JP2014069452A - Lithographic printing plate original plate and method producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an on-machine development-type lithographic printing plate original plate excellent in scratch resistance, printing durability and on-machine developability, and to provide a method for producing the same.SOLUTION: There are provided a lithographic printing plate original plate having an image recording layer in which an unexposed part is removed by at least any one of moistening water and ink on a support, wherein the image recording layer contains (a) a compound in which a linear molecule penetrates through cyclic molecules having a polymerizable group, (b) a polyfunctional monomer, (c) a binder polymer having a mass-average molecular weight of 20,000 to 200,000, (d) a polymerization initiator and (e) a sensitizing dye, and a method for producing the same.

Description

  The present invention relates to a lithographic printing plate precursor and a plate making method thereof, and more particularly to an on-press development type lithographic printing plate precursor excellent in scratch resistance, printing durability, and on-press developability, and a plate making method thereof.

The lithographic printing plate has an oleophilic image area for receiving ink and a hydrophilic non-image area for receiving dampening water in the printing process. Lithographic printing uses the property that water and oil-based ink repel each other, so that the oleophilic image area of the lithographic printing plate is used as the ink receiving area, and the hydrophilic non-image area is used as the dampening water receiving area (ink non-receiving area). In this method, a difference in ink adhesion is caused on the surface of the lithographic printing plate, the ink is applied only to the image area, and then the ink is transferred to a printing medium such as paper for printing.
In order to produce this lithographic printing plate, conventionally, a lithographic printing plate precursor (PS plate) in which an oleophilic photosensitive resin layer (image forming layer, image recording layer) is provided on a hydrophilic support is used. After the PS plate is exposed through a mask such as a lith film, it is developed with an alkaline developer or the like to leave an image forming layer corresponding to the image portion, and an unnecessary image forming layer corresponding to the non-image portion. Was dissolved and removed to obtain a lithographic printing plate.

  The plate making operation for producing a lithographic printing plate from a lithographic printing plate precursor has been simplified, and the lithographic printing plate is currently obtained by CTP (computer to plate) technology for image exposure. That is, a lithographic printing plate can be obtained by scanning and exposing a lithographic printing plate precursor directly using a laser or a laser diode without a lith film, and developing it.

  In addition, regarding development processing after image exposure, environmental issues related to waste liquids associated with wet processing have been highlighted, and simplification and non-processing of the development processing are aimed at. As one of simple development processes, a method called “on-press development” is performed. That is, after the exposure of the lithographic printing plate precursor, the conventional development process is not performed, and the lithographic printing plate precursor is mounted on a printing machine as it is, and the unexposed part (non-image part) of the image recording layer is removed at the initial stage of the normal printing process Is the method.

As a lithographic printing plate capable of on-press development, for example, in Patent Documents 1 and 2, a lithographic printing plate precursor having an image forming layer (thermosensitive layer) containing a microcapsule containing a polymerizable compound on a hydrophilic support. Is described. Patent Document 3 describes a lithographic printing plate precursor in which an image forming layer (photosensitive layer) containing an infrared absorber, a radical polymerization initiator, and a polymerizable compound is provided on a support. Furthermore, in Patent Document 4, on-press development is possible in which an image forming layer containing a polymerizable compound and a graft polymer having a polyethylene oxide chain in the side chain or a block polymer having a polyethylene oxide block is provided on a support. A planographic printing plate precursor is described.
However, these lithographic printing plate precursors are inferior in on-press developability or printing durability, and are still insufficient as on-press development type lithographic printing plate precursors.

  In the on-press development type lithographic printing plate precursor, after image exposure, the image recording layer in the unexposed portion is removed with dampening water and ink on the printing press to form an image. Therefore, it is desirable that the image recording layer is hydrophilic so that dampening water penetrates in order to improve on-press developability, while the image portion is hydrophobic in order to improve printing durability. It is desirable. As described above, in order to achieve both on-press developability and printing durability of the on-press development type lithographic printing plate precursor, it is necessary to finely adjust the characteristics of the image recording layer. In the on-press development process, if the surface of the image area is scratched by contact with a roller or the like of a printing press under pressure, a serious defect is given to the printed matter. Therefore, improvement of scratch resistance is an important issue.

  Patent Document 5 describes a photosensitive resin composition containing a compound in which a linear molecule penetrates a cyclic molecule having a crosslinkable binder and a substituent. Patent Document 6 describes a photocrosslinkable composition having a photocrosslinkable polyrotaxane.

JP 2001-277740 A JP 2001-277742 A JP 2002-287334 A US Patent Application Publication No. 2003/0064318 JP 2008-291208 A JP 2011-46917 A

  An object of the present invention is to provide an on-press development type lithographic printing plate precursor excellent in scratch resistance, printing durability and on-press developability, and a plate making method thereof.

1. A lithographic printing plate precursor having an image recording layer from which an unexposed portion is removed by at least one of dampening water and printing ink on a support, wherein the image recording layer is (a) a cyclic group having a polymerizable group A compound in which a linear molecule penetrates the molecule, (b) a polyfunctional monomer, (c) a binder polymer having a mass average molecular weight of 20,000 to 200,000, (d) a polymerization initiator, and (e) a sensitizing dye A lithographic printing plate precursor.

2. In the above 1., the linear molecule in the compound (a) is polyethylene glycol. The lithographic printing plate precursor described in 1.
3. In the above 1., the cyclic molecule in the compound (a) is cyclodextrin. Or 2. The lithographic printing plate precursor described in 1.
4). 1. The polymerizable group in the compound (a) is a polymerizable ethylenically unsaturated group. ~ 3. The lithographic printing plate precursor as described in any one of the above.
5. 1. The linear molecule in the compound (a) has a blocking group at both ends. ~ 4. The lithographic printing plate precursor as described in any one of the above.
6). The above (1) in which the binder polymer (c) has a crosslinkable group. ~ 5. The lithographic printing plate precursor as described in any one of the above.
7). 1. The above (c) binder polymer is a urethane polymer. ~ 6. The lithographic printing plate precursor as described in any one of the above.
8). 6. The above-mentioned urethane polymer, wherein the urethane polymer is a compound produced using at least one compound represented by the following general formula (2) or general formula (3). The lithographic printing plate precursor described in 1.

(In General Formula (2) and General Formula (3), m represents an integer of 1 to 3, n represents an integer of 2 to 60, l represents an integer of 1 to 6, and R ¹ represents a hydrogen atom or Represents a methyl group, R ² represents a hydrogen atom or an alkyl group having 12 or less carbon atoms, an alkenyl group having 12 or less carbon atoms or an aryl group having 12 or less carbon atoms, and A represents a (l + 2) -valent group.
9. The above (1) wherein the sensitizing dye is an infrared absorber. ~ 8. The lithographic printing plate precursor as described in any one of the above.
10. Above 1. ~ 9. The lithographic printing plate precursor as described in any one of the above is subjected to image exposure with an infrared laser and then attached to a printing machine cylinder, and the unexposed portion of the image recording layer is removed with at least one of dampening water and printing ink. Method.

  According to the present invention, an on-press development type lithographic printing plate precursor excellent in scratch resistance, printing durability and on-press developability and a plate making method thereof can be provided.

  According to the present invention, the image recording layer of an on-press development type lithographic printing plate precursor contains a compound in which a linear molecule penetrates a cyclic molecule having a polymerizable group, thereby improving scratch resistance, printing durability, machine An on-press development type lithographic printing plate having good upper developability can be obtained.

  Although the mechanism of action of the present invention is not clear enough, the impact absorption effect of a compound in which a linear molecule penetrates a cyclic molecule having a polymerizable group improves the printing durability and scratch resistance of the printing plate, and improves the function. During top development, when the image recording layer is pushed by a roller, a compound in which a linear molecule penetrates into a cyclic molecule having a polymerizable group is distorted, so that a space for penetrating dampening water is created. It is estimated that developability is improved.

The lithographic printing plate precursor according to the invention has an image recording layer from which an unexposed portion is removed by at least one of dampening water and printing ink on a support, and the image recording layer has (a) a polymerizable group. A compound having a linear molecule penetrating a cyclic molecule, (b) a polyfunctional monomer, (c) a binder polymer having a mass average molecular weight of 20,000 to 200,000, (d) an initiator, and (e) a sensitizer. It is characterized by including. The lithographic printing plate precursor according to the present invention can be produced by on-press development on a printing machine after image exposure.
The lithographic printing plate precursor according to the invention may have an undercoat layer between the support and the image recording layer, if necessary. The planographic printing plate precursor according to the invention may have a protective layer on the image recording layer.

The lithographic printing plate precursor according to the invention will be described below.
(Image recording layer)
The image recording layer in the lithographic printing plate precursor according to the present invention is an image recording layer in which an unexposed portion is removed by at least one of dampening water and printing ink, and (a) a linear chain to a cyclic molecule having a polymerizable group. And (b) a polyfunctional monomer, (c) a binder polymer having a mass average molecular weight of 20,000 to 200,000, (d) a polymerization initiator, and (e) a sensitizing dye.
The image recording layer can contain components such as (E) polymer fine particles, if necessary, in addition to the above components. Furthermore, various compounds other than the above can be included as required. Below, each component contained in an image recording layer is demonstrated one by one.

(A) A compound in which a linear molecule penetrates a cyclic molecule having a polymerizable group A compound in which a linear molecule penetrates a cyclic molecule having a polymerizable group used in the present invention (hereinafter referred to as “compound (a)”) Is a compound having a molecular skeleton including a cyclic molecule having a polymerizable group and a linear molecule penetrating through the cavity. In the compound (a) used in the present invention, at least one of the cyclic molecules constituting the compound (a) needs to be a cyclic molecule having a polymerizable group, but all of the cyclic molecules are polymerizable groups. It is not essential to be a cyclic molecule having The compound (a) includes compounds called “rotaxane”, “pseudorotaxane”, and “polyrotaxane” (hereinafter also referred to as “rotaxane compound”). The compound (a) preferably has blocking groups at both ends of the linear molecule.

[Cyclic molecule]
The cyclic molecule in compound (a) is not particularly limited as long as it is a cyclic molecule that can move on a linear molecule. “Cyclic” in a cyclic molecule means substantially cyclic. That is, the cyclic molecule may not be completely closed as long as it can move on the linear molecule, and may have a helical structure, for example.
As the cyclic molecule in the compound (a), a cyclic molecule in a known rotaxane compound can be used. For example, cyclic polymers such as cyclic polyether, cyclic polyester, cyclic polyetheramine, and cyclic polyamine, and cyclodextrins such as α-cyclodextrin, β-cyclodextrin, and γ-cyclodextrin are preferably used. In particular, it is preferably used for α-cyclodextrin molecules. One type or two or more types of cyclic molecules may be used.

In the compound (a), the number (inclusion amount) of the cyclic molecule included in the linear molecule is preferably, for example, 5 to 300 per compound when the cyclic molecule is cyclodextrin. Is more preferable, and 40-100 is still more preferable. If the number is less than 5, the effect of pulleys in which the crosslinking point moves freely may not be expressed. If the number exceeds 300, cyclodextrin, which is a cyclic molecule, is arranged too closely, and the mobility of cyclodextrin may be reduced. Further, the insolubility of cyclodextrin itself in an organic solvent is strengthened, so that the solubility of the compound (a) in the organic solvent may be lowered, and the on-press developability may also be lowered.
The inclusion amount of the cyclic molecule can be calculated according to a conventional method by ultraviolet light absorption measurement and NMR measurement.

(Polymerizable group)
The polymerizable group of the cyclic molecule is preferably a group that undergoes polymerization by heat or light, and more preferably a group that can undergo an addition polymerization reaction or a condensation polymerization reaction. Such polymerizable groups include polymerizable ethylenically unsaturated groups or ring-opening polymerizable groups.
More preferred are groups represented by the following P1, P2, P3 and P4.

In the above formulas P1 to P4, R ⁵¹¹ , R ⁵¹² , R ⁵¹³ , R ⁵²¹ , R ⁵²² , R ⁵²³ , R ⁵³¹ , R ⁵³² , R ⁵³³ , R ⁵⁴¹ , R ⁵⁴² , R ⁵⁴³ , R ⁵⁴⁴ , and R ⁵⁴⁵ are Each independently represents a hydrogen atom or an alkyl group. n represents 0 or 1.
The polymerizable group P1, P2, P3 or P4 may be bonded directly to the cyclic molecule or may be bonded via a linking group. The linking group is preferably an alkyleneoxy group, an alkyleneoxycarbonyloxy group, or an alkyleneoxycarbonyl group. Specific examples are shown below.

  That is, as the alkyleneoxy group, for example, an alkyleneoxy group such as ethyleneoxy, propyleneoxy, butyleneoxy, pentyleneoxy, hexyleneoxy, heptyleneoxy, or a substituted alkyleneoxy group containing an ether bond such as ethyleneoxyethoxy, Examples of the alkyleneoxycarbonyloxy group include alkyleneoxycarbonyloxy groups such as ethyleneoxycarbonyloxy, propyleneoxycarbonyloxy, butyleneoxycarbonyloxy, pentyleneoxycarbonyloxy, hexyleneoxycarbonyloxy, heptyleneoxycarbonyloxy and the like. In addition, a substituted alkyleneoxycarbonyloxy group containing an ether bond such as ethyleneoxyethoxycarbonyloxy Examples of the nyl group include an ethyleneoxycarbonyl group, a propyleneoxycarbonyl group, a butyleneoxycarbonyl group, a pentyleneoxycarbonyl group, a hexyleneoxycarbonyl group, a heptyleneoxycarbonyl group and other alkyleneoxycarbonyl groups, or ethyleneoxy A substituted alkyleneoxycarbonyl group containing an ether bond such as an ethoxycarbonyl group can be mentioned.

In the polymerizable group P1, n represents an integer of 0 or 1, and n is preferably 1. When n is 1, P1 represents a substituted or unsubstituted vinyl ether group. The substituents R ⁵¹¹ and R ⁵¹³ of the polymerizable group P1 are each independently a hydrogen atom or an alkyl group (for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, pentyl, hexyl, heptyl, octyl, nonyl). , A lower alkyl group such as methyl and ethyl is preferable, and methyl is more preferable. A combination in which R ⁵¹¹ is a methyl group and R ⁵¹³ is a hydrogen atom, or R ⁵¹¹ and R ⁵¹³ are both hydrogen atoms is preferable.

The substituent R ⁵¹² is a hydrogen atom, a substituted or unsubstituted alkyl group (for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, pentyl, hexyl, heptyl, octyl, nonyl, 2-chloroethyl, 3-methoxyethyl, Methoxyethoxyethyl, and alkyl groups having 1 to 3 carbon atoms such as methyl and ethyl are preferable, and methyl is more preferable.), A hydrogen atom and an alkyl group having 1 to 3 carbon atoms (methyl, ethyl, etc.) A hydrogen atom is more preferable. Accordingly, as the polymerizable group P1, an unsubstituted vinyloxy group which is a functional group having high polymerization activity is generally preferably used.

The polymerizable group P2 represents a substituted or unsubstituted oxirane group. The substituents R ⁵²¹ and R ⁵²² of the polymerizable group P2 are each independently a hydrogen atom or an alkyl group (eg, methyl, ethyl, n-propyl, isopropyl, n-butyl, pentyl, hexyl, heptyl, octyl, nonyl). And an alkyl group having 1 to 3 carbon atoms such as methyl and ethyl is preferable, and methyl is more preferable.), And R ⁵²¹ and R ⁵²² are preferably hydrogen atoms.

The substituent R ⁵²³ is a hydrogen atom, a substituted or unsubstituted alkyl group (for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, pentyl, hexyl, heptyl, octyl, nonyl, 2-chloroethyl, 3-methoxyethyl, Methoxyethoxyethyl is preferred, alkyl groups having 1 to 3 carbon atoms such as methyl and ethyl are preferred, and methyl is more preferred.) Represents a hydrogen atom or having 1 to 3 carbon atoms such as methyl, ethyl and n-propyl. Alkyl groups are preferred.

The polymerizable group P3 represents a substituted or unsubstituted acrylic group. The substituents R ⁵³¹ and R ⁵³³ of the polymerizable group P3 are each independently a hydrogen atom or an alkyl group (eg, methyl, ethyl, n-propyl, isopropyl, n-butyl, pentyl, hexyl, heptyl, octyl, nonyl). R ⁵³¹ is a methyl group and R ⁵³³ is a hydrogen atom, or a combination of both R ⁵³¹ and R ⁵³³ is a hydrogen atom, preferably an alkyl group having 1 to 3 carbon atoms such as methyl and ethyl. Is preferred.

The substituent R ⁵³² is a hydrogen atom, a substituted or unsubstituted alkyl group (for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, pentyl, hexyl, heptyl, octyl, nonyl, 2-chloroethyl, 3-methoxyethyl, Methoxyethoxyethyl is mentioned, an alkyl group having 1 to 3 carbon atoms such as methyl and ethyl is preferable, and methyl is more preferable), and a hydrogen atom is preferable. Accordingly, as the polymerizable group P3, a functional group having a high polymerization activity such as an unsubstituted acryloxy group, methacryloxy group, or crotonyloxy group is preferably used.

The polymerizable group P4 represents a substituted or unsubstituted oxetane group. R ⁵⁴² , R ⁵⁴³ , R ⁵⁴⁴ and R ⁵⁴⁵ are each independently a hydrogen atom or an alkyl group (eg, methyl, ethyl, n-propyl, isopropyl, n-butyl, pentyl, hexyl, heptyl, octyl, nonyl, methyl And an alkyl group having 1 to 3 carbon atoms such as ethyl is preferable, and methyl is more preferable.), And R ⁵⁴² , R ⁵⁴³ , R ⁵⁴⁴ and R ⁵⁴⁵ are all preferably hydrogen atoms.

R ⁵⁴¹ is a hydrogen atom, a substituted or unsubstituted alkyl group (for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, pentyl, hexyl, heptyl, octyl, nonyl, 2-chloroethyl, 3-methoxyethyl, methoxyethoxy Represents an alkyl group having 1 to 3 carbon atoms such as methyl and ethyl, more preferably methyl, and a hydrogen atom or an alkyl group having 1 to 3 carbon atoms such as methyl, ethyl and n-propyl. Is preferred.

[Substituents other than polymerizable groups]
In the compound (a), the cyclic molecule may have a substituent other than the polymerizable group. The following are mentioned as an example of such a substituent which a cyclic molecule has.
That is, a halogen atom (for example, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom), an alkyl group (preferably an alkyl group having 1 to 30 carbon atoms, such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, tert-butyl group, n-octyl group, 2-ethylhexyl group), cycloalkyl group (preferably a substituted or unsubstituted cycloalkyl group having 3 to 30 carbon atoms, such as cyclohexyl group, cyclopentyl group, 4-n- Dodecylcyclohexyl group), bicycloalkyl group (preferably a substituted or unsubstituted bicycloalkyl group having 5 to 30 carbon atoms, that is, a monovalent group obtained by removing one hydrogen atom from a bicycloalkane having 5 to 30 carbon atoms. For example, bicyclo [1,2,2] heptan-2-yl, bicyclo [2,2,2] octan-3-yl ,

An alkenyl group (preferably a substituted or unsubstituted alkenyl group having 2 to 30 carbon atoms, such as a vinyl group or an allyl group), a cycloalkenyl group (preferably a substituted or unsubstituted cycloalkenyl group having 3 to 30 carbon atoms, That is, it is a monovalent group in which one hydrogen atom of a cycloalkene having 3 to 30 carbon atoms is removed, for example, a 2-cyclopenten-1-yl, 2-cyclohexen-1-yl group), a bicycloalkenyl group (substituted or substituted). An unsubstituted bicycloalkenyl group, preferably a substituted or unsubstituted bicycloalkenyl group having 5 to 30 carbon atoms, that is, a monovalent group in which one hydrogen atom of a bicycloalkene having one double bond is removed. A bicyclo [2,2,1] hept-2-en-1-yl group, a bicyclo [2,2,2] oct-2-en-4-yl group), A alkynyl group (preferably a substituted or unsubstituted alkynyl group having 2 to 30 carbon atoms, such as an ethynyl group or a propargyl group), an aryl group (preferably a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, such as phenyl Group, p-tolyl group, naphthyl group),

Heterocyclic group (preferably a monovalent group obtained by removing one hydrogen atom from a 5- or 6-membered substituted or unsubstituted aromatic or non-aromatic heterocyclic compound, more preferably 3 to 3 carbon atoms. 30- or 5-membered aromatic heterocyclic group such as 2-furyl group, 2-thienyl group, 2-pyrimidinyl group, 2-benzothiazolyl group), cyano group, nitro group, alkoxy group (preferably A substituted or unsubstituted alkoxy group having 1 to 30 carbon atoms such as a methoxy group, an ethoxy group, an isopropoxy group, a tert-butoxy group, an n-octyloxy group, and a 2-methoxyethoxy group), an aryloxy group (preferably Is a substituted or unsubstituted aryloxy group having 6 to 30 carbon atoms, such as phenoxy group, 2-methylphenoxy group, 4-tert-butylphenoxy group. Group, 3-nitrophenoxy group, 2-tetradecanoylaminophenoxy group), silyloxy group (preferably a silyloxy group having 3 to 20 carbon atoms, such as trimethylsilyloxy group, tert-butyldimethylsilyloxy group), heterocyclic ring An oxy group (preferably a substituted or unsubstituted heterocyclic oxy group having 2 to 30 carbon atoms, 1-phenyltetrazole-5-oxy group, 2-tetrahydropyranyloxy group), acyloxy group (preferably formyloxy group, C2-C30 substituted or unsubstituted alkylcarbonyloxy group, C6-C30 substituted or unsubstituted arylcarbonyloxy group, for example, formyloxy group, acetyloxy group, pivaloyloxy group, stearoyloxy group, benzoyl Oxy group, p-methoxyphenylcarbo Aryloxy group),

A carbamoyloxy group (preferably a substituted or unsubstituted carbamoyloxy group having 1 to 30 carbon atoms such as N, N-dimethylcarbamoyloxy group, N, N-diethylcarbamoyloxy group, morpholinocarbonyloxy group, N, N -Di-n-octylaminocarbonyloxy group, Nn-octylcarbamoyloxy group), alkoxycarbonyloxy group (preferably a substituted or unsubstituted alkoxycarbonyloxy group having 2 to 30 carbon atoms, such as a methoxycarbonyloxy group, An ethoxycarbonyloxy group, a tert-butoxycarbonyloxy group, an n-octylcarbonyloxy group), an aryloxycarbonyloxy group (preferably a substituted or unsubstituted aryloxycarbonyloxy group having 7 to 30 carbon atoms, such as phenoxyca A bonyloxy group, a p-methoxyphenoxycarbonyloxy group, a pn-hexadecyloxyphenoxycarbonyloxy group), an acylamino group (preferably a formylamino group, a substituted or unsubstituted alkylcarbonylamino group having 1 to 30 carbon atoms, A substituted or unsubstituted arylcarbonylamino group having 6 to 30 carbon atoms such as formylamino group, acetylamino group, pivaloylamino group, lauroylamino group, benzoylamino group),

Aminocarbonylamino group (preferably a substituted or unsubstituted aminocarbonylamino group having 1 to 30 carbon atoms, such as carbamoylamino group, N, N-dimethylaminocarbonylamino group, N, N-diethylaminocarbonylamino group, morpholino Carbonylamino group), alkoxycarbonylamino group (preferably a substituted or unsubstituted alkoxycarbonylamino group having 2 to 30 carbon atoms, for example, methoxycarbonylamino group, ethoxycarbonylamino group, tert-butoxycarbonylamino group, n-octadecyloxy group) Carbonylamino group, N-methyl-methoxycarbonylamino group), aryloxycarbonylamino group (preferably a substituted or unsubstituted aryloxycarbonylamino group having 7 to 30 carbon atoms, such as phenoxyca A bonylamino group, a p-chlorophenoxycarbonylamino group, an mn-octyloxyphenoxycarbonylamino group), a sulfamoylamino group (preferably a substituted or unsubstituted sulfamoylamino group having 0 to 30 carbon atoms, such as , Sulfamoylamino group, N, N-dimethylaminosulfonylamino group, Nn-octylaminosulfonylamino group, alkyl and arylsulfonylamino groups (preferably substituted or unsubstituted alkylsulfonyl having 1 to 30 carbon atoms) Amino, substituted or unsubstituted arylsulfonylamino group having 6 to 30 carbon atoms, such as methylsulfonylamino group, butylsulfonylamino group, phenylsulfonylamino group, 2,3,5-trichlorophenylsulfonylamino group, p-methyl Phenylsulfonyla Amino group),

A mercapto group, an alkylthio group (preferably a substituted or unsubstituted alkylthio group having 1 to 30 carbon atoms, such as a methylthio group, an ethylthio group or an n-hexadecylthio group), an arylthio group (preferably a substituted or unsubstituted group having 6 to 30 carbon atoms). A substituted arylthio group such as phenylthio group, p-chlorophenylthio group, m-methoxyphenylthio group), a heterocyclic thio group (preferably a substituted or unsubstituted heterocyclic thio group having 2 to 30 carbon atoms, such as 2 -Benzothiazolylthio group, 1-phenyltetrazol-5-ylthio group), sulfamoyl group (preferably a substituted or unsubstituted sulfamoyl group having 0 to 30 carbon atoms, such as N-ethylsulfamoyl group, N- ( 3-dodecyloxypropyl) sulfamoyl group, N, N-dimethylsulfamoyl group, -Acetylsulfamoyl group, N-benzoylsulfamoyl group, N- (N′phenylcarbamoyl) sulfamoyl group), sulfo group, alkyl and arylsulfinyl group (preferably substituted or unsubstituted having 1 to 30 carbon atoms) An alkylsulfinyl group, a 6-30 substituted or unsubstituted arylsulfinyl group such as a methylsulfinyl group, ethylsulfinyl group, phenylsulfinyl group, p-methylphenylsulfinyl group), alkyl and arylsulfonyl groups (preferably having a carbon number) 1-30 substituted or unsubstituted alkylsulfonyl groups, 6-30 substituted or unsubstituted arylsulfonyl groups (eg, methylsulfonyl group, ethylsulfonyl group, phenylsulfonyl group, p-methylphenylsulfonyl group),

An acyl group (preferably a formyl group, a substituted or unsubstituted alkylcarbonyl group having 2 to 30 carbon atoms, a substituted or unsubstituted arylcarbonyl group having 7 to 30 carbon atoms, such as an acetyl group or a pivaloylbenzoyl group), Aryloxycarbonyl group (preferably a substituted or unsubstituted aryloxycarbonyl group having 7 to 30 carbon atoms, such as phenoxycarbonyl group, o-chlorophenoxycarbonyl group, m-nitrophenoxycarbonyl group, p-tert-butylphenoxy Carbonyl group), alkoxycarbonyl group (preferably a substituted or unsubstituted alkoxycarbonyl group having 2 to 30 carbon atoms, such as methoxycarbonyl group, ethoxycarbonyl group, tert-butoxycarbonyl group, n-octadecyloxycarbonyl group), carbamoyl Base Preferably, the substituted or unsubstituted carbamoyl group having 1 to 30 carbon atoms, for example, carbamoyl group, N-methylcarbamoyl group, N, N-dimethylcarbamoyl group, N, N-di-n-octylcarbamoyl group, N- (Methylsulfonyl) carbamoyl group), aryl and heterocyclic azo groups (preferably substituted or unsubstituted arylazo groups having 6 to 30 carbon atoms, substituted or unsubstituted heterocyclic azo groups having 3 to 30 carbon atoms, such as phenylazo Group, p-chlorophenylazo group, 5-ethylthio-1,3,4-thiadiazol-2-ylazo group),

Imido group (preferably N-succinimide group, N-phthalimido group), phosphino group (preferably substituted or unsubstituted phosphino group having 2 to 30 carbon atoms, such as dimethylphosphino group, diphenylphosphino group, methyl Phenoxyphosphino group), phosphinyl group (preferably a substituted or unsubstituted phosphinyl group having 2 to 30 carbon atoms, such as phosphinyl group, dioctyloxyphosphinyl group, diethoxyphosphinyl group), phosphinyloxy A group (preferably a substituted or unsubstituted phosphinyloxy group having 2 to 30 carbon atoms, such as a diphenoxyphosphinyloxy group, a dioctyloxyphosphinyloxy group), a phosphinylamino group (preferably, A substituted or unsubstituted phosphinylamino group having 2 to 30 carbon atoms, such as dimethoxy Phosphinylamino group, dimethylaminophosphinylamino group), silyl group (preferably a substituted or unsubstituted silyl group having 3 to 30 carbon atoms, such as trimethylsilyl group, tert-butyldimethylsilyl group, phenyldimethylsilyl group) Group).

Among the above substituents, those having a hydrogen atom may be substituted with the above groups after removing this. Examples of such functional groups include an alkylcarbonylaminosulfonyl group, an arylcarbonylaminosulfonyl group, an alkylsulfonylaminocarbonyl group, and an arylsulfonylaminocarbonyl group. Examples thereof include a methylsulfonylaminocarbonyl group, a p-methylphenylsulfonylaminocarbonyl group, an acetylaminosulfonyl group, and a benzoylaminosulfonyl group. These carbon numbers are the same as the corresponding substituents, and preferred examples are also the same.

  Among the substituents other than the polymerizable group that the cyclic molecule has, preferably an alkyl group, an alkenyl group, an alkynyl group, a silyloxy group, an acyloxy group, an acylamino group, a sulfamoylamino group, an alkyl and arylsulfonylamino group, an alkyl and Arylsulfonyl group, acyl group, aryloxycarbonyl group, alkoxycarbonyl group, silyl group, more preferably alkyl group, alkenyl group, silyloxy group, acyloxy group, alkyl and arylsulfonyl group, acyl group, alkoxycarbonyl group, A silyl group, more preferably an alkyl group, an alkenyl group, a silyloxy group, an acyloxy group, an acyl group, or an alkoxycarbonyl group.

  The cyclic molecule may have a plurality of substituents (including the polymerizable group), and at least one of them is preferably a polymerizable group. When a plurality of substituents are present in the cyclic molecule, examples of combinations of substituents include acetyl group / polymerizable group, alkyl group / polymerizable group, silyloxy group / polymerizable group, and the like. A plurality of substituents may be present on the same cyclic molecule in the compound (a) or may be present on different cyclic molecules.

The number of substituents of the cyclic molecule varies depending on the number of bonds that can be introduced with substituents. For example, when the cyclic molecule is α-cyclodextrin, since the number of hydroxyl groups per cyclic molecule is 18, the number of substituents that can be introduced is 18, and an average of 9 substituents was introduced. In this case, the introduction rate is 50%. The introduction rate of substituents of the cyclic molecule is not particularly limited, but is preferably 5 to 95%.
The introduction ratio of the polymerizable group is preferably from 5 to 90%, more preferably from 20 to 80%, based on the total amount of groups that can be introduced (for example, hydroxyl group in the case of cyclodextrin) present in the cyclic molecule, -70% is particularly preferred. If the amount of the polymerizable group is too small, the pulley effect is lowered, and if the amount of the polymerizable group is too large, problems such as polymerization during coating occur.
Introduction of a substituent (including the polymerizable group) into the cyclic molecule can be performed according to a conventional method.

[Linear molecule]
A linear molecule is a molecule or substance that can be integrated with a cyclic molecule by a mechanical bond rather than a chemical bond such as a covalent bond, and is not particularly limited as long as it is linear.
In the present specification, “linear” of “linear molecule” means substantially “linear”. That is, as long as the cyclic molecule can move on the linear molecule, the linear molecule may have a branched chain or may have a substituent. Examples of the substituent that may be included include the substituents that the cyclic molecule has.

  As a linear molecule, a well-known rotaxane compound can be used. Suitable linear molecules include polyalkylene glycols such as polyethylene glycol, polypropylene glycol and polytetramethylene glycol; polybutadiene diol, polyisoprene diol, polyisobutylene diol, poly (acrylonitrile-butadiene) diol, hydrogenated polybutadiene. Terminal hydroxyl group polyolefins such as diol, polyethylene diol and polypropylene diol; Polycaprolactone diol, Polylactic acid, Polyethylene adipate, Polybutylene adipate, Polyesters such as polyethylene terephthalate, Polybutylene terephthalate; Terminal functionality such as terminal silanol type polydimethylsiloxane Polysiloxanes: terminal amino group polyethylene glycol, terminal amino group polypro Glycol, terminal amino group chain polymer such as the terminal amino groups polybutadiene; and the like above-mentioned functional group polyfunctional chain polymer molecules, three or more functionalities with in one molecule three or more can be mentioned. From the viewpoint of improving the on-press developability, polyalkylene glycol is preferable, and polyethylene glycol is particularly preferable. The linear molecules may be used alone or in combination of two or more.

  The mass average molecular weight of the linear molecule is suitably from 2,000 to 1,000,000, preferably from 10,000 to 500,000. When the molecular weight is less than 2,000, there is an effect of restricting the mobility due to the terminal blocking group, and the stress relaxation effect is not sufficiently exhibited. Moreover, when molecular weight exceeds 1 million, compatibility with a compound (a) and a binder polymer falls, and workability | operativity also falls.

The linear molecule preferably has a reactive group (terminal functional group) capable of binding to a blocking group described later at the terminal. Suitable terminal functional groups include hydroxyl groups, amino groups, carboxyl groups, acid chloride groups, phenol groups, isocyanate groups, vinyl groups, acrylic groups, methacryl groups, styryl groups, active ester groups, thiol groups, and lactone ring groups. , A cyclic / chain acid anhydride group, a carbonate group, a silane group, a silanol group, an alkoxysilyl group, and the like, particularly preferably a hydroxyl group, an amino group, and a carboxyl group. The terminal functional groups of the linear molecule may be the same or different.
The terminal functional group is introduced, for example, by reacting the terminal hydroxyl group of polyethylene glycol with carbonyldiimidazole and subsequently reacting with ethylenediamine to synthesize a terminal amino group polyethylene glycol. Hereinafter, “polyethylene glycol” and “polypropylene glycol” may include cases where these molecular ends are modified by chemical modification.

[Blocking group]
The compound (a) preferably has a structure such that the cyclic molecule does not leave the linear molecule. For this purpose, for example, a blocking group may be introduced at the end of the linear molecule. The blocking group can be used without limitation as long as it is a sufficiently bulky group that binds to the terminal by reacting with the terminal functional group and cannot remove the cyclic molecule. Preferred blocking groups include 2,4-dinitrophenyl group, trityl group, dansyl group, 2,4,6-trinitrophenyl group, triisopropylsilyl group, naphthalene derivative group, anthracene derivative group, fluoresceins, pyrene , Cyclodextrins, adamantanes and the like. The blocking group at the end of the linear molecule may be the same or different. Further, a compound in which a reactive group (for example, a light or heat crosslinkable group such as an ethylenically unsaturated group or an epoxy group is preferable) is further bonded to the blocking group.

Specific examples of the linear molecule, blocking group, cyclic molecule, and polymerizable group are shown in Tables 1-1 to 1-3 below.
Specific examples of the compound (a) according to the present invention are shown in Table 1-1 to Table 1-2.

本発明に係る化合物（a）は、その環状分子が有する重合性基の重合反応の進行により、環状分子間、環状分子と(b)多官能モノマーとの間、環状分子と(c) 質量平均分子量が２万〜２０万のバインダーポリマーが架橋性基を有する場合には、バインダーポリマーとの間に架橋構造が形成され、有効な滑車効果が発現し、高い衝撃吸収効果を有する。

The compound (a) according to the present invention comprises a cyclic molecule, a cyclic molecule and (b) a polyfunctional monomer, a cyclic molecule and (c) a mass average by the progress of the polymerization reaction of the polymerizable group of the cyclic molecule. When the binder polymer having a molecular weight of 20,000 to 200,000 has a crosslinkable group, a crosslinked structure is formed with the binder polymer, an effective pulley effect is exhibited, and a high impact absorbing effect is obtained.

(B) Multifunctional monomer The polyfunctional monomer used in the image recording layer in the invention is an addition polymerizable compound having at least two ethylenically unsaturated double bonds, and has at least two terminal ethylenically unsaturated bonds. A polymerizable compound is preferred.
When the polyfunctional monomer is involved in crosslinking with the compound (a), a pulley effect is exhibited and high impact absorption is achieved.

  Examples of monomers include esters of unsaturated carboxylic acids (for example, acrylic acid, methacrylic acid, etc.) and polyhydric alcohol compounds, and amides of unsaturated carboxylic acids and polyvalent amine compounds. Also, an addition reaction product of an unsaturated carboxylic acid ester or amide having a nucleophilic substituent such as a hydroxy group, amino group or mercapto group with a polyfunctional isocyanate or epoxy, and dehydration with a polyfunctional carboxylic acid A condensation reaction product or the like is also preferably used. Also, addition reaction products of unsaturated carboxylic acid esters or amides having an electrophilic substituent such as an epoxy group or an epoxy group with polyfunctional alcohols, amines or thiols, further halogen groups or tosyloxy groups A substitution reaction product of an unsaturated carboxylic acid ester or amide having a leaving substituent such as polyfunctional alcohols, amines or thiols is also suitable. As another example, it is also possible to use a group of compounds substituted with unsaturated phosphonic acid, styrene, vinyl ether or the like instead of the unsaturated carboxylic acid. These are disclosed in JP-T-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 references including Kaihei 10-333321.

  Specific examples of the monomer of the ester of a polyhydric alcohol compound and an unsaturated carboxylic acid include acrylic acid esters such as ethylene glycol diacrylate, 1,3-butanediol diacrylate, tetramethylene glycol diacrylate, propylene glycol diacrylate, Examples include trimethylolpropane triacrylate, hexanediol diacrylate, tetraethylene glycol diacrylate, pentaerythritol tetraacrylate, sorbitol triacrylate, isocyanuric acid ethylene oxide (EO) -modified triacrylate, and polyester acrylate oligomer. Methacrylic acid esters include tetramethylene glycol dimethacrylate, neopentyl glycol dimethacrylate, trimethylolpropane trimethacrylate, ethylene glycol dimethacrylate, pentaerythritol trimethacrylate, bis [p- (3-methacryloxy-2-hydroxypropoxy) phenyl ] Dimethylmethane, bis- [p- (methacryloxyethoxy) phenyl] dimethylmethane, and the like. Specific examples of amide monomers of polyvalent amine compounds and unsaturated carboxylic acids include methylene bis-acrylamide, methylene bis-methacrylamide, 1,6-hexamethylene bis-acrylamide, 1,6-hexamethylene bis-methacrylic. Examples include amide, diethylenetriamine trisacrylamide, xylylene bisacrylamide, and xylylene bismethacrylamide.

Further, urethane-based addition polymerizable compounds produced by using an addition reaction of isocyanate and hydroxyl group are also suitable. Specific examples thereof include, for example, one molecule described in JP-B-48-41708. A vinyl urethane compound containing two or more polymerizable vinyl groups in one molecule obtained by adding a vinyl monomer containing a hydroxyl group represented by the following general formula (X) to a polyisocyanate compound having two or more isocyanate groups Etc.
^{_{CH 2 = C (R 4)}} COOCH 2 CH (R 5) OH formula (X)
(However, R ⁴ and R ⁵ represent H or CH _3. )

Also, urethanes described in JP-A-51-37193, JP-B-2-32293, JP-B-2-16765, JP-A-2003-344997, and JP-A-2006-65210. Acrylates, JP-B 58-49860, JP-B 56-17654, JP-B 62-39417, JP-B 62-39418, JP-A 2000-250211, JP-A 2007-94138 Urethane compounds having an ethylene oxide-based skeleton described in the publication, and urethane compounds having a hydrophilic group described in US Pat. No. 7,153,632, JP-T 8-505958, JP-A 2007-293221, and JP-A 2007-293223. Are also suitable.
Among them, tris (acryloyloxyethyl) isocyanurate, bis (acryloyloxyethyl) hydroxyethyl isocyanurate, etc. are excellent in the balance between the hydrophilicity involved in on-press developability and the polymerization ability involved in printing durability. Isocyanuric acid ethylene oxide modified acrylates are particularly preferred.

  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 added, can be arbitrarily set according to the performance design of the final lithographic printing plate precursor. The polymerizable compound is preferably used in the range of 5 to 75% by mass, more preferably 25 to 70% by mass, and particularly preferably 30 to 60% by mass with respect to the total solid content of the image recording layer.

(c) Binder polymer having a mass average molecular weight of 20,000 to 200,000 In order to improve the film strength of the image recording layer, a binder polymer having a mass average molecular weight of 20,000 to 200,000 is used in the image recording layer of the present invention. . If the binder polymer that can be used in the present invention has a mass average molecular weight of 20,000 to 200,000, a conventionally known polymer having a film property can be used without limitation. Specifically, an acrylic polymer, a vinyl acetal polymer, a urethane polymer, or the like is preferably used. From the viewpoint of improving the film strength of the image recording layer, it is preferable to use a urethane polymer. As a urethane polymer, the polymer of Unexamined-Japanese-Patent No. 2011-93314 and Unexamined-Japanese-Patent No. 2011-161872 can be used.

  Among them, as a binder polymer suitable for the present invention, it is preferable to form a chemical bond with the polymerizable group of the compound (a) by image exposure to form a crosslinked structure, and therefore, described in JP-A-2008-195018. Examples thereof include those having a crosslinkable group in the main chain or side chain, preferably in the side chain.

  The crosslinkable group is preferably an ethylenically unsaturated group such as a (meth) acryl group, a vinyl group, an allyl group, or a styryl group, or an epoxy group, and these groups are introduced into the polymer by polymer reaction or copolymerization. Can do. For example, a reaction between an acrylic polymer or polyurethane having a carboxy group in the side chain and polyurethane 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.

  The content of the crosslinkable group in the binder polymer is preferably 0.1 to 10.0 mmol, more preferably 1.0 to 7.0 mmol, particularly preferably 2.00.5 to 5.5 mmol per 1 g of the binder polymer. It is.

  The binder polymer preferably further has a hydrophilic group. The hydrophilic group contributes to the improvement of on-press developability of the image recording layer. In particular, coexistence of a crosslinkable group and a hydrophilic group makes it possible to achieve both good printing durability and on-press developability.

  Examples of the hydrophilic group include a hydroxy group, a carboxyl group, an alkylene oxide structure, an amino group, an ammonium group, an amide group, a sulfo group, and a phosphoric acid group. Among these, an alkylene oxide structure is preferable. In order to impart a hydrophilic group to the binder polymer, for example, a monomer having a hydrophilic group may be copolymerized.

  The binder polymer may have a poly (alkylene oxide) moiety as a hydrophilic group in the main chain or a side chain, for example, a graft polymer having a poly (alkylene oxide) moiety in the side chain, A block polymer having a block composed of a repeating unit containing a poly (alkylene oxide) moiety and a block composed of a repeating unit not containing (alkylene oxide) can be mentioned.

  The alkylene oxide in the poly (alkylene oxide) moiety is preferably an alkylene oxide having 2 to 6 carbon atoms, and particularly preferably ethylene oxide or propylene oxide. 2-120 is suitable for the repeating number of the alkylene oxide in a poly (alkylene oxide) site | part, 2-70 are preferable and 2-50 are more preferable. If the number of alkylene oxide repeats is 120 or less, it is preferable because the deterioration of printing durability due to ink acceptability and abrasion is suppressed.

  The poly (alkylene oxide) moiety is preferably contained as a side chain of the binder polymer in a structure represented by the following general formula (a). More preferably, it is contained as a side chain of the binder polymer in a structure represented by the following general formula (a).

In general formula (a), y represents 2-120, 2-70 is preferable and 2-50 is more preferable. R ₁ represents a hydrogen atom or an alkyl group, and R ₂ represents a hydrogen atom or an organic group. As the organic machine, an alkyl group having 1 to 6 carbon atoms is preferable, and a methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, isobutyl group, t-butyl group, n -Pentyl group, isopentyl group, neopentyl group, n-hexyl group, isohexyl group, 1,1-dimethylbutyl group, 2,2-dimethylbutyl group, cyclopentyl group, and cyclohexyl group.

In general formula (a), R ₁ is preferably a hydrogen atom or a methyl group, particularly preferably a hydrogen atom. R ₂ is particularly preferably a hydrogen atom or a methyl group.

  As the urethane polymer, a urethane polymer produced using at least one of a diol compound represented by the following general formula (2) or a diisocyanate compound represented by the general formula (3) is particularly preferable. The urethane polymer improves the film strength of the image recording layer due to hydrogen bonding between urethane polymers, and further develops on-press with a polyalkylene oxide chain contained in the compound represented by formula (2) or (3). Has the effect of improving.

In general formula (2) and general formula (3), m represents an integer of 1 to 3, n represents an integer of 2 to 60, l represents an integer of 1 to 6, and R ¹ represents a hydrogen atom or methyl. R ² represents a hydrogen atom or an alkyl group having 12 or less carbon atoms, an alkenyl group having 12 or less carbon atoms or an aryl group having 12 or less carbon atoms, and A represents a (l + 2) -valent group.
In the production of the urethane polymer, when a plurality of compounds represented by the general formula (2) and the general formula (3) are used, m, n, l, R ¹ , R ² and A in the plurality of compounds are the same. But it may be different.

Specific examples (1) to (12) of the binder polymer used in the present invention are shown below, but the present invention is not limited thereto.
In addition, in the following exemplary compounds, the numerical value written together with the repeating unit of the main chain represents the mole percentage of the repeating unit. The numerical value written together with the repeating unit of the side chain indicates the number of repetitions of the repeating site.

  The mass average molecular weight (Mw) of the binder polymer in the present invention is 20,000 to 200,000, preferably 20,000 to 100,000, more preferably 30,000 to 80,000 as a polystyrene conversion value by the GPC method. When the weight average molecular weight of the binder polymer is 20,000 or more, the printing durability and the scratch resistance are improved by the high impact absorption effect due to the film strength and the pulley effect. The printing durability improves as the molecular weight increases, but on-press developability decreases when the molecular weight exceeds 200,000.

  In the present invention, if necessary, hydrophilic polymers such as polyacrylic acid and polyvinyl alcohol described in JP-A-2008-195018 can be used. Further, a lipophilic binder polymer and a hydrophilic binder polymer can be used in combination.

  The content of the binder polymer is suitably 5 to 90% by mass, preferably 5 to 80% by mass, and more preferably 10 to 70% by mass with respect to the total solid content of the image recording layer.

(D) Polymerization initiator The (d) polymerization initiator used in the present invention is a compound that initiates and accelerates the polymerization of the (b) polyfunctional monomer. As the polymerization initiator according to the present invention, a known thermal polymerization initiator, a compound having a bond with a small bond dissociation energy, a photopolymerization initiator, and the like can be used. For example, (a) organic halide, (b) carbonyl compound, (c) azo compound, (d) organic peroxide, (e) metallocene compound, (f) azide compound, (g) hexaarylbiimidazole compound, (H) A borate compound, (i) a disulfone compound, (j) an oxime ester compound, and (k) an onium salt compound can be used.

(A) As the organic halide, compounds described in paragraph numbers [0022] to [0023] of JP-A-2008-195018 are preferable.

(B) As the carbonyl compound, compounds described in paragraph [0024] of JP-A-2008-195018 are preferable.

  (C) As the azo compound, for example, an azo compound described in JP-A-8-108621 can be used.

  (D) As the organic peroxide, for example, compounds described in paragraph [0025] of JP-A-2008-195018 are preferable.

  As the (e) metallocene compound, for example, the compound described in paragraph [0026] of JP-A-2008-195018 is preferable.

(F) Examples of the azide compound include 2,6-bis (4-azidobenzylidene) -4-methylcyclohexanone.
(G) As the hexaarylbiimidazole compound, for example, a compound described in paragraph [0027] of JP-A-2008-195018 is preferable.

  (H) As the borate compound, for example, compounds described in paragraph [0028] of JP-A-2008-195018 are preferred.

  (I) Examples of the disulfone compound include compounds described in JP-A Nos. 61-166544 and 2002-328465.

  (J) As the oxime ester compound, for example, compounds described in paragraph numbers [0028] to [0030] of JP-A-2008-195018 are preferable.

  (K) Examples of the onium salt compounds include S.I. I. Schlesinger, Photogr. Sci. Eng. , 18, 387 (1974), T.A. S. Bal et al, Polymer, 21, 423 (1980), diazonium salts described in JP-A-5-158230, ammonium described in US Pat. No. 4,069,055, JP-A-4-365049, and the like. Salt, phosphonium salts described in U.S. Pat. Nos. 4,069,055 and 4,069,056, EP 104,143, U.S. Patent Application Publication No. 2008/0311520 JP-A-2-150848, JP-A-2008-195018, or J.P. V. Crivello et al, Macromolecules, 10 (6), 1307 (1977), iodonium salts, European Patent Nos. 370,693, 233,567, 297,443, 297,442, US Patent 4,933,377, 4,760,013, 4,734,444, 2,833,827, German Patents 2,904,626, 3,604,580, Sulfonium salts described in each specification of JP-A-3,604,581; V. Crivello et al, J.A. Polymer Sci. , Polymer Chem. Ed. , 17, 1047 (1979), a selenonium salt described in C.I. S. Wen et al, Teh, Proc. Conf. Rad. Curing ASIA, p478 Tokyo, Oct (1988), and onium salts such as azinium salts described in JP-A-2008-195018.

  As the polymerization initiator, an iodonium salt or a borate compound is preferably used. Although the specific example of these compounds is shown below, it is not limited to this.

  The iodonium salt is preferably a diphenyl iodonium salt, particularly preferably a diphenyl iodonium salt substituted with an electron donating group such as an alkyl group or an alkoxyl group, and more preferably an asymmetric diphenyl iodonium salt. 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-perfluorobutanesulfonate, 4-octyloxyphenyl-2,4,6-trimethoxyphenyliodonium = hexafluorophosphate, bis ( -t- butylphenyl) iodonium tetraphenylborate and the like.

  Specific examples of the borate compound include tetraphenylborate salt, tetratolylborate salt, tetrakis (4-methoxyphenyl) borate salt, tetrakis (pentafluorophenyl) borate salt, tetrakis (3,5-bis (trifluoromethyl) phenyl ) Borate salt, tetrakis (4-chlorophenyl) borate salt, tetrakis (4-fluorophenyl) borate salt, tetrakis (2-thienyl) borate salt, tetrakis (4-phenylphenyl) borate salt, tetrakis (4-t-butylphenyl) ) Borate salt, ethyl triphenyl borate salt, butyl triphenyl borate salt and the like. From the viewpoint of achieving both printing durability and tone reproducibility, tetraphenylborate salts are preferred. Examples of counter cations of these borate salts include known cations such as alkali metal cations, alkaline earth metal cations, ammonium cations, phosphonium cations, sulfonium cations, iodonium cations, diazonium cations, and azinium cations.

As the polymerization initiator, a triarylsulfonium salt in which three or more electron-withdrawing groups having a specific structure are substituted can be preferably used. A triarylsulfonium salt is a salt composed of a monovalent cation and a counter anion having a molecular structure in which three aryl groups are bonded to a sulfur atom. The aryl group is preferably phenyl or naphthyl, and more preferably phenyl.
The specific structure is a triarylsulfonium salt in which three or more electron-withdrawing groups are substituted, wherein at least one aryl group has at least one electron-withdrawing group and has 4 to 12 carbon atoms. A chain, branched or cyclic hydrocarbon group, a group in which a linear, branched or cyclic hydrocarbon group having 4 to 12 carbon atoms is bonded via an oxygen atom or a sulfur atom, a hydrocarbon group having an aromatic ring or a heterocyclic ring, Having at least one group having a structure in which a hydrocarbon group having an aromatic ring or a heterocyclic ring is bonded via an oxygen atom or a sulfur atom, or an alkylene oxide group having 1 to 3 repeating units. Features.

  The electron withdrawing group includes a halogen atom, a halogenated alkyl group, an acyl group, an acyloxy group, an alkanesulfinyl group, a cyano group, a nitro group, an amide group, a carboxyl group, and a carboxylate group. The halogen atom includes a fluorine atom, a chlorine atom, a bromine atom and an iodine atom. The halogenated alkyl group includes a trifluoromethyl group. The acyl group includes an acetyl group and a formyl group. The alkanesulfinyl group includes a methanesulfinyl group. The amide group includes an acetamide group. The carboxylic acid ester group includes a carboxylic acid alkyl ester group and a carboxylic acid phenyl ester group, and the alkyl has 1 to 8 carbon atoms. The electron-withdrawing group is preferably a halogen atom or a halogenated alkyl group, more preferably a fluorine atom, a chlorine atom or a trifluoromethyl group, and particularly preferably a chlorine atom, from the viewpoint of the amount of radicals generated. The number of electron-withdrawing groups of one aryl group in the specific structure is more preferably two. The sum of the electron-withdrawing groups as the triarylsulfonium salt is preferably larger in the range of 3 to 6 from the viewpoint of radical mobility and amount.

  At least one aryl group of the triarylsulfonium salt substituted with three or more electron-withdrawing groups has at least one electron-withdrawing group and is a linear, branched or cyclic carbonization having 4 to 12 carbon atoms. A hydrogen group, a group in which a linear, branched or cyclic hydrocarbon group having 4 to 12 carbon atoms is bonded via an oxygen atom or a sulfur atom, a hydrocarbon group having an aromatic ring or a heterocyclic ring, an aromatic ring or a heterocyclic ring The hydrocarbon group has a group bonded through an oxygen atom or a sulfur atom, or an alkylene oxide group having 1 to 3 repeating units. From the viewpoint of radical mobility, it has at least one electron-withdrawing group, and is a linear, branched or cyclic hydrocarbon group having 4 to 12 carbon atoms, a linear, branched or cyclic group having 4 to 12 carbon atoms. Is preferably a group in which a straight-chain, branched or cyclic hydrocarbon group having 4 to 12 carbon atoms is bonded through an oxygen atom or a sulfur atom. . Particularly preferred is a group in which a linear or branched hydrocarbon group having 6 to 10 carbon atoms is bonded via an oxygen atom.

  The preferred specific examples of the triarylsulfonium salt having a specific structure are shown below, but the present invention is not limited thereto.

  The content of the polymerization initiator is preferably from 0.1 to 50 mass%, more preferably from 0.5 to 30 mass%, particularly preferably from 0.8 to 20 mass%, based on the total solid content of the image recording layer. Within this range, good sensitivity, printing durability, tone reproducibility and on-press developability can be obtained. Only one type of polymerization initiator may be used alone, or two or more types may be used in combination.

(E) Sensitizing dye A sensitizing dye absorbs light at the time of image exposure and is excited to provide energy to the polymerization initiator by electron transfer, energy transfer, or heat generation, thereby improving the polymerization initiation function. If there is no particular limitation, it can be used. In the present invention, a sensitizing dye having absorption in the wavelength range of 300 to 1400 nm is preferably used. Specifically, a sensitizing dye having a maximum absorption in a wavelength region of 300 to 450 nm and a sensitizing dye having a maximum absorption in a wavelength region of 750 to 1400 nm (hereinafter also referred to as an infrared absorber) are preferable.
As a sensitizing dye having a maximum absorption in a wavelength region of 300 to 450 nm, for example, a compound described in European Patent No. 1049882 can be suitably used.
As the infrared absorber, a dye or a pigment is preferably used.

As the infrared absorbing dye, commercially available dyes and known dyes described in documents such as “Dye Handbook” (edited by the Society for Synthetic Organic Chemistry, published in 1970) can be used. Specifically, dyes such as azo dyes, metal complex azo dyes, pyrazolone azo dyes, naphthoquinone dyes, anthraquinone dyes, phthalocyanine dyes, carbonium dyes, quinoneimine dyes, methine dyes, cyanine dyes, squarylium dyes, pyrylium salts, metal thiolate complexes, etc. Is mentioned.
Among these dyes, preferred are cyanine dyes, squarylium dyes, pyrylium salts, nickel thiolate complexes, and indolenine cyanine dyes. Further, cyanine dyes and indolenine cyanine dyes are preferred, and particularly preferred examples include cyanine dyes represented by the following general formula (IV).

In the general formula (IV), ^{X 1} is a hydrogen atom, a halogen ^{atom, -N (R 9) (R} 10), - X 2 -L ¹ or a group shown below. R ⁹ and R ¹⁰ may be the same or different and each may have a substituent, an aromatic hydrocarbon group having 6 to 10 carbon atoms, an alkyl group having 1 to 8 carbon atoms, or a hydrogen atom Or R ⁹ and R ¹⁰ may be bonded to each other to form a ring. Of these, a phenyl group is preferred. X ² represents an oxygen atom or a sulfur atom, and L ¹ represents a hydrocarbon group having 1 to 12 carbon atoms, an aromatic ring group or hetero atom having a hetero atom (N, S, O, halogen atom, Se). And a hydrocarbon group having 1 to 12 carbon atoms. In the following formulas, X _a ^- is Z _a to be described later ^- is synonymous with, R ^a represents a hydrogen atom or an alkyl group, an aryl group, a substituted or unsubstituted amino group, and a halogen atom KARARI substituent selected of.

R ¹ and R ^{2 in} the general formula (IV) each independently represent a hydrocarbon group having 1 to 12 carbon atoms. In view of storage stability of the image recording layer coating solution, R ¹ and R ² are preferably hydrocarbon groups having 2 or more carbon atoms. R ¹ and R ² may be connected to each other to form a ring, and when a ring is formed, it is particularly preferable to form a 5-membered ring or a 6-membered ring.

Ar ¹ and Ar ² may be the same or different and each represents an aryl group which may have a substituent. Preferred aryl groups include a benzene ring group and a naphthalene ring group. Preferred examples of the substituent include a hydrocarbon group having 12 or less carbon atoms, a halogen atom, and an alkoxy group having 12 or less carbon atoms. Y ¹ and Y ² may be the same or different and each represents a sulfur atom or a dialkylmethylene group having 12 or less carbon atoms. R ³ and R ⁴ may be the same or different and each represents a hydrocarbon group having 20 or less carbon atoms, which may have a substituent. Preferred substituents include an alkoxy group having 12 or less carbon atoms, a carboxy group, and a sulfo group. R ⁵ , R ⁶ , R ⁷ and R ⁸ may be the same or different and each represents a hydrogen atom or a hydrocarbon group having 12 or less carbon atoms. In view of easy availability of the raw material, a hydrogen atom is preferred. Z _a ⁻ represents a counter anion. However, when the cyanine dye represented by formula (IV) has an anionic substituent in the structure thereof, Z _a is does not require charge neutralization ^- is not necessary. Preferred Z _a ⁻ is a halide ion, a perchlorate ion, a tetrafluoroborate ion, a hexafluorophosphate ion, or a sulfonate ion, more preferably a perchlorate ion, from the storage stability of the image recording layer coating solution. , Hexafluorophosphate ions or aryl sulfonate ions.

  Specific examples of the cyanine dye represented by the general formula (IV) include paragraph numbers [0017] to [0019] of JP-A No. 2001-133969 and paragraph numbers [0016] to [0021] of JP-A No. 2002-023360. ], Compounds described in paragraphs [0012] to [0037] of JP-A No. 2002-040638, preferably paragraphs [0034] to [0041] of JP-A No. 2002-278057, JP-A No. 2008-195018. The compounds described in paragraph numbers [0080] to [0086] of the gazette, particularly preferably the compounds described in paragraph numbers [0035] to [0043] of JP-A-2007-90850 are exemplified.

  Further, compounds described in paragraph numbers [0008] to [0009] of JP-A No. 5-5005 and paragraph numbers [0022] to [0025] of JP-A No. 2001-222101 can also be preferably used.

  Although the preferable specific example of an infrared absorber is given to the following, this invention is not limited to this.

  An infrared absorber may use only 1 type and may use 2 or more types together. A dye and a pigment may be used in combination. As the pigment, compounds described in paragraph numbers [0072] to [0076] of JP-A-2008-195018 are preferable.

  The content of the sensitizing dye is preferably 0.05 to 30 parts by mass, more preferably 0.1 to 20 parts by mass, and particularly preferably 0.2 to 10 parts by mass with respect to 100 parts by mass of the total solid content of the image recording layer. Part by mass.

(F) Polymer fine particles The image recording layer may contain polymer fine particles in order to improve the on-press developability. In particular, polymer fine particles having a polyalkylene oxide structure are preferred. Polymer fine particles having a polyalkylene oxide group in the side chain are more preferred.
The polymer fine particles improve the permeability of the fountain solution and improve the on-press developability. As the polyalkylene oxide structure, an alkylene oxide structure having 2 to 120 alkylene oxide units having 2 or 3 carbon atoms is preferable, and a polyethylene oxide structure having 2 to 120 ethylene oxide units is more preferable. Particularly preferred is a polyethylene oxide structure having 20 to 100 ethylene oxide units. The polymer fine particles having such a polyalkylene oxide structure can further improve the compatibility between printing durability and on-press developability. Moreover, the inking property can be improved.

  The polymer fine particles are preferably a hydrophobized precursor that can convert the image recording layer to be hydrophobic when heat is applied. The hydrophobized precursor polymer fine particles are preferably at least one particle selected from hydrophobic thermoplastic polymer fine particles, heat-reactive polymer fine particles, microcapsules enclosing a hydrophobic compound, and microgel (crosslinked polymer fine particles). Among these, polymer fine particles and microgels having a polymerizable group are preferable. In order to improve the on-press developability, it may have a polyalkylene oxide structure as described above.

Hydrophobic thermoplastic polymer fine particles include Research Disclosure No. 1 of January 1992. 33303, hydrophobic thermoplastic polymer fine particles described in JP-A-9-123387, JP-A-9-131850, JP-A-9-171249, JP-A-9-171250, European Patent 931647, and the like are suitable. Can be cited as
Specific examples of the polymer constituting the polymer fine particle include ethylene, styrene, vinyl chloride, methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate, vinylidene chloride, acrylonitrile, vinyl carbazole, acrylate having a polyalkylene structure, or Mention may be made of homopolymers or copolymers of monomers such as methacrylates or mixtures thereof. Among them, more preferable examples include a copolymer containing polystyrene, styrene and acrylonitrile, and polymethyl methacrylate.

  The average particle diameter of the hydrophobic thermoplastic polymer fine particles used in the present invention is preferably 0.01 to 2.0 μm.

  Examples of the heat-reactive polymer fine particles used in the present invention include polymer fine particles having a heat-reactive group, and these form a hydrophobized region by cross-linking by a heat reaction and a functional group change at that time.

  The heat-reactive group in the polymer fine particle having a heat-reactive group may be any functional group that performs a reaction as long as a chemical bond is formed, but an ethylenically unsaturated group that performs a radical polymerization reaction (for example, An acryloyl group, a methacryloyl group, a vinyl group, an allyl group, etc.), a cationic polymerizable group (for example, a vinyl group, a vinyloxy group, etc.), an isocyanate group that performs an addition reaction or a block thereof, an epoxy group, a vinyloxy group, and these reactions. Functional group (for example, amino group, hydroxy group, carboxy group, etc.) having an active hydrogen atom as a partner, a carboxy group that performs a condensation reaction, a hydroxy group or amino group that is a reaction partner, an acid anhydride that performs a ring-opening addition reaction In addition, an amino group or a hydroxy group which is a reaction partner can be preferably mentioned.

  As the microcapsules used in the present invention, for example, as described in JP-A-2001-277740, JP-A-2001-277742, and European Patent 2383118, all or a part of the constituent components of the image recording layer may be used. It is preferable that the microcapsules are encapsulated. The constituent components of the image recording layer can also be contained outside the microcapsules. The image recording layer containing microcapsules is preferably a mode in which hydrophobic constituent components are encapsulated in microcapsules and hydrophilic constituent components are contained outside the microcapsules.

  In this invention, the aspect containing a crosslinked resin particle, ie, a microgel, may be sufficient. This microgel can contain a part of the constituents of the image recording layer in and / or on the surface thereof. In particular, (b) a mode in which a reactive microgel is formed by having a polyfunctional monomer on the surface thereof. From the viewpoint of image formation sensitivity and printing durability, it is preferable.

  A known method can be applied to microencapsulate or microgel the constituents of the image recording layer.

  The average particle size of the microcapsules or microgel is preferably 0.01 to 3.0 μm, more preferably 0.05 to 2.0 μm, and particularly preferably 0.10 to 1.0 μm. Within this range, good resolution and stability over time can be obtained.

  The content of the polymer fine particles is preferably in the range of 5 to 90% by mass based on the total solid content of the image recording layer.

(G) Other components The image recording layer according to the present invention may further contain the following components as required.

(G-1) Low molecular weight hydrophilic compound The image recording layer may contain a low molecular weight hydrophilic compound in order to improve the on-press developability without decreasing the printing durability.
As the low molecular weight hydrophilic compound, for example, as the water-soluble organic compound, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol and the like glycols and ether or ester derivatives thereof, glycerin, Polyols such as pentaerythritol and tris (2-hydroxyethyl) isocyanurate, organic amines such as triethanolamine, diethanolamine and monoethanolamine and salts thereof, organic sulfones such as alkylsulfonic acid, toluenesulfonic acid and benzenesulfonic acid Acids and salts thereof, organic sulfamic acids such as alkylsulfamic acid and salts thereof, organic sulfuric acids such as alkylsulfuric acid and alkylethersulfuric acid and salts thereof, phenylphosphonic acid Organic phosphonic acids and salts thereof, tartaric acid, oxalic acid, citric acid, malic acid, lactic acid, gluconic acid, organic carboxylic acids and salts thereof such as amino acids, betaines, and the like.

  In the present invention, 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. Sodium 5,8,11-trioxapentadecane-1-sulfonate, sodium 5,8,11-trioxaheptadecane-1-sulfonate, 13-ethyl-5,8,11-trioxaheptadecane-1; -Sodium sulfonate, alkylsulfonate containing ethylene oxide chain such as sodium 5,8,11,14-tetraoxatetracosane-1-sulfonate, sodium benzenesulfonate, sodium p-toluenesulfonate, p-hydroxybenzene Sulfo Acid sodium, sodium p-styrenesulfonate, sodium dimethyl-5-sulfonate isophthalate, sodium 1-naphthylsulfonate, sodium 4-hydroxynaphthylsulfonate, disodium 1,5-naphthalenedisulfonate, 1,3,6 -Aryl sulfonates such as trisodium naphthalene trisulfonate, paragraph numbers [0026] to [0031] of JP 2007-276454 A, and paragraph numbers [0020] to [0047] of JP 2009-154525 A And the compounds described. The sodium 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, potassium salt or lithium salt. Specific examples thereof include compounds described in paragraph numbers [0034] to [0038] of JP-A-2007-276454.

  As the betaines, compounds having 1 to 5 carbon atoms of the hydrocarbon substituent on the nitrogen atom are preferable. Specific examples include trimethylammonium acetate, dimethylpropylammonium acetate, 3-hydroxy-4-trimethyl. Ammonioobylate, 4- (1-pyridinio) butyrate, 1-hydroxyethyl-1-imidazolioacetate, trimethylammonium methanesulfonate, dimethylpropylammonium methanesulfonate, 3-trimethylammonio-1-propanesulfonate, Examples include 3- (1-pyridinio) -1-propanesulfonate.

  Since low molecular weight hydrophilic compounds have a small hydrophobic part structure and almost no surface activity, dampening water penetrates into the exposed part of the image recording layer (image part), reducing the hydrophobicity and film strength of the image part. In this way, it is possible to keep the image recording layer in a good condition and the printing durability.

The content of the low molecular weight hydrophilic compound is preferably from 0.5 to 20 mass%, more preferably from 1 to 15 mass%, particularly preferably from 2 to 10 mass%, based on the total solid content of the image recording layer. In this range, good on-press developability and printing durability can be obtained.
A low molecular weight hydrophilic compound may be used independently and may be used in mixture of 2 or more types.

(G-2) Grease-sensitizing agent The image-recording layer according to the invention contains a oil-sensitizing agent such as a phosphonium compound, a nitrogen-containing low molecular weight compound, or an ammonium group-containing polymer in order to improve the inking property. be able to. In particular, when the inorganic layered compound is contained in the protective layer, these sensitizers function as a surface coating agent for the inorganic layered compound, and prevent a decrease in the inking property during printing by the inorganic layered compound.

  Suitable phosphonium compounds include 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) butanedi (hexafluorophosphate), 1,7-bis (tri Phenylphosphonio) heptane sulfate, 1,9-bis (triphenylphosphonio) nonane = naphthalene-2,7-disulfonate, and the like.

  Examples of the nitrogen-containing low molecular weight compound include amine salts and quaternary ammonium salts. Also included are imidazolinium salts, benzoimidazolinium salts, pyridinium salts, and quinolinium salts. Of these, quaternary ammonium salts and pyridinium salts are preferred. Specific examples include tetramethylammonium = hexafluorophosphate, tetrabutylammonium = hexafluorophosphate, dodecyltrimethylammonium = p-toluenesulfonate, benzyltriethylammonium = hexafluorophosphate, benzyldimethyloctylammonium = hexafluorophosphate. Fert, benzyldimethyldodecyl ammonium = hexafluorophosphate, paragraph numbers [0021] to [0037] of JP-A-2008-284858, paragraph numbers [0030] to [0057] of JP-A-2009-90645 Compound etc. are mentioned.

  The ammonium group-containing polymer may be any polymer as long as it has an ammonium group in its structure, but a polymer containing 5 to 80 mol% of (meth) acrylate having an ammonium group in the side chain as a copolymerization component is preferable. Specific examples include the polymers described in paragraph numbers [0089] to [0105] of JP2009-208458A.

  The ammonium salt-containing polymer has a reduced specific viscosity (unit: ml / g) determined by the following measurement method, preferably in the range of 5 to 120, more preferably in the range of 10 to 110. Those in the range of 100 are particularly preferred. When the reduced specific viscosity is converted into a mass average molar mass (Mw) in terms of polystyrene by GPC method, it is preferably from 10000 to 150,000, more preferably from 17000 to 140000, and particularly preferably from 20000 to 130,000.

<Measurement method of reduced specific viscosity>
1 g of polymer solid content was weighed into a 20 ml volumetric flask and diluted with N-methylpyrrolidone. This solution is allowed to stand for 30 minutes in a thermostatic bath at 30 ° C., put in an Ubbelohde reduced specific viscosity tube (viscosity constant = 0.010 cSt / s), and the time for flowing down at 30 ° C. is measured. The measurement is performed twice with the same sample, and the average value is calculated. Similarly, in the case of a blank (only N-methylpyrrolidone), the reduced specific viscosity (ml / g) is calculated from the following formula.

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-toluenesulfonate / hexyl methacrylate copolymer (molar 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 million)
(6) 2- (Butyldimethylammonio) ethyl methacrylate = hexafluorophosphate / 3,6-dioxaheptyl methacrylate copolymer (molar ratio 25/75 Mw 650,000)
(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-methacryloyloxypropyl methacrylate copolymer (molar ratio 15/80/5 (Mw 650,000)

  The content of the sensitizer is preferably 0.01 to 30.0% by mass, more preferably 0.1 to 15.0% by mass, and more preferably 1 to 10% by mass with respect to the total solid content of the image recording layer. Further preferred.

(G-3) Others In the image recording layer, as other components, surfactants, colorants, print-out agents, polymerization inhibitors, higher fatty acid derivatives, plasticizers, inorganic fine particles, inorganic layered compounds, and sensitization aids. An agent or a chain transfer agent may be added. Specifically, paragraph numbers [0114] to [0159] of Japanese Patent Application Laid-Open No. 2008-284817, paragraph numbers [0023] to [0027] of Japanese Patent Application Laid-Open No. 2006-091479, and US Patent Publication No. 2008/0311520. The compound and the addition amount described in paragraph [0060] are preferably used.

(Formation of image recording layer)
The image recording layer in the present invention is a coating solution prepared by dispersing or dissolving the necessary components in a known solvent as described in paragraphs [0142] to [0143] of JP-A-2008-195018, for example. This is prepared by coating the substrate by a known method such as bar coater coating and drying. The image recording layer coating amount (solid content) on the support obtained after coating and drying varies depending on the application, but is generally preferably 0.3 to 3.0 g / m ² . Within this range, good sensitivity and good film characteristics of the image recording layer can be obtained.

[Undercoat layer]
In the lithographic printing plate precursor according to the invention, an undercoat layer (sometimes referred to as an intermediate layer) is preferably provided between the image recording layer and the support. The undercoat layer enhances the adhesion between the support and the image recording layer in the exposed area, and easily peels off the image recording layer from the support in the unexposed area. Contributes to improvement. In the case of infrared laser exposure, the undercoat layer functions as a heat insulating layer, thereby preventing the heat generated by the exposure from diffusing to the support and reducing the sensitivity.

  As the compound used for the undercoat layer, an undercoat layer having a compound having an acid group such as phosphonic acid, phosphoric acid, or sulfonic acid is preferably used. Further, an adsorbing group capable of adsorbing on the surface of the support and one having a crosslinkable group for improving the adhesion to the image recording layer are preferable. These compounds may be low molecular weight or high molecular weight polymers. These compounds may be used as a mixture of two or more if necessary.

In the case of 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. Examples of the adsorptive group that can be adsorbed on the support surface include 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 preferred. As the hydrophilic group, a sulfo group is preferable. The crosslinkable group is preferably a methacryl group or an allyl group. The polymer may have a crosslinkable group introduced by salt formation between the polar substituent of the polymer and a compound having a counter charge and an ethylenically unsaturated bond, and Monomers other than those mentioned above, preferably hydrophilic monomers, may be further copolymerized.
Specifically, a silane coupling agent having an addition-polymerizable ethylenic double bond reactive group described in JP-A-10-282679 and an ethylenic compound described in JP-A-2-304441. The phosphorus compound which has a heavy bond reactive group is mentioned suitably. The crosslinkable groups described in JP-A-2005-238816, JP-A-2005-12549, JP-A-2006-239867, JP-A-2006-215263, and JP-A-2011-2445846 (preferably an ethylenic group) Those containing a low molecular or high molecular compound having a saturated bonding group), a functional group that interacts with the support surface, and a hydrophilic group are also preferably used. More preferably, it has an adsorptive group, a hydrophilic group, and a crosslinkable group that can be adsorbed on the surface of the support described in JP-A Nos. 2005-12549, 2006-188038, and 2011-245846. A high molecular polymer is mentioned.

The content of the unsaturated double bond in the polymer for the undercoat layer is preferably 0.1 to 10.0 mmol, more preferably 0.2 to 5.5 mmol per 1 g of the polymer.
The polymer for the undercoat layer preferably has a mass average molecular weight of 5,000 or more, more preferably 10,000 to 300,000.

  In addition to the above compound for the undercoat layer, the undercoat layer is a chelating agent, a secondary or tertiary amine, a polymerization inhibitor, an amino group, or a functional group having a polymerization inhibiting ability and an aluminum support for preventing contamination over time. Compounds having a group that interacts with the surface (for example, 1,4-diazabicyclo [2,2,2] octane (DABCO), 2,3,5,6-tetrahydroxy-p-quinone, chloranil, sulfophthalic acid , Hydroxyethylethylenediaminetriacetic acid, dihydroxyethylethylenediaminediacetic acid, hydroxyethyliminodiacetic acid, and the like.

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

[Support]
As the support used in the lithographic printing plate precursor according to the present invention, a known support is used. Of these, an aluminum plate that has been roughened and anodized by a known method is preferred.
In addition, the above aluminum plate is optionally subjected to micropore enlargement treatment or sealing treatment of an anodized film described in JP-A Nos. 2001-253181 and 2001-322365, and US Pat. 714,066, 3,181,461, 3,280,734 and 3,902,734, or alkali metal silicates as described in U.S. Pat. Surface hydrophilization treatment with polyvinylphosphonic acid or the like as described in each specification of 3,276,868, 4,153,461 and 4,689,272 is appropriately performed and performed. be able to.
The support preferably has a center line average roughness of 0.10 to 1.2 μm.

  The support used in the lithographic printing plate precursor according to the present invention is described on the back surface thereof by an organic polymer compound described in JP-A-5-45885, as described in JP-A-6-35174. A backcoat layer containing a silicon alkoxy compound can be provided.

[Protective layer]
The lithographic printing plate precursor according to the invention preferably has a protective layer (overcoat layer) on the image recording layer. In addition to the function of suppressing the image formation inhibition reaction by blocking oxygen, the protective layer has a function of preventing scratches in the image recording layer and preventing ablation during high-illuminance laser exposure.
The protective layer in the lithographic printing plate precursor according to the invention may be composed of two or more layers. For example, the protective layer may have a two-layer structure including an upper protective layer and a lower protective layer.

The protective layer is described in, for example, US Pat. No. 3,458,311 and Japanese Patent Publication No. 55-49729. As the low oxygen permeability polymer used for the protective layer, either a water-soluble polymer or a water-insoluble polymer can be appropriately selected and used, and two or more types can be mixed and used as necessary. it can. Specific examples include polyvinyl alcohol, modified polyvinyl alcohol, polyvinyl pyrrolidone, water-soluble cellulose derivatives, poly (meth) acrylonitrile, and the like.
As the modified polyvinyl alcohol, acid-modified polyvinyl alcohol having a carboxy group or a sulfo group is preferably used. Specifically, modified polyvinyl alcohols described in JP-A-2005-250216 and JP-A-2006-259137 are suitable.

The protective layer preferably contains an inorganic stratiform compound such as natural mica and synthetic mica as described in JP-A-2005-119273 in order to enhance oxygen barrier properties.
The protective layer may contain a known additive such as a plasticizer for imparting flexibility, a surfactant for improving coating properties, inorganic fine particles for controlling surface slipperiness, and an ultraviolet absorber. it can. Further, the protective layer may contain the sensitizing agent described for the image recording layer.

  Adhesion with the image recording layer and scratch resistance are also extremely important in handling the lithographic printing plate precursor. That is, when a hydrophilic protective layer mainly composed of a water-soluble polymer is laminated on an oleophilic image recording layer, film peeling due to insufficient adhesive force is likely to occur, and the peeled portion may be poorly cured due to oxygen polymerization inhibition. Cause defects. On the other hand, various proposals have been made to improve the adhesion between these two layers. For example, in Japanese Patent Publication No. 54-12215 and British Patent Application No. 1303578, an acrylic emulsion or a water-insoluble vinylpyrrolidone-vinyl acetate copolymer is mixed in an amount of 20 to 60% by mass in a protective layer. Describes that sufficient adhesion can be obtained. Any of these known techniques can be applied to the protective layer in the present invention.

The protective layer can be applied by a known method described in, for example, US Pat. No. 3,458,311 and JP-A-55-49729. Coating amount after drying of the protective layer is preferably from 0.01 to 10 g / ^{m 2,} more preferably ^{0.02~3g / m 2, 0.02~1g / m} 2 is particularly preferred.

[Plate making method]
Plate making of the lithographic printing plate precursor according to the invention is performed by an on-press development method. Plate making by the on-press development method is a printing process in which an image is exposed to a lithographic printing plate precursor, and an oil-based ink and an aqueous component are supplied to the lithographic printing plate precursor after exposure without any development treatment. And an unexposed portion of the image recording layer of the planographic printing plate precursor is removed in the course of the printing step.

As a light source used for image exposure, a laser is preferable. Although the laser used for this invention is not specifically limited, A solid laser, a semiconductor laser, etc. which irradiate infrared rays with a wavelength of 750-1400 nm are mentioned suitably.
Regarding the infrared laser, the output is preferably 100 mW or more, the exposure time per pixel is preferably within 20 microseconds, and the irradiation energy amount is preferably 10 to 300 mJ / cm ² . In laser exposure, it is preferable to use a multi-beam laser device in order to shorten the exposure time.

  The exposed lithographic printing plate precursor is mounted on a plate cylinder of a printing press. In the case of a printing press equipped with a laser exposure device, image exposure is performed after a lithographic printing plate precursor is mounted on a plate cylinder of the printing press.

  When printing is performed by supplying dampening water and printing ink to the lithographic printing plate precursor exposed imagewise, the image recording layer cured by exposure has a printing ink acceptance having an oleophilic surface in the exposed portion of the image recording layer. Forming part. On the other hand, in the unexposed area, the uncured image recording layer is removed by dissolution or dispersion by the supplied dampening water and / or printing ink, and a hydrophilic surface is exposed in that area. As a result, the fountain solution adheres to the exposed hydrophilic surface, and the printing ink is deposited on the image recording layer in the exposed portion and printing is started.

Here, the fountain solution or the printing ink may be supplied to the printing plate first, but the printing ink is first supplied in order to prevent the fountain solution from being contaminated by the removed image recording layer components. Is preferably supplied.
In this way, the planographic printing plate precursor of the present invention is developed on an offset printing machine and used for printing a large number of sheets as it is.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further more concretely, this invention is not limited to a following example. Unless otherwise specified, “part” is based on mass. Moreover, in the polymer compound, the molecular weight is a mass average molecular weight (Mw) except for those specifically defined, and the ratio of the repeating units is a mole percentage.

  Synthesis examples of the compound (a) according to the present invention are shown below.

(Synthesis Example 1: Synthesis of G11 of Compound (a))
<Preparation of end-capped polyrotaxane>
4.5 g of polyethylene glycol bisamine having a mass average molecular weight of 20,000 and 18.0 g of α-cyclodextrin were added to 150 mL of water and heated to 80 ° C. to dissolve. The solution was cooled and allowed to stand at 5 ° C. for 16 hours. The produced white paste-like precipitate was collected and dried.

To the dried product, a mixed solution of 12.0 g of 2,4-dinitrofluorobenzene and 50 g of dimethylformamide was added and stirred at room temperature for 5 hours. The reaction mixture was dissolved by adding 200 mL of dimethyl sulfoxide (DMSO), and then poured into 3750 mL of water to separate a precipitate. The precipitate was redissolved in 250 mL of DMSO and then poured again into 3500 mL of 0.1% saline to separate the precipitate. The precipitate was washed with water and methanol three times each, and then vacuum-dried at 50 ° C. for 12 hours, whereby polyethylene glycol bisamine was included in α-cyclodextrin in a skewered manner, and both terminal amino groups had 2 Thus, 2.0 g of a compound to which a 4-dinitrophenyl group was bonded was obtained.

  When the amount of inclusion of α-cyclodextrin was calculated by performing ultraviolet light absorption measurement and 1H-NMR measurement of the obtained compound (end-capped polyrotaxane), the amount of inclusion was 72. Specifically, in the ultraviolet light absorption measurement, the molar absorption coefficient at 360 nm of each of the obtained compound and 2,4-dinitroaniline was measured, and the inclusion amount of cyclodextrin was calculated. In 1H-NMR measurement, the amount of inclusion was calculated from the integral ratio of hydrogen atoms in the polyethylene part and hydrogen atoms in the cyclodextrin part.

<Acetyl modification of end-capped polyrotaxane>
1 g of the clathrate compound synthesized above (end-capped polyrotaxane) was dissolved in 50 g of an 8% solution of lithium chloride / N, N-dimethylacetamide. Thereto were added 6.7 g of acetic anhydride, 5.2 g of pyridine, and 100 mg of N, N-dimethylaminopyridine, and the mixture was stirred overnight at room temperature. The reaction solution was poured into methanol, and the precipitated solid was separated by centrifugation. The separated solid was dried and then dissolved in acetone. The solution was poured into water, and the precipitated solid was separated by centrifugation and dried, whereby 1.2 g of acetyl-modified polyrotaxane was obtained.
The obtained acetyl-modified polyrotaxane was subjected to 1H-NMR measurement, and the acetyl introduction rate was calculated to be 75%.

<Introduction of polymerizable group>
1 g of the acetyl-modified polyrotaxane synthesized above was dissolved in 50 g of an 8% solution of lithium chloride / N, N-dimethylacetamide. Thereto were added 5.9 g of acrylic acid chloride, 5.2 g of pyridine, and 100 mg of N, N-dimethylaminopyridine, and the mixture was stirred at room temperature overnight. The reaction solution was poured into methanol, and the precipitated solid was separated by centrifugation. The separated solid was dried and then dissolved in acetone. The solution was poured into water, and the precipitated solid was separated by centrifugation and dried to obtain 0.8 g of acryloyl and acetyl modified polyrotaxane.
The obtained acryloyl and acetyl modified polyrotaxane were subjected to 1H-NMR measurement, and the acryloyl introduction rate was calculated to be 12%.

  G12 to G20 of the compound (a) were synthesized in the same manner by changing the charging ratio, reaction time, etc. in the synthesis method of G-11.

[Examples 1 to 15 and Comparative Examples 1 to 4]
1. Preparation of lithographic printing plate precursor (1) Preparation of support In order to remove rolling oil on the surface of an aluminum plate (material JIS A 1050) having a thickness of 0.3 mm, a 10 mass% sodium aluminate aqueous solution was used at 50 ° C. for 30 minutes. After degreasing for 2 seconds, the aluminum surface was grained using ^three bundled nylon brushes having a bristle diameter of 0.3 mm and a pumice-water suspension (specific gravity 1.1 g / cm ³ ) having a median diameter of 25 μm. Wash well with water. This plate was etched by being immersed in a 25 mass% sodium hydroxide aqueous solution at 45 ° C for 9 seconds, washed with water, further immersed in a 20 mass% nitric acid aqueous solution at 60 ° C for 20 seconds, and washed with water. At this time, the etching amount of the grained surface was about 3 g / m ² .

Next, an electrochemical roughening treatment was performed continuously using an alternating voltage of 60 Hz. The electrolytic solution at this time was a 1% by mass nitric acid aqueous solution (containing 0.5% by mass of aluminum ions) and a liquid temperature of 50 ° C. The AC power supply waveform is electrochemical roughening treatment using a trapezoidal rectangular wave AC with a time TP of 0.8 msec until the current value reaches a peak from zero, a duty ratio of 1: 1, and a trapezoidal rectangular wave AC. Went. Ferrite was used for the auxiliary anode. The current density was 30 A / dm ² at the peak current value, and 5% of the current flowing from the power source was shunted to the auxiliary anode. The amount of electricity in nitric acid electrolysis was 175 C / dm ² when the aluminum plate was the anode. Then, water washing by spraying was performed.

Subsequently, nitric acid electrolysis was performed with an aqueous solution of 0.5% by mass hydrochloric acid (containing 0.5% by mass of aluminum ions) and an electrolytic solution having a liquid temperature of 50 ° C. under the condition of an electric quantity of 50 C / dm ² when the aluminum plate was the anode. In the same manner as above, an electrochemical surface roughening treatment was performed, followed by washing with water by spraying.
Next, after providing a direct current anodic oxide film of 2.5 g / m ² at a current density of 15 A / dm ² using a 15 mass% sulfuric acid aqueous solution (containing 0.5 mass% of aluminum ions) as an electrolytic solution on the aluminum plate, Washing with water and drying yielded a support (1).
Thereafter, in order to ensure the hydrophilicity of the non-image area, the support (1) 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 a support. (2) was obtained. The adhesion amount of Si was 10 mg / m ² . The centerline average roughness (Ra) of this substrate was measured using a needle having a diameter of 2 μm and found to be 0.51 μm.

(2) Formation of undercoat layer Next, the following undercoat layer coating solution (1) is applied onto the support (2) so that the dry coating amount is 20 mg / m ² , and a support having an undercoat layer is obtained. Produced.

<Undercoat layer coating solution (1)>
・ Undercoat layer compound (1) 0.25 g having the following structure
・ Hydroxyethyliminodiacetic acid 0.08g
・ Methanol 50.24g
・ Water 8.15g

(3) Formation of image recording layer The image recording layer coating solution (1) having the following composition was bar-coated on the undercoat layer formed as described above, and then oven-dried at 100 ° C for 60 seconds to obtain a dry coating amount. An image recording layer of 1.0 g / m ² was formed.
The image recording layer coating solution (1) was obtained by mixing and stirring the following photosensitive solution (1) and microgel solution (1) immediately before coating.

<Photosensitive solution (1)>
Compound (a) [compound shown in Table 2] 0.200 g
・ Polyfunctional monomer [Monomer shown in Table 2] 0.200 g
-Binder polymer (1) [Binders shown in Table 2] 0.200 g
Infrared absorbing dye (1) [the following structure] 0.030 g
・ Polymerization initiator (1) [the following structure] 0.152 g
・ Low molecular weight hydrophilic compound Tris (2-hydroxyethyl) isocyanurate 0.050 g
・ Low molecular weight hydrophilic compound (1) [following structure] 0.040 g
-Sensitizing agent Phosphonium compound (1) [the following structure] 0.055 g
・ Sensitizer Benzyldimethyloctylammonium ・ PF ₆ salt 0.018g
-Sensitizer Ammonium group-containing polymer [the following structure, reduced specific viscosity 44 ml / g] 0.035 g
・ Fluorosurfactant (1) [The following structure] 0.008g
・ 2-butanone 1.091g
・ 1-methoxy-2-propanol 8.609g

<Microgel solution (1)>
・ Microgel (1) 3000g
・ Distilled water 2.425g

  Binder polymer (1), infrared absorbing dye (1), polymerization initiator (1), phosphonium compound (1), low molecular weight hydrophilic compound (1), ammonium group-containing polymer and fluorine-based surfactant (1) The structure of) is as shown below.

-Synthesis of microgel (1)-
As an oil phase component, trimethylolpropane and xylene diisocyanate adduct (Mitsui Chemical Polyurethane Co., Ltd., Takenate D-110N) 10 g, pentaerythritol triacrylate (Nippon Kayaku Co., Ltd., SR444) 3.15 g, And 0.1 g of Pionein A-41C (manufactured by Takemoto Yushi Co., Ltd.) was dissolved in 17 g of ethyl acetate. As an aqueous phase component, 40 g of a 4 mass% aqueous solution of PVA-205 (manufactured by Kuraray Co., Ltd.) was prepared. The oil phase component and the aqueous phase component were mixed and emulsified for 10 minutes at 12,000 rpm using a homogenizer. The obtained emulsion was added to 25 g of distilled water, stirred at room temperature for 30 minutes, and then stirred at 50 ° C. for 3 hours. The microgel solution thus obtained was diluted with distilled water so that the solid content concentration was 15% by mass, and this was designated as microgel (1). When the average particle size of the microgel was measured by a light scattering method, the average particle size was 0.2 μm.

(4) Formation of Protective Layer After the bar coating of the protective layer coating solution (1) having the following composition was applied on the image recording layer, it was oven-dried at 120 ° C. for 60 seconds, and the dry coating amount was 0.15 g / m ^2. A lithographic printing plate precursor was prepared by forming a protective layer.

<Protective layer coating solution (1)>
・ Inorganic layered compound dispersion (1) 2.0 g
-Polyvinyl alcohol (Nippon Synthetic Chemical Industry Co., Ltd. CKS50, sulfonic acid modification,
Saponification degree 99 mol% or more, polymerization degree 300) 6% by mass aqueous solution 0.55 g
・ Polyvinyl alcohol (PVA-405 manufactured by Kuraray Co., Ltd.)
Degree of saponification 81.5 mol%, degree of polymerization 500) 6% by weight aqueous solution 0.03 g
・ Surfactant (Emulex 710 manufactured by Nippon Emulsion Co., Ltd.)
1% by weight aqueous solution 0.86g
・ Ion-exchanged water 6.0g

(Preparation of inorganic layered compound dispersion (1))
6.4 g of synthetic mica Somasif ME-100 (manufactured by Coop Chemical Co., Ltd.) was added to 193.6 g of ion-exchanged water, and dispersed using an homogenizer until the average particle size (laser scattering method) became 3 μm. The aspect ratio of the obtained dispersed particles was 100 or more.
2. Evaluation of lithographic printing plate precursor The on-press developability, printing durability and scratch resistance of each lithographic printing plate precursor were evaluated as follows. The results are shown in Table 2.

(1) On-machine developability The lithographic printing plate precursor was exposed with a Luxel PLANETTER T-6000III equipped with an infrared semiconductor laser under the conditions of an outer drum rotation speed of 1000 rpm, a laser output of 70%, and a resolution of 2400 dpi. The exposure image included a solid image and a 50% halftone dot chart of a 20 μm dot FM screen.
The obtained exposed original plate was attached to a plate cylinder of a printing machine LITHRONE 26 manufactured by Komori Corporation without developing. Equality-2 (manufactured by FUJIFILM Corporation) / tap water = 2/98 (volume ratio) dampening water and Values-G (N) black ink (manufactured by Dainippon Ink & Chemicals, Inc.) After dampening water and ink were supplied by the standard automatic printing start method of LITHRONE 26 and developed on the machine, 100 sheets were printed on Tokuhishi Art (76.5 kg) paper at a printing speed of 10,000 sheets per hour.
On-press development was evaluated based on the number of print sheets required until the on-press development on the printing machine of the unexposed portion of the image recording layer was completed and the ink was not transferred to the non-image portion.

(2) Printing durability After the on-press developability was evaluated, printing was further continued. As the number of printed sheets was increased, the image recording layer was gradually worn out, so that the ink density on the printed material decreased. The number of copies printed when the dot area ratio of 50% halftone dots of FM screen in the printed matter was 5% lower than the measurement value of the 100th printed sheet was evaluated as printing durability.

(3) Scratch resistance The lithographic printing plate precursor is exposed under the above-mentioned conditions, and the exposed portion of the solid image is scratched by changing the load with a scratch tester having a rubber needle having a diameter of 5.0 mmφ, and then the above-mentioned On-machine development was performed under the conditions, and the maximum load at which scratches were not scratched on the printed material was determined and evaluated as scratch resistance.

  From the results shown in Table 2, the compound (a) according to the present invention, that is, a compound in which a linear molecule penetrates a cyclic molecule having a polymerizable group, (b) a polyfunctional monomer, (c) a weight average molecular weight 2 A lithographic printing plate precursor having an image recording layer containing a binder (d) a polymerization initiator and (e) a sensitizing dye is excellent in all of scratch resistance, printing durability, and on-press developability. I understand that.

PEG: Polyethylene glycol (Mw 20,000)
Monomer M1: Dipentaerythritol pentaacrylate (SR-399, manufactured by Sartomer)
Monomer M2: Isocyanuric skeleton-containing urethane acrylate (UA-32P, manufactured by Shin-Nakamura Chemical Co., Ltd.)
Monomer M3: Tris (acryloyloxyethyl) isocyanurate (NK ester A-9300, manufactured by Shin-Nakamura Chemical Co., Ltd.)
Binder (1): Binder polymer (1)
Binder (2): Molecular weight modified product of the above binder polymer (1) (Mw 40,000)
Binder (3): Molecular weight modified product of the above binder polymer (1) (Mw 100,000)
Binder (4): Molecular weight modified product of the above binder polymer (1) (Mw 10,000)
Binder (5): Urethane polymer with the following composition (Mw 50,000)
(The numbers at the bottom represent the composition ratio (mol%).)

Claims (10)

  A lithographic printing plate precursor having an image recording layer from which an unexposed portion is removed by at least one of dampening water and printing ink on a support, wherein the image recording layer is (a) a cyclic group having a polymerizable group A compound in which a linear molecule penetrates the molecule, (b) a polyfunctional monomer, (c) a binder polymer having a mass average molecular weight of 20,000 to 200,000, (d) a polymerization initiator, and (e) a sensitizing dye A lithographic printing plate precursor.   The lithographic printing plate precursor as claimed in claim 1, wherein the linear molecule in the compound (a) is polyethylene glycol.   The lithographic printing plate precursor as claimed in claim 1 or 2, wherein the cyclic molecule in the compound (a) is cyclodextrin.   The lithographic printing plate precursor according to any one of claims 1 to 3, wherein the polymerizable group in the compound (a) is a polymerizable ethylenically unsaturated group.   The lithographic printing plate precursor according to any one of claims 1 to 4, wherein the linear molecule in the compound (a) has blocking groups at both ends thereof.   The lithographic printing plate precursor as claimed in any one of claims 1 to 5, wherein the binder polymer (c) has a crosslinkable group.   The lithographic printing plate precursor as claimed in any one of claims 1 to 6, wherein the binder polymer (c) is a urethane polymer. The lithographic printing plate precursor as claimed in claim 7, wherein the urethane polymer is a compound produced using at least one of the compounds represented by the following general formula (2) or general formula (3).

(In General Formula (2) and General Formula (3), m represents an integer of 1 to 3, n represents an integer of 2 to 60, l represents an integer of 1 to 6, and R ¹ represents a hydrogen atom or Represents a methyl group, R ² represents a hydrogen atom or an alkyl group having 12 or less carbon atoms, an alkenyl group having 12 or less carbon atoms or an aryl group having 12 or less carbon atoms, and A represents a (l + 2) -valent group.   The lithographic printing plate precursor according to any one of claims 1 to 8, wherein the (e) sensitizing dye is an infrared absorber.   The lithographic printing plate precursor according to any one of claims 1 to 9 is image-exposed with an infrared laser and then attached to a printing machine cylinder, and an unexposed portion of the image recording layer is dampened with water or at least one of printing inks. Plate making method to remove by