for the shape of the mica compound, from the viewpoint of diffusion control, the thinner the thickness, the better, and the plane size is better as long as it does not hinder the smoothness of the coated surface and the transmission of active rays. Therefore, the aspect ratio is preferably 20 or more, more preferably 100 or more, and particularly preferably 200 or more. The aspect ratio is the ratio of the major axis to the thickness of the particles, which can be measured, for example, from a micrograph projection of the particles. The larger the aspect ratio, the greater the effect obtained.

The average major axis of the mica compound is preferably 0.3 μm to 20 μm, more preferably 0.5 μm to 10 μm, and particularly preferably 1 μm to 5 μm. The average thickness of the particles is preferably 0.1 μm or less, more preferably 0.05 μm or less, and particularly preferably 0.01 μm or less. Specifically, for example, in the case of a swellable synthetic mica which is a typical compound, the preferred embodiment is such that the thickness is about 1 nm to 50 nm and the surface size (major axis) is about 1 μm to 20 μm.

The content of the inorganic layered compound is preferably 1% by mass to 60% by mass, more preferably 3% by mass to 50% by mass, based on the total solid content of the protective layer. Even when a plurality of types of inorganic layered compounds are used in combination, the total amount of the inorganic layered compounds is preferably the above content. Oxygen blocking property is improved in the above range, and good sensitivity can be obtained. In addition, it is possible to prevent a decrease in meat-forming property.

The protective layer may contain known additives such as a plasticizer for imparting flexibility, a surfactant for improving coatability, and inorganic particles for controlling the slipperiness of the surface. Further, the protective layer may contain the oil-sensitive agent described in the image recording layer.

The protective layer is applied by a known method. The coating amount of the protective layer (solid content) is ^preferably from ^{0.01g / m 2 ~10g / m 2} , more preferably ^{0.02g / m 2 ~3g / m 2} , 0.02g / m 2 ~1g / m ² is particularly preferable.

(Planographic printing plate manufacturing method and lithographic printing method)
A lithographic printing plate can be produced by subjecting the original plate of the lithographic printing plate according to the present disclosure to an image and developing the plate.
The method for producing a lithographic printing plate according to the present disclosure consists of a step of exposing the lithographic printing plate original plate according to the present disclosure to an image (hereinafter, also referred to as an “exposure step”), and a group consisting of printing ink and dampening water. It is preferable to include a step of supplying at least one of the selected ones and removing the image recording layer of the non-image portion on the printing machine (hereinafter, also referred to as “on-machine development step”).
The lithographic printing method according to the present disclosure includes a step of exposing the lithographic printing plate original plate according to the present disclosure to an image (exposure step) and printing by supplying at least one selected from the group consisting of printing ink and dampening water. It is preferable to include a step of removing the image recording layer of the non-image portion on the machine to produce a lithographic printing plate (on-machine development step) and a step of printing with the obtained lithographic printing plate (printing step).
Hereinafter, preferred embodiments of each step will be described in order with respect to the method for producing a lithographic printing plate according to the present disclosure and the lithographic printing method according to the present disclosure. The lithographic printing plate original plate according to the present disclosure can also be developed with a developing solution.
Hereinafter, the exposure step and the on-machine development step in the lithographic printing plate manufacturing method will be described, but the exposure step in the lithographic printing plate manufacturing method according to the present disclosure and the exposure step in the lithographic printing method according to the present disclosure are the same. It is a step, and the on-machine development step in the lithographic printing plate manufacturing method according to the present disclosure and the on-machine development step in the lithographic printing method according to the present disclosure are the same steps.
Further, it is estimated that a part of the outermost layer is removed at the time of on-machine development, and a part remains on the surface of the image part or permeates into the inside of the image part by printing ink.

<Exposure process>
The method for producing a lithographic printing plate according to the present disclosure preferably includes an exposure step of exposing the lithographic printing plate original plate according to the present disclosure to an image to form an exposed portion and an unexposed portion. The planographic printing plate original plate according to the present disclosure is preferably exposed by laser exposure through a transparent original image having a line image, a halftone dot image, or the like, or by laser light scanning with digital data or the like.
The wavelength of the light source is preferably 750 nm to 1,400 nm. As a light source of 750 nm to 1,400 nm, a solid-state laser and a semiconductor laser that emit infrared rays are suitable. For the infrared laser, the output is preferably more than 100 mW, preferably, the exposure time per pixel is preferably within 20 microseconds, also that the amount of irradiation energy is 10mJ ^/ cm ² ~300mJ ^/ cm 2 preferable. Further, it is preferable to use a multi-beam laser device in order to shorten the exposure time. The exposure mechanism may be any of an inner drum method, an outer drum method, a flatbed method and the like.
Image exposure can be performed by a conventional method using a platesetter or the like. In the case of on-machine development, the lithographic printing plate original plate may be mounted on the printing machine and then the image may be exposed on the printing machine.

<In-machine development process>
The method for producing a lithographic printing plate according to the present disclosure involves an on-machine development step of supplying at least one selected from the group consisting of printing ink and dampening water to remove an image recording layer in a non-image area on a printing machine. It is preferable to include it.
The on-machine development method will be described below.

[In-machine development method]
In the on-machine development method, the image-exposed lithographic printing plate original plate supplies oil-based ink and water-based components on the printing machine, and the image recording layer in the non-image area is removed to produce a lithographic printing plate. Is preferable.
That is, either the flat plate printing plate original plate is mounted on the printing machine as it is without any development processing after the image exposure, or the flat plate printing plate original plate is mounted on the printing machine and then the image is exposed on the printing machine, and then When printing is performed by supplying an oil-based ink and a water-based component, in the non-image area, an uncured image recording layer is formed by either or both of the supplied oil-based ink and the water-based component in the initial stage of printing. It dissolves or disperses and is removed, exposing a hydrophilic surface in that area. On the other hand, in the exposed portion, the image recording layer cured by exposure forms an oil-based ink receiving portion having a lipophilic surface. The first supply to the printing plate may be an oil-based ink or a water-based component, but the oil-based ink is first supplied in terms of preventing contamination by the components of the image recording layer from which the water-based components have been removed. Is preferable. In this way, the lithographic printing plate original plate is developed on the printing machine and used as it is for printing a large number of sheets. As the oil-based ink and the water-based component, ordinary printing ink for lithographic printing and dampening water are preferably used.

The wavelength of the light source is preferably 300 nm to 450 nm or 750 nm to 1,400 nm as the laser for image-exposing the lithographic printing plate original plate according to the present disclosure. In the case of a light source of 300 nm to 450 nm, a lithographic printing plate original plate containing a sensitizing dye having an absorption maximum in this wavelength region in the image recording layer is preferably used, and the light source of 750 nm to 1,400 nm is preferably used as described above. Be done. A semiconductor laser is suitable as a light source of 300 nm to 450 nm.

<Developer development process>
The method for producing a lithographic printing plate according to the present disclosure includes a step of exposing the lithographic printing plate original plate according to the present disclosure to an image, and a step of removing an image recording layer in a non-image area with a developing solution to prepare a lithographic printing plate ( It may also be a method including "developer development step").
Further, the lithographic printing method according to the present disclosure includes a step of exposing the lithographic printing plate original plate according to the present disclosure to an image, and a step of removing the image recording layer of the non-image portion with a developing solution to prepare a lithographic printing plate. A method may include a step of printing with the obtained lithographic printing plate.
As the developing solution, a known developing solution can be used.
The pH of the developing solution is not particularly limited and may be a strong alkaline developing solution, but a developing solution having a pH of 2 to 11 is preferable. As the developer having a pH of 2 to 11, for example, a developer containing at least one of a surfactant and a water-soluble polymer compound is preferable.
In the development process using a strong alkaline developer, a method in which the protective layer is removed by a pre-washing step, then alkaline development is performed, the alkali is washed and removed in a post-washing step, a gum solution treatment is performed, and the drying step is performed. Can be mentioned.
When the developer containing a surfactant or a water-soluble polymer compound is used, the developer-gum solution treatment can be performed at the same time. Therefore, the post-washing step is not particularly required, and the drying step can be performed after the development and the gum liquid treatment are performed with one liquid. Further, since the protective layer can be removed at the same time as the development and the gum solution treatment, the pre-washing step is not particularly required. After the development treatment, it is preferable to remove excess developer using a squeeze roller or the like and then dry.

<Printing process>
The lithographic printing method according to the present disclosure includes a printing step of supplying printing ink to a lithographic printing plate to print a recording medium.
The printing ink is not particularly limited, and various known inks can be used as desired. Further, as the printing ink, oil-based ink or ultraviolet curable ink (UV ink) is preferably mentioned.
Further, in the printing process, dampening water may be supplied as needed.
Further, the printing step may be continuously performed in the on-machine development step or the developer development step without stopping the printing machine.
The recording medium is not particularly limited, and a known recording medium can be used as desired.

In the method for producing a lithographic printing plate from the lithographic printing plate original plate according to the present disclosure and the lithographic printing method according to the present disclosure, lithographic printing is performed before, during, and between exposure and development as necessary. The entire surface of the original plate may be heated. By such heating, the image formation reaction in the image recording layer is promoted, and advantages such as improvement of sensitivity and printing durability and stabilization of sensitivity can occur. Heating before development is preferably performed under mild conditions of 150 ° C. or lower. In the above aspect, it is possible to prevent problems such as hardening of the non-image portion. It is preferable to use very strong conditions for heating after development, preferably in the range of 100 ° C. to 500 ° C. Within the above range, a sufficient image enhancement effect can be obtained, and problems such as deterioration of the support and thermal decomposition of the image portion can be suppressed.

Hereinafter, the present disclosure will be described in detail by way of examples, but the present disclosure is not limited thereto. In addition, in this Example, "%" and "part" mean "mass%" and "part by mass", respectively, unless otherwise specified. In the polymer compound, the molecular weight is the weight average molecular weight (Mw), and the ratio of the constituent repeating units is a molar percentage, except for those specified specifically. The weight average molecular weight (Mw) is a value measured as a polystyrene-equivalent value by a gel permeation chromatography (GPC) method. Further, the average particle size means a volume average particle size unless otherwise specified.

<Preparation of support>
In order to remove the rolling oil on the surface of an aluminum plate (material JIS A 1050) having a thickness of 0.3 mm, degreasing treatment was performed at 50 ° C. for 30 seconds using a 10 mass% sodium aluminate aqueous solution, and then the hair diameter was 0. The surface of the aluminum plate was sanded using ^three 3 mm bundled nylon brushes and a Pamis-aqueous suspension (specific gravity 1.1 g / cm ³ ) having a median diameter of 25 μm, and washed thoroughly with water. The aluminum plate was immersed in a 25 mass% sodium hydroxide aqueous solution at 45 ° C. for 9 seconds for etching, washed with water, and then further immersed in a 20 mass% nitric acid aqueous solution at 60 ° C. for 20 seconds and washed with water. The etching amount on the sand trimming surface was about 3 g / m ² .

Next, an electrochemical roughening treatment was continuously performed using an AC voltage of 60 Hz. The electrolytic solution was a 1% by mass aqueous solution of nitric acid (containing 0.5% by mass of aluminum ions), and the liquid temperature was 50 ° C. The AC power supply waveform is electrochemically roughened using a carbon electrode as a counter electrode using a trapezoidal square wave AC with a TP of 0.8 ms and a duty ratio of 1: 1 for the time from zero to the peak of the current value. Was done. Ferrite was used as the auxiliary anode. The current density was 30 A / dm ² at the peak value of the current, and 5% of the current flowing from the power supply was diverted to the auxiliary anode. The amount of electricity in nitric acid electrolysis was 175 C / dm ² when the aluminum plate was an anode. Then, it was washed with water by spraying.

Subsequently, in a 0.5% by mass aqueous solution of hydrochloric acid (containing 0.5% by mass of aluminum ions) and an electrolytic solution having a liquid temperature of 50 ° C., nitrate is used under the condition that the amount of electricity is 50 C / dm ² when the aluminum plate is an anode. The surface was electrochemically roughened by the same method as electrolysis, and then washed with water by spraying.
Next, a 15 mass% sulfuric acid aqueous solution (containing 0.5 mass% of aluminum ions) having a liquid temperature of 54 ° C. was used as an electrolytic solution on an aluminum plate, and a DC anodic oxide film having a current density of 15 A / dm ² and 2.5 g / m ² was used. Was washed with water and dried to prepare a support A. The average pore diameter (surface average pore diameter) in the surface layer of the anodized film was 10 nm.
To measure the pore diameter on the surface layer of the anodic oxide film, an ultra-high resolution SEM (S-900 manufactured by Hitachi, Ltd.) is used, and a thin-film deposition process that imparts conductivity is performed at a relatively low acceleration voltage of 12 V. The surface was observed at a magnification of 150,000 times without application, and 50 pores were randomly sampled to obtain an average value. The standard error was ± 10% or less.
Further, in the present disclosure, the average thickness of the anodic oxide film is calculated as an arithmetic mean value by taking an SEM photograph (150,000 times) of the cross section of the anodic oxide film and measuring the thickness of 25 or more anodic oxide films. It shall be.

Then, in order to ensure the hydrophilicity of the non-imaged portion, the support A was silicate-treated at 50 ° C. for 7 seconds with a 2.5 mass% No. 3 sodium silicate aqueous solution, and then washed with water by spray to support. Body B was made. The amount of Si adhered was 11 mg / m ² . The average thickness of the anodized film was 0.8 μm.

In the production of the support A, the support C was produced in the same manner as the method for producing the support A, except that the electrolytic solution at the time of forming the DC anodized film was changed to a 22 mass% phosphoric acid aqueous solution. The average pore diameter (surface average pore diameter) on the surface layer of the anodized film was measured by the same method as above and found to be 25 nm.

Then, in order to ensure the hydrophilicity of the non-imaged portion, the support C was subjected to a silicate treatment at 60 ° C. for 10 seconds using a 2.5 mass% No. 3 sodium silicate aqueous solution, and then washed with water to obtain the support D. Made. The amount of Si adhered was 10 mg / m ² . When the center line average roughness (Ra) of the support D was measured using a needle having a diameter of 2 μm, it was 0.52 μm. The average thickness of the anodized film was 1.0 μm.

<Preparation of undercoat layer coating solution>
An undercoat layer coating solution having the following composition was prepared.
(Undercoat layer coating liquid)
-Polymer (UC-1) (below): 0.18 parts by mass-Hydroxyethyliminodiacetic acid: 0.10 parts by mass-Water: 61.4 parts by mass

<Preparation of protective layer coating solution>
A protective layer coating solution having the following composition was prepared.
(Protective layer coating liquid)
-Polyvinyl alcohol (CKS50, manufactured by Nippon Synthetic Chemical Industry Co., Ltd., sulfonic acid modification, saponification degree 99 mol% or more, degree of polymerization 300) 6% by mass aqueous solution: 0.55 parts by mass-Polyvinyl alcohol (PVA-405, Co., Ltd.) ) Made by Kuraray, saponification degree 81.5 mol%, degree of polymerization 500) 6% by mass aqueous solution: 0.03 parts by mass · surfactant (polyoxyethylene lauryl ether, Emarex (registered trademark) 710, Nippon Emulsion Co., Ltd. (Manufactured) 1% by mass aqueous solution: 0.86 parts by mass, ion-exchanged water: 6.0 parts by mass

<Preparation of image recording layer coating liquid (1)>
An image recording layer coating liquid (1) having the following composition was prepared. The image recording layer coating liquid (1) was prepared by mixing and stirring a photosensitive liquid in which the following components other than the specific compound were mixed and the specific compound immediately before coating.

-Image recording layer coating liquid (1)-
-Binder polymer (B-1) (below): 0.240 parts by mass-Infrared absorber (K-1): 0.024 parts by mass-Polymerization initiator (I-1) (below): 0.245 parts by mass -Polymerization initiator (R-1) (below): 0.05 parts by mass-Polymerable compound (Tris (acryloyloxyethyl) isocyanurate (NK ester A-9300, manufactured by Shin-Nakamura Chemical Industry Co., Ltd.): 0. 192 parts by mass, low molecular weight hydrophilic compound (T-2): 0.062 parts by mass, fluorine-based surfactant (1) (below): 0.008 parts by mass, acid color former (2'-anilino-6' -(N-ethyl-N-isopentylamino) -3'-methylspiro [phthalide-3,9'-xanthene], S-205 (manufactured by Fukui Yamada Chemical Industry Co., Ltd.): 0.060 parts by mass, 2- Butanone: 1.091 parts by mass, 1-methoxy-2-propanol: 8.609 parts by mass, distilled water: 2.425 parts by mass, specific compounds shown in Table 1: amounts shown in Table 1.

<Preparation of image recording layer coating liquid (2)>
An image recording layer coating liquid (2) having the following composition was prepared. The image recording layer coating liquid (2) was prepared by mixing and stirring a photosensitive liquid containing a component other than the specific compound and the specific compound immediately before coating.

-Image recording layer coating liquid (2)-
-Infrared absorber (K-2): 0.018 parts by mass-Polymerization initiator (I-2): 0.150 parts by mass-Polymerization initiator (R-1) (below): 0.010 parts by mass-Polymerization Sex compound (dipentaerythritol pentaacrylate, SR-399 (manufactured by Sartmer)): 1.500 parts by mass, acid color initiator (2'-anilino-6'-(N-ethyl-N-isopentylamino) -3 '-Methylspiro [phthalide-3,9'-xanthene], S-205 (manufactured by Fukui Yamada Chemical Industry Co., Ltd.): 0.070 parts by mass, mercapto-3-triazole: 0.200 parts by mass, Byk 336 ( Byk Chemie): 0.4 parts by mass Klucel M (Hercules, T-3 below): 4.8 parts by mass ELVACITE 4026 (Ineos Acrylics): 2.5 parts by mass n-propanol: 55.0 parts by mass ・ 2-butanone: 17.0 parts by mass ・ Specific compounds shown in Table 2: Amounts shown in Table 2.

The compounds used in the image recording layer coating liquids (1) and (2) are as follows.

Binder polymer B-1: A compound having the following structure

Infrared absorbers K-1 and K-2: A compound having the following structure, Ph represents a phenyl group.

Polymerization Initiators I-1 to I-3: Compounds with the following structure

Polymerization Initiator R-1: Compound with the following structure

<Low molecular weight hydrophilic compound>
T-1: Tris (2-hydroxyethyl) isocyanurate T-2: Compound having the following structure T-3: Hydroxypropyl cellulose (Klucel M, manufactured by Hercules)

<Fat sensitive agent>
C-1: Compound with the following structure C-2: Benzyldimethyloctylammonium / PF ₆ salt C-3: Compound with the following structure

Fluorine-based surfactant (1): Compound W-1 having the following structure

In the structure of the above polymer compound, the subscript at the lower right of the parentheses of each structural unit indicates the content ratio (mass ratio).

Byk 336: Polyester-modified dimethylpolysiloxane copolymer ELVACITE 4026: Polymethylmethacrylate

(Examples 1 to 10 and Comparative Examples 1 and 2)
<Preparation of lithographic printing plate original plate>
The planographic printing plate original plates of Examples 1 to 10 and Comparative Examples 1 and 2 were prepared by the following methods, respectively.
The undercoat layer coating solution was applied onto the support B so that the dry coating amount was 20 mg / m ² to form an undercoat layer. The image recording layer coating liquid (1) was bar-coated on the undercoat layer and dried in an oven at 120 ° C. for 40 seconds to form an image recording layer having a dry coating amount of 1.0 g / m ² .
For the lithographic printing plate original plate having a protective layer (described as "Yes" in the column of the protective layer in Table 1), the above protective layer coating solution is bar-coated on the image recording layer and dried in an oven at 120 ° C. for 60 seconds. A protective layer having a dry coating amount of 0.15 g / m ² was formed.
The lithographic printing plate original plates of Examples 1 to 3 and 5 to 10 obtained have a discontinuous (sea-island-structured sea-structured) water-insoluble layer made of a specific compound as the outermost layer. The planographic printing plate original plate of Example 4 had a continuous water-insoluble layer made of a specific compound as the outermost layer.

<Evaluation of lithographic printing plate original plate>
The lithographic printing plate original plate is mounted on a Kodak Magnus 800 Quantum equipped with an infrared semiconductor laser, and has an output of 27 W, an outer drum rotation speed of 450 rpm (revolutions per minute), and a resolution of 2,400 dpi (dot per inch, 1 inch is 2.54 cm). (Equivalent to irradiation energy of 110 mJ / cm ² ). The exposed image includes a solid image and a chart of AM screen (Amplitude Modulation Screen) 3% halftone dots.

(1) Machine-Developability The exposed planographic printing plate original plate was attached to the cylinder of a chrysanthemum-sized (636 mm × 939 mm) printing machine SX-74 manufactured by Heidelberg Co., Ltd. without developing. A non-woven fabric filter and a 100 L dampening water circulation tank with a built-in temperature control device are connected to the printing machine, and 80 L of dampening water S-Z1 (manufactured by FUJIFILM Corporation) 2.0% by mass is supplied. It was charged in the circulation device. As the printing ink, T & K UV OFS K-HS ink GE-M (manufactured by T & K TOKA Co., Ltd.), which is an ultraviolet curable ink, was used. After supplying dampening water and ink by the standard automatic printing start method, 500 sheets were printed on Tokubishi Art Paper (ream weight: 76.5 kg) at a printing speed of 10,000 sheets per hour.
In the above-mentioned on-machine development, the number of printing papers required until the ink was not transferred to the non-image area was measured as the on-machine developability. It can be said that the smaller the number of sheets, the better the on-machine developability. The evaluation results are shown in Table 1.

(2) UV curable ink print resistance (UV print resistance)
After evaluating the on-machine developability, printing was continued. As the number of printed sheets was increased, the image portion was gradually worn, and the ink density on the printed matter decreased. The number of printed sheets is taken as the number of printed sheets when the value measured by the Gretag densitometer (manufactured by Gretag Macbeth) is 1% lower than the measured value of the 500th printed sheet. The printing resistance of UV curable ink was evaluated. The UV curable ink print resistance was evaluated by the relative print resistance of 100 when the number of printed sheets was 50,000. The larger the value, the better the UV curable ink printing resistance. The evaluation results are shown in Table 1.
Relative printing resistance = (number of prints of target lithographic printing plate original plate) / 50,000 x 100

(3) Scratch-stain suppressing property A surface measuring machine TRIBOGEAR TYPE: 18LFW (manufactured by Shinto Kagaku Co., Ltd.) was used. Using a sapphire needle of 0.1 mm, the surface of the printing plate was scanned at a scanning speed of 20 mm / s while changing the load from 20 g / m ² to 50 g / m ^{2 in} 5 g / m ² increments to generate scratches. On-machine development and printing were performed using a scratched printing plate, and the load at which scratches and stains were generated on the 100th sheet of the printing start was evaluated.

(4) Filling property Development is performed by the same method as the above-mentioned evaluation of on-machine developability, and after development, dampening water and ink are supplied by the same method as the above-mentioned evaluation of on-machine developability to make Tokuryo Art Paper. Printing was started at (ream weight: 76.5 kg), and the number of sheets of printing paper required for the ink density of the image portion, which is the exposed portion, to reach the specified ink density was measured as the ink fillability.

(5) Contact angle Using DMo-701 (manufactured by Kyowa Interface Science Co., Ltd.), the contact angle of water with respect to the lithographic printing plate original was determined by the aerial water droplet method. The water droplet volume used for the measurement is 1 μL.

(6) Dynamic friction coefficient By surface measuring machine TRIBOGEAR TYPE: 18LFW (manufactured by Shinto Kagaku Co., Ltd.), using a sapphire needle 0.1 mm, a load of 40 g / m ² , a scanning speed of 20 mm / s, the highest in the lithographic printing plate original plate. The surface of the outer layer is scanned, and the coefficient of dynamic friction at the time of scratching is calculated from the resistance force at the time of scanning.

Details of the specific compounds listed in Table 1 are shown below. The same applies to Table 2 described later.
Monostearin: Glyceryl monostearate (manufactured by Kao Corporation)
Sarakos 121: Mono (hydroxystearic acid) glyceryl (manufactured by Nisshin Oillio Group Co., Ltd.)
Tristearyl phosphite: manufactured by Johoku Chemical Industry Co., Ltd. Tristearyl borate: manufactured by Tokyo Chemical Industry Co., Ltd. Monolaurin: glyceryl monolaurate (manufactured by Tokyo Chemical Industry Co., Ltd.)
Monocaprylin: Glyceryl monocaprylate (manufactured by Tokyo Chemical Industry Co., Ltd.)
Behenic acid amide: manufactured by Tokyo Chemical Industry Co., Ltd.

From the results shown in Table 1, the lithographic printing plate originals of Examples 1 to 10 which are the lithographic printing plate originals according to the present disclosure have a low coefficient of dynamic friction and a low contact angle, so that they are resistant to scratches and stains. Not only is it excellent, but it is also excellent in on-machine developability and inking property.
Further, from the results shown in Table 1, in the lithographic printing plate original plates of Examples 1 to 10 which are the lithographic printing plate original plates according to the present disclosure, the specific compound has surface uneven distribution. Since it does not affect the configuration of the image recording layer, it has excellent printing resistance, especially UV printing resistance.

(Examples 11 to 22 and Comparative Examples 3 and 4
<Preparation of lithographic printing plate original plate>
The planographic printing plate original plates of Examples 11 to 22 and Comparative Examples 3 and 4 were prepared by the following methods, respectively.
The undercoat layer coating solution was applied onto the support D so that the dry coating amount was 20 mg / m ² to form an undercoat layer. The image recording layer coating liquid (2) was bar-coated on the undercoat layer and dried in an oven at 70 ° C. for 60 seconds to form an image recording layer having a dry coating amount of 0.6 g / m ² .
For the lithographic printing plate original plate having a protective layer (described as "Yes" in the column of the protective layer in Table 2), the above protective layer coating solution is bar-coated on the image recording layer and dried in an oven at 120 ° C. for 60 seconds. A protective layer having a dry coating amount of 0.15 g / m ² was formed.
The lithographic printing plate original plates of Examples 11 to 13 and 15 to 22 obtained have a discontinuous (sea structure of sea-island structure) water-insoluble layer made of a specific compound as the outermost layer. The planographic printing plate original plate of Example 14 had a continuous water-insoluble layer made of a specific compound as the outermost layer.

<Evaluation of lithographic printing plate original plate>
The obtained lithographic printing plate original plate was evaluated for on-machine developability, UV curable ink printing resistance, scratch stain suppression property, and inking property by the same method as in Example 1. In addition, the contact angle and the coefficient of dynamic friction were measured by the same method as in Example 1. The results are shown in Table 2.

Details of the specific compounds listed in Table 2 other than those described above are shown below.
Monopalmitin: Glyceryl monopalmitate (manufactured by Tokyo Chemical Industry Co., Ltd.)
Monoolein: Glyceryl monooleate (manufactured by Tokyo Chemical Industry Co., Ltd.)

From the results shown in Table 2, the lithographic printing plate original plates of Examples 11 to 20, which are the lithographic printing plate original plates according to the present disclosure, have a low coefficient of dynamic friction and a low contact angle, and thus have high scratch resistance and stain suppression. Not only is it excellent, but it is also excellent in on-machine developability and inking property.
Further, from the results shown in Table 2, in the lithographic printing plate original plates of Examples 11 to 20 which are the lithographic printing plate original plates according to the present disclosure, the specific compound has surface uneven distribution, so that the optimum amount of the compound is added. Since it does not affect the configuration of the image recording layer, it has excellent printing resistance, especially UV printing resistance.

Claims (16)

It has a support, an image recording layer, and an outermost layer in this order.
The image recording layer contains an infrared absorber and a polymer, and contains
A lithographic printing plate original plate in which the outermost layer is a continuous or discontinuous water-insoluble layer. The planographic printing plate original plate according to claim 1, wherein the coefficient of dynamic friction of the outermost layer surface measured by a sapphire needle having a tip diameter of 0.1 mm is 0.01 to 0.05. The planographic printing plate original plate according to claim 1 or 2, wherein the contact angle of water on the outermost layer surface by the aerial water droplet method is 50 ° or less. The lithographic printing plate original plate according to any one of claims 1 to 3, wherein the polymer is polymer particles. The planographic printing plate original plate according to any one of claims 1 to 4, wherein the outermost layer contains a compound having a melting point of 40 ° C. to 150 ° C. The planographic printing plate original plate according to claim 5, wherein the compound having a melting point of 40 ° C. to 150 ° C. and a molecular weight of 300 to 1,000. The planographic printing plate original plate according to any one of claims 1 to 6, wherein the outermost layer contains a compound having 12 to 22 carbon atoms. The planographic printing plate original plate according to claim 7, wherein the compound having 12 to 22 carbon atoms has a molecular weight of 300 to 1,000. The planographic printing plate original plate according to any one of claims 1 to 8, wherein the outermost layer contains a compound having two or more hydroxy groups. Claims 1 to 9 wherein the support is an aluminum support having an anodized film on the surface on the image recording layer side, and the average thickness of the anodized film is 0.5 μm to 3.0 μm. The planographic printing plate original plate described in any one of the above. The lithographic printing plate original plate according to any one of claims 1 to 10, wherein the polymer contains a polymer having a hydrophilic structure. The planographic printing plate original plate according to claim 11, wherein the hydrophilic structure contains a structural unit represented by the following formula (AN) or a group represented by the following formula Z.
* -Q-W-Y 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, and Y represents a monovalent group having a hydrophilic structure. Represented, either W or Y has a hydrophilic structure, and * represents a binding site with another structure.

In formula (AN), ^RAN represents a hydrogen atom or a methyl group. The lithographic printing plate original plate according to any one of claims 1 to 12, wherein the polymer contains polymer particles having a polymerizable group. The lithographic printing plate original plate according to any one of claims 1 to 13, which is an on-machine developing type lithographic printing plate original plate. The step of exposing the planographic printing plate original plate according to any one of claims 1 to 14 to an image.
A method for producing a lithographic printing plate, comprising a step of supplying at least one selected from the group consisting of printing ink and dampening water on a printing machine to remove an image recording layer in a non-image area. The step of exposing the planographic printing plate original plate according to any one of claims 1 to 14 to an image.
A step of supplying at least one selected from the group consisting of printing ink and dampening water to remove the image recording layer of the non-image area on the printing machine to prepare a lithographic printing plate.
A lithographic printing method including a step of printing with the obtained lithographic printing plate.