JP5740234B2 - Planographic printing plate precursor and novel betaine-containing polymer used therefor - Google Patents

Description

  The present invention relates to a lithographic printing plate precursor and a novel betaine-containing polymer used therefor. More specifically, the present invention relates to a lithographic printing plate precursor that can be directly made by laser image exposure.

In general, a lithographic printing plate comprises an oleophilic image area that receives ink in the printing process and a hydrophilic non-image area that receives dampening water. Lithographic printing utilizes the property that water and oil-based inks repel each other, so that the oleophilic image area of the lithographic printing plate is the ink receiving area, and the hydrophilic non-image area is dampened with the water receiving area (ink non-receiving area). In this method, a difference in ink adhesion is caused on the surface of the lithographic printing plate, and after ink is applied only to the image area, the ink is transferred to a printing medium such as paper and printed.
In order to produce this lithographic printing plate, conventionally, a lithographic printing plate precursor (PS plate) in which an oleophilic photosensitive resin layer (image recording layer) is provided on a hydrophilic support has been widely used. Usually, the lithographic printing plate precursor is exposed through an original image such as a lithographic film, then the image recording layer that becomes the image portion remains, and the alkaline development that dissolves and removes the unnecessary image recording layer corresponding to the non-image portion A lithographic printing plate was obtained by developing with a liquid or the like.

  Due to recent advances in this field, lithographic printing plates are now available with CTP (computer to plate) technology. That is, a lithographic printing plate can be obtained by scanning and exposing a lithographic printing plate precursor directly using a laser or a laser diode without a lith film, and developing it.

Under such circumstances, development issues related to the lithographic printing plate precursor are concentrated on improvements in image formation characteristics, printing characteristics, physical characteristics and the like corresponding to the CTP.
Another development issue related to lithographic printing plate precursors is an environmental issue related to waste liquids associated with wet processing such as development processing, which has become a major concern of the industry in recent years due to consideration for the global environment. .

For the environmental problems described above, simplification and no processing of development or plate making are directed. As one simple plate making method, a method called “on-press development” is performed. That is, after the exposure of the lithographic printing plate precursor, conventional development is not performed, but it is mounted on a printing machine as it is, and unnecessary portions of the image recording layer are removed at the initial stage of a normal printing process.
Further, as a simple development method, the unnecessary portion of the image recording layer is removed by a finisher or gum solution having a pH close to neutrality used in the post-development processing instead of the conventional highly alkaline developer. A method called “gum development” is also performed.

  In the simplification of the plate making operation as described above, a system using an image recording layer and a light source that can be handled in a bright room or under a yellow light is preferable from the viewpoint of ease of work, and such a light source has a wavelength of 760. A solid-state laser such as a semiconductor laser that emits infrared light of up to 1200 nm and a YAG laser is used. A UV laser can also be used.

  As a lithographic printing plate precursor that can be developed on the machine, for example, in Patent Document 1, an image recording layer (photosensitive layer) containing an infrared absorber, a radical polymerization initiator, and a polymerizable compound is provided on a support. A planographic printing plate precursor is described. Further, as a lithographic printing plate precursor capable of gum development, for example, a lithographic printing plate precursor of a type in which development is performed with a finisher or gum solution having a pH close to neutral as in Patent Documents 2 and 3 is known.

  As a lithographic printing plate precursor capable of on-machine development, for example, in Patent Documents 1 and 2, a lithographic printing plate having an image recording layer (thermosensitive layer) containing a microcapsule containing a polymerizable compound on a hydrophilic support. The original edition is listed. Patent Document 3 describes a lithographic printing plate precursor in which an image recording layer (photosensitive layer) containing an infrared absorber, a radical polymerization initiator, and a polymerizable compound is provided on a support. Further, in Patent Document 4, on-press development is possible in which an image recording layer containing a polymerizable compound and a graft polymer having a polyethylene oxide chain in the side chain or a block polymer having a polyethylene oxide block is provided on a support. A planographic printing plate precursor is described.

  However, these simple processing type lithographic printing plate precursors are conventionally hydrophilic in the image recording layer in order to enable development with a low pH developer or a dampening solution (usually almost neutral) on a printing press. There is a problem that it is difficult to achieve both coexistence of using a high component, so that the printing durability becomes insufficient, and conversely, if the hydrophilicity is lowered to improve the printing durability, the developing property deteriorates.

  Various studies have been made to improve this problem. For example, Patent Document 5 describes that an image recording layer contains a low molecular weight hydrophilic compound, polyols, organic sulfates, organic sulfonates, or betaines. Patent Document 6 describes a composition containing a polymerizable compound having a sulfobetaine structure. However, even if these techniques are used, the compatibility between developability and printing durability is not yet sufficient, and further improvements have been desired.

JP 2001-277740 A JP 2001-277742 A JP 2002-287334 A US Patent Application Publication No. 2003/0064318 JP 2009-172790 A JP-A-5-179155

  An object of the present invention is to provide a simple development type and on-press development type lithographic printing plate precursor capable of image recording by laser exposure, excellent in developability and stain resistance, and having sufficient printing durability, And a novel betaine-containing polymer used therein.

（一般式（１）中、Ｒ _１ 〜Ｒ _４ は各々独立に置換基を有してもよい炭素原子数１〜１０のアルキル基、アルケニル基、アルキニル基、シクロアルキル基又はアリール基を表す。あるいはＲ _１ 、Ｒ _２ 、Ｒ _３ 、Ｒ _４ の任意の２つが互いに結合して複素環を形成してもよい。Ｗ _１ 、Ｙ _１ 、Ｙ _２ は各々独立に置換基を有してもよい２価の連結基を表す。Ｖは各々独立にＳＯ _３ ⁻ 又はＣＯＯ ⁻ のいずれかを表す。
ただし、Ｒ _１ 〜Ｒ _４ 、Ｗ _１ 、Ｙ _１ 、Ｙ _２ のうち少なくとも１つは、連結基を介してポリマー主鎖に結合する基である。）
＜４＞ 前記エチレン性ポリマーが、下記一般式（２）で表される構造を有するモノマー単位を少なくとも含むポリマーであることを特徴とする＜３＞記載の平版印刷版原版。

（一般式（２）中、Ｒ _１ 〜Ｒ _４ は各々独立に置換基を有してもよい炭素原子数１〜６のアルキル基、アルケニル基、アルキニル基、シクロアルキル基又はアリール基を表す。あるいはＲ _１ 、Ｒ _２ 、Ｒ _３ 、Ｒ _４ の任意の２つが互いに結合して複素環を形成してもよい。Ｗ _１ 、Ｙ _１ 、Ｙ _２ は各々独立に置換基を有してもよい２価の連結基を表す。
ただし、Ｒ _１ 〜Ｒ _４ 、Ｗ _１ 、Ｙ _１ 、Ｙ _２ のうち少なくとも１つは、連結基を介してポリマー主鎖に結合する基である。）
＜５＞ 前記エチレン性ポリマーが、下記一般式（３）及び（４）で表されるモノマー単位の少なくともいずれかを含むポリマーであることを特徴とする＜４＞記載の平版印刷版原版。

（一般式（３）中、Ｒ _１０ 〜Ｒ _１３ は各々独立に置換基を有してもよい炭素原子数１〜６のアルキル基、アルケニル基、アルキニル基、シクロアルキル基又はアリール基を表す。あるいはＲ _１０ 〜Ｒ _１３ の任意の２つが互いに結合して複素環を形成してもよい。Ｒ _９ は水素原子又はメチル基を表し、Ｚ _１ は−ＣＯ−、−Ｏ−、−ＣＨ _２ Ｏ−、又は置換基を有してもよいフェニレン基を表す。Ｗ _３ は炭素原子数１０以下の３価の連結基を表し、Ｙ _５ 、Ｙ _６ は各々独立に置換基を有してもよい炭素原子数１〜６のアルキレン基を表す。）（式（４）中、Ｒ _１５ 〜Ｒ _１７ は各々独立に置換基を有してもよい炭素原子数１〜６のアルキル基、アルケニル基、アルキニル基、シクロアルキル基又はアリール基を表す。あるいはＲ _１５ 〜Ｒ _１７ の任意の２つが互いに結合して複素環を形成しても良い。Ｒ _１４ は水素原子又はメチル基を表し、Ｚ _２ は−ＣＯ−、−Ｏ−、−ＣＨ _２ Ｏ−、又は置換基を有してもよいフェニレン基を表す。Ｘ _１ 、Ｘ _２ は各々独立に炭素原子数１０以下の２価の連結基を表し、Ｙ _７ 、Ｙ _８ は各々独立に置換基を有しても良い炭素原子数１〜６のアルキレン基を表す。）
＜６＞ 前記一般式（３）及び（４）のＲ _１０ 〜Ｒ _１３ 、Ｒ _１５ 〜Ｒ _１７ が各々独立にメチル基、エチル基、又は（Ｒ _１０ 、Ｒ _１１ 、Ｒ _１２ 、Ｒ _１３ ）若しくは（Ｒ _１５ 、Ｒ _１６ 、Ｒ _１７ ）の群の任意の２つが互いに結合した５員若しくは６員の複素環を含有する基を表し、Ｚ _１ 、Ｚ _２ が各々独立に−ＣＯ−又は置換基を有してもよいフェニレン基を表し、Ｗ _３ が炭素原子数１０以下の３価の連結基を表し、Ｘ _１ 、Ｘ _２ が各々独立に炭素原子数１０以下の２価の連結基を表し、Ｙ _５ 〜Ｙ _８ が各々独立に炭素原子数２〜５のアルキレン基を表すことを特徴とする＜５＞記載の平版印刷版原版。
＜７＞ 前記エチレン性ポリマーが、下記一般式（５）で表されるモノマー単位を少なくとも含むポリマーであることを特徴とする＜６＞記載の平版印刷版原版。

（一般式（５）中、Ｒ _１９ 〜Ｒ _２２ は各々独立にメチル基又はエチル基を表し、Ｒ _１８ は水素原子又はメチル基を表し、Ｌ _１ 、Ｌ _２ は各々独立に炭素原子数５以下の２価の連結基を表す。Ｙ _９ 、Ｙ _１０ は各々独立に炭素原子数２〜５のアルキレン基を表す。）
＜８＞ 前記エチレン性ポリマーが、更に（１）支持体表面と相互作用する構造を側鎖に有するモノマー単位、及び（２）エチレン性不飽和重合性基を側鎖に有するモノマー単位を含み、かつ下塗り層に含有されることを特徴とする＜１＞〜＜７＞のいずれか一項に記載の平版印刷版原版。
＜９＞ 前記エチレン性ポリマーが、更に（２）エチレン性不飽和重合性基を側鎖に有するモノマー単位、及び（３）親水性基を有するモノマー単位を含み、かつ画像記録層に含有されることを特徴とする＜１＞〜＜７＞のいずれか一項に記載の平版印刷版原版。
＜１０＞ 前記エチレン性ポリマーが、更に（３）親水性基を有するモノマー単位、及び（４）アクリロニトリル単位を含むポリマー微粒子であり、かつ画像記録層に含有されることを特徴とする＜１＞〜＜７＞のいずれか一項に記載の平版印刷版原版。
＜１１＞ 前記画像記録層が、画像様露光後に印刷機上で印刷インキ及び湿し水の少なくともいずれかを供給することにより未露光部分の除去が可能な画像記録層であることを特徴とする＜１＞〜＜１０＞のいずれか一項に記載の平版印刷版原版。
＜１２＞ 下記一般式（５）で表される構造を有するモノマー単位を少なくとも含むことを特徴とするポリマー。

（一般式（５）中、Ｒ _１９ 〜Ｒ _２２ は各々独立にメチル基又はエチル基を表し、Ｒ _１８ は水素原子又はメチル基を表し、Ｌ _１ 、Ｌ _２ は各々独立に炭素原子数５以下の２価の連結基を表す。Ｙ _９ 、Ｙ _１０ は各々独立に炭素原子数２〜５のアルキレン基を表す。）
本発明は、上記＜１＞〜＜１２＞に記載の平版印刷版原版及びポリマーに関するものであるが、その他の事項についても参考のために記載する。
１．支持体上に、画像記録層と、必要に応じて下塗り層を有し、画像記録層又は下塗り層の少なくともいずれかに（Ａ）ベタイン構造を少なくとも２つ有するモノマー単位を含むエチレン性ポリマーを含有することを特徴とする平版印刷版原版。
２．前記ベタイン構造が、スルホベタイン又はカルボベタインであることを特徴とする前記１記載の平版印刷版原版。
３．前記エチレン性ポリマーが、下記一般式（１）で表される構造を有するモノマー単位を少なくとも含むポリマーであることを特徴とする前記２記載の平版印刷版原版。 <1> On the support, it has an image recording layer containing at least (B) a polymerization initiator and (C) a polymerizable compound, and, if necessary, an undercoat layer, and is at least either of the image recording layer or the undercoat layer. (A) A lithographic printing plate precursor comprising an ethylenic polymer containing a monomer unit having at least two betaine structures.
<2> The lithographic printing plate precursor as described in <1>, wherein the betaine structure is sulfobetaine or carbobetaine.
<3> The lithographic printing plate precursor as described in <2>, wherein the ethylenic polymer is a polymer containing at least a monomer unit having a structure represented by the following general formula (1).

(In General Formula (1), R < ₁ > -R < ₄ > represents the C1-C10 alkyl group, alkenyl group, alkynyl group, cycloalkyl group, or aryl group which may have a substituent each independently. Alternatively , any _{two of} R ₁ , R ₂ , R ₃ and R ₄ may be bonded to each other to form a heterocyclic ring, and W ₁ , Y ₁ and Y ₂ may each independently have a substituent. Represents a divalent linking group, and each V independently represents either SO ₃ ^— or COO ^— .
However, at least one of R _{1 to} R ₄ , W ₁ , Y ₁ and Y ₂ is a group bonded to the polymer main chain via a linking group. )
<4> The lithographic printing plate precursor as described in <3>, wherein the ethylenic polymer is a polymer containing at least a monomer unit having a structure represented by the following general formula (2).

(In General Formula (2), R < ₁ > -R < ₄ > represents the C1-C6 alkyl group, alkenyl group, alkynyl group, cycloalkyl group, or aryl group which may have a substituent each independently. Alternatively , any _{two of} R ₁ , R ₂ , R ₃ and R ₄ may be bonded to each other to form a heterocyclic ring, and W ₁ , Y ₁ and Y ₂ may each independently have a substituent. Represents a divalent linking group.
However, at least one of R _{1 to} R ₄ , W ₁ , Y ₁ and Y ₂ is a group bonded to the polymer main chain via a linking group. )
<5> The lithographic printing plate precursor as described in <4>, wherein the ethylenic polymer is a polymer containing at least one of monomer units represented by the following general formulas (3) and (4).

(In General Formula (3), R _{10 to} R ₁₃ each independently represents an alkyl group, alkenyl group, alkynyl group, cycloalkyl group or aryl group having 1 to 6 carbon atoms which may have a substituent. Alternatively , any two of R _{10 to} R ₁₃ may be bonded to each other to form a heterocyclic ring, R ₉ represents a hydrogen atom or a methyl group, and Z ₁ represents —CO— , —O— , —CH ₂ O. -Represents a phenylene group that may have a substituent, W ₃ represents a trivalent linking group having 10 or less carbon atoms, and Y ₅ and Y ₆ may each independently have a substituent. Represents an alkylene group having 1 to 6 carbon atoms.) (In formula (4), R _{15 to} R ₁₇ are each independently an alkyl group having 1 to 6 carbon atoms, an alkenyl group, which may have a substituent, alkynyl group, a cycloalkyl group or an aryl group. Alternatively _R 15 to R Any two of which may form a heterocyclic ring bonded to each other _{.R 14} of ₇ represents a hydrogen atom or a methyl group, _{Z 2} is -CO -, - O -, - CH 2 O-, or a substituent X ₁ and X ₂ each independently represents a divalent linking group having 10 or less carbon atoms, and Y ₇ and Y ₈ may each independently have a substituent. Represents a good alkylene group having 1 to 6 carbon atoms.)
<6> R _{10 to} R ₁₃ and R _{15 to} R _{17 in the} general formulas (3) and (4) are each independently a methyl group, an ethyl group, or (R ₁₀ , R ₁₁ , R ₁₂ , R ₁₃ ) or Any two members of the group (R ₁₅ , R ₁₆ , R ₁₇ ) represent a group containing a 5-membered or 6-membered heterocyclic ring bonded to each other, and Z ₁ and Z ₂ are each independently —CO— or a substituent. Represents a phenylene group that may have, W ₃ represents a trivalent linking group having 10 or less carbon atoms, and X ₁ and X ₂ each independently represents a divalent linking group having 10 or less carbon atoms. characterized by representing the Y ₅ to Y ₈ are each independently an alkylene group having 2 to 5 carbon atoms <5> the lithographic printing plate precursor as described.
<7> The lithographic printing plate precursor as described in <6>, wherein the ethylenic polymer is a polymer containing at least a monomer unit represented by the following general formula (5).

(In General Formula (5), R _{19 to} R ₂₂ each independently represent a methyl group or an ethyl group, R ₁₈ represents a hydrogen atom or a methyl group, and L ₁ and L ₂ each independently represent 5 or less carbon atoms. Y ₉ and Y ₁₀ each independently represents an alkylene group having 2 to 5 carbon atoms.)
<8> The ethylenic polymer further includes (1) a monomer unit having a structure that interacts with the support surface in the side chain, and (2) a monomer unit having an ethylenically unsaturated polymerizable group in the side chain, The lithographic printing plate precursor as described in any one of <1> to <7>, which is contained in an undercoat layer.
<9> The ethylenic polymer further includes (2) a monomer unit having an ethylenically unsaturated polymerizable group in the side chain, and (3) a monomer unit having a hydrophilic group, and is contained in the image recording layer. The lithographic printing plate precursor as described in any one of <1> to <7>, wherein
<10> The ethylenic polymer is a polymer fine particle further comprising (3) a monomer unit having a hydrophilic group and (4) an acrylonitrile unit, and is contained in the image recording layer <1> The lithographic printing plate precursor as described in any one of-<7>.
<11> The image recording layer is an image recording layer in which an unexposed portion can be removed by supplying at least one of printing ink and fountain solution on a printing machine after imagewise exposure. The lithographic printing plate precursor as described in any one of <1> to <10>.
<12> A polymer comprising at least a monomer unit having a structure represented by the following general formula (5).

(In General Formula (5), R _{19 to} R ₂₂ each independently represent a methyl group or an ethyl group, R ₁₈ represents a hydrogen atom or a methyl group, and L ₁ and L ₂ each independently represent 5 or less carbon atoms. Y ₉ and Y ₁₀ each independently represents an alkylene group having 2 to 5 carbon atoms.)
The present invention relates to the lithographic printing plate precursor and polymer described in <1> to <12> above, but other matters are also described for reference.
1. Containing an ethylenic polymer comprising an image recording layer and, if necessary, an undercoat layer on a support, and (A) at least one of the monomer units having at least two betaine structures in at least one of the image recording layer and the undercoat layer A lithographic printing plate precursor characterized by:
2. 2. The lithographic printing plate precursor as described in 1 above, wherein the betaine structure is sulfobetaine or carbobetaine.
3. 3. The lithographic printing plate precursor as described in 2 above, wherein the ethylenic polymer is a polymer containing at least a monomer unit having a structure represented by the following general formula (1).

(In General Formula (1), R < ₁ > -R < ₄ > represents the C1-C10 alkyl group, alkenyl group, alkynyl group, cycloalkyl group, or aryl group which may have a substituent each independently. Alternatively, any _{two of} R ₁ , R ₂ , R ₃ and R ₄ may be bonded to each other to form a heterocyclic ring, and W ₁ , Y ₁ and Y ₂ may each independently have a substituent. Represents a divalent linking group, and each V independently represents either SO ₃ ^— or COO ^— .
However, at least one of R _{1 to} R ₄ , W ₁ , Y ₁ and Y ₂ is a group bonded to the polymer main chain via a linking group. )

4). 4. The lithographic printing plate precursor as described in 3 above, wherein the ethylenic polymer is a polymer containing at least a monomer unit having a structure represented by the following general formula (2).

(In General Formula (2), R < ₁ > -R < ₄ > represents the C1-C6 alkyl group, alkenyl group, alkynyl group, cycloalkyl group, or aryl group which may have a substituent each independently. Alternatively, any _{two of} R ₁ , R ₂ , R ₃ and R ₄ may be bonded to each other to form a heterocyclic ring, and W ₁ , Y ₁ and Y ₂ may each independently have a substituent. Represents a divalent linking group.
However, at least one of R _{1 to} R ₄ , W ₁ , Y ₁ and Y ₂ is a group bonded to the polymer main chain via a linking group. )

5. 5. The lithographic printing plate precursor as described in 4 above, wherein the ethylenic polymer is a polymer containing at least one of monomer units represented by the following general formulas (3) and (4).

(In General Formula (3), R _{10 to} R ₁₃ each independently represents an alkyl group, alkenyl group, alkynyl group, cycloalkyl group or aryl group having 1 to 6 carbon atoms which may have a substituent. Alternatively, any two of R _{10 to} R ₁₃ may be bonded to each other to form a heterocyclic ring, R ₉ represents a hydrogen atom or a methyl group, and Z ₁ represents —CO—, —O—, —CH ₂ O. -Represents a phenylene group that may have a substituent, W ₃ represents a trivalent linking group having 10 or less carbon atoms, and Y ₅ and Y ₆ may each independently have a substituent. Represents an alkylene group having 1 to 6 carbon atoms.) (In general formula (4), R _{15 to} R ₁₇ are each independently an alkyl group or alkenyl group having 1 to 6 carbon atoms which may have a substituent. Represents an alkynyl group, a cycloalkyl group or an aryl group, or R ₁₅ to Any two of R ₁₇ may be bonded to each other to form a heterocyclic ring, R ₁₄ represents a hydrogen atom or a methyl group, and Z ₂ represents —CO—, —O—, —CH ₂ O—, or a substituted group. X ₁ and X ₂ each independently represent a divalent linking group having 10 or less carbon atoms, and Y ₇ and Y ₈ each independently have a substituent. Represents a good alkylene group having 1 to 6 carbon atoms.)

6). In the general formulas (3) and (4), R _{10 to} R ₁₃ and R _{15 to} R ₁₇ are each independently a methyl group, an ethyl group, or (R ₁₀ , R ₁₁ , R ₁₂ , R ₁₃ ) or (R ₁₅ , R ₁₆ , R ₁₇ ) represents a group containing a 5-membered or 6-membered heterocyclic ring bonded to each other, and Z ₁ and Z ₂ each independently have —CO— or a substituent. A phenylene group that may be, W ₃ represents a trivalent linking group having 10 or less carbon atoms, X ₁ and X ₂ each independently represents a divalent linking group having 10 or less carbon atoms, and Y ₅ the lithographic printing plate precursor of the 5 wherein to Y _8, characterized in that the each independently represent an alkylene group having 2 to 5 carbon atoms.
7). The lithographic printing plate precursor as described in 6 above, wherein the ethylenic polymer is a polymer containing at least a monomer unit represented by the following general formula (5).

(In the formula, R _{19 to} R ₂₂ each independently represents a methyl group or an ethyl group, R ₁₈ represents a hydrogen atom or a methyl group, and L ₁ and L ₂ each independently represent a divalent group having 5 or less carbon atoms. Represents a linking group, Y ₉ and Y ₁₀ each independently represents an alkylene group having 2 to 5 carbon atoms.)

8). The ethylenic polymer further comprises (1) a monomer unit having a structure interacting with the support surface in the side chain, and (2) a monomer unit having an ethylenically unsaturated polymerizable group in the side chain, and an undercoat layer The lithographic printing plate precursor as described in any one of 1 to 7 above, which is contained in
9. The ethylenic polymer further contains (2) a monomer unit having an ethylenically unsaturated polymerizable group in the side chain, and (3) a monomer unit having a hydrophilic group, and is contained in the image recording layer. The lithographic printing plate precursor as described in any one of 1 to 7 above.
10. Any of the above 1 to 7, wherein the ethylenic polymer is (3) a polymer fine particle containing a monomer unit having a hydrophilic group and (4) an acrylonitrile unit, and is contained in an image recording layer. The lithographic printing plate precursor described in Crab.
11. The lithographic printing plate precursor as described in any one of 1 to 10, wherein the image recording layer further contains at least (B) a polymerization initiator and (C) a polymerizable compound.
12 The image recording layer is an image recording layer capable of removing an unexposed portion by supplying at least one of printing ink and fountain solution on a printing press after imagewise exposure. The lithographic printing plate precursor as described in any one of 11 above.
13. A polymer comprising at least a monomer unit having a structure represented by the general formula (5).

(In the formula, R _{19 to} R ₂₂ each independently represents a methyl group or an ethyl group, R ₁₈ represents a hydrogen atom or a methyl group, and L ₁ and L ₂ each independently represent a divalent group having 5 or less carbon atoms. Represents a linking group, Y ₉ and Y ₁₀ each independently represents an alkylene group having 2 to 5 carbon atoms.)

  According to the present invention, it is possible to provide a simple development type and on-press development type lithographic printing plate precursor capable of image recording by laser exposure, having excellent developability and stain resistance, and having sufficient printing durability. it can.

It is a schematic block diagram of an automatic processor.

[Lithographic printing plate precursor]
The lithographic printing plate precursor according to the invention has an image recording layer and, if necessary, an undercoat layer on a support, and (A) at least two betaine structures in at least one of the image recording layer and the undercoat layer. It is characterized by containing an ethylenic polymer containing monomer units. Hereinafter, elements and components of the lithographic printing plate precursor according to the invention will be described in detail.

(Image recording layer)
(A) Ethylene polymer containing monomer units having at least two betaine structures The ethylenic polymer of the present invention is characterized by containing monomer units having at least two betaine structures.
The ethylenic polymer is a polymer obtained by polymerization of an ethylenically unsaturated double bond, and examples of the functional group having an ethylenically unsaturated double bond include groups such as a vinyl group and a (meth) acryloyl group. be able to.

[I] Monomer unit having at least two betaine structures Examples of the betaine structure in the ethylenic polymer of the present invention include a sulfobetaine structure, a carbobetaine structure, a phosphobetaine structure, and the like, and preferably a sulfobetaine structure and a carbobetaine structure. It is a betaine structure, more preferably a sulfobetaine structure. Examples of the sulfobetaine structure and carbobetaine structure include structures represented by the following general formula (1).

(In General Formula (1), R < ₁ > -R < ₄ > represents the C1-C10 alkyl group, alkenyl group, alkynyl group, cycloalkyl group, or aryl group which may have a substituent each independently. Alternatively, any _{two of} R ₁ , R ₂ , R ₃ and R ₄ may be bonded to each other to form a heterocyclic ring, and W ₁ , Y ₁ and Y ₂ may each independently have a substituent. Represents a divalent linking group, and each V independently represents either SO ₃ ^— or COO ^— .
However, at least one of R _{1 to} R ₄ , W ₁ , Y ₁ and Y ₂ is a group bonded to the polymer main chain via a linking group. )

Preferred embodiments in the above formula are shown below.
In general formula (1), R < ₁ > -R < ₄ > represents the C1-C6 alkyl group, alkenyl group, alkynyl group, cycloalkyl group, or aryl group which may have a substituent each independently. Alternatively, any _{two of} R ₁ , R ₂ , R ₃ and R ₄ may be bonded to each other to form a heterocyclic ring.
Examples of the substituent that can be introduced include a halogen atom, hydroxy group, carboxy group, sulfonate group, nitro group, cyano group, amide group, amino group, alkyl group, alkenyl group, alkynyl group, aryl group, substituted oxy group, Examples thereof include a substituted sulfonyl group, a substituted carbonyl group, a substituted sulfinyl group, a sulfo group, a phosphono group, a phosphonato group, a silyl group, and a heterocyclic group.
Y ₁ and Y ₂ each independently represents an alkylene group having 1 to 6 carbon atoms which may have a substituent. Examples of the substituent that can be introduced include a halogen atom, a hydroxy group, a carboxy group, and a sulfonate group. Nitro group, cyano group, amide group, amino group, alkyl group, alkenyl group, alkynyl group, aryl group, substituted oxy group, substituted sulfonyl group, substituted carbonyl group, substituted sulfinyl group, sulfo group, phosphono group, phosphonate group, A silyl group, a heterocyclic group, etc. are mentioned.
W ₁ is an organic group composed of 3 to 10 non-metallic atoms each independently, for example, 1 to 60 carbon atoms, 0 to 10 nitrogen atoms, 0 to 50 atoms Organic groups composed of at least one element selected from oxygen atoms, 1 to 100 hydrogen atoms, and 0 to 20 sulfur atoms.
More specific examples include organic groups composed of the following structures singly or in combination.

The organic group represented by W ₁ may further have a substituent, and examples of the substituent that can be introduced include a halogen atom, a hydroxy group, a carboxy group, a sulfonate group, a nitro group, a cyano group, and an amide group. Amino group, alkyl group, alkenyl group, alkynyl group, aryl group, substituted oxy group, substituted sulfonyl group, substituted carbonyl group, substituted sulfinyl group, sulfo group, phosphono group, phosphonato group, silyl group, heterocyclic group, etc. Can be mentioned. The organic group represented by W ₁ may contain an ether bond, an ester bond, or a ureido bond.

  The betaine structure in the ethylenic polymer of the present invention is more preferably a sulfobetaine structure represented by the following general formula (2).

(In Formula (2), R < ₁ > -R < ₄ > represents the C1-C6 alkyl group, alkenyl group, alkynyl group, cycloalkyl group, or aryl group which may have a substituent each independently. Any _{two of} R ₁ , R ₂ , R ₃ , and R ₄ may be bonded to each other to form a heterocyclic ring, and W ₁ , Y ₁ , and Y ₂ may each independently have a substituent. Represents a valent linking group.
However, at least one of R _{1 to} R ₄ , W ₁ , Y ₁ and Y ₂ is a group bonded to the polymer main chain via a linking group. )

Preferred embodiments in the above formula are shown below.
In the general formula (2), R _{1 to} R ₄ are a methyl group or an ethyl group, or contain a 5-membered or 6-membered heterocyclic ring in which any two of (R _{1 to} R ₄ ) are bonded to each other. It is preferably a group, more preferably a methyl group or an ethyl group, and most preferably a methyl group.
Y ₁ and Y ₂ are preferably each independently an alkylene group having 2 to 5 carbon atoms, more preferably an alkylene group having 3 to 5 carbon atoms, and an alkylene group having 3 or 4 carbon atoms. Most preferably it is.
W ₁ is preferably an organic group having 10 or less carbon atoms, and more preferably an organic group having 8 or less carbon atoms.
Further, any two or more of (R ₁ , R ₂ , R ₃ , R ₄ , W ₁ ) may be bonded to each other to form a heterocyclic ring.
However, at least one of R _{1 to} R ₄ , W ₁ , Y ₁ and Y ₂ is a group bonded to the polymer main chain through a linking group.

  The monomer unit having at least two betaine structures of the present invention preferably includes a sulfobetaine structure, and more preferably a monomer unit represented by the following general formula (3) or (4).

In General Formula (3), R _{10 to} R ₁₃ each independently represent an alkyl group, alkenyl group, alkynyl group, cycloalkyl group, or aryl group having 1 to 6 carbon atoms that may have a substituent. Alternatively, any two of R ₁₀ , R ₁₁ , R ₁₂ and R ₁₃ may be bonded to each other to form a heterocyclic ring. R ₉ represents a hydrogen atom or a methyl group, and Z ₁ represents —CO—, —O—, —CH ₂ O— or a phenylene group which may have a substituent. W ₃ represents a trivalent linking group having 10 or less carbon atoms, and Y ₅ and Y ₆ each independently represent an alkylene group having 1 to 6 carbon atoms which may have a substituent.
In the general formula (4), R _{15 to} R ₁₇ each independently represent a C 1-6 alkyl group, alkenyl group, alkynyl group, cycloalkyl group or aryl group which may have a substituent. Alternatively, any two of R ₁₅ , R ₁₆ and R ₁₇ may be bonded to each other to form a heterocyclic ring. R ₁₄ represents a hydrogen atom or a methyl group, and Z ₂ represents —CO—, —O—, —CH ₂ O—, or an optionally substituted phenylene group. X ₁ and X ₂ each independently represent a divalent linking group having 10 or less carbon atoms, and Y ₇ and Y ₈ each independently represent an alkylene group having 1 to 6 carbon atoms which may have a substituent. Represent.

Examples of the substituent include alkyl group, aryl group, heteroaryl group, alkenyl group, alkynyl group, aralkyl group, halogen atom, hydroxy group, alkoxy group, aryloxy group, mercapto group, alkylthio group, arylthio group, alkyldithio group, Amino group, acyloxy group, carbamoyloxy group, sulfoxy group, ureido group, oxycarbonylamino group, formyl group, acyl group, carbonyl group, oxycarbonyl group, carbamoyl group, sulfinyl group, sulfonyl group, sulfo group (—SO ₃ H ) And conjugated base groups (hereinafter referred to as sulfonate groups), sulfinamoyl groups, phosphono groups (—PO ₃ H ₂ ) and conjugated base groups (hereinafter referred to as phosphonate groups), phosphonooxy groups (—OPO ₃ H). ₂₎ and its conjugated base group (hereinafter, phosphonato Referred to as carboxymethyl group), a cyano group, a nitro group, and the like.

Preferred embodiments in the above formula are shown below.
R ₁₀ , R ₁₁ , R ₁₂ , R ₁₃ , R ₁₅ , R ₁₆ , R ₁₇ are each independently a methyl group or an ethyl group, or each of (R _{10 to} R ₁₃ ) and (R _{15 to} R ₁₇ ) Any two members in the group are preferably groups containing 5-membered or 6-membered heterocycles bonded to each other, more preferably a methyl group or an ethyl group, and most preferably a methyl group.
Z ₁ and Z ₂ are each independently preferably —CO— or a phenylene group which may have a substituent, and more preferably —CO—.
W ₃ is preferably a trivalent linking group having 8 or less carbon atoms, and more preferably a linking group having 6 or less carbon atoms. Further, when Z ₁ is —CO—, W ₃ is particularly preferably a linking group capable of forming an amide bond with Z ₁ .
Specific examples of W ₃ include the following structures.

X ₁ and X ₂ are each independently preferably a divalent linking group having 8 or less carbon atoms, more preferably a divalent linking group having 6 or less carbon atoms, and more preferably 4 or less carbon atoms. Most preferred is an alkylene group.
Y _{5 to} Y ₈ are preferably each independently an alkylene group having 2 to 5 carbon atoms, more preferably an alkylene group having 3 to 5 carbon atoms, and an alkylene group having 3 or 4 carbon atoms. Most preferably.

Specific examples of monomer units containing a betaine structure contained in the ethylenic polymer of the present invention are shown below. Specific examples corresponding to the structural formulas (A1) to (K1), (A2) to (K2), and (L) to (S) are shown in the table. The first column in each table represents the compound number, and the first symbol of the compound number, for example A1, indicates that it corresponds to the structural formula (A1). The second and subsequent columns in each table indicate the contents of symbols in the structural formula.
The present invention is not limited to these compounds.

  As for the monomer unit having at least two betaine structures, only one type may be used in the ethylenic polymer according to the present invention, or two or more types may be included. The monomer units containing these betaine structures are preferably contained in the ethylenic polymer in an amount of 5 to 70% by mass, more preferably 5 to 60% by mass, from the viewpoint of developability and stain resistance. Preferably, it is the range of 8-50 mass% most preferably.

  The monomer unit having at least two betaine structures used in the present invention is a monomer such as (meth) acrylic acid ester, (meth) acrylamide or styrene derivative having at least two tertiary amino groups, and 1,2- It can be obtained by a method of reacting sultone such as ethane sultone, 1,3-propane sultone, 1,4-butane sultone, or cyclic sulfate such as ethylene sulfate, 1-methyl-ethylene sulfate, 1,3-propylene sulfate, etc. it can.

[II] Other monomer units constituting the ethylenic polymer The ethylenic polymer of the present invention may contain other monomer units in addition to the monomer unit having the betaine structure. Other monomer units can be selected and used depending on the use of the ethylenic polymer of the present invention, that is, whether it is used for an image recording layer or an undercoat layer.

<< Other monomer units for use in the image recording layer >>
Examples of other monomer units when the ethylenic polymer of the present invention is used for the image recording layer include monomer units represented by the following general formula (6).

In the above formula, R ₂₃ represents a hydrogen atom, a halogen atom, or a substituent having 1 to 12 carbon atoms, and R ₂₄ represents a group having an ester group, an amide group, a cyano group, a hydroxy group, or an aryl group.

Preferred embodiments in the above formula are shown below.
R ₂₃ is preferably a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, more preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and a hydrogen atom or a methyl group. Is most preferred.
R ₂₄ is preferably a group having an ester bond or an amide bond, a phenyl group which may have a substituent, or a cyano group. Substituents include alkyl groups, aryl groups, heteroaryl groups, alkenyl groups, alkynyl groups, aralkyl groups, halogen atoms, hydroxy groups, alkoxy groups, aryloxy groups, mercapto groups, alkylthio groups, arylthio groups, alkyldithio groups, amino groups. Group, acyloxy group, carbamoyloxy group, sulfoxy group, ureido group, oxycarbonylamino group, formyl group, acyl group, carbonyl group, oxycarbonyl group, carbamoyl group, sulfinyl group, sulfonyl group, sulfo group (—SO ₃ H) And its conjugate base group (hereinafter referred to as sulfonate group), sulfinamoyl group, phosphono group (—PO ₃ H ₂ ) and its conjugate base group (hereinafter referred to as phosphonate group), phosphonooxy group (—OPO ₃ H _2). ) And its conjugate base group (hereinafter referred to as phosphine) Referred to as Natookishi group), a cyano group, a nitro group, and the like.

Specific examples of the monomer corresponding to the monomer unit of the general formula (6) include styrene, vinyl chloride, methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate, vinylidene chloride, acrylonitrile, methacrylonitrile, vinyl carbazole. And acrylate or methacrylate having a polyalkylene structure. Among these, styrene, acrylonitrile and methyl methacrylate are particularly preferable.
The ethylenic polymer of the present invention may contain a plurality of monomer units derived therefrom.
These monomer units are preferably contained in the ethylenic polymer in an amount of 30 to 95% by mass, and in an amount of 40 to 95% by mass in order to balance developability, stain resistance and printing durability. More preferably, it is the range of 50-92 mass%.

The ethylenic polymer of the present invention imparts good on-press developability to an on-press development type lithographic printing plate precursor by having R _{24 in the} general formula (6) having a monomer unit containing a polyalkyleneoxy group. Can do. The polyalkyleneoxy group is preferably a polyethyleneoxy group or a polypropyleneoxy group, and particularly preferably a polyethyleneoxy group. Here, the number of repeating units of the alkyleneoxy group is preferably 1 to 100, more preferably 2 to 80, and particularly preferably 4 to 50.
Although the preferable example of such a monomer unit is shown below, this invention is not limited to these.

(In the formula, n represents an integer of 1 to 100, and R ₁ and R ₂ each independently represents a hydrogen atom or a methyl group.)

  More specific examples include the following structures, but the present invention is not limited to these.

  The monomer unit having a side chain containing a polyalkyleneoxy group is preferably contained in the ethylenic polymer in an amount of about 1 to about 70% by mass, more preferably about 2 to about 50% by mass. About 3 to about 40% by mass is particularly preferable.

  In the case of a lithographic printing plate precursor of a developer processing system, it is preferable that a monomer unit containing an acid group is contained in the ethylenic polymer from the viewpoint of removal with a developer. Examples of the acid group include a carboxylic acid group, a sulfonic acid group, a phosphonic acid group, a phosphoric acid group, and a sulfonamide group, but a carboxylic acid group is particularly preferable, and a monomer unit derived from acrylic acid and methacrylic acid or the following general formula The monomer unit represented by (c) is preferably used.

(In General Formula (c), R ¹ represents a hydrogen atom or a methyl group, R ² represents a single bond or an n + 1 valent linking group, A represents an oxygen atom or NR ³ , and R ³ represents a hydrogen atom or carbon. Represents a monovalent hydrocarbon group having 1 to 10 atoms, and n represents an integer of 1 to 5.)

The linking group represented by R ² in the general formula (c) is composed of at least one of a carbon atom, a hydrogen atom, an oxygen atom, a nitrogen atom, a sulfur atom and a halogen atom, and the number of atoms is preferably 1-80. Specific examples include an alkylene group, a substituted alkylene group, an arylene group, and a substituted arylene group. The divalent group may have a structure in which a plurality of these divalent groups are linked by an amide bond or an ester bond. R ² is preferably a single bond, an alkylene group, or a substituted alkylene group, and particularly preferably a single bond, an alkylene group having 1 to 5 carbon atoms, or a substituted alkylene group having 1 to 5 carbon atoms. A single bond, an alkylene group having 1 to 3 carbon atoms, or a substituted alkylene group having 1 to 3 carbon atoms is most preferable.
Examples of the substituent include a monovalent non-metallic atomic group excluding a hydrogen atom, a halogen atom (—F, —Br, —Cl, —I), a hydroxyl group, an alkoxy group, an aryloxy group, a mercapto group, An acyl group, a carboxyl group and its conjugate base group, an alkoxycarbonyl group, an aryloxycarbonyl group, a carbamoyl group, an aryl group, an alkenyl group, an alkynyl group and the like can be mentioned.

R ³ is preferably a hydrogen atom or a hydrocarbon group having 1 to 5 carbon atoms, particularly preferably a hydrogen atom or a hydrocarbon group having 1 to 3 carbon atoms, and most preferably a hydrogen atom or a methyl group. n is preferably 1 to 3, particularly preferably 1 or 2, and most preferably 1.

  The proportion of the monomer unit having a carboxylic acid group in the ethylenic polymer is preferably 1 to 70% by mass from the viewpoint of developability. Considering compatibility between developability and printing durability, 1 to 50% by mass is more preferable, and 1 to 30% by mass is particularly preferable.

  The acid group of the ethylenic polymer containing an acid group may be neutralized with a basic compound, and in particular, neutralized with a compound containing basic nitrogen such as an amino group, an amidine group, or a guanidine group. It is preferable. Furthermore, it is also preferred that the compound containing basic nitrogen has an ethylenically unsaturated group. Specific examples of the compound include those described in International Publication No. 2007/057442 pamphlet.

Furthermore, the ethylenic polymer used in the present invention preferably has a monomer unit having an ethylenically unsaturated polymerizable group in the side chain in order to improve the film strength of the image area. In particular, R _{24 in the} general formula (6) is more preferably a group containing an ethylenically unsaturated polymerizable group selected from the following general formulas (7) to (9).
These groups can be introduced into the polymer by polymer reaction or copolymerization. For example, a reaction between an acrylic polymer having a carboxy group in the side chain and glycidyl methacrylate, or a reaction between a polymer having an epoxy group and an ethylenically unsaturated group-containing carboxylic acid such as methacrylic acid can be used.

(In the formula, X and Y each independently represent an oxygen atom or —N (R ₃₆ ) —. Z represents an oxygen atom, —N (R ₃₆ ) — or a phenylene group. R _{25 to} R ₃₆ each represent Independently represents a hydrogen atom or a monovalent substituent.)

  The content of the ethylenically unsaturated polymerizable group of the ethylenic polymer (content of unsaturated double bond capable of radical polymerization by iodine titration) is preferably 0.1 to 10.0 mmol per 1 g of the ethylenic polymer. Preferably it is 1.0-7.0 mmol, Most preferably, it is 2.0-5.5 mmol. Within this range, good sensitivity and good storage stability can be obtained.

  Specific examples of the monomer unit having an ethylenically unsaturated polymerizable group in the side chain include, for example, the structures shown below, but the present invention is not limited thereto.

  The ethylenic polymer of the present invention has a monomer unit having a sulfonamide group in the side chain in order to satisfy developability, non-image portion fine line reproducibility, suppression of residue generation, and printing durability when using UV ink. It may be copolymerized. Specific examples of the monomer for such a monomer unit include compounds described in paragraph numbers [0024] to [0027] of JP-A No. 2009-241258.

  In addition, an lipophilic group such as an alkyl group, an aryl group, an aralkyl group, or an alkenyl group can be introduced into the ethylenic polymer of the present invention in order to control the inking property. Specifically, a lipophilic group-containing monomer such as an alkyl methacrylate may be copolymerized.

The ethylenic polymer of the present invention may be present in the image recording layer as a binder or may be present as polymer fine particles. When present as fine particles, the average particle size is preferably 0.01 to 3.0 μm.
The ethylenic polymer content in the image recording layer is 5 to 90% by mass, preferably 5 to 80% by mass, more preferably 10 to 70% by mass, based on the total solid content of the image recording layer. preferable.

  Although the specific example of the ethylenic polymer in this invention is given to the following table | surfaces, it is not limited to these. The mass average molar mass (Mw) in the table is measured by gel permeation chromatography (GPC) using polystyrene as a standard substance.

<< Other monomer units for use in the undercoat layer >>
The ethylenic polymer of the present invention can be used not only for the image recording layer but also for an undercoat layer provided between the image recording layer and the support, if necessary. The ethylenic polymer for the undercoat layer includes, as other monomer units, (1) a monomer unit having a structure that interacts with the support surface in the side chain, (2) a monomer unit having a hydrophilic group, and (3) It is preferable to contain a monomer unit having an ethylenically unsaturated polymerizable group in the side chain.

(1) Monomer unit having a structure that interacts with the surface of the support in the side chain The ethylenic polymer of the present invention has the following general formulas (a2-1) and (a2-2) in order to improve the adhesion to the support. ), (A2-3), (a2-4), (a2-5), and (a2-6) containing a monomer unit having any of the structures interacting with the support surface in the side chain. It is preferable.

[In the general formulas (a2-1) to (a2-6), M ²¹ and M ²² each independently represent a hydrogen atom, a metal atom contained in an alkali metal or an alkaline earth metal, or ammonium. R ^{21 to} R ²³ each independently represents a hydrogen atom or an alkyl group. Y ² represents a single bond or a divalent linking group selected from the group consisting of —CO—, —O—, —NH—, a divalent aliphatic group, a divalent aromatic group, and combinations thereof. Represent. * Represents a site connected to the main chain of the polymer compound. ]

Examples of the alkyl group represented by R ^{21 to} R ²³ include a methyl group, an ethyl group, a propyl group, an octyl group, an isopropyl group, a t-butyl group, an isopentyl group, a 2-ethylhexyl group, a 2-methylhexyl group, and a cyclopentyl group. Etc.
Y ² represents a single bond or a divalent linking group selected from the group consisting of —CO—, —O—, —NH—, a divalent aliphatic group, a divalent aromatic group, and combinations thereof. Represent.

Specific examples of Y ² composed of the above combinations are given below. In the following examples, the left side is bonded to the main chain.
L1: -CO-O-divalent aliphatic group-
L2: —CO—O—divalent aromatic group—
L3: -CO-NH-divalent aliphatic group-
L4: —CO—NH—divalent aromatic group—

The divalent aliphatic group and the divalent aromatic group are the same as the divalent aliphatic group and the divalent aromatic group in Y ^{1, and} the divalent aliphatic group and the divalent aromatic group are the same. Examples of the substituent of the group are the same as in Y ¹ .

Y ² is preferably a single bond, —CO—, a divalent aliphatic group, a divalent aromatic group, or the above L1 to L4, more preferably a single bond, a divalent aromatic group, or L1 to L4. A single bond, L1, is most preferred.

From the viewpoint of stain resistance and printing durability, the structure that interacts with the support surface is preferably the general formula (a2-1), (a2-2), or (a2-6), and the general formula (a2) -1) or (a2-2) is more preferable, and general formula (a2-2) is most preferable. In both general formulas (a2-1) and (a2-2), M ²¹ and M ²² are preferably hydrogen atoms.
Specifically, the following structures can be mentioned.

  The monomer unit having at least one structure that interacts with the support surface is preferably a monomer unit represented by the following general formula (A2).

In General Formula (A2), R ^{201 to} R ²⁰³ each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a halogen atom. Q represents a structure that interacts with the surface of the support selected from the above general formulas (a2-1) to (a2-6), and preferred embodiments are also represented by the above general formulas (a2-1) to (a2-6). This is the same as the preferred embodiment.

  The proportion of monomer units having at least one functional group that interacts with the support surface in the ethylenic polymer of the present invention is in the range of 2 to 95% by mass of the total monomer units from the viewpoint of stain resistance and printing durability. Preferably, the range is 3 to 50% by mass, and most preferably 5 to 25% by mass.

(2) Monomer unit having hydrophilic group Examples of the hydrophilic group include sulfonic acid or a salt thereof, and a polyoxyalkylene structure.
To introduce a monomer unit having a sulfonic acid or a salt thereof as a hydrophilic group, it is preferable to copolymerize 2-acrylamido-2-methylpropanesulfonic acid or a salt thereof.
The polyoxyalkylene structure is preferably a polyoxyalkylene structure represented by the following general formula (a4-1).

In the general formula (a4-1), R ⁴¹ represents a hydrogen atom or an alkyl group. ^R42 represents a hydrogen atom, an alkyl group or an aryl group. a represents an integer of 1 to 5. l represents an integer of 2 to 150. Y ⁴ represents a single bond or a divalent linking group selected from the group consisting of —CO—, —O—, —NH—, a divalent aliphatic group, a divalent aromatic group, and combinations thereof. Represent. * Represents a site linked to the polymer main chain. Here, the divalent aliphatic group and the divalent aromatic group have the same meaning as in the case of Y ¹ described above.

In the general formula (a4-1), examples of the alkyl group represented by R ⁴¹ and R ⁴² are each independently a methyl group, an ethyl group, a propyl group, an octyl group, an isopropyl group, a t-butyl group, an isopentyl group, 2 -An ethylhexyl group, 2-methylhexyl group, a cyclopentyl group, etc. are mentioned. Examples of the aryl group R ⁴² include phenyl group, 1-naphthyl group, 2-naphthyl group.
R ⁴¹ is most preferably a hydrogen atom, and R ⁴² is preferably a hydrogen atom or a methyl group, more preferably a methyl group.
a represents preferably 1 or 2 and most preferably 1 from the viewpoint of soiling properties. l represents an integer of 2 to 150, and is preferably 9 to 150, more preferably 9 to 100, still more preferably 20 to 100, and particularly preferably 50 to 100, from the viewpoint of soiling properties.

Y ⁴ is most preferably a linking group represented by the following L17.
L17: -CO-O-
L17 is bonded to the main chain on the left side.
In the most preferred combination of Y ⁴ , R ⁴¹ and R ⁴² , Y ⁴ is L17, R ⁴¹ is a hydrogen atom, and R ⁴² is a methyl group.

Examples of the polyoxyalkylene structure include the following specific examples.
In specific examples, the n value including a decimal number indicates an average value of the number of repetitions in a mixture having a different number of oxyalkylene repetitions.

  In the present invention, the monomer unit having a polyoxyalkylene structure is preferably represented by the following (A4).

In the above formula, R ^{401 to} R ⁴⁰³ each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a halogen atom. J is the polyoxyalkylene structure represented by the general formula (a4-1) described above, and the preferred embodiment is the same as the embodiment of the general formula (a4-1).

  The proportion of the monomer unit having a polyoxyalkylene structure in the ethylenic polymer in the present invention is 5 to 95% by mass with respect to all monomer units constituting the ethylenic polymer from the viewpoint of on-press development property and stain resistance. The range is preferable, the range of 20 to 80% by mass is more preferable, and the range of 20 to 49% by mass is most preferable.

(3) Monomer unit having an ethylenically unsaturated polymerizable group in the side chain The ethylenic polymer for the undercoat layer may have a monomer unit having an ethylenically unsaturated polymerizable group in the side chain from the viewpoint of printing durability. preferable. Examples of the monomer unit having an ethylenically unsaturated polymerizable group in the side chain include the same monomer units having an ethylenically unsaturated polymerizable group in the side chain that can be introduced into the above-described ethylenic polymer for an image recording layer. Can do.
The content of the unsaturated double bond in the ethylenic polymer for the undercoat layer is preferably 0.1 to 10.0 mmol, most preferably 0.2 to 5.5 mmol per 1 g of the polymer.

(4) Still other monomer units The ethylenic polymer for the undercoat layer of the present invention may have a monomer unit represented by the general formula (6), if necessary, in addition to the above monomer units.

As the ethylenic polymer for undercoat layer of the present invention, two or more types of ethylenic polymer for undercoat layer can be used in the undercoat layer.
The content of the ethylenic polymer in the undercoat layer is preferably 10 to 100% by mass, more preferably 20 to 100% by mass, and most preferably 50 to 100% by mass based on the total mass of the undercoat layer.

The ethylenic polymer in the present invention preferably has a mass average molar mass (Mw) of 2000 or more, more preferably 5000 or more, and still more preferably 10,000 to 300,000.
Specific examples of the ethylenic polymer of the present invention are shown in Tables 6 to 9 below. Tables 6 and 8 are for the image recording layer of the on-press development type lithographic printing plate precursor, Table 7 is for the image recording layer of the lithographic printing plate precursor subjected to the developer treatment, and Table 9 is the planographic plate Those suitable for the undercoat layer of the printing plate precursor were shown. The present invention is not limited to these compounds.

(B) Polymerization initiator As the polymerization initiator used in the present invention, a radical polymerization initiator is preferably used.
As the radical polymerization initiator, those known to those skilled in the art can be used without limitation, and specifically include, for example, trihalomethyl compounds, carbonyl compounds, organic peroxides, azo compounds, azide compounds, metallocene compounds, hexaarynes. Examples include rubiimidazole compounds, organic boron compounds, disulfone compounds, oxime ester compounds, onium salts, and iron arene complexes. Among these, at least one selected from the group consisting of hexaarylbiimidazole compounds, onium salts, trihalomethyl compounds and metallocene compounds is preferable, and hexaarylbiimidazole compounds and onium salts are particularly preferable. Two or more polymerization initiators may be used in combination as appropriate.

  Examples of the hexaarylbiimidazole compound include lophine dimers described in the specifications of European Patent No. 24629, European Patent No. 107792, and US Pat. No. 4,410,621, such as 2,2′-bis (o- Chlorophenyl) -4,4 ', 5,5'-tetraphenylbiimidazole, 2,2'-bis (o-bromophenyl) -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'-tetraphenylbiimidazole, 2,2'-bis (o-nitrophenyl) Nil) -4,4 ', 5,5'-tetraphenylbiimidazole, 2,2'-bis (o-methylphenyl) -4,4', 5,5'-tetraphenylbiimidazole, 2,2 ' -Bis (o-trifluoromethylphenyl) -4,4 ', 5,5'-tetraphenylbiimidazole and the like. The hexaarylbiimidazole compound is particularly preferably used in combination with a sensitizing dye having a maximum absorption in a wavelength region of 300 to 450 nm.

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

  Of these, more preferred are iodonium salts, sulfonium salts, and azinium salts. Although the specific example of these compounds is shown below, it is not limited to this.

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

  Examples of sulfonium salts include triphenylsulfonium = hexafluorophosphate, triphenylsulfonium = benzoylformate, bis (4-chlorophenyl) phenylsulfonium = benzoylformate, bis (4-chlorophenyl) -4-methylphenylsulfonium = Examples thereof include tetrafluoroborate, tris (4-chlorophenyl) sulfonium = 3,5-bis (methoxycarbonyl) benzenesulfonate, and tris (4-chlorophenyl) sulfonium = hexafluorophosphate.

Examples of azinium salts include 1-cyclohexylmethyloxypyridinium = hexafluorophosphate, 1-cyclohexyloxy-4-phenylpyridinium = hexafluorophosphate, 1-ethoxy-4-phenylpyridinium = hexafluorophosphate, 1-cyclohexyl (2-ethylhexyloxy) -4-phenylpyridinium = hexafluorophosphate, 4-chloro-1-cyclohexylmethyloxypyridinium = hexafluorophosphate, 1-ethoxy-4-cyanopyridinium = hexafluorophosphate, 3,4 -Dichloro-1- (2-ethylhexyloxy) pyridinium = hexafluorophosphate, 1-benzyloxy-4-phenylpyridinium = hexafluorophosphate, 1-phenethylo Ci-4-phenylpyridinium = hexafluorophosphate, 1- (2-ethylhexyloxy) -4-phenylpyridinium = p-toluenesulfonate, 1- (2-ethylhexyloxy) -4-phenylpyridinium = perfluorobutanesulfonate 1- (2-ethylhexyloxy) -4-phenylpyridinium bromide, 1- (2-ethylhexyloxy) -4-phenylpyridinium tetrafluoroborate.
The onium salt is particularly preferably used in combination with an infrared absorber having a maximum absorption in a wavelength range of 750 to 1400 nm.

  In addition, polymerization initiators described in paragraph numbers [0071] to [0129] of JP-A-2007-206217 can also be preferably used.

  The polymerization initiator is preferably 0.1 to 50% by mass, more preferably 0.5 to 30% by mass, and particularly preferably 0.8 to 20% by mass with respect to the total solid content constituting the image recording layer. Can be added. Within this range, good sensitivity and good stain resistance of the non-image area during printing can be obtained.

(C) Polymerizable compound The image-recording layer of the invention has at least one addition polymerizable compound having at least one ethylenically unsaturated double bond, particularly at least one terminal ethylenically unsaturated bond, preferably two or more. It preferably contains a polymerizable compound. These have chemical forms such as monomers, prepolymers, ie dimers, trimers and oligomers, or mixtures thereof. Examples of monomers include unsaturated carboxylic acids (for example, acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid, maleic acid, etc.), esters and amides thereof, preferably unsaturated carboxylic acids. Esters of an acid and a polyhydric alcohol compound and amides of an unsaturated carboxylic acid and a polyamine compound are used. Also, addition reaction products of unsaturated carboxylic acid esters or amides having a nucleophilic substituent such as hydroxy group, amino group, mercapto group and the like with monofunctional or polyfunctional isocyanates or epoxies, and monofunctional or polyfunctional A dehydration condensation reaction product with a functional carboxylic acid is also preferably used. In addition, unsaturated carboxylic acid esters or amides having an electrophilic substituent such as an isocyanate group or an epoxy group, addition products of monofunctional or polyfunctional alcohols, amines, thiols, halogen groups, A substitution reaction product of an unsaturated carboxylic acid ester or amide having a leaving substituent such as a tosyloxy group and a monofunctional or polyfunctional alcohol, amine or thiol is also suitable. It is also possible to use a compound group in which the unsaturated carboxylic acid is replaced with unsaturated phosphonic acid, styrene, vinyl ether or the like. These are disclosed in JP-T-2006-508380, JP-A-2002-287344, JP-A-2008-256850, JP-A-2001-342222, JP-A-9-179296, JP-A-9-179297. JP-A-9-179298, JP-A-2004-294935, JP-A-2006-243493, JP-A-2002-275129, JP-A-2003-64130, JP-A-2003-280187, It is described in Japanese Laid-Open Patent Publication No. 10-333321.

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

  In addition, urethane-based addition-polymerizable compounds produced by using an addition reaction between an isocyanate and a hydroxy group are also suitable, and specific examples thereof include, for example, one molecule described in Japanese Patent Publication No. 48-41708. A vinyl containing two or more polymerizable vinyl groups in one molecule obtained by adding a vinyl monomer containing a hydroxy group represented by the following general formula (b) to a polyisocyanate compound having two or more isocyanate groups. A urethane compound etc. are mentioned.

_{CH 2 = C (R 4)} COOCH 2 CH (R 5) OH (b)
(However, R ₄ and R ₅ represent H or CH _3. )

  Also, photo-oxidizable polymerizable compounds described in JP-T-2007-506125 are suitable, and polymerizable compounds containing at least one urea group and / or tertiary amino group are particularly preferred. Specific examples include the following compounds.

  Also, urethanes described in JP-A-51-37193, JP-B-2-32293, JP-B-2-16765, JP-A-2003-344997, and JP-A-2006-65210. Acrylates, JP-B 58-49860, JP-B 56-17654, JP-B 62-39417, JP-B 62-39418, JP-A 2000-250211, JP-A 2007-94138 Urethane compounds having an ethylene oxide skeleton described in the publication, US Pat. No. 7,153,632, JP-T 8-505958, JP-A 2007-293221, and JP-A 2007-293223. Urethane compounds having a hydrophilic group described in (2) are also suitable.

  Among the above, in the case of a lithographic printing plate precursor to which on-press development is applied, tris (acryloyloxyethyl) isocyanate is excellent in that it has a good balance of hydrophilicity involved in on-press developability and polymerization ability involved in printing durability. Isocyanuric acid ethylene oxide-modified acrylates such as nurate and bis (acryloyloxyethyl) hydroxyethyl isocyanurate are particularly preferred.

  Details of the method of use, such as the structure of the polymerizable compound, whether it is used alone or in combination, and the amount added, can be arbitrarily set according to the performance design of the final lithographic printing plate precursor. The polymerizable compound is preferably used in the range of 5 to 75% by mass, more preferably 10 to 70% by mass, and particularly preferably 15 to 60% by mass with respect to the total solid content of the image recording layer.

<Other ingredients>
The image recording layer in the invention may further contain other components as required.

(D) Sensitizing dye The sensitizing dye used in the image recording layer absorbs light at the time of image exposure to an excited state, supplies energy to the polymerization initiator by electron transfer, energy transfer or heat generation, and initiates polymerization. Any device that improves the function can be used without particular limitation. In particular, a sensitizing dye having a maximum absorption in a wavelength range of 300 to 450 nm or 750 to 1400 nm is preferably used.

  Examples of the sensitizing dye having the maximum absorption in the wavelength range of 350 to 450 nm include merocyanines, benzopyrans, coumarins, aromatic ketones, anthracenes, styryls, and oxazoles.

  Of the sensitizing dyes having an absorption maximum in the wavelength range of 350 to 450 nm, a dye more preferable from the viewpoint of high sensitivity is a dye represented by the following general formula (I).

In general formula (I), A represents an aryl group or heteroaryl group which may have a substituent, and X represents an oxygen atom, a sulfur atom or N (R ₃ ). R ₁ , R ₂ and R ₃ each independently represents a monovalent non-metallic atomic group, and A and R ₁ or R ₂ and R ₃ are bonded to each other to form an aliphatic or aromatic group. A ring may be formed.

The general formula (I) will be described in more detail. The monovalent nonmetallic atomic group represented by R ₁ , R ₂ or R ₃ is preferably a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted aryl group. Represents a substituted or unsubstituted heteroaryl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted alkylthio group, a hydroxy group, or a halogen atom.

The aryl group and heteroaryl group which may have a substituent represented by A are each a substituted or unsubstituted aryl group and a substituted or unsubstituted heteroaryl group represented by R ₁ , R ₂ and R ₃ , respectively. It is the same.

  As specific examples of such a sensitizing dye, compounds described in paragraph numbers [0047] to [0053] of JP-A-2007-58170 are preferably used.

  Furthermore, sensitizing dyes represented by the following general formula (II) or (III) can also be used.

In formula (II), R ^{1 to} R ¹⁴ each independently represents a hydrogen atom, an alkyl group, an alkoxy group, a cyano group, or a halogen atom. However, at least one of R ^{1 to} R ¹⁰ represents an alkoxy group having 2 or more carbon atoms.
In the formula (III), R ^{15 to} R ³² each independently represents a hydrogen atom, an alkyl group, an alkoxy group, a cyano group, or a halogen atom. However, at least one of R ^{15 to} R ²⁴ represents an alkoxy group having 2 or more carbon atoms.

  As specific examples of such sensitizing dyes, compounds described in European Patent Application Publication No. 1349006 and International Publication No. 2005/029187 are preferably used.

  JP-A-2006-189604, JP-A-2007-171406, JP-A-2007-206216, JP-A-2007-206217, JP-A-2007-225701, JP-A-2007-225702, JP-A-2007-316582 The sensitizing dyes described in JP-A-2007-328243 are also preferably used.

  Then, it describes about the sensitizing dye (henceforth an infrared absorber) which has maximum absorption in the wavelength range of 750-1400 nm. As the infrared absorber, a dye or a pigment is preferably used.

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

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

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

Ar ¹ and Ar ² may be the same or different and each represents an aryl group which may have a substituent. Preferred aryl groups include a benzene ring group and a naphthalene ring group. Moreover, as a preferable substituent, a C12 or less hydrocarbon group, a halogen atom, and a C12 or less alkoxy group are mentioned. Y ¹ and Y ² may be the same or different and each represents a sulfur atom or a dialkylmethylene group having 12 or less carbon atoms. R ³ and R ⁴ may be the same or different and each represents a hydrocarbon group having 20 or less carbon atoms, which may have a substituent. Preferred substituents include an alkoxy group having 12 or less carbon atoms, a carboxy group, and a sulfo group. R ⁵ , R ⁶ , R ⁷ and R ⁸ may be the same or different and each represents a hydrogen atom or a hydrocarbon group having 12 or less carbon atoms. In view of easy availability of the raw material, a hydrogen atom is preferred. Z _a ⁻ represents a counter anion. However, when the cyanine dye represented by formula (a) has an anionic substituent in the structure thereof, Z _a is does not require charge neutralization ^- is not necessary. Preferred Z _a ⁻ is a halide ion, a perchlorate ion, a tetrafluoroborate ion, a hexafluorophosphate ion, and a sulfonate ion, particularly preferably a perchlorate ion, from the storage stability of the image recording layer coating solution. , Hexafluorophosphate ions and aryl sulfonate ions.

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

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

  Only 1 type may be used for an infrared absorption dye, 2 or more types may be used together, and infrared absorbers other than infrared absorption dyes, such as a pigment, may be used together. As the pigment, the compounds described in JP-A-2008-195018, paragraphs [0072] to [0076] are preferable.

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

(E) Organic fine particles In the present invention, in particular, in a lithographic printing plate precursor to which on-press development is applied, in order to improve on-press developability, organic fine particles can be contained in the image recording layer. The organic fine particles in the present invention are at least selected from hydrophobic thermoplastic polymer fine particles, thermoreactive polymer fine particles, polymer fine particles having a polymerizable group, microcapsules enclosing a hydrophobic compound, and microgel (crosslinked polymer fine particles). One is preferable. Among these, polymer fine particles and microgels having a polymerizable group are preferable. The organic fine particles in the present invention may be discrete particles of the ethylenic polymer of the present invention. In a particularly preferred embodiment, the organic fine particles include at least one ethylenically unsaturated polymerizable group. Due to the presence of such organic fine particles, an effect of improving the printing durability of the exposed portion and the on-press developability of the unexposed portion can be obtained.

Hydrophobic thermoplastic polymer fine particles include Research Disclosure No. 1 of January 1992. 331,003, JP-A-9-123387, JP-A-9-131850, JP-A-9-171249, JP-A-9-171250 and European Patent No. 931647 are suitable. Can be cited as
Specific examples of polymers constituting such polymer fine particles include ethylene, styrene, vinyl chloride, methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate, vinylidene chloride, acrylonitrile, vinyl carbazole, and polyalkylene structures. Mention may be made of homopolymers or copolymers of monomers such as acrylates or methacrylates or mixtures thereof. Among them, more preferable examples include a copolymer containing polystyrene, styrene and acrylonitrile, and polymethyl methacrylate.
The average particle size of the hydrophobic thermoplastic polymer fine particles used in the present invention is preferably 0.01 to 3.0 μm.

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

  The thermoreactive group in the polymer fine particles having a thermoreactive group used in the present invention may be any functional group that performs any reaction as long as a chemical bond is formed, but is preferably a polymerizable group, Examples include ethylenically unsaturated groups that undergo radical polymerization reactions (eg, acryloyl groups, methacryloyl groups, vinyl groups, allyl groups, etc.), cationic polymerizable groups (eg, vinyl groups, vinyloxy groups, epoxy groups, oxetanyl groups, etc.) ), An isocyanate group that performs an addition reaction or a block thereof, an epoxy group, a vinyloxy group, and a functional group having an active hydrogen atom that is a reaction partner thereof (for example, an amino group, a hydroxy group, a carboxy group, etc.), a condensation reaction Carboxy group to be carried out and reaction partner hydroxy group or amino group, acid anhydride to carry out ring-opening addition reaction and reaction An amino group or a hydroxyl group a manual may be mentioned as suitable.

  As the microcapsules used in the present invention, for example, as described in JP-A Nos. 2001-277740 and 2001-277742, all or part of the constituent components of the image recording layer are encapsulated in the microcapsules. Is. The constituent components of the image recording layer can also be contained outside the microcapsules. Furthermore, it is preferable that the image recording layer containing the microcapsule includes a hydrophobic constituent component in the microcapsule and a hydrophilic constituent component outside the microcapsule.

  In this invention, the aspect containing a crosslinked resin particle, ie, a microgel, may be sufficient. This microgel can contain a part of the constituent components of the image recording layer in at least one of the inside and the surface thereof, and in particular, an embodiment in which a reactive microgel is formed by having a radical polymerizable group on the surface thereof, This is particularly preferable from the viewpoint of image formation sensitivity and printing durability.

  As a method for microencapsulating or microgelling the constituent components of the image recording layer, known methods can be applied.

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

  The organic fine particle content is preferably in the range of 5 to 90% by mass of the total solid content of the image recording layer.

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

  Among these, in the present invention, it is preferable to contain at least one selected from the group of polyols, organic sulfates, and organic sulfonates.

  Specific examples of organic sulfonates include alkyl sulfonates such as sodium n-butyl sulfonate, sodium n-hexyl sulfonate, sodium 2-ethylhexyl sulfonate, sodium cyclohexyl sulfonate, and sodium n-octyl sulfonate. Sodium 5,8,11-trioxapentadecane-1-sulfonate, sodium 5,8,11-trioxaheptadecane-1-sulfonate, 13-ethyl-5,8,11-trioxaheptadecane-1; Alkyl sulfonates containing ethylene oxide chains such as sodium sulfonate, 5,8,11,14-tetraoxatetradecosane-1-sodium sulfonate; sodium benzenesulfonate, sodium p-toluenesulfonate, p-hydroxy Benzenesulfo Acid sodium, sodium p-styrenesulfonate, sodium dimethyl-5-sulfonate isophthalate, sodium 1-naphthylsulfonate, sodium 4-hydroxynaphthylsulfonate, disodium 1,5-naphthalenedisulfonate, 1,3,6 -Aryl sulfonates such as trisodium naphthalene trisulfonate, compounds described in JP-A 2007-276454 [0026] to [0031], JP-A 2009-154525 [0020] to [0047], and the like. The salt may be a potassium salt or a lithium salt.

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

  The above low molecular weight hydrophilic compound has a small hydrophobic part structure and almost no surface-active action, so that dampening water penetrates into the exposed part of the image recording layer (image part) and the hydrophobicity and film strength of the image part. Ink acceptability and printing durability of the image recording layer can be maintained satisfactorily.

The addition amount of these low molecular weight hydrophilic compounds to the image recording layer is 0.5% by mass or more and 20% by mass or less of the total solid content of the image recording layer, together with the addition amount of the polymerizable betaine compound (a) of the present invention. It is preferable that More preferably, they are 1 mass% or more and 15 mass% or less, More preferably, they are 2 mass% or more and 10 mass% or less. In this range, good on-press developability and printing durability can be obtained.
These compounds may be used alone or in combination of two or more.

(G) Grease Sensitizer In the image recording layer of the present invention, a lipid sensitizer such as a phosphonium compound, a nitrogen-containing low molecular weight compound, or an ammonium group-containing polymer is used for the image recording layer in order to improve the inking property. be able to. In particular, when an inorganic layered compound is contained in the protective layer, these compounds function as a surface coating agent for the inorganic layered compound, and prevent a decrease in the inking property during printing by the inorganic layered compound.

  Suitable phosphonium compounds include phosphonium compounds described in JP-A-2006-297907 and JP-A-2007-50660. Specific examples include tetrabutylphosphonium iodide, butyltriphenylphosphonium bromide, tetraphenylphosphonium bromide, 1,4-bis (triphenylphosphonio) butanedi (hexafluorophosphate), 1,7-bis (tri Phenylphosphonio) heptane sulfate, 1,9-bis (triphenylphosphonio) nonane = naphthalene-2,7-disulfonate, and the like.

  Examples of the nitrogen-containing low molecular weight compound include amine salts and quaternary ammonium salts. Also included are imidazolinium salts, benzoimidazolinium salts, pyridinium salts, and quinolinium salts. Of these, quaternary ammonium salts and pyridinium salts are preferable. Specific examples include tetramethylammonium = hexafluorophosphate, tetrabutylammonium = hexafluorophosphate, dodecyltrimethylammonium = p-toluenesulfonate, benzyltriethylammonium = hexafluorophosphate, benzyldimethyloctylammonium = hexafluorophosphate. And the compounds described in JP-A 2008-284858 [0021] to [0037], JP-A 2009-90645 [0030] to [0057], and the like.

  The ammonium group-containing polymer may be any polymer as long as it has an ammonium group in its structure, but a polymer containing 5 to 80 mol% of a (meth) acrylate having an ammonium group in the side chain as a copolymerization component is preferable. . Specific examples include the polymers described in JP-A-2009-208458 [0089] to [0105].

  The ammonium salt-containing polymer has a reduced specific viscosity (unit: ml / g) determined by the following measurement method, preferably in the range of 5 to 120, more preferably in the range of 10 to 110, 15 Those in the range of ~ 100 are particularly preferred. When the said reduced specific viscosity is converted into a mass mean molar mass (Mw), 10,000-150,000 are preferable, 17000-140000 are more preferable, 20000-130000 are especially preferable.

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

Specific examples of the ammonium group-containing polymer are shown below.
(1) 2- (Trimethylammonio) ethyl methacrylate = p-toluenesulfonate / 3,6-dioxaheptyl methacrylate copolymer (molar ratio 10/90 mass average molar mass (Mw) 45,000)
(2) 2- (Trimethylammonio) ethyl methacrylate = hexafluorophosphate / 3,6-dioxaheptyl methacrylate copolymer (molar ratio 20/80 Mw: 60,000)
(3) 2- (Ethyldimethylammonio) ethyl methacrylate = p-toluenesulfonate / hexyl methacrylate copolymer (molar ratio 30/70 Mw: 45,000)
(4) 2- (Trimethylammonio) ethyl methacrylate = hexafluorophosphate / 2-ethylhexyl methacrylate copolymer (molar ratio 20/80 Mw: 60,000)
(5) 2- (Trimethylammonio) ethyl methacrylate = methyl sulfate / hexyl methacrylate copolymer (molar ratio 40/60 Mw: 7 million)
(6) 2- (butyldimethylammonio) ethyl methacrylate = hexafluorophosphate / 3,6-dioxaheptyl methacrylate copolymer (molar ratio 25/75 Mw: 65,000)
(7) 2- (Butyldimethylammonio) ethyl acrylate = hexafluorophosphate / 3,6-dioxaheptyl methacrylate copolymer (molar ratio 20/80 Mw: 65,000)
(8) 2- (butyldimethylammonio) ethyl methacrylate = 13-ethyl-5,8,11-trioxa-1-heptadecanesulfonate / 3,6-dioxaheptyl methacrylate copolymer (molar ratio 20/80 (Mw: 75,000)
(9) 2- (butyldimethylammonio) ethyl methacrylate = hexafluorophosphate / 3,6-dioxaheptyl methacrylate / 2-hydroxy-3-methacryloyloxypropyl methacrylate copolymer (molar ratio 15/80/5 (Mw: 65,000)

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

(H) Others As other components, surfactants, colorants, baking-out agents, polymerization inhibitors, higher fatty acid derivatives, plasticizers, inorganic fine particles, inorganic layered compounds, and co-sensitizers or chain transfer agents, etc. Can be added. Specifically, paragraph numbers [0114] to [0159] of Japanese Patent Application Laid-Open No. 2008-284817, paragraph numbers [0023] to [0027] of Japanese Patent Application Laid-Open No. 2006-091479, and US Patent Publication No. 2008/0311520. [0060] The compounds and addition amounts described in [0060] are preferred.

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

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

The above-mentioned ethylenic polymer is used for the undercoat layer of the present invention. Further, when the ethylenic polymer is used for the image recording layer, a known undercoat layer compound may be used.
As the known undercoat compound, those having an adsorptive group capable of being adsorbed on the surface of the support and a crosslinkable group for improving the adhesion to the image recording layer are preferable. Furthermore, compounds having a hydrophilicity-imparting group such as a sulfo group can also be mentioned as suitable compounds. These compounds may be low molecular weight or high molecular weight polymers. Moreover, you may use these compounds in mixture of 2 or more types as needed.
In the case of a high molecular polymer, a copolymer of a monomer having an adsorptive group, a monomer having a hydrophilic group, and a monomer having a crosslinkable group is preferable. The adsorbable adsorptive group to the surface of the support, a phenolic hydroxy group, a carboxy _{group, -PO 3 H 2, -OPO 3} H 2, -CONHSO 2 -, - SO 2 NHSO 2 -, - COCH 2 COCH 3 Is preferred. As the hydrophilic group, a sulfo group is preferable. The crosslinkable group is preferably a methacryl group or an allyl group.
This polymer may have a crosslinkable group introduced by salt formation between the polar substituent of the polymer, a substituent having a counter charge and a compound having an ethylenically unsaturated bond, Other monomers, preferably hydrophilic monomers, may be further copolymerized.
Specifically, a silane coupling agent having an addition-polymerizable ethylenic double bond reactive group described in JP-A-10-282679 and an ethylenic compound described in JP-A-2-304441. The phosphorus compound which has a heavy bond reactive group is mentioned suitably. Crosslinkable group (preferably ethylenically unsaturated bond group) described in JP-A-2005-238816, JP-A-2005-12549, JP-A-2006-239867, JP-A-2006-215263, surface of support Those containing a low-molecular or high-molecular compound having a functional group that interacts with each other and a hydrophilic group are also preferably used. More preferable are polymer polymers having an adsorbable group, a hydrophilic group, and a crosslinkable group that can be adsorbed on the support surface described in JP-A Nos. 2005-125749 and 2006-188038.

The content of unsaturated double bonds in the polymer resin for the undercoat layer is preferably 0.1 to 10.0 mmol, and most preferably 0.2 to 5.5 mmol per 1 g of the polymer.
The polymer for the undercoat layer preferably has a mass average molar mass of 5000 or more, more preferably 10,000 to 300,000.

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

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

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

  If necessary, the support of the present invention includes an organic polymer compound described in JP-A-5-45885 and a silicon alkoxy compound described in JP-A-6-35174 on the back surface. A backcoat layer can be provided.

(Protective layer)
In the lithographic printing plate precursor according to the invention, a protective layer (overcoat layer) can be provided on the image recording layer as necessary. In addition to the function of suppressing the image formation inhibition reaction by blocking oxygen, the protective layer has a function of preventing scratches in the image recording layer and preventing ablation during high-illuminance laser exposure.

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

Further, in order to enhance the oxygen barrier property, the protective layer preferably contains an inorganic layered compound such as natural mica and synthetic mica as described in JP-A-2005-119273.
Further, the protective layer may contain known additives such as a plasticizer for imparting flexibility, a surfactant for improving coating properties, and inorganic fine particles for controlling surface slipperiness. Further, the protective layer can contain the sensitizer described in the description of the image recording layer.

The protective layer is applied by a known method. The coating amount of the protective layer, the coating amount after drying is preferably in the range of 0.01 to 10 g / ^{m 2,} more preferably in the range of 0.02 to 3 g / ^{m 2,} and most preferably 0. in the range of 02~1g / ^{m 2.}

[Preparation method of planographic printing plate]
A lithographic printing plate can be produced by subjecting the lithographic printing plate precursor according to the invention to image exposure and development.

<Image exposure>
The lithographic printing plate precursor is imagewise exposed by laser exposure through a transparent original image having a line image, a halftone dot image or the like, or by laser beam scanning by digital data.
The wavelength of the light source is preferably 300 to 450 nm or 750 to 1400 nm. In the case of a light source of 300 to 450 nm, a lithographic printing plate precursor containing a sensitizing dye having an absorption maximum in this wavelength region in the image recording layer is preferably used, and in the case of a light source of 750 to 1400 nm, it absorbs in this wavelength region. A lithographic printing plate precursor containing an infrared absorbing agent, which is a sensitizing dye having a colorant, in an image recording layer is preferably used. As the light source of 300 to 450 nm, a semiconductor laser is suitable. As a light source of 750 to 1400 nm, a solid laser and a semiconductor laser emitting infrared rays are suitable. Regarding the infrared laser, the output is preferably 100 mW or more, the exposure time per pixel is preferably within 20 microseconds, and the irradiation energy amount is preferably 10 to 300 mJ / cm ² . In order to shorten the exposure time, it is preferable to use a multi-beam laser device. The exposure mechanism may be any of an internal drum system, an external drum system, a flat bed system, and the like.
Image exposure can be performed by a conventional method using a plate setter or the like. In the case of on-press development, the lithographic printing plate precursor may be mounted on a printing press and then image exposure may be performed on the printing press.

<Development processing>
Development processing is (1) a method of developing with a developer having a pH of 2 to 14 (developer processing method), or (2) a method of developing while adding dampening water and / or ink on a printing press. (On-press development method).

<Developer processing method>
In the developer processing method, the lithographic printing plate precursor subjected to image exposure is processed with a developer having a pH of 2 to 14, and the image recording layer in the non-exposed portion is removed to prepare a lithographic printing plate.
In the development processing using a highly alkaline developer (pH 12 or more), usually, the protective layer is removed by a pre-water washing step, then alkali development is performed, the alkali is washed away by water in the post-water washing step, gum solution treatment is performed, and drying is performed. A lithographic printing plate is produced by drying in the process.
According to a preferred embodiment of the present invention, a developer having a pH of 2 to 14 is used. In this embodiment, it is preferable that a surfactant or a water-soluble polymer compound is contained in the developer, whereby the development and the gum solution treatment can be performed simultaneously. Therefore, the post-water washing step is not particularly required, and the development-gum solution treatment can be performed with one solution. Further, no pre-water washing step is required, and the protective layer can be removed simultaneously with the development-gum solution treatment. After the development-gum treatment, for example, it is preferable to perform drying after removing excess developer using a squeeze roller.

  The developer treatment of the lithographic printing plate precursor according to the invention is carried out in accordance with a conventional method at a temperature of 0 to 60 ° C., preferably 15 to 40 ° C. It can be carried out by a method of rubbing with a brush, a method of spraying a developer by spraying and rubbing with a brush.

  In the present invention, the development treatment with a developer having a pH of 2 to 14 can be preferably carried out by an automatic development processor equipped with a developer supply means and a rubbing member. An automatic developing processor using a rotating brush roll as the rubbing member is particularly preferable. Further, the automatic processor preferably includes a means for removing excess developer such as a squeeze roller and a drying means such as a warm air device after the development processing means. Further, the automatic development processor may be provided with a preheating means for heat-treating the lithographic printing plate precursor after image exposure before the development processing means.

  In the present invention, the developer used for the developer processing is an aqueous solution having a pH of 2 to 14. An aqueous solution containing water as a main component (containing 60% by mass or more of water) is preferable. In particular, an aqueous solution containing a surfactant (anionic, nonionic, cationic, amphoteric ion, etc.) or a water-soluble polymer compound. An aqueous solution containing is preferred. An aqueous solution containing both a surfactant and a water-soluble polymer compound is also preferred. The pH of the developer is more preferably 3.5 to 13, further preferably 6 to 13, and particularly preferably 6.5 to 10.5.

  The anionic surfactant used in the developer of the present invention is not particularly limited, but fatty acid salts, abietic acid salts, hydroxyalkanesulfonic acid salts, alkanesulfonic acid salts, dialkylsulfosuccinic acid salts, linear alkylbenzenesulfonic acid salts. Branched alkylbenzene sulfonates, alkyl naphthalene sulfonates, alkyl diphenyl ether (di) sulfonates, alkylphenoxy polyoxyethylene alkyl sulfonates, polyoxyethylene alkyl sulfophenyl ether salts, N-alkyl-N-oleyl taurine Sodium, N-alkylsulfosuccinic acid monoamide disodium salt, petroleum sulfonate, sulfated castor oil, sulfated beef tallow oil, fatty acid alkyl ester sulfate ester salt, alkyl Acid ester salts, polyoxyethylene alkyl ether sulfates, fatty acid monoglyceride sulfates, polyoxyethylene alkylphenyl ether sulfates, polyoxyethylene styryl phenyl ether sulfates, alkyl phosphate esters, polyoxyethylene alkyl ether phosphates Ester salts, polyoxyethylene alkylphenyl ether phosphate ester salts, saponified saponified styrene-maleic anhydride copolymers, partially saponified olefin-maleic anhydride copolymers, naphthalene sulfonate formalin condensates, etc. Is mentioned. Of these, alkylbenzene sulfonates, alkylnaphthalene sulfonates, and alkyl diphenyl ether (di) sulfonates are particularly preferably used.

  Although it does not specifically limit as a cationic surfactant used for the developing solution of this invention, A conventionally well-known thing can be used. Examples thereof include alkylamine salts, quaternary ammonium salts, alkyl imidazolinium salts, polyoxyethylene alkylamine salts, and polyethylene polyamine derivatives.

  The nonionic surfactant used in the developer of the present invention is not particularly limited, but is a polyethylene glycol type higher alcohol ethylene oxide adduct, alkylphenol ethylene oxide adduct, alkyl naphthol ethylene oxide adduct, phenol ethylene oxide adduct. , Naphthol ethylene oxide adduct, fatty acid ethylene oxide adduct, polyhydric alcohol fatty acid ester ethylene oxide adduct, higher alkylamine ethylene oxide adduct, fatty acid amide ethylene oxide adduct, fat and oil ethylene oxide adduct, polypropylene glycol ethylene oxide addition Dimethylsiloxane-ethylene oxide block copolymer, dimethylsiloxane- (propylene oxide-ethylene oxide) Id) block copolymer, fatty acid ester of polyhydric alcohol type glycerol, fatty acid ester of pentaerythritol, fatty acid ester of sorbitol and sorbitan, fatty acid ester of sucrose, alkyl ether of polyhydric alcohol, fatty acid amide of alkanolamines, etc. It is done. Among these, those having an aromatic ring and an ethylene oxide chain are preferable, and an alkyl-substituted or unsubstituted phenol ethylene oxide adduct or an alkyl-substituted or unsubstituted naphthol ethylene oxide adduct is more preferable.

  The zwitterionic surfactant used in the developer of the present invention is not particularly limited, and examples thereof include amine oxides such as alkyldimethylamine oxide, betaines such as alkylbetaine, and amino acids such as sodium alkylamino fatty acid. . In particular, alkyldimethylamine oxide which may have a substituent, alkylcarboxybetaine which may have a substituent, and alkylsulfobetaine which may have a substituent are preferably used. Specifically, a compound represented by the formula (2) in paragraph No. [0256] of JP-A-2008-203359, a formula (I), a formula (II) in paragraph No. [0028] of JP-A-2008-276166, A compound represented by the formula (VI) or a compound represented by paragraph numbers [0022] to [0029] of JP-A-2009-47927 can be used.

  Two or more surfactants may be used in the developer. 0.01-20 mass% is preferable and, as for the quantity of surfactant contained in a developing solution, 0.1-10 mass% is more preferable.

  Examples of the water-soluble polymer compound used in the developer of the present invention include soybean polysaccharide, modified starch, gum arabic, dextrin, fiber derivatives (eg, carboxymethyl cellulose, carboxyethyl cellulose, methyl cellulose, etc.) and modified products thereof, pullulan, polyvinyl Alcohol and derivatives thereof, polyvinylpyrrolidone, polyacrylamide and acrylamide copolymer, vinyl methyl ether / maleic anhydride copolymer, vinyl acetate / maleic anhydride copolymer, styrene / maleic anhydride copolymer, polyvinyl sulfonic acid and The salt, polystyrene sulfonic acid, its salt, etc. are mentioned.

  A well-known thing can be used for the said soybean polysaccharide, for example, there exists a brand name Soya Five (made by Fuji Oil Co., Ltd.) as a commercial item, and the thing of various grades can be used. What can be preferably used is one in which the viscosity of a 10% by mass aqueous solution is in the range of 10 to 100 mPa / sec.

  As the modified starch, known ones can be used. For example, starch such as corn, potato, tapioca, rice, wheat etc. is decomposed with acid or enzyme in the range of 5-30 glucose residues per molecule, and further alkali It can be made by a method of adding oxypropylene in the inside.

  Two or more water-soluble polymer compounds may be used in combination in the developer. The content of the water-soluble polymer compound in the developer is preferably from 0.1 to 20% by mass, and more preferably from 0.5 to 10% by mass.

  The developer used in the present invention may contain a pH buffer. The developer of the present invention can be used without particular limitation as long as it is a buffering agent that exhibits a buffering action at a pH of 2 to 14. In the present invention, weakly alkaline buffering agents are preferably used. For example, (a) carbonate ions and hydrogen carbonate ions, (b) borate ions, (c) water-soluble amine compounds and ions of the amine compounds, and their Combination use etc. are mentioned. That is, for example, a combination of (a) carbonate ion-bicarbonate ion, (b) borate ion, or (c) water-soluble amine compound-amine compound ion exhibits pH buffering action in the developer. Even when the developer is used for a long period of time, fluctuations in pH can be suppressed, and therefore, development loss due to fluctuations in pH, development debris generation, and the like can be suppressed. Particularly preferred is a combination of carbonate ions and bicarbonate ions.

  In order for carbonate ions and bicarbonate ions to be present in the developer, carbonate and bicarbonate may be added to the developer, or by adjusting the pH after adding carbonate or bicarbonate, Ions and bicarbonate ions may be generated. The carbonate and bicarbonate are not particularly limited, but are preferably alkali metal salts. Examples of the alkali metal include lithium, sodium, and potassium, and sodium is particularly preferable. Alkali metals may be used alone or in combination of two or more.

  The total amount of carbonate ions and bicarbonate ions is preferably 0.05 to 5 mol / L, more preferably 0.07 to 2 mol / L, and particularly preferably 0.1 to 1 mol / L with respect to the developer.

  The developer of the present invention may contain an organic solvent. Examples of the organic solvent that can be contained include aliphatic hydrocarbons (hexane, heptane, Isopar E, H, G (manufactured by Esso Chemical Co., Ltd.)), aromatic hydrocarbons (toluene, xylene, etc.), halogens, and the like. Hydrocarbons (methylene dichloride, ethylene dichloride, trichlene, monochlorobenzene, etc.) and polar solvents. Examples of polar solvents include alcohols (methanol, ethanol, propanol, isopropanol, 1-butanol, 1-pentanol, 1-hexanol, 1-heptanol, 1-octanol, 2-octanol, 2-ethyl-1-hexanol, 1 -Nonanol, 1-decanol, benzyl alcohol, ethylene glycol monomethyl ether, 2-ethoxyethanol, diethylene glycol monoethyl ether, diethylene glycol monohexyl ether, triethylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monomethyl ether, polyethylene glycol monomethyl Ether, polypropylene glycol, tetraethylene glycol, ethylene glycol monobutyl ether Ter, ethylene glycol monobenzyl ether, ethylene glycol monophenyl ether, propylene glycol monophenyl ether, methylphenyl carbinol, n-amyl alcohol, methyl amyl alcohol, etc.), ketones (acetone, 2-butanone, ethyl butyl ketone, methyl) Isobutyl ketone, cyclohexanone, etc.) Esters (ethyl acetate, propyl acetate, butyl acetate, amyl acetate, benzyl acetate, methyl lactate, butyl lactate, ethylene glycol monobutyl acetate, propylene glycol monomethyl ether acetate, diethylene glycol acetate, diethyl phthalate, levulin Acid butyl, etc.), other (triethyl phosphate, tricresyl phosphate, N-phenylethanolamine, N Phenyl diethanolamine, N- methyldiethanolamine, N- ethyldiethanolamine, 4- (2-hydroxyethyl) morpholine, N, N- dimethylacetamide, N- methylpyrrolidone and the like) and the like.

  Two or more organic solvents can be used in combination in the developer. When the organic solvent is insoluble in water, it can be used after being solubilized in water using a surfactant or the like. When the developer contains an organic solvent, the concentration of the organic solvent is preferably less than 40% by mass from the viewpoint of safety and flammability.

  In addition to the above components, the developer of the present invention may contain preservatives, chelate compounds, antifoaming agents, organic acids, inorganic acids, inorganic salts, and the like. Specifically, compounds described in paragraph numbers [0266] to [0270] of JP-A-2007-206217 can be preferably used.

  The developer of the present invention can be used as a developer and a development replenisher for an exposed lithographic printing plate precursor. Further, the present invention can be preferably applied to the automatic developing processor as described above. When developing using an automatic developing processor, 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.

<On-press development method>
In the on-press development system, an image-exposed lithographic printing plate precursor is supplied with oil-based ink and an aqueous component on a printing machine, and an unexposed image recording layer is removed to produce a lithographic printing plate.
In other words, after image exposure of the lithographic printing plate precursor, it is mounted on the printing machine without any development processing, or after the lithographic printing plate precursor is mounted on the printing machine, image exposure is performed on the printing machine. When printing is performed by supplying the oil-based ink and the aqueous component, the uncured image recording layer is dissolved or dispersed by the supplied oil-based ink and / or the aqueous component in the unexposed area at an early stage of printing. And a hydrophilic surface is exposed at the portion. On the other hand, in the exposed portion, the image recording layer cured by exposure forms an oil-based ink receiving portion having a lipophilic surface. Oil-based ink or water-based component may be first supplied to the plate surface, but oil-based ink is supplied first in order to prevent the water-based component from being contaminated by the removed image recording layer component. Is preferred. In this way, the lithographic printing plate precursor is subjected to on-press development on a printing machine and used as it is for printing a large number of sheets. As the oil-based ink and the aqueous component, ordinary lithographic printing ink and fountain solution are preferably used.

  In the method of preparing a lithographic printing plate from the lithographic printing plate precursor according to the present invention, the entire lithographic printing plate precursor is exposed before exposure, during exposure, and from exposure to development, regardless of the development method. You may heat. By such heating, an image forming reaction in the image recording layer is promoted, and advantages such as improvement in sensitivity and printing durability and stabilization of sensitivity may occur. In the case of the developer processing method, it is also effective to perform whole surface post-heating or whole surface exposure on the image after the development processing for the purpose of improving the image strength and printing durability. Usually, heating before development is preferably performed under a mild condition of 150 ° C. or less. If the temperature is too high, problems such as curing of the unexposed area may occur. Very strong conditions are used for heating after development. Usually, it is the range of 100-500 degreeC. If the temperature is low, sufficient image reinforcing action cannot be obtained. If the temperature is too high, problems such as deterioration of the support and thermal decomposition of the image area may occur.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to these. In addition, in a high molecular compound, molecular weight is a mass mean molar mass (Mw), and the ratio of a repeating unit is a mole percentage except what was specially prescribed | regulated.

[Synthesis Example of Ethylene Polymer of the Present Invention]

Step 1 for synthesizing a monomer having at least two betaine structures
In a 300 ml three-necked flask equipped with a stirrer and a thermometer, weigh 25.10 g of 3,3′-iminobis (N, N-dimethylisopropylamine), 31.02 g of potassium carbonate, 100 g of ethyl acetate and 50 g of water, and put them in an ice bath. Then, 11.76 g of acrylic acid chloride was added dropwise over 30 minutes. The mixture was further stirred at 0 ° C. for 30 minutes, and the resulting white precipitate was filtered off. The organic phase was dried over anhydrous magnesium sulfate and the solvent was distilled off under reduced pressure. The obtained yellow crude product was purified by alumina column chromatography (development with ethyl acetate / methanol) to obtain 7.73 g of N, N-bis (3- (dimethylamino) propyl) acrylamide.

Step 2
In a 200 ml three-necked flask equipped with a stirrer, thermometer and reflux tube, 7.73 g of N, N-bis (3- (dimethylamino) propyl) acrylamide obtained in Step 1, 3.0 mg of p-methoxyphenol, 40 g of acetonitrile. Was weighed. 8.77 g of 1,4-butane sultone was added dropwise at room temperature, and the mixture was heated to 80 ° C. and reacted for 4 hours. After allowing to cool, the supernatant was removed by decantation, and the purified white precipitate was reslurried with 20 ml of methanol / 800 ml of ethyl acetate, and then the precipitate was collected by suction filtration under a nitrogen atmosphere. The solid was dried in a vacuum oven at 40 ° C. to obtain 15.30 g of a bis-type sulfobetaine compound as a white solid.
The NMR measurement results of the white solid compound are shown below.

1H-NMR (400 MHz, D2O): δ = 6.62 ppm (a: 1H, t), 6.16 ppm, 5.79 ppm (b, c: 2H, 2d), 3.40-3.15 ppm (d + e + f: 12H, m), 2.96 ppm (g: 12H, s), 2.84 ppm (h: 4H, t), 1.96-1.69 ppm (i + j + k: 12H, m)

Synthesis of ethylenic polymer (P-80) A 1000 ml four-necked flask is equipped with a stirrer, thermometer, dropping funnel, nitrogen inlet tube, reflux condenser, and introduced with nitrogen gas to deoxygenate, while polyethylene glycol 10 g of methyl ether methacrylate (the average repeating unit of PEGMA ethylene glycol is 45), 5 g of the bis-type sulfobetaine monomer synthesized above, 200 g of distilled water and 200 g of n-propanol were added and heated until the internal temperature reached 70 ° C. Next, 10 g of premixed styrene (St), 75 g of acrylonitrile (AN) and 0.8 g of 2,2′-azobisisobutyronitrile were added dropwise over 1 hour. After completion of the dropwise addition, the reaction was continued for 5 hours, and then 0.4 g of 2,2′-azobisisobutyronitrile was added to raise the internal temperature to 80 ° C. Subsequently, 0.5 g of 2,2′-azobisisobutyronitrile was added over 6 hours. Polymerization proceeded at 98% or more at the stage of reaction for a total of 20 hours, and the particle size distribution of the obtained polymer fine particles had a maximum value at a particle size of 150 nm.

[Preparation of lithographic printing plate precursor]
The lithographic printing plate precursors A-1 to A-89 of the present invention and comparative examples are combined by combining an aluminum support, an undercoat layer, an image recording layer, and a protective layer having the following specifications as shown in Tables 10-1 to 10-3. Lithographic printing plate precursors B-1 to B-10 were prepared.

[Preparation of Aluminum Support 1]
In order to remove rolling oil on the surface of an aluminum plate (material: JIS A1050) having a thickness of 0.3 mm, after degreasing at 50 ° C. for 30 seconds using a 10 mass% sodium aluminate aqueous solution, the hair diameter is 0.3 mm. The aluminum surface was grained using 3 bundle-planted nylon brushes and a pumice-water suspension (specific gravity 1.1 g / cm ³ ) having a median diameter of 25 μm and washed thoroughly with water. This plate was etched by being immersed in a 25 mass% aqueous sodium hydroxide solution at 45 ° C for 9 seconds, washed with water, further immersed in a 20 mass% nitric acid aqueous solution at 60 ° C for 20 seconds, and washed with water. At this time, the etching amount of the grained surface was about 3 g / m ² .

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

Next, a 0.5% by mass hydrochloric acid aqueous solution (containing 0.5% by mass of aluminum ions) and an electrolytic solution having a liquid temperature of 50 ° C. and nitric acid electrolysis under the condition of an electric quantity of 50 C / dm ² when the aluminum plate is an anode. In the same manner as above, an electrochemical surface roughening treatment was performed, followed by washing with water by spraying. The plate was provided with a DC anodized film of 2.5 g / m ² at a current density of 15 A / dm ² using a 15% by mass sulfuric acid aqueous solution (containing 0.5% by mass of aluminum ions) as an electrolyte, then washed with water and dried. An aluminum support 1 was prepared.
The center line average roughness (Ra indication according to JIS B0601) of the support thus obtained was measured using a needle having a diameter of 2 μm and found to be 0.51 μm.

[Preparation of aluminum support 2]
An aluminum plate (material 1050, tempered H16) having a thickness of 0.24 mm was immersed in a 5% by mass aqueous sodium hydroxide solution maintained at 65 ° C., degreased for 1 minute, and then washed with water. The aluminum plate was neutralized by immersing it in a 10% by mass hydrochloric acid aqueous solution maintained at 25 ° C. for 1 minute, and then washed with water. Subsequently, this aluminum plate was subjected to electrolytic surface roughening with an alternating current for 60 seconds under conditions of 25 ° C. and a current density of 100 A / dm ^{2 in} a 0.3 mass% hydrochloric acid aqueous solution, and then kept at 60 ° C. In addition, the desmut treatment was performed for 10 seconds in a 5% by mass aqueous sodium hydroxide solution. This aluminum plate was anodized in a 15% by mass sulfuric acid aqueous solution at 25 ° C., a current density of 10 A / dm ² , and a voltage of 15 V for 1 minute to produce an aluminum support 2. The centerline surface roughness (Ra) was measured and found to be 0.44 μm.

(Formation of undercoat layer)
An undercoat layer coating solution having the following composition was applied to a support with a bar coater and dried at 100 ° C. for 1 minute to form an undercoat layer. The dry coating amount of the undercoat layer was 20 mg / m ² .

<Coating liquid for undercoat layer (1)>
-Undercoat polymer described in Table 10 or the following undercoat compound (Z-1)
Or 0.18 g of the compound for comparative undercoat (Z-2) shown below
・ Hydroxyethyliminodiacetic acid 0.10g
・ Methanol 55.24g
・ Water 6.15g

[Formation of Image Recording Layer 1]
The image recording layer coating solution 1 having the following composition was bar coated and then oven dried at 90 ° C. for 60 seconds to form an image recording layer 1 having a dry coating amount of 1.3 g / m ² .

<Image recording layer coating solution 1>
-The binder polymer described in Table 10 or the following binder polymer (Z-3) (Mw: 80,000) or the following comparative binder polymer (Z-4) (Mw: 80,000) 0.34 g
・ The following polymerizable compound (1) (PLEX6661-O, manufactured by Degussa Japan) 0.58 g
・ The following sensitizing dye (1) 0.06 g
・ The following polymerization initiator (1) 0.18 g
・ The following chain transfer agent (1) 0.02 g
・ 0.40 g of ε-phthalocyanine pigment dispersion
(Pigment: 15 parts by mass, dispersant (allyl methacrylate / methacrylic acid copolymer (Mw: 60,000, copolymer molar ratio: 83/17)):
(10 parts by mass, cyclohexanone: 15 parts by mass)
-Thermal polymerization inhibitor N-nitrosophenylhydroxylamine aluminum salt 0.01 g
-The following fluorosurfactant (1) (Mw: 10,000) 0.001 g
・ Polyoxyethylene-polyoxypropylene condensate 0.02g
(Pluronic L44, manufactured by ADEKA Corporation)
・ Dispersion of yellow pigment 0.04g
(Yellow pigment Novoperm Yellow H2G (manufactured by Clariant): 15 parts by mass, dispersant (allyl methacrylate / methacrylic acid copolymer (Mw: 60,000, copolymer molar ratio 83/17)): 10 parts by mass, cyclohexanone: 15 parts by mass Part)
・ 3.5 g of 1-methoxy-2-propanol
・ 2-butanone 8.0g

[Formation of Image Recording Layer 2]
The image recording layer coating solution 2 having the following composition was bar coated and then oven dried at 100 ° C. for 60 seconds to form an image recording layer 2 having a dry coating amount of 1.0 g / m ² . The image recording layer coating solution 2 was prepared by mixing and stirring the following photosensitive solution (1) and hydrophobic precursor solution (1) immediately before coating.

<Photosensitive solution (1)>
-The binder polymer described in Table 10 or the following binder polymer (Z-5)
Alternatively, the following comparative binder polymer (Z-6) 0.162 g
・ The following infrared absorbing dye (1) 0.030 g
-The following polymerization initiator (3) 0.162g
・ Polymerizable compound (Aronix M215, manufactured by Toagosei Co., Ltd.) 0.285 g
・ Pionine A-20 (Takemoto Yushi Co., Ltd.) 0.055g
・ The following oil sensitizer (1) 0.044 g
・ 0.008 g of the above-mentioned fluorosurfactant (1)
・ 2-butanone 1.091g
・ 1-methoxy-2-propanol 8.609g

<Hydrophobic precursor liquid (1)>
-Hydrophobic precursor aqueous dispersion (1) below 2.640 g
・ Distilled water 2.425g

(Production of hydrophobized precursor aqueous dispersion (1))
A stirrer, thermometer, dropping funnel, nitrogen inlet tube, reflux condenser is applied to a 1000 ml four-necked flask, and 350 mL of distilled water is added while deoxygenating by introducing nitrogen gas, and the internal temperature becomes 80 ° C. Until heated. 1.5 g of sodium dodecyl sulfate was added as a dispersant, 0.45 g of ammonium persulfide was added as an initiator, and then a mixture of 45.0 g of glycidyl methacrylate and 45.0 g of styrene was added from the dropping funnel over about 1 hour. It was dripped. After the completion of the dropwise addition, the reaction was continued as it was for 5 hours, and then the unreacted monomer was removed by steam distillation. Thereafter, the mixture was cooled and adjusted to pH 6 with ammonia water, and finally purified water was added so that the nonvolatile content was 15% by mass to obtain a hydrophobized precursor aqueous dispersion (1) composed of polymer fine particles. The particle size distribution of the polymer fine particles had a maximum value at a particle size of 60 nm.

  The particle size distribution is obtained by taking an electron micrograph of polymer fine particles, measuring the total particle size of 5000 particles on the photograph, and dividing the obtained particle size measurement value from the maximum value to 0 on a logarithmic scale by 50. Then, the appearance frequency of each particle size was plotted and determined. For non-spherical particles, the particle size of spherical particles having the same particle area as that on the photograph was used as the particle size.

[Formation of Image Recording Layer 3]
The image recording layer coating solution 3 having the following composition was coated with a bar and then oven-dried at 70 ° C. for 60 seconds to prepare an image recording layer 3 having a dry coating amount of 0.6 g / m ² .

<Image recording layer coating solution 3>
-Polymer fine particle water dispersion [following (1)-(5)] 20.0g
・ Infrared absorbing dye (2) [The following structure] 0.2g
・ Polymerization initiator Irgacure250 (Ciba Specialty Chemicals) 0.5g
-Polymerizable compound SR-399 (Sartomer) 1.50 g
・ Mercapto-3-triazole 0.2g
・ Byk336 (Byk Chimie) 0.4g
・ KlucelM (Hercules) 4.8g
・ ELVACITE4026 (Ineos Acrylica) 2.5g
・ N-propanol 55.0g
・ 2-butanone 17.0g

In addition, the compounds described by trade names in the above composition are as follows.
Irgacure 250: (4-methoxyphenyl) [4- (2-methylpropyl) phenyl] iodonium = hexafluorophosphate (75% by mass propylene carbonate solution)
SR-399: Dipentaerythritol pentaacrylate Byk336: Modified dimethylpolysiloxane copolymer (25% by mass xylene / methoxypropyl acetate solution)
・ KlucelM: Hydroxypropyl cellulose (2 mass% aqueous solution)
ELVACITE 4026: Hyperbranched polymethyl methacrylate (10% by mass 2-butanone solution)

(Production of polymer fine particle aqueous dispersions (1) to (4))
A 1000 ml four-necked flask is equipped with a stirrer, thermometer, dropping funnel, nitrogen inlet tube, reflux condenser, and nitrogen gas is introduced to perform deoxygenation, while polyethylene glycol methyl ether methacrylate (average of PEGMA ethylene glycol) The repeating unit was 50) 10 g, betaine compounds (1) to (4) 5 g selected from the following structure, 200 g of distilled water and 200 g of n-propanol were added and heated until the internal temperature reached 70 ° C. Next, 10 g of premixed styrene (St), 75 g of acrylonitrile (AN) and 0.8 g of 2,2′-azobisisobutyronitrile were added dropwise over 1 hour. After completion of the dropwise addition, the reaction was continued for 5 hours, and then 0.4 g of 2,2′-azobisisobutyronitrile was added to raise the internal temperature to 80 ° C. Subsequently, 0.5 g of 2,2′-azobisisobutyronitrile was added over 6 hours. Polymerization has progressed 98% or more at the stage of reaction for a total of 20 hours, and the particle size distribution of the obtained polymer fine particles (1) to (4) all have a maximum value at a particle size of 150 nm. It was.

(Production of polymer fine particle aqueous dispersion (5))
A 1000 ml four-necked flask is equipped with a stirrer, thermometer, dropping funnel, nitrogen inlet tube, reflux condenser, and nitrogen gas is introduced to perform deoxygenation, while polyethylene glycol methyl ether methacrylate (average of PEGMA ethylene glycol) The repeating unit was 50) 10 g, distilled water 200 g and n-propanol 200 g were added and heated until the internal temperature reached 70 ° C. Next, a premixed mixture of 10 g of styrene (St), 80 g of acrylonitrile (AN) and 0.8 g of 2,2′-azobisisobutyronitrile was added dropwise over 1 hour. After completion of the dropwise addition, the reaction was continued for 5 hours, and then 0.4 g of 2,2′-azobisisobutyronitrile was added to raise the internal temperature to 80 ° C. Subsequently, 0.5 g of 2,2′-azobisisobutyronitrile was added over 6 hours. Polymerization proceeded at 98% or more at the stage of reaction for a total of 20 hours, and the particle size distribution of the obtained polymer fine particles had a maximum value at a particle size of 150 nm.

  Here, the particle size distribution is obtained by taking an electron micrograph of polymer fine particles, measuring a total of 5000 fine particle sizes on the photograph, and a logarithmic scale between 0 and the maximum value of the obtained particle size measurement values. And the frequency of appearance of each particle size was plotted and obtained. For non-spherical particles, the particle size of spherical particles having the same particle area as that on the photograph was used as the particle size.

[Formation of Protective Layer 1]
A protective layer coating solution 1 having the following composition was applied using a bar so that the dry coating amount was 0.75 g / m ^2, and then dried at 125 ° C. for 70 seconds to form a protective layer.

<Protective layer coating solution 1>
・ Polyvinyl alcohol PVA105
(Kuraray Co., Ltd., fighting degree 98.5 mol%, polymerization degree 500) 40 g
・ Polyvinylpyrrolidone K30 (molecular weight: 50,000)
(Tokyo Chemical Industry Co., Ltd., molecular weight Mw = 40,000) 5g
・ Poly [vinyl pyrrolidone / vinyl acetate] LUVITEC VA64W
(Manufactured by ISP, copolymerization ratio = 6/4) 0.5 g
・ Surfactant (Emalex 710, manufactured by Nippon Emulsion Co., Ltd.) 0.5g
・ 950g of water

[Formation of Protective Layer 2]
A protective layer coating solution 2 having the following composition was applied using a bar so that the dry coating amount was 0.75 g / m ^2, and then dried at 125 ° C. for 70 seconds to form a protective layer.

<Protective layer coating solution 2>
-1.5 g of the following inorganic layered compound dispersion (1)
・ 0.55 g of 6% by weight aqueous solution of sulfonic acid-modified polyvinyl alcohol
(Nippon Synthetic Chemical Co., Ltd. CKS50, saponification degree 99 mol% or more, polymerization degree 300)
・ Polyvinyl alcohol 6 mass% aqueous solution 0.03g
(Kuraray Co., Ltd. PVA-405, saponification degree 81.5 mol%, polymerization degree 500)
-1% by weight aqueous solution of surfactant (Emulex 710, manufactured by Nippon Emulsion Co., Ltd.) 8.60 g
・ Ion-exchanged water 6.0g

(Preparation of inorganic layered compound dispersion (1))
6.4 g of synthetic mica Somasif ME-100 (manufactured by Coop Chemical Co., Ltd.) is added to 193.6 g of ion-exchanged water, and the mixture is dispersed using a homogenizer until the average particle size (laser scattering method) is 3 μm. An inorganic layered compound dispersion (1) was prepared. The aspect ratio of the obtained dispersed particles was 100 or more.

[Examples 1 to 40 and Comparative Examples 1 to 9] Evaluation of planographic printing plate precursor (Part 1)

[Exposure, development and printing]
The lithographic printing plate precursors (A-1) to (A-34) and (B-1) to (B-3) were obtained from FUJIFILM Electronic Imaging Ltd. Image exposure was performed with a Violet semiconductor laser plate setter Vx9600 (InGaN-based semiconductor laser (with an emission wavelength of 405 nm ± 10 nm / output 30 mW) mounted) manufactured by (FFEI). Image exposure was performed at a resolution of 2,438 dpi, using an FM screen (TAFFETA 20) manufactured by Fuji Film Co., Ltd., with a plate surface exposure of 0.05 mJ / cm ² so that the dot area ratio was 50%.
Next, after preheating at 100 ° C. for 30 seconds, development processing was carried out using an automatic developing processor having a structure as shown in FIG. The automatic processor has one brush roll with an outer diameter of 50 mm in which fibers made of polybutylene terephthalate (hair diameter 200 μm, hair length 17 mm) are implanted, and rotates 200 times per minute in the same direction as the conveying direction ( The peripheral speed of the brush tip was 0.52 m / sec). The temperature of the developer was 30 ° C. The planographic printing plate precursor was transported at a transport speed of 100 cm / min. After the development processing, drying was performed in a drying section. The drying temperature was 80 ° C. However, when the developer 2 was used, it was washed with water before the post-development drying step.

  Below, the composition of developer 1-4 is shown. In the following composition, New Coal B13 (manufactured by Nippon Emulsifier Co., Ltd.) is polyoxyethylene β-naphthyl ether (oxyethylene average number n = 13), and gum arabic has Mw of 200,000.

<Developer 1>
・ 13.0 g of sodium carbonate
・ Sodium bicarbonate 7.0g
・ New call B13 50.0g
・ Ammonium phosphate 2.0g
2-bromo-2-nitropropane-1,3-diol 0.01 g
・ 2-methyl-4-isothiazolin-3-one 0.01 g
・ Trisodium citrate 15.0g
・ 913.98 g of distilled water

The pH of this developer was 9.9.

<Developer 2>
・ Potassium hydroxide 0.15g
・ New Call B13 5.0g
・ Kirest 400 (chelating agent) 0.1g
・ 94.75g of distilled water

The pH of this developer was 11.5.

<Developer 3>
・ Arabic gum 25.0g
・ Enzyme-modified potato starch 70.0g
・ Sodium salt of dioctylsulfosuccinate 5.0g
・ Primary ammonium phosphate 1.0g
・ Citric acid 1.0g
・ 2-bromo-2-nitropropane-1,3-diol 0.01 g
・ 2-methyl-4-isothiazolin-3-one 0.01 g
・ The following amphoteric surfactant (W-1) 2.5 g
・ 2.5 g of the following anionic surfactant (AN-1)
・ 824.98 g of distilled water
(Phosphoric acid and sodium hydroxide are added to adjust the pH to 4.5)

<Developer 4>
・ Water 88.6g
-2.4 g of the following nonionic surfactant (W-2)
-2.4 g of the following nonionic surfactant (W-3)
・ Nonionic surfactant 1.0g
(Emalex 710, manufactured by Nippon Emulsion Co., Ltd.)
・ Phenoxypropanol 1.0g
・ Octanol 0.6g
-N- (2-hydroxyethyl) morpholine 1.0 g
・ Triethanolamine 0.5g
・ Sodium gluconate 1.0g
・ Trisodium citrate 0.5g
・ Ethylenediaminetetraacetate tetrasodium 0.05g
・ 1.0 g of polystyrene sulfonic acid
(Versa TL77 (30% solution), manufactured by Alco Chemical)
(Add phosphoric acid and adjust pH to 7.0)

  The obtained lithographic printing plate is attached to a printing machine SOR-M manufactured by Heidelberg, and fountain solution (EU-3 (etch solution manufactured by FUJIFILM Corporation) / water / isopropyl alcohol = 1/89/10 (volume ratio). )) And TRANS-G (N) black ink (manufactured by Dainippon Ink & Chemicals, Inc.), printing was performed at a printing speed of 6000 sheets per hour.

[Evaluation]
Each lithographic printing plate precursor was evaluated for printing durability, stain resistance, and developability as follows. The results are shown in Table 13.

<Print durability>
As the number of printed sheets increased, the image recording layer was gradually worn out and the ink acceptance decreased, so that the ink density in the printing paper decreased. In the printing plate exposed with the same exposure amount, the printing durability was evaluated by the number of printed sheets when the ink density (reflection density) was reduced by 0.1 from the start of printing.

<Stain resistance>
The printed material on the 20th sheet was taken out after the start of printing, and the stain resistance was evaluated based on the ink density adhered to the non-image area. In visual evaluation, a score of 10 was assigned. The higher the score, the better the stain resistance.

<Developability>
Development processing was performed at various transport speeds, and the cyan density of the non-image area of the obtained lithographic printing plate was measured with a Macbeth densitometer. The transport speed at which the cyan density of the non-image area was equal to the cyan density of the aluminum support was determined and used as developability. The evaluation of developability was represented by the relative developability defined as follows, with Comparative Example 1 as the standard (1.0). The larger the value of the relative developability, the higher the developability and the better the performance.
Relative developability = (transport speed of target lithographic printing plate precursor) / (transport speed of reference lithographic printing plate precursor)

[Examples 41 to 95 and Comparative Examples 10 to 16] Evaluation of planographic printing plate precursor (Part 2)

[Exposure, on-press development and printing]
The lithographic printing plate precursors (A-35) to (A-89) and (B-4) to (B-10) were placed on an external drum using a Luxel PLANETSETTER T-6000III manufactured by Fuji Film Co., Ltd. equipped with an infrared semiconductor laser. The exposure was performed under the conditions of a rotational speed of 1000 rpm, a laser output of 70%, and a resolution of 2400 dpi. The exposure image included a solid image and a 50% halftone dot chart of a 20 μm dot FM screen.
The obtained exposed original plate was attached to a plate cylinder of a printing machine LITHRONE 26 manufactured by Komori Corporation without developing. Equality-2 (manufactured by FUJIFILM Corporation) / tap water = 2/98 (volume ratio) dampening water and Values-G (N) black ink (manufactured by Dainippon Ink & Chemicals, Inc.) After fountain solution and ink were supplied by the standard automatic printing start method of LITHRONE26 and developed on the machine, printing was performed using Tokuhishi Art (76.5 kg) paper at a printing speed of 10,000 sheets per hour.

[Evaluation]
Each lithographic printing plate precursor was evaluated for on-press developability, stain resistance, and printing durability as follows. The results are shown in Tables 14 and 15.

(1) On-press developability Necessary to start printing as described above, complete on-press development on the printing press in the unexposed area of the image recording layer, and no ink is transferred to the non-image area. The number of printed sheets was measured as on-press developability.

(2) Printing durability After the above-described evaluation of on-press developability, the printing was further continued. As the number of printed sheets was increased, the image recording layer was gradually worn out, so that the ink density on the printed material decreased. Printing durability was evaluated using the number of printed copies when the value measured by the Gretag densitometer for the 50% halftone dot area ratio of the FM screen in the printed material was 5% lower than the measured value for the 100th printed sheet. .

(3) Stain resistance After the on-press development was completed, the printed material on the 20th sheet was taken out, and the stain resistance was evaluated based on the ink concentration adhered to the non-image area. In visual evaluation, a score of 10 was assigned. The higher the score, the better the stain resistance.

  As can be seen from Tables 13 to 15, according to the present invention, it is possible to provide a lithographic printing plate precursor exhibiting good stain resistance and having both good developability and printing durability. Although the mechanism of action of the present invention is not clear, the following is presumed. In the unexposed area, it is presumed that the compound of the present invention having a plurality of highly hydrophilic sulfobetaine structures improves the permeability of the fountain solution and exhibits good developability. In addition, the printing durability was unexpectedly improved by adopting a monomer structure having two sulfobetaine structures, but this is because the monomer unit having the sulfobetaine structure is thermally decomposed and hydrophobized in the exposed area. It is presumed that the permeability of the fountain solution is lowered and the thermal decomposition product contains radical chemical species to promote radical polymerization, thereby further increasing the curability of the image.

4 Planographic printing plate precursor (PS version)
6 Developing Unit 10 Drying Unit 16 Loading Roller 20 Developing Tank 22 Transporting Roller 24 Brush Roller 26 Squeeze Roller (Unloading Roller)
28 Backup roller 36 Guide roller 38 Skewer roller

Claims (12)

On the support, (B) a polymerization initiator, and (C) an image recording layer containing at least a polymerizable compound, and, if necessary, an undercoat layer, and at least one of the image recording layer and the undercoat layer ( A) A lithographic printing plate precursor comprising an ethylenic polymer containing a monomer unit having at least two betaine structures.   2. The lithographic printing plate precursor as claimed in claim 1, wherein the betaine structure is sulfobetaine or carbobetaine. The lithographic printing plate precursor as claimed in claim 2, wherein the ethylenic polymer is a polymer containing at least a monomer unit having a structure represented by the following general formula (1).

(In General Formula (1), R < ₁ > -R < ₄ > represents the C1-C10 alkyl group, alkenyl group, alkynyl group, cycloalkyl group, or aryl group which may have a substituent each independently. Alternatively, any _{two of} R ₁ , R ₂ , R ₃ and R ₄ may be bonded to each other to form a heterocyclic ring, and W ₁ , Y ₁ and Y ₂ may each independently have a substituent. Represents a divalent linking group, and each V independently represents either SO ₃ ^— or COO ^— .
However, at least one of R _{1 to} R ₄ , W ₁ , Y ₁ and Y ₂ is a group bonded to the polymer main chain via a linking group. ) The lithographic printing plate precursor as claimed in claim 3, wherein the ethylenic polymer is a polymer containing at least a monomer unit having a structure represented by the following general formula (2).

(In General Formula (2), R < ₁ > -R < ₄ > represents the C1-C6 alkyl group, alkenyl group, alkynyl group, cycloalkyl group, or aryl group which may have a substituent each independently. Alternatively, any _{two of} R ₁ , R ₂ , R ₃ and R ₄ may be bonded to each other to form a heterocyclic ring, and W ₁ , Y ₁ and Y ₂ may each independently have a substituent. Represents a divalent linking group.
However, at least one of R _{1 to} R ₄ , W ₁ , Y ₁ and Y ₂ is a group bonded to the polymer main chain via a linking group. ) The lithographic printing plate precursor as claimed in claim 4, wherein the ethylenic polymer is a polymer containing at least one of monomer units represented by the following general formulas (3) and (4).

(In General Formula (3), R _{10 to} R ₁₃ each independently represents an alkyl group, alkenyl group, alkynyl group, cycloalkyl group or aryl group having 1 to 6 carbon atoms which may have a substituent. Alternatively, any two of R _{10 to} R ₁₃ may be bonded to each other to form a heterocyclic ring, R ₉ represents a hydrogen atom or a methyl group, and Z ₁ represents —CO—, —O—, —CH ₂ O. -Represents a phenylene group that may have a substituent, W ₃ represents a trivalent linking group having 10 or less carbon atoms, and Y ₅ and Y ₆ may each independently have a substituent. Represents an alkylene group having 1 to 6 carbon atoms.) (In formula (4), R _{15 to} R ₁₇ are each independently an alkyl group having 1 to 6 carbon atoms, an alkenyl group, which may have a substituent, alkynyl group, a cycloalkyl group or an aryl group. Alternatively _R 15 to R Any two of which may form a heterocyclic ring bonded to each other _{.R 14} of ₇ represents a hydrogen atom or a methyl group, _{Z 2} is -CO -, - O -, - CH 2 O-, or a substituent X ₁ and X ₂ each independently represents a divalent linking group having 10 or less carbon atoms, and Y ₇ and Y ₈ may each independently have a substituent. Represents a good alkylene group having 1 to 6 carbon atoms.) In the general formulas (3) and (4), R _{10 to} R ₁₃ and R _{15 to} R ₁₇ are each independently a methyl group, an ethyl group, or (R ₁₀ , R ₁₁ , R ₁₂ , R ₁₃ ) or (R ₁₅ , R ₁₆ , R ₁₇ ) represents a group containing a 5-membered or 6-membered heterocyclic ring bonded to each other, and Z ₁ and Z ₂ each independently have —CO— or a substituent. A phenylene group that may be, W ₃ represents a trivalent linking group having 10 or less carbon atoms, X ₁ and X ₂ each independently represents a divalent linking group having 10 or less carbon atoms, and Y ₅ the lithographic printing plate precursor according to claim 5, wherein to Y _8, characterized in that the each independently represent an alkylene group having 2 to 5 carbon atoms. The lithographic printing plate precursor as claimed in claim 6, wherein the ethylenic polymer is a polymer containing at least a monomer unit represented by the following general formula (5).

(In General Formula (5), R _{19 to} R ₂₂ each independently represent a methyl group or an ethyl group, R ₁₈ represents a hydrogen atom or a methyl group, and L ₁ and L ₂ each independently represent 5 or less carbon atoms. Y ₉ and Y ₁₀ each independently represents an alkylene group having 2 to 5 carbon atoms.)   The ethylenic polymer further comprises (1) a monomer unit having a structure interacting with the support surface in the side chain, and (2) a monomer unit having an ethylenically unsaturated polymerizable group in the side chain, and an undercoat layer The lithographic printing plate precursor as claimed in claim 1, wherein the lithographic printing plate precursor is contained in the lithographic printing plate precursor.   The ethylenic polymer further contains (2) a monomer unit having an ethylenically unsaturated polymerizable group in the side chain, and (3) a monomer unit having a hydrophilic group, and is contained in the image recording layer. The lithographic printing plate precursor according to any one of claims 1 to 7.   The ethylenic polymer is a polymer fine particle further comprising (3) a monomer unit having a hydrophilic group and (4) an acrylonitrile unit, and is contained in the image recording layer. The lithographic printing plate precursor as described in any one of the above items. The image recording layer is an image recording layer in which an unexposed portion can be removed by supplying at least one of printing ink and fountain solution on a printing press after imagewise exposure. to 1 0 lithographic printing plate precursor according to any one of. A polymer comprising at least a monomer unit having a structure represented by the following general formula (5).

(In General Formula (5), R _{19 to} R ₂₂ each independently represent a methyl group or an ethyl group, R ₁₈ represents a hydrogen atom or a methyl group, and L ₁ and L ₂ each independently represent 5 or less carbon atoms. Y ₉ and Y ₁₀ each independently represents an alkylene group having 2 to 5 carbon atoms.)

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