JP5443737B2 - Planographic printing plate precursor - Google Patents

Description

  The present invention relates to a negative planographic printing plate precursor having a polymerization type recording layer capable of direct drawing with an infrared laser beam and having excellent sensitivity, stability over time, and printing durability.

  In general, a negative lithographic printing plate is obtained by coating a photosensitive composition on a roughened aluminum plate or other support, exposing a desired image thereto, and polymerizing or crosslinking an exposed portion to develop a developer. The image is formed by a process of insolubilizing the unexposed portion with a developing solution. Conventionally, photopolymerizable compositions are well known as compositions used for such purposes, and some of them have been put to practical use. High-sensitivity photopolymers that incorporate recent photoinitiative technology that is highly sensitive to visible light have become more sensitive to the area used for direct plate making with visible lasers, and have spread as so-called CTP (Computer To Plate) plates. ing.

However, image formation using the above-mentioned photopolymerizable composition has increased the demand for handling (lighting room) under a yellow light or a white light instead of a dark room in terms of workability. Photopolymerizable compositions that can be used in combination with an exposure method such as an ultraviolet-violet laser having a wavelength of 300 to 450 nm and an infrared laser having a wavelength of 800 to 1,200 nm have been studied (for example, see Patent Documents 1 to 4). .)
Patent Document 5 discloses (A) a polymerizable compound having an asymmetric structure and having an ethylenically unsaturated bond, and (B) a binder polymer that is substantially soluble or swellable in water or an alkaline aqueous solution, A polymerizable composition comprising (C) a compound that generates radicals by light or heat is disclosed.

JP 2000-147663 A JP 2001-133969 A JP 2005-523484 A International Publication No. 2007/23133 Pamphlet JP 2005-283632 A

As CTP plates are used in a wide range of fields, high sensitivity and high printing durability are also required. It is also desired that the CTP plate has stable performance after long-term storage.
Therefore, in the current CTP plate market, further improvements in performance are required for all of sensitivity, storage stability, and printing durability.
This invention makes it a subject to achieve the following objectives based on the said market request | requirement.
That is, an object of the present invention is to provide a negative lithographic printing plate precursor which can be directly drawn by an infrared laser and is excellent in sensitivity, stability over time, and printing durability.

The above-described problems of the present invention have been solved by the means described in <1> below. It is described below together with <2> to <10> which are preferred embodiments.
<1> On a support, (A) a cyanine dye represented by the following formula (I), (B) an ethylenically unsaturated compound having a urethane bond, (C) a polymerization initiator, and (D) a binder polymer A lithographic printing plate precursor comprising a photosensitive layer containing

（式（I）中、Ｘ¹及びＸ²はそれぞれ独立に、Ｓ、Ｏ、ＮＲ及びＣ（アルキル）₂よりなる群から選ばれた二価の連結基を表し、Ｒ^1a及びＲ^1bはそれぞれ独立に、アルキル基、アルキルスルホネート基、アルキルカルボキシレート基又はアルキルアンモニウム基を表し、Ｒ²は、ＳＲ、ＳＯ₂Ｒ、又は、ＯＲを表し、Ｒ^3a及びＲ^3bはそれぞれ独立に、アルキル基、ＣＯＯＲ、ＯＲ、ＳＲ、ＮＲ₂若しくはハロゲン原子を表すか、又は、２つ以上のＲ^3a若しくは２つ以上のＲ^3bが結合して形成される縮合ベンゼン環を表し、Ｒはアリール基を表し、Ｚは式（I）で表されるシアニン色素全体として電荷的中性を得るのに十分なアニオンを表し、Ｒ^4a及びＲ^4bは、共に水素原子を表すか、又は、Ｒ^4aとＲ^4bとが結合し、かつ長さが炭素数２若しくは３である二価の炭化水素基を表し、ｎ１及びｎ２はそれぞれ独立に、０〜３の整数を表し、ｍ１及びｍ２はそれぞれ独立に、０〜４の整数を表す。）

(In formula (I), X ¹ and X ² each independently represent a divalent linking group selected from the group consisting of S, O, NR and C (alkyl) ₂ , wherein R ^1a and R ^1b are each Independently represents an alkyl group, an alkyl sulfonate group, an alkyl carboxylate group or an alkyl ammonium group, R ² represents SR, SO ₂ R, or OR, R ^3a and R ^3b each independently represents an alkyl group, COOR, OR, SR, NR ₂ or a halogen atom, or a condensed benzene ring formed by combining two or more R ^3a or two or more R ^3b , R represents an aryl group, Z represents an anion sufficient to obtain charge neutrality as the whole cyanine dye represented by formula (I), and R ^4a and R ^4b both represent a hydrogen atom, or R ^4a and R ^4b Are bonded and the length is 2 or 3 carbon atoms Represents a certain divalent hydrocarbon radical, in each of n1 and n2 independently represents an integer of 0 to 3, and m1 and m2 each independently represents an integer of 0 to 4.)

<2> The lithographic printing plate precursor as described in <1> above, wherein R ^1a and R ^1b in the formula (I) are each independently an alkyl group,
<3> The lithographic printing plate precursor as described in <1> or <2> above, wherein R ² in the formula (I) is SR,
<4> The lithographic printing plate precursor as described in any one of <1> to <3> above, wherein R ^3a and R ^3b in formula (I) are each independently an alkyl group or a halogen atom,
<5> The lithographic printing plate precursor as described in any one of <1> to <4> above, wherein X ¹ and X ² in the formula (I) are each independently C (alkyl) ₂
<6> The lithographic printing plate according to any one of <1> to <5>, wherein the cyanine dye represented by the formula (I) is a cyanine dye represented by the following formula (II): Original,

（式（II）中、Ｚ’^-は一価のアニオンを表す。）

(In the formula (II), Z ^'- represents a monovalent anion.)

  <7> The lithographic printing plate precursor as described in any one of <1> to <6>, wherein the ethylenically unsaturated compound (B) having a urethane bond includes a compound represented by the following formula (III): ,

<8> The lithographic printing plate precursor as described in any one of <1> to <7> above, wherein the (C) polymerization initiator is an onium salt,
<9> The lithographic printing plate precursor as described in any one of <1> to <8> above, wherein the (D) binder polymer is a urethane resin,
<10> The lithographic printing plate precursor as described in any one of <1> to <9>, wherein the (D) binder polymer is a urethane resin having a crosslinkable group in a side chain.

  According to the present invention, it is possible to provide a negative lithographic printing plate precursor capable of direct drawing with an infrared laser and having excellent sensitivity, stability over time, and printing durability.

  Hereinafter, the lithographic printing plate precursor according to the invention will be described in detail.

<Negative lithographic printing plate precursor>
The lithographic printing plate precursor according to the invention is a negative lithographic printing plate precursor (A) a cyanine dye represented by the following formula (I) on the support, and (B) an ethylenically unsaturated compound having a urethane bond. , (C) a polymerization initiator, and (D) a photosensitive layer containing a binder polymer (hereinafter also referred to as “image recording layer”, “specific recording layer”, or “recording layer”). .

（式（I）中、Ｘ¹及びＸ²はそれぞれ独立に、Ｓ、Ｏ、ＮＲ及びＣ（アルキル）₂よりなる群から選ばれた二価の連結基を表し、Ｒ^1a及びＲ^1bはそれぞれ独立に、アルキル基、アルキルスルホネート基、アルキルカルボキシレート基又はアルキルアンモニウム基を表し、Ｒ²は、ＳＲ、ＳＯ₂Ｒ、又は、ＯＲを表し、Ｒ^3a及びＲ^3bはそれぞれ独立に、アルキル基、ＣＯＯＲ、ＯＲ、ＳＲ、ＮＲ₂若しくはハロゲン原子を表すか、又は、２つ以上のＲ^3a若しくは２つ以上のＲ^3bが結合して形成される縮合ベンゼン環を表し、Ｒはアリール基を表し、Ｚは式（I）で表されるシアニン色素全体として電荷的中性を得るのに十分なアニオンを表し、Ｒ^4a及びＲ^4bは、共に水素原子を表すか、又は、Ｒ^4aとＲ^4bとが結合し、かつ長さが炭素数２若しくは３である二価の炭化水素基を表し、ｎ１及びｎ２はそれぞれ独立に、０〜３の整数を表し、ｍ１及びｍ２はそれぞれ独立に、０〜４の整数を表す。）

(In formula (I), X ¹ and X ² each independently represent a divalent linking group selected from the group consisting of S, O, NR and C (alkyl) ₂ , wherein R ^1a and R ^1b are each Independently represents an alkyl group, an alkyl sulfonate group, an alkyl carboxylate group or an alkyl ammonium group, R ² represents SR, SO ₂ R, or OR, R ^3a and R ^3b each independently represents an alkyl group, COOR, OR, SR, NR ₂ or a halogen atom, or a condensed benzene ring formed by combining two or more R ^3a or two or more R ^3b , R represents an aryl group, Z represents an anion sufficient to obtain charge neutrality as the whole cyanine dye represented by formula (I), and R ^4a and R ^4b both represent a hydrogen atom, or R ^4a and R ^4b Are bonded and the length is 2 or 3 carbon atoms Represents a certain divalent hydrocarbon radical, in each of n1 and n2 independently represents an integer of 0 to 3, and m1 and m2 each independently represents an integer of 0 to 4.)

  Each member constituting the lithographic printing plate precursor according to the invention will be described.

(Photosensitive layer)
Since the photosensitive layer in the lithographic printing plate precursor according to the present invention is sensitive to infrared light, it can be recorded by an infrared laser useful for CTP.
The cyanine dye contained in the photosensitive layer is in an electronically excited state with high sensitivity to infrared laser irradiation (exposure), and the electron transfer, energy transfer, heat generation (photothermal conversion function), etc. related to the electronically excited state are present in the photosensitive layer. It acts on the polymerization initiators coexisting with each other to cause a chemical change in the polymerization initiator to generate radicals.
Examples of the radical generation mechanism include a mechanism in which heat generated by the photothermal conversion function of the cyanine dye thermally decomposes a polymerization initiator described later to generate radicals. Then, the monomer causes a polymerization reaction by the generated radical, and the exposed portion is cured to form an image portion.

The lithographic printing plate precursor according to the invention is particularly suitable for plate making directly drawn with an infrared laser beam having a wavelength of 700 nm to 1,400 nm because the photosensitive layer contains a cyanine dye. Compared with the original plate, it can exhibit high image forming properties.
Below, each component which comprises a photosensitive layer is demonstrated.

(A) Cyanine Dye Represented by Formula (I) The photosensitive layer in the lithographic printing plate precursor according to the invention contains (A) a cyanine dye represented by formula (I).
The photosensitive layer contains a cyanine dye as a compound having an absorption maximum at 700 to 1,400 nm from the viewpoint of improving sensitivity. By containing the cyanine dye, the lithographic printing plate precursor is sensitive to the infrared wavelength region.
The cyanine dye that can be used in the present invention has an absorption maximum at a wavelength of 700 to 1,400 nm from the viewpoint of compatibility with an easily available high-power laser, and further exhibits excellent interaction with a urethane monomer described later. From the viewpoint, it is a cyanine dye represented by the following formula (I).

（式（I）中、Ｘ¹及びＸ²はそれぞれ独立に、Ｓ、Ｏ、ＮＲ及びＣ（アルキル）₂よりなる群から選ばれた二価の連結基を表し、Ｒ^1a及びＲ^1bはそれぞれ独立に、アルキル基、アルキルスルホネート基、アルキルカルボキシレート基又はアルキルアンモニウム基を表し、Ｒ²は、ＳＲ、ＳＯ₂Ｒ、又は、ＯＲを表し、Ｒ^3a及びＲ^3bはそれぞれ独立に、アルキル基、ＣＯＯＲ、ＯＲ、ＳＲ、ＮＲ₂若しくはハロゲン原子を表すか、又は、２つ以上のＲ^3a若しくは２つ以上のＲ^3bが結合して形成される縮合ベンゼン環を表し、Ｒはアリール基を表し、Ｚは式（I）で表されるシアニン色素全体として電荷的中性を得るのに十分なアニオンを表し、Ｒ^4a及びＲ^4bは、共に水素原子を表すか、又は、Ｒ^4aとＲ^4bとが結合し、かつ長さが炭素数２若しくは３である二価の炭化水素基を表し、ｎ１及びｎ２はそれぞれ独立に、０〜３の整数を表し、ｍ１及びｍ２はそれぞれ独立に、０〜４の整数を表す。）

(In formula (I), X ¹ and X ² each independently represent a divalent linking group selected from the group consisting of S, O, NR and C (alkyl) ₂ , wherein R ^1a and R ^1b are each Independently represents an alkyl group, an alkyl sulfonate group, an alkyl carboxylate group or an alkyl ammonium group, R ² represents SR, SO ₂ R, or OR, R ^3a and R ^3b each independently represents an alkyl group, COOR, OR, SR, NR ₂ or a halogen atom, or a condensed benzene ring formed by combining two or more R ^3a or two or more R ^3b , R represents an aryl group, Z represents an anion sufficient to obtain charge neutrality as the whole cyanine dye represented by formula (I), and R ^4a and R ^4b both represent a hydrogen atom, or R ^4a and R ^4b Are bonded and the length is 2 or 3 carbon atoms Represents a certain divalent hydrocarbon radical, in each of n1 and n2 independently represents an integer of 0 to 3, and m1 and m2 each independently represents an integer of 0 to 4.)

X ¹ and X ² in formula (I) each independently represent a divalent linking group selected from the group consisting of S, O, NR and C (alkyl) _2, and should be C (alkyl) _2. Preferably, C (CH ₃ ) ₂ is more preferable. R in the NR represents an aryl group.
R ^1a and R ^1b in formula (I) each independently represent an alkyl group, an alkyl sulfonate group, an alkyl carboxylate group or an alkyl ammonium group, preferably an alkyl group, and an alkyl group having 1 to 8 carbon atoms. More preferably, it is more preferably a methyl group or an ethyl group, and particularly preferably a methyl group. In addition, the other three groups on the nitrogen atom in the alkylammonium group can each independently be exemplified by a hydrogen atom, an alkyl group, or an aryl group.
R ² in formula (I) represents SR, SO ₂ R, or OR, preferably SR, and more preferably a thiophenyl group. Moreover, R of these SR, SO ₂ R and OR represents an aryl group, and is preferably a phenyl group.

The substituents R ^3a and R ^3b on the aromatic ring in formula (I) each independently represent an alkyl group, COOR, OR, SR, NR ₂ or a halogen atom, or two or more R ^3a or two R ^3b represents a condensed benzene ring formed by bonding R ^3b above, and R ^3a and R ^3b are each independently preferably an alkyl group or a halogen atom, more preferably a halogen atom, More preferably, it is an atom.
M1 and m2 which are the numbers of the substituents R ^3a and R ^3b on the aromatic ring each independently represent an integer of 0 to 4, preferably 0 or 1, and more preferably 0.
In the formula (I), m1 being 0 means that there is no substituent R ^3a on the aromatic ring, and among the carbon atoms forming the ring member of the aromatic ring bonded to X ¹ , group attached to a carbon atom other than a carbon atom bonded to a carbon atom and a nitrogen atom bonded to X ¹ represents that all hydrogen atoms. Similarly, in the formula (I), m2 is 0 means that there is no substituent R ^3b on the aromatic ring, and the carbon atom forming the ring member of the aromatic ring bonded to X ² Of these, all the groups bonded to carbon atoms other than the carbon atom bonded to X ² and the carbon atom bonded to the nitrogen atom are hydrogen atoms.

Z in the formula (I) represents an anion sufficient to obtain charge neutrality as the whole cyanine dye represented by the formula (I).
Z can be used without particular limitation as long as it is a monovalent or higher anion sufficient to obtain charge neutrality as a whole of the cyanine dye represented by formula (I). Z may be one anion or two or more anions. Furthermore, Z may be one kind of anion or two or more kinds of anions.
Specific examples of Z include sulfonate anion, benzoylformate anion, AsF ₆ ⁻ , PF ₆ ⁻ , BF ₄ ⁻ , ClO ₄ ⁻ , carboxylate anion, sulfinate anion, sulfate anion and boron anion in terms of stability. Preferred examples include halide ions, polymer-type sulfonate anions, polymer-type benzoylformate anions, polymer-type carboxylate anions, and the like. Among these, a sulfonate anion is preferable, and a triflate anion (CF ₃ SO ₃ ⁻ ) is more preferable.

R ^4a and R ^4b in the formula (I) both represent a hydrogen atom or a divalent hydrocarbon group in which R ^4a and R ^4b are bonded and the length is 2 or 3. either both represent hydrogen atom, or, preferably and R ^4a and R ^4b is an ethylene group or propylene group bound, it is more preferable and R ^4a and R ^4b is a propylene group attached.
N1 and n2 in Formula (I) each independently represent an integer of 0 to 3, and it is preferable that both n1 and n2 are 1.
X ¹ and X ² in formula (I) are preferably the same group. Similarly, R ^1a and R ^1b , n1 and n2, m1 and m2 in formula (I) are each preferably the same group.
In the formula (I), R ^3a and R ^3b are preferably the same group, and the substitution position on the aromatic ring is preferably a line-symmetrical position around R ² .

  The cyanine dye represented by the formula (I) is preferably a cyanine dye represented by the following formula (II). In addition, the chemical structural formula in this invention may describe a hydrocarbon chain by the simplified structural formula which abbreviate | omitted the symbol of carbon (C) and hydrogen (H).

（式（II）中、Ｚ’^-は一価のアニオンを表す。）

(In the formula (II), Z ^'- represents a monovalent anion.)

Z ′ ⁻ in the formula (II) represents a monovalent anion.
Z ^'- as, if a monovalent anion, can be used without particular limitation.
Z ′ ⁻ is specifically, from the viewpoint of stability, a sulfonate anion, a benzoylformate anion, AsF ₆ ⁻ , PF ₆ ⁻ , BF ₄ ⁻ , ClO ₄ ⁻ , a carboxylate anion, a sulfinate anion, a boron anion, Preferred examples include halide ions. Among these, a sulfonate anion is preferable, and a triflate anion (CF ₃ SO ₃ ⁻ ) is more preferable.

  Specific examples of the cyanine dye represented by the formula (I) include the following compounds.

  (A) The cyanine dye represented by the formula (I) is preferably added in an amount of 0.5 to 5% by weight based on the total solid content constituting the photosensitive layer. Within the above range, good sensitivity in the change in characteristics due to exposure can be obtained, and sufficient film uniformity and strength can be maintained.

(B) Ethylenically unsaturated compound having urethane bond The photosensitive layer in the lithographic printing plate precursor according to the invention contains (B) an ethylenically unsaturated compound having a urethane bond.
The ethylenically unsaturated compound having a urethane bond may be a compound having one or more urethane bonds and one or more ethylenically unsaturated groups, but two or more urethane bonds and two or more ethylenic compounds. A compound having an unsaturated group is preferable, a compound having two urethane bonds and two or more ethylenically unsaturated groups is more preferable, and having two urethane bonds and two ethylenically unsaturated groups More preferably, it is a compound.
(B) Ethylenically unsaturated compounds having urethane bonds (hereinafter also referred to as “urethane monomers” or “specific polymerizable compounds”) are divided into cases where the number of ethylenically unsaturated bonds is 2 and 3 or more. I will explain.
A polymerizable compound having a urethane bond and two ethylenically unsaturated bonds in the molecule (hereinafter sometimes referred to as “bifunctional polymerizable compound”) is represented by the following formula (1).
X-R-U-A-U-R-X (1)

  In the formula (1), A represents a chain or cyclic alkylene group, an aralkylene group, an arylene group, or an oxyalkylene group, U is independently a urethane bond, and X is independently a methacryloyl group or acryloyl group. Represents a group or a vinyl group, and each R independently represents a divalent linking group, for example, an oxyalkylene group, an alkyleneoxy group, or an aralkylene group.

As A in Formula (1), 2,2,4-trimethylhexyl group, hexamethylene group, ethylene oxide group, propylene oxide group, cyclohexyl group and the like are preferable.
As X in Formula (1), an acryloyl group and / or a methacryloyl group are preferable, and a methacryloyl group is more preferable.

  In the formula (1), preferred groups in the oxyalkylene group, alkyleneoxy group, and aralkylene group represented by R are the same as the preferred groups in the oxyalkylene group, alkyleneoxy group, and aralkylene group represented by A. is there.

  Specific examples of the bifunctional polymerizable compound include polymerizable compounds (M-1 to M-40) having the following structures.

The specific polymerizable compound may have a structure containing three or more ethylenically unsaturated bonds in the molecule. As the polymerizable compound having a urethane bond and four or more ethylenically unsaturated bonds, a compound represented by the following formula (3) is used.
D-(-UR- (X) _m ) _n ... Formula (3)
In formula (3), n represents 2 or 3, D represents a divalent or trivalent organic group, U represents each independently a urethane bond, and R each independently represents a trivalent or tetravalent group. A linking group composed of a carbon atom or a carbon atom and an oxygen atom is represented, X represents each independently a methacryloyl group, an acryloyl group, or a vinyl group, and m represents each independently 2 or 3.
Moreover, it is preferable that all -UR- (X) _{m which} exists in the compound represented by Formula (3) is the same group.

  Specific examples of the specific polymerizable compound containing four or more ethylenically unsaturated bonds in the molecule include polymerizable compounds (N-1 to N-7 and N-15 to N-25) having the following structures.

  Among the above specific examples, the specific polymerizable compound is preferably M-1, M-11, and N-2, and more preferably M-1.

A specific polymeric compound may be used individually by 1 type, or may use 2 or more types.
The amount (total amount) of the specific polymerizable compound added to the total solid content of the photosensitive layer is preferably 10 to 60% by weight, more preferably 20 to 50% by weight, and even more preferably 30 to 45% by weight. Within the above range, there is no case where the sensitivity is low, or the recording layer is sticky and the production suitability is not inferior.

(C) Polymerization initiator The photosensitive layer in the lithographic printing plate precursor according to the invention contains (C) a polymerization initiator.
In the present invention, the polymerization initiator that can be used in the photosensitive layer is a light or thermal polymerization initiator that generates radicals by light or thermal energy, and is a compound that initiates or accelerates the polymerization of an ethylenically unsaturated compound. The polymerization initiator can be appropriately selected from known radical polymerization initiators and compounds having a bond with a small bond dissociation energy.
Examples of the polymerization initiator include organic halogen compounds, carbonyl compounds, organic peroxides, azo compounds, azide compounds, metallocene compounds, hexaarylbiimidazole compounds, organic boron compounds, disulfone compounds, oxime ester compounds, and onium salt compounds. Can be mentioned.

Specific examples of the organic halogen compound include Wakabayashi et al., “Bull. Chem. Soc. Japan”, 42, 2924 (1969), US Pat. No. 3,905,815, Japanese Patent Publication No. 46-4605. ,
JP 48-36281, JP 53-133428, JP 55-3070, JP 60-239736, JP 61-169835, JP 61-169837, JP 62-58241, JP-A-62-212401, JP-A-63-70243, JP-A-63-298339, MP Hutt, “Journal of Heterocyclic Chemistry”, 1 (No. 3) (1970) ). Of these, oxazole compounds and s-triazine compounds substituted with a trihalomethyl group are preferred.

  More preferably, an s-triazine derivative in which at least one mono-, di-, or trihalogen-substituted methyl group is bonded to the s-triazine ring and an oxadiazole derivative in which the oxadiazole ring is bonded. Specifically, for example, 2,4,6-tris (monochloromethyl) -s-triazine, 2,4,6-tris (dichloromethyl) -s-triazine, 2,4,6-tris (trichloromethyl) -S-triazine, 2-methyl-4,6-bis (trichloromethyl) -s-triazine, 2-n-propyl-4,6-bis (trichloromethyl) -s-triazine, 2- (α, α, β-trichloroethyl) -4,6-bis (trichloromethyl) -s-triazine, 2- (3,4-epoxyphenyl) -4,6-bis (trichloromethyl) -s-triazine, 2- [1- (P-methoxyphenyl) -2,4-butadienyl] -4,6-bis (trichloromethyl) -s-triazine, 2-styryl-4,6-bis (trichloromethyl) -s-triazine, 2- ( -Methoxystyryl) -4,6-bis (trichloromethyl) -s-triazine, 2- (pi-propyloxystyryl) -4,6-bis (trichloromethyl) -s-triazine, 2- (p- Tolyl) -4,6-bis (trichloromethyl) -s-triazine, 2- (4-methoxynaphthyl) -4,6-bis (trichloromethyl) -s-triazine, 2-phenylthio-4,6-bis ( Trichloromethyl) -s-triazine, 2-benzylthio-4,6-bis (trichloromethyl) -s-triazine, 2,4,6-tris (dibromomethyl) -s-triazine, 2,4,6-tris ( Tribromomethyl) -s-triazine, 2-methyl-4,6-bis (tribromomethyl) -s-triazine, 2-methoxy-4,6-bis (tribromomethyl) Etc. -s- triazine and the following compounds.

  Examples of the carbonyl compound include benzophenone, Michler's ketone, 2-methylbenzophenone, 3-methylbenzophenone, 4-methylbenzophenone, 2-chlorobenzophenone, 4-bromobenzophenone, benzophenone derivatives such as 2-carboxybenzophenone, 2,2-dimethoxy- 2-phenylacetophenone, 2,2-diethoxyacetophenone, 1-hydroxycyclohexyl phenyl ketone, α-hydroxy-2-methylphenylpropanone, 1-hydroxy-1-methylethyl- (p-isopropylphenyl) ketone, 1- Hydroxy-1- (p-dodecylphenyl) ketone, 2-methyl- (4 ′-(methylthio) phenyl) -2-morpholino-1-propanone, 1,1,1-trichloromethyl- (p-butylpheny ) Acetophenone derivatives such as ketones, thioxanthone derivatives such as thioxanthone, 2-ethylthioxanthone, 2-isopropylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2,4-diisopropylthioxanthone, p And benzoic acid ester derivatives such as ethyl dimethylaminobenzoate and ethyl p-diethylaminobenzoate.

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

The azide compound is preferably an aromatic azide compound in which an azide group is bonded to an aromatic ring directly or via a carbonyl group or a sulfonyl group. In these, the azide group is decomposed by light to generate nitrene, and the nitrene causes various reactions to be insolubilized.
Preferred aromatic azide compounds include compounds containing one or more groups such as azidophenyl, azidostyryl, azidobenzal, azidobenzoyl and azidocinnamoyl, such as 4,4′-diazidochalcone, 4-azido -4 '-(4-azidobenzoylethoxy) chalcone, N, N-bis-p-azidobenzal-p-phenylenediamine, 1,2,6-tri (4'-azidobenzoxy) hexane, 2-azido-3-chloro -Benzoquinone, 2,4-diazide-4'-ethoxyazobenzene, 2,6-di (4'-azidobenzal) -4-methylcyclohexanone, 4,4'-diazidobenzophenone, 2,5-diazide-3,6 -Dichlorobenzoquinone, 2,5-bis (4-azidostyryl) -1,3,4-oxadiazole, 2 (4-azidocinnamoyl) thiophene, 2,5-di (4′-azidobenzal) cyclohexanone, 4,4′-diazidophenylmethane, 1- (4-azidophenyl) -5-furyl-2-penta-2 , 4-Dien-1-one, 1- (4-azidophenyl) -5- (4-methoxyphenyl) -penta-1,4-dien-3-one, 1- (4-azidophenyl) -3- (1-naphthyl) propen-1-one, 1- (4-azidophenyl) -3- (4-dimethylaminophenyl) -propan-1-one, 1- (4-azidophenyl) -5-phenyl-1 , 4-Pentadien-3-one, 1- (4-azidophenyl) -3- (4-nitrophenyl) -2-propen-1-one, 1- (4-azidophenyl) -3- (2-furyl) ) -2-propen-1-o 1,2,6-tri (4′-azidobenzoxy) hexane, 2,6-bis- (4-azidobenzilidine-pt-butyl) cyclohexanone, 4,4′-diazidobenzalacetone, 4, , 4′-diazidostilbene-2,2′-disulfonic acid, 4′-azidobenzalacetophenone-2-sulfonic acid, 4,4′-diazidostilbene-α-carboxylic acid, di- (4-azido- 2′-hydroxybenzal) acetone-2-sulfonic acid, 4-azidobenzalacetophenone-2-sulfonic acid, 2-azido-1,4-dibenzenesulfonylaminonaphthalene, 4,4′-diazidostilbene-2 , 2'-disulfonic acid anilide and the like.
In addition to these low molecular weight aromatic azide compounds, Japanese Patent Publication Nos. 44-9047, 44-31837, 45-9613, 45-24915, 45-25713, and Japanese Patent Laid-Open No. 50-5102. The azide group-containing polymers described in JP-A-50-84302, JP-A-50-84303 and JP-A-53-12984 are also suitable.

  Examples of the organic peroxide include trimethylcyclohexanone peroxide, acetylacetone peroxide, 1,1-bis (tert-butylperoxy) -3,3,5-trimethylcyclohexane, 1,1-bis (tert-butyl). Peroxy) cyclohexane, 2,2-bis (tert-butylperoxy) butane, tert-butyl hydroperoxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide, 2,5-dimethylhexane-2,5-dihydro Peroxide, 1,1,3,3-tetramethylbutyl hydroperoxide, tert-butylcumyl peroxide, dicumyl peroxide, 2,5-dimethyl-2,5-di (tert-butylperoxy) hexane, 2, -Oxanoyl peroxide, succinic peroxide, benzoyl peroxide, 2,4-dichlorobenzoyl peroxide, diisopropyl peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate, di-2-ethoxyethyl peroxydicarbonate , Dimethoxyisopropyl peroxycarbonate, di (3-methyl-3-methoxybutyl) peroxydicarbonate, tert-butyl peroxyacetate, tert-butyl peroxypivalate, tert-butyl peroxyneodecanoate, tert- Butyl peroxyoctanoate, tert-butyl peroxylaurate, 3,3 ′, 4,4′-tetra- (t-butylperoxycarbonyl) benzophenone, 3,3 ′, 4,4′-tetra- ( t-he Sylperoxycarbonyl) benzophenone, 3,3 ′, 4,4′-tetra- (p-isopropylcumylperoxycarbonyl) benzophenone, carbonyldi (t-butylperoxydihydrogen diphthalate), carbonyldi (t-hexylper) Oxydihydrogen diphthalate) and the like.

  Examples of the metallocene compound include JP-A-59-152396, JP-A-61-151197, JP-A-63-41484, JP-A-2-249, JP-A-2-4705, and JP-A-5-83588. Various titanocene compounds described in each of the above publications, for example, bis (cyclopentadienyl) bis (phenyl) titanium, bis (cyclopentadienyl) bis (2,6-difluorophen-1-yl) titanium, bis ( Cyclopentadienyl) bis (2,4,6-trifluorophen-1-yl) titanium, bis (cyclopentadienyl) bis (2,3,5,6-tetrafluorophen-1-yl) titanium, Bis (cyclopentadienyl) bis (2,3,4,5,6-pentafluorophen-1-yl) titanium, bis (methylcyclopenta Enyl) bis (2,6-difluorophen-1-yl) titanium, bis (methylcyclopentadienyl) bis (2,3,4,5,6-pentafluorophen-1-yl) titanium, bis (methyl Cyclopentadienyl) bis (2,3,5,6-tetrafluorophen-1-yl) titanium, bis (methylcyclopentadienyl) bis (2,3,4,5,6-pentafluorophen-1 -Yl) titanium, bis (cyclopentadienyl) bis [2,6-difluoro-3- (pyridin-1-yl) phenyl] titanium, and JP-A-1-304453 and JP-A-1-152109. And the described iron-arene complexes.

  Examples of the hexaarylbiimidazole compound include each specification of JP-B-6-29285, US Pat. Nos. 3,479,185, 4,311,783, and 4,622,286. Etc., specifically 2,2′-bis (o-chlorophenyl) -4,4 ′, 5,5′-tetraphenylbiimidazole, 2,2′-bis (o-bromo) Phenyl)) 4,4 ′, 5,5′-tetraphenylbiimidazole, 2,2′-bis (o, p-dichlorophenyl) -4,4 ′, 5,5′-tetraphenylbiimidazole, 2,2 '-Bis (o-chlorophenyl) -4,4', 5,5'-tetra (m-methoxyphenyl) biimidazole, 2,2'-bis (o, o'-dichlorophenyl) -4,4 ', 5 , 5'-Tetraphenyl Imidazole, 2,2′-bis (o-nitrophenyl) -4,4 ′, 5,5′-tetraphenylbiimidazole, 2,2′-bis (o-methylphenyl) -4,4 ′, 5 Examples include 5′-tetraphenylbiimidazole, 2,2′-bis (o-trifluorophenyl) -4,4 ′, 5,5′-tetraphenylbiimidazole, and the like.

  Examples of the organic boron compound include JP-A-62-143044, JP-A-62-1050242, JP-A-9-188585, JP-A-9-188686, JP-A-9-188710, JP-A 2000-. No. 131837, Japanese Patent Application Laid-Open No. 2002-107916, Japanese Patent No. 2764769, Japanese Patent Application Laid-Open No. 2002-116539, Organic Boric Acid described in Martin Kunz, Rad Tech '98. Proceeding April, 19-22, 1998, Chicago, etc. Salts, organoboron sulfonium complexes or organoboron oxosulfonium complexes described in JP-A-6-157623, JP-A-6-175564, JP-A-6-175561, JP-A-6-175554, JP-A-6 Organoboron iodonium complex described in JP-A-175553, and organoboron phosphine described in JP-A-9-188710. Nitrogen complexes, organoboron transition metal coordination complexes described in JP-A-6-348011, JP-A-7-128785, JP-A-7-140589, JP-A-7-306527, and JP-A-7-292014 Etc.

  Examples of the disulfone compound include compounds described in JP-A Nos. 61-166544 and 2003-328465.

  Examples of the oxime ester compound include JCS Perkin II, 1653-1660 (1979), JCS Perkin II, 156-162 (1979), Journal of Photopolymer Science and Technology, 202-232 (1995), JP 2000-66385 A. And compounds described in JP-A No. 2000-80068. Specific examples include compounds represented by the following structural formula. In addition, the wavy line in the following structural formula represents that either the (E) body or the (Z) body of oxime may be used.

Examples of the onium salt compounds include diazonium salts described in SI Schlesinger, Photogr. Sci. Eng., 18, 387 (1974), TS Bal et al., Polymer, 21, 423 (1980), US Pat. , 069,055, JP-A-4-365049 and the like, phosphonium salts described in U.S. Pat. Nos. 4,069,055 and 4,069,056, The sulfonium salts described in European Patent Nos. 104 and 143, U.S. Pat. Nos. 339,049, 410,201,580 and 3,604,581, JV Crivello et al ., Macromolecules, 10 (6), 1307 (1977), Selenonium salt described in JVCrivello et al., J. Polymer Sci., Polymer Chem. Ed., 17, 1047 (1979), CS Wen et al., The Examples include the arsonium salts described in Proc. Conf. Rad. Curing ASIA, p. 478, Tokyo, Oct. (1988).
In the present invention, these onium salt compounds can function as radical polymerization initiators, not as acid generators.

  Preferred onium salt compounds are onium salts represented by the following formulas (RI-I) to (RI-III).

In the formula (RI-I), Ar ¹¹ represents an aryl group having 20 or less carbon atoms which may have 1 to 6 substituents.
Preferred substituents include an alkyl group having 12 or less carbon atoms, an alkenyl group having 12 or less carbon atoms, an alkynyl group having 12 or less carbon atoms, an aryl group having 12 or less carbon atoms, an alkoxy group having 12 or less carbon atoms, and 12 or less carbon atoms. Aryloxy group, halogen atom, alkylamino group having 12 or less carbon atoms, dialkylamino group having 12 or less carbon atoms, alkylamide group or arylamide group having 12 or less carbon atoms, carbonyl group, carboxyl group, cyano group, sulfonyl group, Examples thereof include a thioalkyl group having 12 or less carbon atoms and a thioaryl group having 12 or less carbon atoms.
Z ^11- represents a monovalent anion, specifically, halide ion, perchlorate ion, hexafluorophosphate ion, tetrafluoroborate ion, sulfonate ion, sulfinate ion, thiosulfonate ion, sulfate ion Is mentioned. Among these, perchlorate ion, hexafluorophosphate ion, tetrafluoroborate ion, sulfonate ion and sulfinate ion are preferable from the viewpoint of stability.

In the formula (RI-II), Ar ²¹ and Ar ²² each independently represent an aryl group having 20 or less carbon atoms which may have 1 to 6 substituents.
Preferred substituents include an alkyl group having 12 or less carbon atoms, an alkenyl group having 12 or less carbon atoms, an alkynyl group having 12 or less carbon atoms, an aryl group having 12 or less carbon atoms, an alkoxy group having 12 or less carbon atoms, and 12 or less carbon atoms. Aryloxy group, halogen atom, alkylamino group having 12 or less carbon atoms, dialkylamino group having 12 or less carbon atoms, alkylamide group or arylamide group having 12 or less carbon atoms, carbonyl group, carboxyl group, cyano group, sulfonyl group, Examples thereof include a thioalkyl group having 12 or less carbon atoms and a thioaryl group having 12 or less carbon atoms.
Z ^21- represents a monovalent anion. Specific examples include halide ions, perchlorate ions, hexafluorophosphate ions, tetrafluoroborate ions, sulfonate ions, sulfinate ions, thiosulfonate ions, sulfate ions, and carboxylate ions. Among these, perchlorate ion, hexafluorophosphate ion, tetrafluoroborate ion, sulfonate ion, sulfinate ion, and carboxylate ion are preferable from the viewpoint of stability and reactivity.

In the formula (RI-III), R ³¹ , R ³² and R ³³ are each independently an aryl group, an alkyl group, an alkenyl group having 20 or less carbon atoms, which may have 1 to 6 substituents, or Represents an alkynyl group. Among these, an aryl group is preferable from the viewpoint of reactivity and stability.
Examples of the substituent include an alkyl group having 12 or less carbon atoms, an alkenyl group having 12 or less carbon atoms, an alkynyl group having 12 or less carbon atoms, an aryl group having 12 or less carbon atoms, an alkoxy group having 12 or less carbon atoms, and an alkyl group having 12 or less carbon atoms. Aryloxy group, halogen atom, alkylamino group having 12 or less carbon atoms, dialkylamino group having 12 or less carbon atoms, alkylamide group or arylamide group having 12 or less carbon atoms, carbonyl group, carboxyl group, cyano group, sulfonyl group, carbon Examples thereof include a thioalkyl group having a number of 12 or less and a thioaryl group having a carbon number of 12 or less.
Z ^31- represents a monovalent anion. Specific examples include halide ions, perchlorate ions, hexafluorophosphate ions, tetrafluoroborate ions, sulfonate ions, sulfinate ions, thiosulfonate ions, sulfate ions, and carboxylate ions. Among these, perchlorate ion, hexafluorophosphate ion, tetrafluoroborate ion, sulfonate ion, sulfinate ion, and carboxylate ion are preferable from the viewpoints of stability and reactivity. More preferred are the carboxylate ions described in JP-A No. 2001-343742, and particularly preferred are the carboxylate ions described in JP-A No. 2002-148790.

  Specific examples of the onium salts represented by formulas (RI-I) to (RI-III) are shown below, but the present invention is not limited to these.

The polymerization initiator is preferably an organic halogen compound, a metallocene compound, a hexaarylbiimidazole compound, an organic boron compound, an oxime ester compound, and / or an onium salt compound, particularly from the viewpoint of reactivity and stability. , Metallocene compounds, hexaarylbiimidazole compounds, and / or onium salt compounds are more preferable, and onium salt compounds are particularly preferable.
A polymerization initiator may be used independently and may use 2 or more types together.
The content of the polymerization initiator is preferably from 0.1 to 50% by weight, more preferably from 0.5 to 30% by weight, even more preferably from 0.8 to 20% by weight, based on the total solid content of the photosensitive layer.

(D) Binder polymer The photosensitive layer in the lithographic printing plate precursor according to the invention contains (D) a binder polymer.
The chemical structure of the binder polymer that can be used in the present invention is not particularly limited, but is preferably an organic polymer having an acid group from the viewpoint of solubility in a weak alkaline processing solution, that is, developability, and particularly a carboxyl group (carboxyl group). An organic polymer containing an acid group) or a salt thereof is more preferable.
As the binder polymer that can be used in the present invention, a carboxylic acid group-containing alkaline water-soluble or swellable organic polymer is used.
Examples of such organic polymers include addition polymers having a carboxylic acid group in the side chain, such as JP-A-59-44615, JP-B-54-34327, JP-B-58-12777, and JP-B-54-25957. , JP-A-54-92723, JP-A-59-53836, JP-A-59-71048, ie, methacrylic acid copolymer, acrylic acid copolymer, itacon Acid copolymers, crotonic acid copolymers, maleic acid copolymers, partially esterified maleic acid copolymers and the like are useful. As the binder polymer, a copolymer containing a monomer unit derived from a (meth) acrylic acid ester containing a carboxylic acid (salt) group is preferable.
Also useful are acidic cellulose derivatives having a carboxylic acid group in the side chain, and those obtained by adding a cyclic acid anhydride to an addition polymer having a hydroxyl group.
Further, Japanese Patent Publication No. 7-120040, Japanese Patent Publication No. 7-120041, Japanese Patent Publication No. 7-120042, Japanese Patent Publication No. 8-12424, Japanese Patent Publication No. 63-287944, Japanese Patent Publication No. 63-287947, Japanese Patent Publication No. Hei 1 Polyurethane resins described in JP-A Nos. 271741 and 11-352691 are also useful as alkaline water-soluble or swellable binders.
As the binder polymer used in the present invention, an acrylic resin, a methacrylic resin, or a urethane resin is preferably used.

An example of a material suitable as a binder polymer that can be used in the present invention includes the following (a) a monomer unit containing a carboxylic acid group (including a salt thereof) and (b) a monomer unit imparting radical crosslinkability. It is a copolymer.
(A) Although it does not specifically limit as a monomer unit containing a carboxylic acid group, The following structure is used preferably.

（式（Ｄ−Ｉ）中、Ｒ¹は水素原子又はメチル基を表し、Ｒ²は炭素原子、水素原子、酸素原子、窒素原子、及び、硫黄原子からなる群より選択される２以上の原子を含んで構成され、その原子数が２〜８２である連結基を表し、Ａは酸素原子又は−ＮＲ³−を表し、Ｒ³は水素原子又は炭素数１〜１０の１価の炭化水素基を表し、ｎは１〜５の整数を表す。）

(In the formula (DI), R ¹ represents a hydrogen atom or a methyl group, and R ² represents two or more atoms selected from the group consisting of a carbon atom, a hydrogen atom, an oxygen atom, a nitrogen atom, and a sulfur atom. And A represents an oxygen atom or —NR ³ —, and R ³ represents a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms. And n represents an integer of 1 to 5.)

In the formula (DI), the linking group represented by R ² includes two or more atoms selected from the group consisting of a carbon atom, a hydrogen atom, an oxygen atom, a nitrogen atom, and a sulfur atom, The total number of atoms is 2 to 82, preferably 2 to 50, more preferably 2 to 30. The linking group represented by R ² may have a substituent. The total number of atoms shown here refers to the number of atoms including the substituent when the linking group has a substituent. More specifically, the number of atoms constituting the main skeleton of the linking group represented by R ² is preferably 1-30, more preferably 3-25, and 4-20. More preferred is 5-10. The “main skeleton of the linking group” in the present invention refers to an atom or an atomic group used only for linking A and the terminal COOH in the formula (DI), and in particular, there are a plurality of linking paths. In some cases, it refers to an atom or atomic group that constitutes the path with the least number of atoms used. Therefore, when a linking group has a ring structure, the number of atoms to be included differs depending on the linking site (for example, o-, m-, p-, etc.).

More specifically, as the linking group represented by R ² in the formula (DI), alkylene, substituted alkylene, arylene, substituted arylene, or a hydrogen atom on any carbon atom constituting these groups is excluded. Examples include (n + 1) -valent groups, and those having a structure in which a plurality of these groups are linked by amide bonds or ester bonds are preferred. In particular, those having 5 to 10 atoms constituting the main skeleton of the linking group are preferable. Structurally, the structure is a chain structure having an ester bond in the structure, or a cyclic structure as described above. What has is preferable.
Examples of the substituent that can be introduced into the linking group represented by R ² include monovalent nonmetallic atomic groups other than hydrogen, such as halogen atoms (—F, —Br, —Cl, —I), carbonization. Examples thereof include a hydrogen group (alkyl group, aryl group, alkenyl group, alkynyl group), alkoxy group, and aryloxy group.
A in formula (DI) is preferably an oxygen atom or —NH— because synthesis is easy.
N in the formula (D-I) represents an integer of 1 to 5, and is preferably 1 in terms of printing durability.

  (A) Specific examples of the monomer unit imparting alkali solubility include compounds having the structures shown in (a-1) to (a-12) shown below.

  When the total number of monomer units is 100, the content of the monomer containing (a) carboxylic acid is preferably 5 to 50 units, more preferably 5 to 25 units, More preferably, it is 15 units.

  Specific examples of the monomer unit that imparts (b) radical crosslinkability include the following structures (b-1) to (b-11).

  The content of the monomer unit that imparts (b) radical crosslinkability, when the total number of monomer units is 100, is preferably 5 to 90 units, more preferably 20 to 85 units, More preferably, it is 40 to 80 units.

The binder polymer that can be used in the present invention is a copolymer of monomer units derived from an ethylenically unsaturated compound that contains neither (a) a monomer unit that imparts alkali solubility nor (b) a monomer unit that imparts radical crosslinkability. You may have as a component. As such a monomer unit, a monomer unit derived from (meth) acrylic acid ester or (meth) acrylic acid amide is preferable. In particular, a monomer unit derived from an amide group (meth) acrylic acid amide described in paragraphs 0061 to 0084 of JP-A-2007-272134 is preferably used.
The content of this monomer is preferably 5 to 50 units, more preferably 5 to 35 units, even more preferably 5 to 25 units, when the total number of monomer units is 100. .

In the photosensitive layer of the present invention, it is preferable to use a urethane resin (also referred to as “polyurethane resin”) as a binder polymer in addition to the above-mentioned addition polymer having a combination of monomer units, and a crosslinkable group in the side chain. It is more preferable to use a urethane resin having
Here, the crosslinkable group is a group capable of crosslinking the binder polymer by a chemical reaction that occurs in the image forming layer when the lithographic printing plate precursor is exposed. The chemical structure is not particularly limited as long as it is a group having such a function. Examples of the functional group capable of addition polymerization include cyclic ether groups such as an ethylenically unsaturated group and an epoxy group / oxetanyl group. Moreover, the functional group which can become a radical by light irradiation may be sufficient, and as such a crosslinkable group, a thiol group, a halogen atom, an onium salt structure etc. are mentioned, for example. Among these, an ethylenically unsaturated group is preferable and includes functional groups described in paragraphs 0130 to 0139 of JP2007-17948A.

The polyurethane resin having a crosslinkable group in the above side chain not only functions as a film-forming agent for the photosensitive layer, but also needs to be dissolved in an alkaline processing solution, so that it may be soluble or swellable in alkaline water. Required. Therefore, in addition to the crosslinkable group, the side chain has an alkali water-soluble group such as a carboxyl group (including salts thereof). Polyurethane resin can suppress the development damage of the exposed area without lowering the developability of the unexposed area even if the acid value of the photosensitive layer is low, and can have both good stain resistance and high printing durability. This is preferable.
The polyurethane resin having a crosslinkable group in the side chain will be described in more detail below.

  The polyurethane resin having a crosslinkable group in the side chain particularly preferably used in the present invention comprises (i) a diisocyanate compound, (ii) a diol compound having a carboxyl group, (iii) a diisocyanate compound having a crosslinkable group, and if necessary. (Iv) It can be obtained by polyaddition reaction of a diol compound having no carboxyl group and (v) a compound having an amino group.

  Examples of the compounds (i), (ii) and (iii) include formulas (4) to (10) and specific examples described in paragraphs 0142 to 0167 of JP-A No. 2007-17948.

  Here, as a method for introducing a crosslinkable group into the side chain of the polyurethane resin, a method using a diisocyanate compound containing a crosslinkable group in the side chain as a raw material for producing the polyurethane resin is suitable. A diisocyanate compound obtained by addition reaction of a triisocyanate compound and a monofunctional alcohol having a crosslinkable group or 1 equivalent of a monofunctional amine compound, having a crosslinkable group in the side chain, The compounds of paragraphs 0179 to 0178 of Kaikai 2007-17948 are included.

(Iv) Diol compound having no carboxyl group As a method for introducing an unsaturated group into the side chain of the polyurethane resin, a method using a diol compound containing an unsaturated group in the side chain as a raw material for producing the polyurethane resin is also employed. it can. Such diol compounds include, for example, those commercially available such as trimethylolpropane monoallyl ether, halogenated diol compounds, triol compounds, aminodiol compounds, carboxylic acids containing unsaturated groups, acids Also included are compounds produced by reaction with chlorides, isocyanates, alcohols, amines, thiols, alkyl halide compounds. Specific examples of these compounds include general formula (A ′), formulas (a) to (e), formulas (11) to (22) described in paragraphs 0180 to 0225 of JP-A No. 2007-17948, and Specific compounds are included.

(V) A compound having an amino group As a binder polymer that can be used in an image forming layer, in the production of a polyurethane resin, an amino group-containing compound is further combined and reacted with a diisocyanate compound to form a urea structure and incorporated into the structure of the polyurethane resin. But you can. Amino group-containing compounds include Formula (31) and Formula (32) and specific compounds described in paragraphs 0227 to 0230 of JP2007-17948A.

  In addition to the polyurethane resin obtained by introducing a crosslinkable group into the side chain during the synthesis of the polyurethane resin, the binder polymer that can be used in the present invention includes a carboxyl as described in JP-A-2003-270775. A polyurethane resin obtained by introducing a crosslinkable group into a polyurethane resin having a group by a polymer reaction is also included.

In the present invention, in particular, a combination of a monomer having a melting point of 45 ° C. or higher and a urethane resin having a crosslinkable group having a Tg of 45 ° C. or higher, more preferably 50 ° C. or higher among the urethane resins having the crosslinkable group is particularly preferable. Used.
Specific examples of such urethane resins are shown below, but the present invention is not limited thereto. In addition, the number on the lower right of the parenthesis representing each structural unit of the following urethane resin represents the molar ratio of each structural unit.

  In order to maintain the developability of the photosensitive layer, the binder polymer used preferably has an appropriate molecular weight, and the weight average molecular weight is more preferably 5,000 to 300,000, and 20,000 to 150. Is particularly preferred.

  These binder polymers can be contained in an arbitrary amount in the image forming layer, preferably 10 to 90% by weight, and more preferably 30 to 80% by weight. When the content is in the above range, preferable results can be obtained in terms of the image strength to be formed.

[Other additives for photosensitive layer]
In the photosensitive layer of the lithographic printing plate precursor according to the invention, unnecessary thermal polymerization of the ethylenically unsaturated compound is prevented during the production or storage of the composition for forming the photosensitive layer (photosensitive composition). Therefore, it is preferable to add a small amount of a thermal polymerization inhibitor.
Suitable thermal polymerization inhibitors include hydroquinone, p-methoxyphenol, di-t-butyl-p-cresol, pyrogallol, t-butylcatechol, benzoquinone, 4,4′-thiobis (3-methyl-6-t- Butylphenol), 2,2′-methylenebis (4-methyl-6-tert-butylphenol), N-nitrosophenylhydroxylamine cerium salt, N-nitrosophenylhydroxylamine aluminum salt and the like.
The addition amount of the thermal polymerization inhibitor is preferably 0.01% by weight to 5% by weight with respect to the total weight of the photosensitive layer. If necessary, in order to prevent polymerization inhibition by oxygen, higher fatty acid derivatives such as behenic acid and behenic acid amide are added, and are unevenly distributed on the surface of the photosensitive layer in the drying process after coating. Also good.
The addition amount of the higher fatty acid derivative is preferably 0.5% by weight to 10% by weight with respect to the total weight of the photosensitive layer.

Further, a coloring agent may be added for the purpose of coloring the photosensitive layer.
Examples of the colorant include phthalocyanine pigments (CI Pigment Blue 15: 3, 15: 4, 15: 6, etc.), azo pigments, pigments such as carbon black and titanium oxide, ethyl violet, crystal violet, There are azo dyes, anthraquinone dyes, and cyanine dyes.
The addition amount of the dye and the pigment is preferably 0.5% by weight to 5% by weight with respect to the total weight of the photosensitive layer.
In addition, in order to improve the physical properties of the cured film, an additive such as an inorganic filler or a plasticizer such as dioctyl phthalate, dimethyl phthalate, or tricresyl phosphate may be added.
These additives are preferably 10% by weight or less based on the total weight of the photosensitive layer.
Further, a surfactant can be added to the composition for forming the photosensitive layer in order to improve the coated surface state. Suitable surfactants include, for example, fluorine-based nonionic surfactants.

[Solvent for photosensitive layer]
In the present invention, the composition that can be used for forming the photosensitive layer is coated on a support that has been subjected to various surface treatments if desired, but when the composition is coated on the support, Can be used by dissolving in various organic solvents.
Solvents include acetone, methyl ethyl ketone, cyclohexane, ethyl acetate, ethylene dichloride, tetrahydrofuran, toluene, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol dimethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, acetylacetone, cyclohexanone, Diacetone alcohol, ethylene glycol monomethyl ether acetate, ethylene glycol ethyl ether acetate, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether acetate, 3-methoxypropanol, methoxymethoxyethanol, diethylene glycol monomethyl ether, diethylene glycol Cole monoethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, 3-methoxypropyl acetate, N, N-dimethylformamide, dimethyl sulfoxide, γ-butyrolactone, methyl lactate, ethyl lactate Etc.
These solvents can be used singly or in combination of two or more. In addition, it is preferable that the solid content concentration in a coating solution is 1 to 50 weight%.
The coating amount of the photosensitive layer in the lithographic printing plate precursor according to the invention is preferably in the range of 0.1 to 10 g / m ^{2 by} weight after coating and drying, and is in the range of 0.3 to 5 g / m ^2. Is more preferable, and the range of 0.5 to 3 g / m ² is more preferable.

(Protective layer (oxygen barrier layer))
The lithographic printing plate precursor according to the invention is preferably provided with a protective layer (oxygen blocking layer) on the photosensitive layer in order to block diffusion and penetration of oxygen that hinders the polymerization reaction during exposure.
The protective layer in the lithographic printing plate precursor according to the invention preferably has an oxygen permeability A at 25 ° C. and 1 atm of 1.0 ≦ A ≦ 20 (cc / m ² · day). When the oxygen permeability A is 1.0 (cc / m ² · day) or more, unnecessary polymerization reaction does not occur during production and raw storage, and unnecessary fogging and thickening of image lines occur during image exposure. It does not cause the problem that it occurs.
Further, if the oxygen permeability A is 20 (cc / m ² · day) or less, the sensitivity is not lowered. In addition to the oxygen permeability described above, the properties desired for the protective layer further do not substantially inhibit the transmission of light used for exposure, have excellent adhesion to the photosensitive layer, and are easy in the development process after exposure. It is preferable that it can be removed. Such a protective layer has been conventionally devised and described in detail in US Pat. No. 3,458,311 and Japanese Patent Publication No. 55-49729.

  As a material that can be used for the protective layer, for example, a water-soluble polymer compound having relatively excellent crystallinity is preferably used. Specifically, polyvinyl alcohol, vinyl alcohol / vinyl phthalate copolymer, vinyl acetate / vinyl are used. Examples include water-soluble polymers such as alcohol / vinyl phthalate copolymer, vinyl acetate / crotonic acid copolymer, polyvinyl pyrrolidone, acidic celluloses, gelatin, gum arabic, polyacrylic acid, and polyacrylamide. Or it can be used in combination. Among these, it is preferable to use polyvinyl alcohol as a main component because it can give the best results in oxygen barrier properties and development removability.

The polyvinyl alcohol that can be used in the protective layer may be partially substituted with an ester, an ether, and an acetal as long as it contains an unsubstituted vinyl alcohol unit that has the necessary oxygen barrier properties and water solubility. . Similarly, some of them may have other copolymer components.
Specific examples of polyvinyl alcohol include those that are hydrolyzed by 71 to 100 mol% and have a polymerization repeating unit in the range of 300 to 2,400.
Specifically, PVA-105, PVA-110, PVA-117, PVA-117H, PVA-120, PVA-124, PVA-124H, PVA-CS, PVA-CST, PVA-HC made by Kuraray Co., Ltd. , PVA-203, PVA-204, PVA-205, PVA-210, PVA-217, PVA-220, PVA-224, PVA-217EE, PVA-217E, PVA-220E, PVA-224E, PVA-405, PVA -420, PVA-613, L-8 and the like. These can be used alone or in combination.
The content of polyvinyl alcohol in the protective layer is preferably 20 to 95% by weight, and more preferably 30 to 90% by weight.

As a component used by mixing with polyvinyl alcohol, polyvinyl pyrrolidone or a modified product thereof is preferable from the viewpoints of oxygen barrier properties and development removability.
The content of polyvinylpyrrolidone or a modified product thereof in the protective layer is preferably 3.5 to 80% by weight, more preferably 10 to 60% by weight, and further preferably 15 to 30% by weight. preferable.

Components of the protective layer (selection of PVA, use of additives), coating amount, and the like are selected in consideration of fogging, adhesion, and scratch resistance in addition to oxygen barrier properties and development removability. Generally, the higher the hydrolysis rate of the PVA (polyvinyl alcohol) used (the higher the content of the unsubstituted vinyl alcohol unit in the protective layer), the higher the film thickness, the higher the oxygen barrier property, and the more advantageous in terms of sensitivity. It is.
The oxygen permeability A at 25 ° C. and 1 atm of the protective layer in the present invention is preferably 1.0 ≦ A ≦ 20 (cc / m ² · day), and 1.5 ≦ A ≦ 12 (cc / m ² · day) is more preferable, and 2.0 ≦ A ≦ 8.0 (cc / m ² · day) is further preferable. Within the above range, it is possible to suppress unnecessary polymerization reaction during production and raw storage, and it is possible to suppress unnecessary fogging and image line thickness during image exposure.
The molecular weight of the (co) polymer such as polyvinyl alcohol (PVA) is preferably in the range of 2,000 to 10 million, more preferably in the range of 20,000 to 3 million.

As another composition of the protective layer, glycerin, dipropylene glycol, and the like can be added in an amount corresponding to several weight percent with respect to the (co) polymer to impart flexibility.
In addition, anionic surfactants such as sodium alkyl sulfate and sodium alkyl sulfonate; amphoteric surfactants such as alkylaminocarboxylate and alkylaminodicarboxylate; nonionic surfactants such as polyoxyethylene alkylphenyl ether ( Several weight percent can be added to the (co) polymer.
The thickness of the protective layer is preferably 0.5 to 5 μm, and particularly preferably 1 to 3 μm.

  In addition, adhesion to the image area and scratch resistance are extremely important in handling the plate. That is, when a hydrophilic layer made of a water-soluble polymer is laminated on an oleophilic polymer layer, film peeling due to insufficient adhesion tends to occur, and the peeled portion causes defects such as poor film hardening due to inhibition of oxygen polymerization. On the other hand, various proposals have been made to improve the adhesion between these two layers. For example, in a hydrophilic polymer mainly composed of polyvinyl alcohol, an acrylic emulsion or a water-insoluble vinyl pyrrolidone-vinyl acetate copolymer is mixed in an amount of 20 to 60% by weight and laminated on the polymerized layer. It is mentioned that adhesiveness is obtained. Any of these known techniques can be applied to the protective layer in the present invention. Such a coating method of the protective layer is described in detail in, for example, US Pat. No. 3,458,311 and Japanese Patent Publication No. 55-49729.

  The protective layer may be added with a colorant (water-soluble dye) that is excellent in the transparency of light used when exposing the recording layer and that can efficiently absorb light having a wavelength that is not related to exposure. Good. Thereby, safelight aptitude can be improved, without reducing a sensitivity.

The coating amount of the protective layer is preferably 0.1 to 10 g / m ² , more preferably 0.5 to 5 g / m ² as a dry weight.

(Support)
As a support in the lithographic printing plate precursor according to the invention, a conventionally known support used in a lithographic printing plate can be used without limitation. The support is preferably a hydrophilic support.
The support used is preferably a dimensionally stable plate, for example, paper, paper laminated with plastic (eg, polyethylene, polypropylene, polystyrene, etc.), metal plate (eg, aluminum, zinc). , Copper, etc.), plastic films (for example, cellulose diacetate, cellulose triacetate, cellulose propionate, cellulose butyrate, cellulose acetate butyrate, cellulose nitrate, polyethylene terephthalate, polyethylene, polystyrene, polypropylene, polycarbonate, polyvinyl acetal, etc.) Such as paper or plastic film laminated or vapor-deposited with such metals, and appropriate physical and chemical treatments suitable for the purpose of imparting hydrophilicity and improving the strength as necessary. May be applied.

  In particular, preferred hydrophilic supports include paper, polyester film or aluminum plate. Among them, the surface has good dimensional stability, is relatively inexpensive, and has excellent hydrophilicity and strength by surface treatment as required. An aluminum plate capable of providing A composite sheet in which an aluminum sheet is bonded on a polyethylene terephthalate film as described in Japanese Patent Publication No. 48-18327 is also preferable.

  The aluminum substrate is a dimensionally stable metal plate mainly composed of aluminum. In addition to a pure aluminum plate, an alloy plate containing aluminum as a main component and containing a trace amount of foreign elements, or aluminum (alloy) is laminated. Or it is chosen from the vapor-deposited plastic film or paper.

  In the following description, the above-described substrates made of aluminum or aluminum alloy are collectively referred to as an aluminum substrate. The foreign elements contained in the aluminum alloy include silicon, iron, manganese, copper, magnesium, chromium, zinc, bismuth, nickel, titanium, etc., and the content of the foreign elements in the alloy is 10% by weight or less. In the present invention, a pure aluminum plate is suitable, but since completely pure aluminum is difficult to manufacture in the refining technique, it may contain a slightly different element.

  Thus, the composition of the aluminum plate applied to the present invention is not specified, and it is a conventionally known material such as JIS A 1050, JIS A 1100, JIS A 3103, JIS A 3005, etc. Can be used as appropriate. The thickness of the aluminum substrate that can be used in the present invention is preferably 0.1 mm to 0.6 mm, more preferably 0.15 mm to 0.4 mm, and 0.2 mm to 0.3 mm. More preferably it is. This thickness can be changed as appropriate according to the size of the printing press, the size of the printing plate, and the desire of the user. The aluminum substrate may or may not be subjected to a substrate surface treatment described below as required.

The aluminum substrate is preferably roughened.
Examples of the roughening treatment method include mechanical roughening, chemical etching, and electrolytic grain as disclosed in JP-A-56-28893. Furthermore, the electrochemical surface roughening method in which the surface is electrochemically roughened in hydrochloric acid or nitric acid electrolyte solution, the aluminum surface is scratched with a metal wire, the wire brush grain method, the aluminum surface is grained with a polishing ball and an abrasive. It is possible to use a mechanical surface roughening method such as a pole grain method, or a brush grain method in which the surface is roughened with a nylon brush and an abrasive. Moreover, the said roughening method can also be used individually or in combination. Among them, the method usefully used for roughening is an electrochemical method in which roughening is chemically carried out in hydrochloric acid or nitric acid electrolytic solution, and the preferred anodic electricity is 50 C / dm ^{2 to} 400 C / dm ^2. Range. More specifically, in the electrolytic solution containing from 0.1 to 50% by weight hydrochloric acid or nitric acid, the temperature 20 to 80 ° C., for 1 second to 30 minutes, at a current density of 100C / dm ² ~400C / dm ² It is preferable to perform alternating current and / or direct current electrolysis.

The roughened aluminum substrate may be chemically etched with acid or alkali.
Etching agents suitably used are caustic soda, sodium carbonate, sodium aluminate, sodium metasilicate, sodium phosphate, potassium hydroxide, lithium hydroxide, etc., and preferred ranges of concentration and temperature are 1 to 50% by weight, 20 to 100 ° C.
It is preferable that pickling is performed to remove dirt (smut) remaining on the surface after etching. As the acid used, nitric acid, sulfuric acid, phosphoric acid, chromic acid, hydrofluoric acid, borohydrofluoric acid and the like are used. In particular, as a method for removing smut after the electrochemical surface roughening treatment, it is preferably contacted with 15 to 65% by weight sulfuric acid at a temperature of 50 to 90 ° C. as described in JP-A-53-12739. And the alkali etching method described in Japanese Patent Publication No. 48-28123. After the processing as described above, the method condition is not particularly limited as long as the center line average group Ra Ra of the processing surface is 0.2 to 0.5 μm.

The aluminum substrate that has been roughened as described above is then anodized to form an oxide film. In the anodizing treatment, sulfuric acid, phosphoric acid, oxalic acid, or an aqueous solution of boric acid / sodium borate is used as a main component of the electrolytic bath singly or in combination. In this case, the electrolyte solution may of course contain at least components normally contained in at least an Al alloy plate, an electrode, tap water, groundwater and the like. Further, the second and third components may be added. Here, the second and third components are, for example, ions of metals such as Na, K, Mg, Li, Ca, Ti, Al, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, and ammonium. Examples of the ions include cations, nitrate ions, carbonate ions, chloride ions, phosphate ions, fluorine ions, sulfite ions, titanate ions, silicate ions, borate ions, and the like, and the concentration is 0 to About 10,000 ppm may be contained.
There are no particular limitations on the conditions of the anodizing treatment, but the treatment is preferably carried out by direct current or alternating current electrolysis at a current density of 0.1 to 40 A / m ² at 30 to 500 g / liter, a treatment liquid temperature of 10 to 70 ° C. . The thickness of the anodic oxide film to be formed is preferably in the range of 0.5 to 1.5 μm, and more preferably in the range of 0.5 to 1.0 μm.

  Furthermore, after performing these treatments, water-soluble resins such as polyvinylphosphonic acid, polymers and copolymers having sulfo groups in the side chain, polyacrylic acid, water-soluble metal salts (for example, zinc borate), A yellow dye or an undercoat of an amine salt or the like is also suitable. Further, a sol-gel treated substrate in which a functional group capable of causing an addition reaction by a radical as disclosed in JP-A-7-159983 is covalently used.

  As another preferred example, a substrate provided with a water-resistant hydrophilic layer as a surface layer on an arbitrary support can be raised. As such a surface layer, for example, US Pat. No. 3,055,295, a layer comprising an inorganic pigment and a binder described in JP-A-56-13168, and JP-A-9-80744 described And a sol-gel film made of titanium oxide, polyvinyl alcohol and silicic acid described in JP-A-8-507727. These hydrophilic treatments are performed to make the surface of the support hydrophilic, in order to prevent harmful reactions of the photosensitive layer provided thereon, and to improve the adhesion of the photosensitive layer, etc. It is to be given.

(Middle layer)
In the lithographic printing plate precursor according to the invention, an intermediate layer may be provided for the purpose of improving the adhesion and soiling between the photosensitive layer and the support.
Specific examples of such an intermediate layer include JP-B-50-7481, JP-A-54-72104, JP-A-59-101651, JP-A-60-149491, JP-A-60-232998, JP-A-3-56177, JP-A-4-282737, JP-A-5-16558, JP-A-5-246171, JP-A-7-159983, JP-A-7-314937, JP-A-8-202025, Special Kaihei 8-320551, JP 9-34104, JP 9-236911, JP 9-269593, JP 10-69092, JP 10-115931, JP 10-161317, JP 10-260536, JP-A-10-282682, JP-A-11-84684, JP-A-11-38635, JP-A-11-38629, JP 10-282645, JP 10-301262, JP 11-24277, JP 11-109641, JP 10-319600, JP 11-327152, JP 2000-10292, JP Examples described in JP 2000-235254 A, JP 2000-352824 A, JP 2001-209170 A, and the like.

<Plate making method of lithographic printing plate>
Next, the plate making method of the planographic printing plate of the present invention will be described in detail.
The plate making method of the lithographic printing plate of the present invention comprises an exposure step of image exposure of the lithographic printing plate precursor of the present invention, and a development step of removing the photosensitive layer in the non-exposed area in the presence of a developer. To do.
Below, the developing solution which can be used for the plate-making method of this invention is demonstrated.

(Developer)
The developer that can be used in the plate making method of the lithographic printing plate of the present invention is not particularly limited. For example, it contains an inorganic alkali salt and a nonionic surfactant and has a pH of 11.0 to 12.7. Those are preferably used.

  The inorganic alkali salt can be used as appropriate. For example, sodium hydroxide, potassium, ammonium, lithium, sodium silicate, potassium, ammonium, lithium, tribasic sodium phosphate, potassium, ammonium Inorganic alkaline agents such as sodium carbonate, potassium, ammonium, sodium hydrogencarbonate, potassium, ammonium, sodium borate, potassium, and ammonium. These may be used alone or in combination of two or more.

In the case of using silicate, developability is achieved by adjusting the mixing ratio and concentration of silicon oxide SiO ₂ which is a component of silicate and alkali oxide M ₂ O (M represents an alkali metal or ammonium group). Can be adjusted easily. Among the developers, those having a mixing ratio (SiO ₂ / M ₂ O: molar ratio) of silicon oxide SiO ₂ and alkali oxide M ₂ O of 0.5 to 3.0 are preferable, and 1.0 to 2.0 Are more preferred. The added amount of SiO ₂ / M ₂ O is preferably 1 to 10% by weight, more preferably 3 to 8% by weight, and most preferably 4 to 7% by weight based on the weight of the developer. When this concentration is within the above-mentioned range, there is no decrease in developability and processing capacity, no precipitation or crystal formation, no gelation during neutralization during waste liquid, and no trouble in waste liquid processing.

In addition, an organic alkali agent may be supplementarily used in order to finely adjust the alkali concentration and supplement the solubility of the photosensitive layer.
Examples of the organic alkali agent include monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monoisopropylamine, diisopropylamine, triisopropylamine, n-butylamine, monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, Examples thereof include diisopropanolamine, ethyleneimine, ethylenediamine, pyridine, tetramethylammonium hydroxide and the like.
These organic alkali agents are used alone or in combination of two or more.

  The surfactant can be used as appropriate. For example, nonionic surfactants having a polyoxyalkylene ether group, polyoxyethylene alkyl esters such as polyoxyethylene stearate, sorbitan monolaurate, sorbitan monostearate Nonionic surfactants such as sorbitan alkyl esters such as sorbitan distearate, sorbitan monooleate, sorbitan sesquioleate, sorbitan trioleate, and monoglyceride alkyl esters such as glycerol monostearate and glycerol monooleate; Alkyl benzene sulfonates such as sodium acetate, sodium butyl naphthalene sulfonate, sodium pentyl naphthalene sulfonate, sodium hexyl naphthalene sulfonate Anion interfaces such as alkyl naphthalene sulfonates such as sodium, sodium octyl naphthalene sulfonate, alkyl sulfates such as sodium lauryl sulfate, alkyl sulfonates such as sodium dodecyl sulfonate, and sulfosuccinate esters such as sodium dilauryl sulfosuccinate Activators; alkylbetaines such as lauryl betaine and stearyl betaine, amphoteric surfactants such as amino acids, and the like. Of these, nonionic surfactants having a polyoxyalkylene ether group are particularly preferred.

As the surfactant containing a polyoxyalkylene ether group, one having a structure of the following formula (XI) is preferably used.
R ₄₀ —O— (R ₄₁ —O) _p —H (XI)
In the formula, R ₄₀ is an alkyl group having 3 to 15 carbon atoms, an aromatic hydrocarbon group having 6 to 15 carbon atoms, or a heteroaromatic ring group having 4 to 15 carbon atoms (in addition, the substituent is 1 to 1 carbon atoms). 20 alkyl groups, halogen atoms such as Br, Cl, and I, aromatic hydrocarbon groups having 6 to 15 carbon atoms, aralkyl groups having 7 to 17 carbon atoms, alkoxy groups having 1 to 20 carbon atoms, and 2 to 20 carbon atoms R ₄₁ represents an alkylene group having 1 to 100 carbon atoms, and p represents an integer of 1 to 100. Each of these groups may have a substituent, and examples of the substituent include an alkyl group having 1 to 20 carbon atoms and an aromatic hydrocarbon group having 6 to 15 carbon atoms.

In the definition of the formula (XI), specific examples of the “aromatic hydrocarbon group” include phenyl group, tolyl group, naphthyl group, anthryl group, biphenyl group, phenanthryl group and the like.
Specific examples of the “heteroaromatic ring group” include furyl group, thionyl group, oxazolyl group, imidazolyl group, pyranyl group, pyridinyl group, acridinyl group, benzofuranyl group, benzothionyl group, benzopyranyl group, benzoxazolyl group. Group, benzimidazolyl group and the like.

Further, the part of (R ₄₁ —O) _{p in} the formula (XI) may be two or three kinds of groups as long as it is in the above range. Specific examples include a combination of ethyleneoxy group and propyleneoxy group, ethyleneoxy group and isopropyloxy group, ethyleneoxy group and butyleneoxy group, ethyleneoxy group and isobutylene group, etc. in random or block form. It is done.
In the present invention, the surfactant having a polyoxyalkylene ether group is used alone or in combination, and it is effective to add 1 to 30% by weight, more preferably 2 to 20% by weight in the developer. is there. Within the above range, developability is excellent, and damage during development can be reduced, so the printing plate has excellent printing durability.

  Examples of the nonionic surfactant having a polyoxyalkylene ether group represented by the formula (XI) include polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, and polyoxyethylene stearyl ether. , Polyoxyethylene aryl ethers such as polyoxyethylene phenyl ether and polyoxyethylene naphthyl ether, polyoxyethylene alkyl aryl ethers such as polyoxyethylene methyl phenyl ether, polyoxyethylene octyl phenyl ether and polyoxyethylene nonyl phenyl ether Is mentioned.

Surfactant can be used individually by 1 type or in combination of 2 or more types.
Further, the content of the surfactant in the developer is preferably in the range of 0.1 to 20% by weight.

  The pH of the developer that can be used in the plate-making method of the present invention is preferably 11.0 to 12.7 from the viewpoint of damage during image formation and development of the exposed portion, and 11.5 to 12.5. It is more preferable that

  The conductivity of the developer that can be used in the present invention is preferably 3 to 30 mS / cm, particularly preferably 5 to 20 mS / cm. Within the above range, the elution of the photosensitive layer component on the aluminum support is easy, stains during printing can be suppressed, the elution rate of the photosensitive layer is moderate, and a residual film is generated in the unexposed area. Can be prevented.

(Exposure and development processing)
The light source used for the exposure process may be any light source that can be exposed at a wavelength of 700 nm to 1,400 nm, and an infrared laser is preferable. Among these, image exposure is preferably performed by a solid laser or semiconductor laser that emits infrared rays having a wavelength of 750 nm to 1,400 nm. The laser output is preferably 100 mW or more, and a multi-beam laser device is preferably used to shorten the exposure time. The exposure time per pixel is preferably within 20 μsec. The amount of energy per unit irradiated on the lithographic printing plate precursor is preferably 10 to 300 mJ / cm ² .

  In this exposure processing, exposure can be performed by overlapping the light beams of the light sources. Overlap means that exposure is performed under the condition that the sub-scanning pitch width is smaller than the beam diameter. The overlap can be expressed quantitatively by FWHM / sub-scanning pitch width (overlap coefficient), for example, when the beam diameter is expressed by the full width at half maximum (FWHM) of the beam intensity. In the present invention, this overlap coefficient is preferably 0.1 or more.

  The light source scanning method of the exposure apparatus is not particularly limited, and a cylindrical outer surface scanning method, a cylindrical inner surface scanning method, a planar scanning method, and the like can be used. The channel of the light source may be a single channel or a multi-channel, but in the case of a cylindrical outer surface system, a multi-channel is preferably used.

  A heating process for 1 second to 5 minutes may be performed at a temperature of 50 ° C. to 140 ° C. for the purpose of increasing the curing rate of the recording layer between image exposure and development. When the heating temperature is in the above range, there is an effect of increasing the curing rate, and a residual film due to dark polymerization in the unexposed area does not occur.

  In addition, as described above, an oxygen blocking layer (protective layer) may be provided on the photosensitive layer of the negative lithographic printing plate precursor in the present invention. A method of simultaneously removing the unexposed portion of the recording layer or a method of removing the oxygen blocking layer with water or warm water first and then removing the unexposed portion of the recording layer by development is known. Alternatively, the warm water may contain a preservative described in JP-A-10-10754, an organic solvent described in JP-A-8-278636, and the like.

  The negative lithographic printing plate according to the present invention is developed with the developer according to a conventional method at a temperature of 0 to 60 ° C., preferably about 15 to 40 ° C., for example, using an exposed negative lithographic printing plate as a developer. It is performed by dipping and rubbing with a brush.

  Further, when developing using an automatic developing machine, the developing solution becomes fatigued according to the amount of processing, so that the processing capability may be restored by using a replenishing solution or a fresh developing solution. The negative lithographic printing plate developed in this way is washed with water or an interface as described in JP-A Nos. 54-8002, 55-11545, 59-58431, etc. It is post-treated with a rinsing solution containing an active agent and the like, a desensitizing solution containing gum arabic, starch derivatives and the like. In the present invention, these treatments can be used in various combinations for the post-treatment of the negative lithographic printing plate.

  The printing plate obtained by the above treatment can be improved in printing durability by post-exposure treatment or heating treatment such as burning according to the method described in JP-A-2000-89478. The planographic printing plate obtained by such processing is loaded on an offset printing machine and used for printing a large number of sheets.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. However, the present invention is not limited to the following examples unless it exceeds the gist thereof.

(Method for producing aluminum support)
An aluminum plate having a thickness of 0.3 mm was etched by being immersed in a 10 wt% aqueous sodium hydroxide solution at 60 ° C. for 25 seconds, washed with running water, neutralized with a 20 wt% nitric acid aqueous solution, and then washed with water. This was subjected to an electrolytic surface roughening treatment using a sinusoidal alternating waveform current in a 1 wt% aqueous nitric acid solution at an anode time electricity of 300 coulomb / dm ² . Subsequently, after being immersed in a 1% by weight sodium hydroxide aqueous solution at 40 ° C. for 5 seconds, immersed in a 30% by weight sulfuric acid aqueous solution and desmutted at 60 ° C. for 40 seconds, a current density of 2 A in a 20% by weight sulfuric acid aqueous solution was obtained. Anodization was performed for 2 minutes so that the thickness of the anodized film was 2.7 g / m ² under the conditions of / dm ² . When the surface roughness was measured, it was 0.3 μm (Ra display according to JIS B0601).

(Formation of intermediate layer)
The following intermediate layer solution was first applied to the aluminum plate subjected to the electric field roughening treatment using a bar coater and then dried at 150 ° C. for 4 seconds. The intermediate layer coating weight after drying was 25 mg / m ² .

[Intermediate layer liquid]
・ 100 parts by weight of the following sol liquid 900 parts by weight of methanol

[Sol solution]
-Phosmer PE (Unichemical Co., Ltd.) 5 parts by weight-Methanol 45 parts by weight-Water 10 parts by weight-85% by weight phosphoric acid 5 parts by weight-Tetraethoxysilane 20 parts by weight-3-Methacryloxypropyltrimethoxysilane 15 Parts by weight

(Formation of photosensitive layer)
On this intermediate layer, a photopolymerizable composition having the following composition was applied using a bar coater so that the dry coating weight was 1.3 g / m ^2, and dried at 95 ° C. for 50 seconds. A photosensitive layer of a comparative example was formed.

[Photopolymerizable composition]
Cyanine dye (compound described in Table 1) 0.31 part by weight Monomer (compound described in Table 1) 4.2 part by weight Polymerization initiator (compound described in Table 1) 1.2 part by weight Binder Polymer (compound described in Table 1) 3.6 parts by weight • ε-phthalocyanine dispersion 0.92 parts by weight • Fluorine nonionic surfactant Megafac F780 0.05 parts by weight (Megafac F780, Dainippon Ink & Chemicals, Inc.) (Made by Co., Ltd.)
Additive E-1 (compound described later) 0.6 parts by weight Additive E-2 (compound described later) 0.6 parts by weight 62 parts by weight methyl ethyl ketone 57 parts by weight propylene glycol monomethyl ether acetate

  The above-mentioned thing was used for M-1, M-11, N-2, (I) -21, and S-19 shown in Table 1. D-1 to D-3, D'-1, D'-2, M'-1 to M'-4, B-1 to B-4, E-1, and E-2 are shown below. I used something.

  In addition, the numbers on the lower right of the parentheses indicating the respective structural units of B-1 to B-4 represent the molar ratio of each structural unit.

(Formation of protective layer)
A mixed aqueous solution of polyvinyl alcohol (saponification degree: 98 mol%, polymerization degree: 500) and polyvinylpyrrolidone (BASF Corp., Rubiscol K-30) is applied to the surface of the recording layer with a wire bar. A protective layer was formed by drying at 125 ° C. for 75 seconds with a drying apparatus to prepare a lithographic printing plate precursor (negative lithographic printing plate precursor). The content ratio of polyvinyl alcohol / polyvinylpyrrolidone was 4/1 (weight ratio), and the coating amount (coating amount after drying) was 2.45 g / m ² .

[Evaluation]
<Stability over time>
The obtained lithographic printing plate precursor was exposed with a Trend setter 3244 manufactured by Creo at a resolution of 1,200 dpi and a 50% flat screen image of AM100 line at an output of 4.5 W, an outer drum rotation speed of 150 rpm, and a plate surface energy of 70 mJ / cm ² . did. The exposure was performed under conditions of 25 ° C. and 50% RH. The developer used was a silicate-containing developer LP-DZ (stock solution, no dilution with water, pH 12.30 at 25 ° C.) manufactured by Fuji Film Co., Ltd., and the finisher was FP- manufactured by Fuji Film Co., Ltd. A 2 W 1: 3 water dilution was used. The developing machine used was a PS processor IP850HD manufactured by G & J, and the development was carried out with a preheating temperature of 115 ° C., a liquid temperature of 25 ° C., and a development time of 28 seconds. The halftone dot area ratio (sensitivity (1)) of the lithographic printing plate obtained by development was measured with an iC Plate II manufactured by GretagMacbeth.
Further, the lithographic printing plate obtained by exposing and developing in the same manner as described above except that the obtained lithographic printing plate precursor was sealed with aluminum kraft paper together with interleaving paper and allowed to stand at 60 ° C. for 3 days. The average value obtained by measuring n5 dot area ratio on the plate with iC PlateII manufactured by GretagMacbeth was used as an index of sensitivity after long-term storage, and the sensitivity (1) (sensitivity when the lithographic printing plate precursor was new) was used as a reference. The amount of change Δ was used as an indicator of stability over time. The smaller the Δ, the better the stability over time.

  The evaluation results are shown in Table 2.

  From the examples, it was found that when the cyanine dye represented by the formula (I) in the present invention and the urethane monomer are combined, the temporal stability is specifically good. Comparative Examples 2 to 4 using a cyanine dye different from the present invention were inferior in stability over time. Comparative Example 1 using a monomer different from the urethane monomer also had poor stability over time.

Claims (8)

On the support,
(A) a cyanine dye represented by the following formula (I):
(B) an ethylenically unsaturated compound having a urethane bond,
(C) a polymerization initiator, and
(D) having a photosensitive layer containing a binder polymer;
Wherein (C) a polymerization initiator, Ri onium salts der,
The lithographic printing plate precursor, wherein the binder polymer (D) is a urethane resin having a crosslinkable group in the side chain .

(In formula (I), X ¹ and X ² each independently represent a divalent linking group selected from the group consisting of S, O, NR and C (alkyl) ₂ , wherein R ^1a and R ^1b are each Independently represents an alkyl group, an alkyl sulfonate group, an alkyl carboxylate group or an alkyl ammonium group, R ² represents SR, SO ₂ R, or OR, R ^3a and R ^3b each independently represents an alkyl group, COOR, OR, SR, NR ₂ or a halogen atom, or a condensed benzene ring formed by combining two or more R ^3a or two or more R ^3b , R represents an aryl group, Z represents an anion sufficient to obtain charge neutrality as the whole cyanine dye represented by formula (I), and R ^4a and R ^4b both represent a hydrogen atom, or R ^4a and R ^4b Are bonded and the length is 2 or 3 carbon atoms Represents a certain divalent hydrocarbon radical, in each of n1 and n2 independently represents an integer of 0 to 3, and m1 and m2 each independently represents an integer of 0 to 4.) The lithographic printing plate precursor according to claim 1, wherein R ^1a and R ^1b in the formula (I) are each independently an alkyl group. The lithographic printing plate precursor as claimed in claim 1 or 2, wherein R ² in the formula (I) is SR. The lithographic printing plate precursor as claimed in any one of claims 1 to 3, wherein R ^3a and R ^3b in the formula (I) are each independently an alkyl group or a halogen atom. The lithographic printing plate precursor as claimed in any one of Claims 1 to 4, wherein X ¹ and X ² in the formula (I) are each independently C (alkyl) ₂ . The lithographic printing plate precursor as claimed in any one of claims 1 to 5, wherein the cyanine dye represented by the formula (I) (A) is a cyanine dye represented by the following formula (II).

(In the formula (II), Z ^'- represents a monovalent anion.) The lithographic printing plate precursor as claimed in any one of claims 1 to 6, wherein the ethylenically unsaturated compound (B) having a urethane bond contains the following M-1.

The lithographic printing plate precursor as claimed in any one of claims 1 to 7, wherein the onium salt is an onium salt represented by the following formulas (RI-I) to (RI-III).

(In Formula (RI-I) to Formula (RI-III), Ar ¹¹ represents an aryl group having 20 or less carbon atoms which may have 1 to 6 substituents, and Z ^11- represents a monovalent shade. Ar ²¹ and Ar ²² each independently represents an aryl group having 20 or less carbon atoms which may have 1 to 6 substituents; Z ^21- represents a monovalent anion; to ^31, R ³² and R ³³ each independently represent a substituted group 1-6 having optionally also be aryl group having 20 or less carbon atoms, an alkyl group, an alkenyl group, or an alkynyl group, Z ^31- is Represents a monovalent anion, and each of the substituents independently represents an alkyl group having 12 or less carbon atoms, an alkenyl group having 12 or less carbon atoms, an alkynyl group having 12 or less carbon atoms, an aryl group having 12 or less carbon atoms, or a carbon number. 12 or less alkoxy group, 12 or less aryloxy group, halogen atom, 12 carbon atoms Lower alkylamino group, dialkylamino group having 12 or less carbon atoms, alkylamide group or arylamide group having 12 or less carbon atoms, carbonyl group, carboxyl group, cyano group, sulfonyl group, thioalkyl group having 12 or less carbon atoms, or Represents a thioaryl group having 12 or less carbon atoms.)