JP2014024893A - Color developing curable composition, and lithographic printing original plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a color developing photosensitive composition exhibiting high color development and low decoloration after the color development by an infrared laser exposure, to provide lithographic printing original plate having the composition as an image recording layer and good storage stability, high plate inspectability, printing durability and no image development process, and to provide an engraving method using the lithographic printing original plate.SOLUTION: A color developing composition contains a compound (A) represented by general formula (1), a sensitizer (B), and a binder (C), where Ar, Arand Arare each an aryl group, Arand Arare each independently a phenyl group or a naphthyl group having an amino group at 4-position, Ris a hydrogen atom, an alkyl group or an aryl group, Arand Ar, or Arand Rmay bind each other via an oxygen atom, a nitrogen atom or a sulfur atom to form a ring structure when Ris an aryl group, and Xis a cation.

Description

  The present invention relates to a color forming composition, a color forming curable composition, a lithographic printing plate precursor in which the color forming curable composition is applied to an image recording layer, and a plate making method using the same. More specifically, the present invention relates to a lithographic printing plate precursor that can be directly made by laser image exposure, and a plate making method for developing the lithographic printing plate precursor on-press.

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 is used. After exposure through a mask such as a film, development with an alkaline developer is performed to leave the image recording layer corresponding to the image area, and dissolve and remove the unnecessary image recording layer corresponding to the non-image area. And obtained a lithographic printing plate.

  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.

  Along with the above progress, problems related to the lithographic printing plate precursor have been changed to improvements in image formation characteristics, printing characteristics, physical characteristics and the like corresponding to the CTP technology. In addition, due to increasing interest in the global environment, environmental issues related to waste liquids associated with wet processing such as development processing have been highlighted as another issue related to lithographic printing plate precursors.

  For the above environmental problems, 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.

  In the simplification of the plate making operation as described above, a system using a lithographic printing plate precursor and a light source that can be handled in a bright room or under a yellow light is preferable in terms of ease of work. A solid-state laser such as a semiconductor laser or a YAG laser emitting an infrared ray of 1200 nm is used. Further, a UV laser can be used.

  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 absorbing dye, a radical polymerization initiator, and a polymerizable compound is provided on a support. Furthermore, in Patent Document 4, on-press development is possible in which an image 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.

  In general, as a pre-process for attaching the printing plate to the printing machine, an operation (inspection) for inspecting and identifying the image on the printing plate is performed to check whether the image is recorded on the printing plate as intended. In general lithographic printing plate precursors with a development process, a colored image can be obtained by development processing if the image recording layer is colored, so it is easy to check the image before attaching the printing plate to the printing press. is there.

  In an on-press development type or unprocessed (no development) type lithographic printing plate precursor that does not undergo development processing, there is no image on the printing plate at the stage of attaching the printing plate to the printing press, and plate inspection cannot be performed. In particular, whether or not it is possible to determine that a register mark (register mark) that serves as a registration mark in multi-color printing is drawn is important for the printing operation. Therefore, on-machine development type or unprocessed (no development) type lithographic printing plate precursor is required to produce a so-called print-out image in which the image is confirmed at the stage of exposure, that is, the exposed area is colored or decolored. Has been. Furthermore, from the viewpoint of improving workability, it is also required to maintain the colored or decolored exposure area where the colored or decolored exposure area does not change after a lapse of time.

A lithographic printing plate precursor using a compound that generates an acid, base, or radical by light or heat and a compound that changes color by interacting with the generated acid, base, or radical has been proposed (for example, , See Patent Document 5). It has also been proposed to use the color change of a thermally decomposable compound as a printing-out agent for a direct-drawing lithographic printing plate precursor having a heat-sensitive layer (see, for example, Patent Document 6). Furthermore, it has also been proposed to use a thermally decomposable dye having a thermal decomposition temperature of 250 ° C. or lower as a printing-out agent (for example, see Patent Document 7).
According to these, coloring or decoloring occurs in the exposed area, and the plate inspection performance of the image is improved to some extent, but it is still not sufficient.

  Patent Document 8 discloses a print-out image at a level that has good visibility and can be inspected by a system containing a cyanine dye-based infrared absorbing dye having a 5-membered ring in the methine chain and a radical generator. It is described that it is obtained. However, this technique is insufficient in that good visibility is maintained even after a lapse of time.

  In Patent Document 9, there is a description that good visibility is obtained by a compound having a property of decomposing by heat or light stimulation. It is described that the compound undergoes a pi-conjugated system change at the time of decomposition, and a colored body is formed. However, the present technology is insufficient as compared with a normal lithographic printing plate precursor accompanied by a development process, and a higher color developability is required.

  On the other hand, image strength is one of the problems with an unprocessed (no development) type lithographic printing plate precursor. In the example of the above-mentioned non-processed lithographic printing plate precursor, the image strength is slightly inferior to that of a normal lithographic printing plate precursor accompanied by a development processing step, so that the printing durability is insufficient.

JP 2001-277740 A JP 2001-277742 A JP 2002-287334 A US Patent Application Publication No. 2003/0064318 JP-A-11-277927 JP 2000-335129 A JP 2003-191657 A JP 2007-090850 A JP 2010-221692 A

The object of the present invention is to provide a color-developable photosensitive composition with high color development and less fading after color development by infrared laser exposure, good storage stability having the composition as an image recording layer, high plate inspection, printing durability, And a lithographic printing plate precursor requiring no development process and a plate making method using the lithographic printing plate precursor.
Color development means that there is almost no absorption in the visible light region (> 400 nm) before exposure, and intense coloration or absorption becomes longer after exposure.

1. (A) A color forming composition containing a compound represented by the general formula (1), (B) a sensitizer, and (C) a binder.

(In General Formula (1), Ar ¹ , Ar ² , and Ar ³ each represents an aryl group, Ar ⁴ and Ar ⁵ each independently represent a phenyl group or a naphthyl group having an amino group at the 4-position, and R ¹ represents a hydrogen atom, an alkyl group, or an aryl group, and when R ¹ represents an aryl group, Ar ⁴ and Ar ⁵ , or Ar ⁵ and R ¹ , respectively, are bonded to each other through an oxygen atom, a nitrogen atom, or a sulfur atom. And may be linked to form a ring structure. X ⁺ represents a cation.)
2. (A) The color-forming composition according to 1, wherein the compound represented by the general formula (1) is a compound represented by the general formula (2).

(In General Formula (2), R ² , R ³ , R ⁴ , R ⁷ , R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ , R ¹² and R ¹³ are each independently a hydrogen atom, alkyl group, aryl Represents a group, a halogen atom, or OR ^20. R ² and R ³ , R ⁶ and R ⁷ , or R ¹⁰ and R ¹¹ may be linked to each other to form a ring structure.
R ⁵ and R ⁶ are each independently a hydrogen atom, an alkyl group, an aryl group, a halogen atom, or OR ²⁰ , or R ⁵ and R ⁶ are each an oxygen atom, a nitrogen atom, or a sulfur atom It is the ring structure connected through either.
R ¹⁴ , R ¹⁵ , R ¹⁶ , R ¹⁷ , R ¹⁸ , and R ¹⁹ each independently represents an alkyl group or an aryl group. R ¹⁴ and R ¹⁵ , R ¹⁶ and R ¹⁷ , or R ¹⁸ and R ¹⁹ may be linked to each other to form a ring structure.
R ²⁰ represents an alkyl group.
Ar ^{< 1 >} -Ar ^{< 3 >} and X ^<+> are synonymous with General formula (1). )
3. In the general formula (2), R ² , R ⁶ , and R ¹⁰ each independently represent an alkyl group or OR ²⁰ (R ²⁰ represents an alkyl group), and R ³ , R ⁴ , R ⁵ , R ^{7, R 8, R 9,} R 11, R 12 and ^{R 13} is a hydrogen atom, coloring composition according to 2.
4). The color-forming composition according to 2 or 3, wherein in the general formula (2), Ar ¹ , Ar ² , and Ar ³ are each independently a phenyl group or a 1-naphthyl group.
5. 5. The color forming composition according to any one of 1 to 4, wherein the color forming composition further contains (D) an onium-based radical generator.
6). (B) The infrared color-forming composition according to any one of 1 to 5, wherein the sensitizer is an infrared absorbing dye.
7). The color-forming curable composition according to any one of 1 to 6, wherein the color-forming composition further contains (E) a polymerizable compound.
8). A lithographic printing plate precursor having an image recording layer formed of the color-forming curable composition according to 7, on a support.
9. The lithographic printing plate precursor as described in 8, wherein the image recording layer contains a hydrophobized precursor.
10. The lithographic printing plate precursor as described in 8 or 9, further comprising a protective layer on the image recording layer.
11. The lithographic printing plate precursor as described in 10, wherein the protective layer contains an inorganic stratiform compound.
The lithographic printing plate precursor according to any one of 12.8 to 11 is imagewise exposed and then subjected to on-press development processing by supplying printing ink and fountain solution on the printing press to remove non-image portions. The plate making method.

In this invention, the subject was able to be achieved by making it contain combining the compound (A) shown by General formula (1), a sensitizer (B), and a binder (C). This mechanism of action is presumed as follows.
After the electron transfer proceeds from the compound (A) represented by the general formula (1) to the sensitizer (B) by the action of light, the decomposition reaction of the compound (A) represented by the general formula (1) proceeds. A leuco dye is produced. Since this color develops, the baking property is improved.

  According to the present invention, by infrared laser exposure, high color development and low color fading after color development, good color storage composition having the composition as an image recording layer, good plate stability, printing durability, In addition, it is possible to provide a lithographic printing plate precursor that does not require a development step and a plate making method using the lithographic printing plate precursor.

[Coloring composition]
The color-forming composition of the present invention is characterized by containing the compound (A) represented by the general formula (1), the sensitizer (B) and the binder (C).

(A) Compound represented by general formula (1) Hereinafter, the compound represented by general formula (1) is also referred to as a specific compound.
In the compound represented by the general formula (1), when exposure is triggered and electron transfer proceeds, B— of (Ar ¹ ) (Ar ² ) (Ar ³ ) BC (R ¹ ) (Ar ⁴ ) (Ar ⁵ ) Color develops due to the progress of the C bond cleavage reaction and the formation of borane and dye. That is, the C (R ¹ ) (Ar ⁴ ) (Ar ⁵ ) group represents a color developing group. Color development here means that in the state where B ⁻ -C is covalently bonded, there is almost no absorption in the visible light region (> 400 nm), and the covalent bond is cleaved by exposure, and C (R ¹ ) (Ar ⁴ ) ( It shows that the coloring or absorption becomes longer after the release of the Ar ⁵ ) group. A preferable range of absorption after color development is a maximum absorption wavelength (λmax) = 450 nm to 650 nm, more preferably 500 nm to 600 nm, from the viewpoint of visibility.
In the formula, Ar ¹ , Ar ² , and Ar ^{3 each} represent an aryl group, and Ar ⁴ and Ar ⁵ each independently represent a phenyl group or naphthyl group having an amino group at the 4-position.
Ar ¹ , Ar ² , and Ar ³ may have a substituent. Examples of the substituent include an alkyl group, an alkoxy group, and a halogen atom, and a halogen atom is particularly preferable.
Ar ⁴ and Ar ⁵ may have a substituent. Examples of the substituent include an aryl group, an alkyl group, an alkoxy group, an alkylthio group, and a halogen atom, and an alkyl group and an alkoxy group are particularly preferable.
R ¹ represents a hydrogen atom, an alkyl group, or an aryl group. R ¹ may have a substituent. Examples of the substituent include an amino group, an aryl group, an alkyl group, an alkoxy group, an alkylthio group, and a halogen atom, and an amino group, an alkyl group, and an alkoxy group are particularly preferable.
When R ¹ represents an aryl group, Ar ⁴ and Ar ⁵ , or Ar ⁵ and R ¹ may be linked to each other via an oxygen atom, a nitrogen atom, or a sulfur atom to form a ring structure. X ⁺ represents a cation.

The aryl group represented by Ar ¹ , Ar ² , and Ar ³ is preferably an aryl group having 6 to 30 carbon atoms, more preferably an aryl group having 6 to 20 carbon atoms, and most preferably an aryl group having 6 to 12 carbon atoms. .
Specifically, for example, phenyl group, biphenyl group, 1-naphthyl group, 2-naphthyl group, 9-fluorenyl group, terphenyl group, o-, m-, and p-tolyl group, xylyl group, o-, m- and p-cumenyl, mesityl, biphenylenyl, indacenyl, fluorenyl, p-chlorophenyl, p-bromophenyl, p-fluorophenyl, o-chlorophenyl, o-bromophenyl, o -Fluorophenyl group, m-chlorophenyl group, m-bromophenyl group, m-fluorophenyl group, p-methoxyphenyl group, m-methoxyphenyl group, p-dimethylaminophenyl group, p-methylthiophenyl group, m-methylthio Phenyl group, p-phenylthiophenyl group, 2,3-difluorophenyl group, 2,3-chlorophenyl group 2,4-difluorophenyl group, 2,4-dichlorophenyl group, 2,5-difluorophenyl group, 2,5-dichlorophenyl group, 2,6-difluorophenyl group, 2,6-dichlorophenyl group, 2,4,6 -Trifluorophenyl group, 2,4,6-trichlorophenyl group, 3,4,5-trifluorophenyl group, 3,4,5-trichlorophenyl group and the like.
Among these aryl groups, a phenyl group, a 1-naphthyl group, a p-chlorophenyl group, a p-fluorophenyl group, an m-chlorophenyl group, and an m-fluorophenyl group are particularly preferable, and a phenyl group and A 1-naphthyl group is most preferred.

The phenyl group or naphthyl group having an amino group at the 4-position represented by Ar ⁴ and Ar ⁵ is preferably a phenyl group or naphthyl group having 6 to 30 carbon atoms, more preferably a phenyl group or naphthyl group having 6 to 20 carbon atoms. A phenyl group or naphthyl group having 6 to 12 carbon atoms is most preferable.
Specific examples of the phenyl group having an amino group at the 4-position represented by Ar ⁴ and Ar ⁵ include a group represented by the following general formula (4).
As the naphthyl group having an amino group at the 4-position shown by Ar ⁴ and Ar ⁵ , A ¹ and A ² or A ³ and A ^{4 in the following} general formula (4) are connected to each other to form a benzene ring. Groups.

In the formula, A ¹ , A ² , A ³ , and A ⁴ each independently represent a hydrogen atom, an alkyl group, an aryl group, a halogen atom, OR ²⁰ , or SR ²¹ . A ⁵ and A ⁶ each independently represent an alkyl group or an aryl group, and A ⁵ and A ⁶ may be linked to each other to form a ring structure.
The alkyl group represented by A ¹ , A ² , A ³ , A ⁴ , A ⁵ , and A ⁶ is preferably an alkyl group having 1 to 20 carbon atoms, more preferably an alkyl group having 1 to 10 carbon atoms, Most preferred are 1-4 alkyl groups.
Specifically, for example, methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, hexadecyl group, octadecyl group Group, eicosyl group, isopropyl group, isobutyl group, s-butyl group, t-butyl group, isopentyl group, neopentyl group, 1-methylbutyl group, isohexyl group, 2-ethylhexyl group, 2-methylhexyl group, cyclohexyl group, cyclopentyl Group, 2-norbornyl group and the like.
Among these alkyl groups, a methyl group, an ethyl group, a propyl group, and a butyl group are particularly preferable.

The aryl group represented by A ¹ , A ² , A ³ , A ⁴ , A ⁵ and A ⁶ is preferably an aryl group having 6 to 30 carbon atoms, more preferably an aryl group having 6 to 20 carbon atoms, and 6 carbon atoms. Most preferred are aryl groups of ˜12.
Specifically, for example, phenyl group, biphenyl group, 1-naphthyl group, o-tolyl group, m-tolyl group, p-tolyl group, xylyl group, p-methoxyphenyl group, m-methoxyphenyl group, p- Examples include dimethylaminophenyl group, p-methylthiophenyl group, m-methylthiophenyl group, p-phenylthiophenyl group, and 2,4-dimethoxyphenyl group.
Of these aryl groups, a phenyl group, a p-methoxyphenyl group, and a p-dimethylaminophenyl group are particularly preferable.

The ^{A 1, A 2, A 3} , and halogen atom represented by ^{A 4,} a chlorine atom, a bromine atom, and an iodine atom, a chlorine atom is preferable.

When A ⁵ and A ⁶ are connected to each other to form a ring structure, the number of ring members formed is preferably 5 or 6, and most preferably an alicyclic 5-membered ring.

R ²⁰ and R ²¹ each independently represents an alkyl group, and a preferred embodiment of the alkyl group is a preferred embodiment in the case where A ¹ , A ² , A ³ , A ⁴ , A ⁵ , and A ⁶ represent an alkyl group. It is the same.

The preferred embodiment of the alkyl group represented by R ¹ is the same as the preferred embodiment in the case where A ¹ , A ² , A ³ , A ⁴ , A ⁵ , and A ⁶ represent an alkyl group.

The aryl group represented by R ¹ is preferably an aryl group having 6 to 30 carbon atoms, more preferably an aryl group having 6 to 20 carbon atoms, and most preferably an aryl group having 6 to 12 carbon atoms.
Specifically, for example, phenyl group, 1-naphthyl group, 2-naphthyl group, o-, m-, and p-tolyl group, xylyl group, p-chlorophenyl group, p-bromophenyl group, p-fluorophenyl. Group, o-chlorophenyl group, o-bromophenyl group, o-fluorophenyl group, m-chlorophenyl group, m-bromophenyl group, m-fluorophenyl group, p-methoxyphenyl group, m-methoxyphenyl group, p- Examples thereof include a dimethylaminophenyl group, a p-methylthiophenyl group, an m-methylthiophenyl group, a p-phenylthiophenyl group, and a phenyl group having an amino group at the 4-position indicated by Ar ⁴ and Ar ⁵ .
Among these aryl groups, a phenyl group and a phenyl group having an amino group at the 4-position are particularly preferable from the viewpoint of color developability.

When the combination of Ar ⁴ and Ar ⁵ and Ar ⁵ and R ¹ is linked via an oxygen atom, a nitrogen atom, or a sulfur atom, the number of ring members formed by the combination is preferably 6.

X ⁺ represents a cation that neutralizes charge, and is a cation selected from an organic cation and an inorganic cation, and the inorganic cation and the organic cation are preferably a lithium cation, a sodium cation, a potassium cation, an ammonium cation, and a pyridinium cation. As mentioned. A lithium cation, a sodium cation, and an ammonium cation are more preferable, and a lithium cation and a sodium cation are most preferable.

  Among the above, the specific compound of the present invention is more preferably a compound represented by the following general formula (2).

In the general formula (2), R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ , R ¹² , and R ¹³ are each independently a hydrogen atom. , an alkyl group, or ^{oR 20.} R ²⁰ represents an alkyl group. R ⁵ and R ⁶ may be linked to each other via an oxygen atom, a nitrogen atom, or a sulfur atom to form a ring structure. R ² and R ³ , R ⁶ and R ⁷ , or R ¹⁰ and R ¹¹ may be connected to each other to form a ring structure. R ¹⁴ , R ¹⁵ , R ¹⁶ , R ¹⁷ , R ¹⁸ , and R ¹⁹ each independently represent an alkyl group or an aryl group, and R ¹⁴ and R ¹⁵ , R ¹⁶ and R ¹⁷ , or R ¹⁸ and R ¹⁹ May be linked to each other to form a ring structure.

Preferred embodiments of the alkyl group and aryl group represented by R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ , R ¹² , and R ¹³ are represented by the general formula: (4) ^a 1 ^{in, a 2, a 3, a} 4, a 5, and is the same as that of each of the preferred embodiments of the ^{a 6.}

The preferable aspect of the alkyl group and aryl group which R <^14> , R <^15> , R <^16> , R <^17> , R <^18> and R < ¹⁹ > show is A < ¹ >, A < ² >, A < ³ >, A < ⁴ >, A in General formula (4). ⁵ and A ⁶ are the same as the preferred embodiments.

The preferred embodiment of the alkyl group represented by R ²⁰ is the same as that of R ^{20 in} the description of the general formula (1).

When R ² and R ³ , R ⁶ and R ⁷ , or R ¹⁰ and R ¹¹ are connected to each other to form a ring structure, the number of ring members forming the ring structure by connection is preferably 6 or 7, particularly 6 members. Most preferred is an aromatic ring.

A preferred embodiment of the ring structure in the case where R ¹⁴ and R ¹⁵ , R ¹⁶ and R ¹⁷ , or R ¹⁸ and R ¹⁹ are linked to each other to form a ring structure, is A ⁵ and A ^{6 in the} general formula (4). Are the same as the preferred embodiment of the ring structure in the case where they are linked to each other to form a ring structure.

Ar ^{1 to} Ar ³ and X ⁺ are the same as those shown for the general formula (1), and preferred embodiments are also the same.

In the compound represented by the general formula (2), R ² , R ⁶ , and R ¹⁰ each independently represents an alkyl group or OR ²⁰ (R ²⁰ represents an alkyl group), and R ³ , R ⁴ , R ⁵ , R ⁷ , R ⁸ , R ⁹ , R ¹¹ , R ¹² , and R ¹³ are preferably a hydrogen atom.

(Synthesis of specific compounds)
The specific compound of this invention can be obtained according to the general synthetic method shown below as a synthetic scheme.
This synthesis method is a method in which an alkyl anion prepared from an alkyl metal reagent is reacted with triarylborane in tetrahydrofuran (THF) or diethyl ether at −78 ° C.

Although the preferable specific example of a compound shown by General formula (1) below is given, this invention is not limited to this.
Note that the numbers in the table ^{below, -C (R 1) (Ar} 4) corresponding to the numbers and the group represented by ^{(Ar 5), -B - (} Ar 1) (Ar 2) (Ar 3) The number of the compound having an anion formed by combining with the group represented by Further, X ⁺ which is a counter cation represents a lithium cation.

  The compound represented by the general formula (1) of the present invention can be contained in an arbitrary amount in the composition, but the total solid content of the composition is preferably 0.1 to 50% by mass, more preferably 0.5 to 30% by mass, and more preferably 1 to 20% by mass.

(B) Sensitizing dye The sensitizing dye used in the present invention absorbs light during image exposure to be in an excited state, receives electrons from the compound represented by (A) general formula (1), and (A) general formula Any compound can be used without particular limitation as long as it causes the decomposition reaction of the compound shown in (1) to proceed. In particular, a sensitizing dye having a maximum absorption in the wavelength range of 300 to 450 nm or an infrared sensitizing dye having a maximum absorption in the wavelength range of 750 to 1400 nm is preferably used.
In the present specification, (B) the color forming composition containing an infrared sensitizing dye as the sensitizing dye is also referred to as an infrared color forming composition.

  Examples of the sensitizing dye having maximum absorption in the wavelength range of 300 to 450 nm include merocyanines, benzopyrans, coumarins, aromatic ketones, anthracenes, styryls, oxazoles and the like.

  Of the sensitizing dyes having an absorption maximum in the wavelength range of 300 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.

  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, a sensitizing dye 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 formula (III), R ^{15 to} R ³² each independently represent 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.

  Subsequently, an infrared sensitizing dye having a maximum absorption in the wavelength range of 750 to 1400 nm (hereinafter sometimes referred to as an infrared absorber) will be described. 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, etc. 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 (IV).

In the general formula (IV), ^{X 1} is a hydrogen atom, a halogen ^{atom, -N (R 9) (R} 10), - X 2 -L ¹ or a group shown below. 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. Or it represents a hydrogen atom, and R ⁹ and R ¹⁰ may be bonded to each other to form a ring. Among them, a phenyl group is preferable as R ⁹ and R ¹⁰ . 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 (IV) each independently represent a hydrocarbon group having 1 to 12 carbon atoms. In view of storage stability of the color forming composition 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 (IV) has an anionic substituent in the structure thereof, Z _a is does not require charge neutralization ^- is not necessary. Preferred Z _a ⁻ is a halide ion, a perchlorate ion, a tetrafluoroborate ion, a hexafluorophosphate ion, and a sulfonate ion, particularly preferably a perchlorate ion, from the storage stability of the polymerizable composition solution. , Hexafluorophosphate ions and aryl sulfonate ions.

  Specific examples of the cyanine dye represented by formula (IV) include compounds described in paragraph numbers [0017] to [0019] of JP-A No. 2001-133969, paragraph number of JP-A No. 2002-023360 [0016]. ] To [0021], compounds described in paragraph numbers [0012] to [0037] of JP-A No. 2002-040638, preferably paragraph numbers [0034] to [0041] of JP-A No. 2002-278057, 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.

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

  As the infrared sensitizing dye, an infrared absorbent other than an infrared absorbing dye such as a pigment may be used. As the pigment, compounds described in paragraph numbers [0072] to [0076] of JP-A-2008-195018 are preferable.

Only one type of sensitizing dye may be used, or two or more types may be used in combination.
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 100 parts by mass with respect to 100 parts by mass of the total solid content of the color forming composition. 10 parts by mass.

  The preferred combination of (B) the sensitizing dye of the present invention and (A) the compound represented by the general formula (1) is most preferably a combination of the preferred embodiments.

(C) Binder As the binder used in the present invention, conventionally known binders can be used without limitation, and a polymer having film properties is preferred. Of these, acrylic resins, polyvinyl acetal resins, and polyurethane resins are preferable.

  In particular, when the color forming composition of the present invention is applied to a lithographic printing plate precursor, as a suitable binder, as described in JP-A-2008-195018, for improving the film strength of the image area. Examples thereof include those having a crosslinkable functional group in the main chain or side chain, preferably in the side chain. Crosslinking is formed between the polymer molecules by the crosslinkable group, and curing is accelerated.

  The crosslinkable functional group is preferably an ethylenically unsaturated group such as a (meth) acryl group, a vinyl group or an allyl group, or an epoxy group, and these groups can be introduced into the polymer by polymer reaction or copolymerization. . For example, a reaction between an acrylic polymer or polyurethane having a carboxy group in the side chain and polyurethane and glycidyl methacrylate, or a reaction between a polymer having an epoxy group and an ethylenically unsaturated group-containing carboxylic acid such as methacrylic acid can be used.

  The content of the crosslinkable group in the binder is preferably 0.1 to 10.0 mmol, more preferably 1.0 to 7.0 mmol, and most preferably 2.0 to 5.5 mmol per 1 g of the binder.

  Moreover, when using for a lithographic printing plate precursor, it is preferable to use a binder according to the development method.

<Binder for alkali development>
The chemical structure of the binder is not particularly limited, but is preferably an organic polymer having an acid group from the viewpoint of solubility in an alkaline processing liquid, that is, developability, and more preferably an organic polymer containing a carboxylic acid or a salt thereof. .
Examples of the binder that can be used in the color developing composition for an alkali development type lithographic printing plate precursor include carboxylic acid-containing alkaline water-soluble or swellable organic polymers. Examples of such an organic polymer include addition polymers having a carboxylic acid group in the side chain, such as JP-B-59-44615, JP-B-54-34327, JP-B-58-12777, and JP-B-54-25957. JP-A-54-92723, JP-A-59-53836, JP-A-59-71048, ie, methacrylic acid copolymer, acrylic acid copolymer, itaconic acid Copolymers, crotonic acid copolymers, maleic acid copolymers, partially esterified maleic acid copolymers and the like are useful. As the binder, a copolymer containing a monomer unit derived from a (meth) acrylic acid ester containing a carboxylic acid (salt) group is preferable.
Also useful are acidic cellulose derivatives having a carboxylic acid group in the side chain and those obtained by adding a cyclic acid anhydride to an addition polymer having a hydroxy group. Further, Japanese Patent Publication Nos. 7-120040, 7-120041, 7-120042, 8-12424, JP-A 63-287944, JP-A 63-287947, JP-A 1-1-2 Polyurethane resins described in JP-A Nos. 271741 and 11-352691 are also useful as alkaline water-soluble or swellable binders. As the binder that can be used in the present invention, an acrylic resin, a methacrylic resin, or a urethane resin is preferably used.

  An example of a material suitable as the binder for alkali development is a copolymer having (a) a monomer unit containing a carboxylic acid group (including a salt thereof) and (b) a monomer unit imparting radical crosslinkability.

(A) Although it does not specifically limit as a monomer unit containing a carboxylic acid group, The structure as described in paragraph number [0059]-[0075] of Unexamined-Japanese-Patent No. 2002-40652 and Unexamined-Japanese-Patent No. 2005-300650 is preferable. Used.
(B) Although it does not specifically limit as a monomer unit which provides radical crosslinkability, The structure as described in paragraph number [0041]-[0053] of Unexamined-Japanese-Patent No. 2007-248863 is used preferably.

The binder for alkali development has, as a copolymerization component, a monomer unit derived from an ethylenically unsaturated compound containing neither (a) a monomer unit containing a carboxylic acid group nor (b) a monomer unit imparting radical crosslinkability. It may be.
As such a monomer unit, a monomer unit derived from (meth) acrylic acid ester or (meth) acrylic acid amide is preferable. In particular, monomer units derived from amide group (meth) acrylic acid amides described in paragraph numbers [0061] to [0084] of JP-A-2007-272134 are preferably used. The content of this monomer is preferably 5 to 50 units, more preferably 5 to 35 units, even more preferably 5 to 25 units, when the total number of monomer units is 100. .

  In the color-forming composition in the present invention, a urethane resin having a crosslinkable group in the side chain can be used as a binder in addition to the addition polymer having the above-mentioned combination of monomer units. Here, the crosslinkable group is a group capable of crosslinking the binder by a chemical reaction occurring in the image recording layer when the lithographic printing plate precursor is exposed. The chemical structure is not particularly limited as long as it has such a function. For example, an ethylenically unsaturated group is preferable as a functional group capable of addition polymerization. Moreover, the functional group described in paragraph number [0130]-[0139] of Unexamined-Japanese-Patent No. 2007-17948 can be illustrated.

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

  Examples of the compounds (i), (ii) and (iii) include the formulas (4) to (10) and specific examples described in paragraph numbers [0142] to [0167] of JP-A No. 2007-17948. It is done. The compound of (iv) is a compound represented by general formula (A ′), formulas (a) to (e), and formulas (11) to (11) described in paragraph numbers [0180] to [0225] of JP-A No. 2007-17948. 22) and specific compounds. Examples of the compound (v) include formula (31) and formula (32) and specific compounds described in paragraph numbers [0227] to [0230] of JP-A No. 2007-17948. In addition to the above-described polyurethane resin, a polyurethane resin obtained by introducing a crosslinkable group into a polyurethane having a carboxyl group as described in JP-A-2003-270775 by a polymer reaction can also be exemplified.

  In order to maintain the developability of the image recording layer of the lithographic printing plate precursor, the binder used preferably has an appropriate molecular weight, and the mass average molar mass (Mw) is 5 in terms of polystyrene converted by the GPC method. Is more preferably 20,000 to 300,000, still more preferably 20,000 to 150,000.

  These alkali developing binders can be contained in any amount in the color forming composition, but the binder content should be 10 to 90% by mass with respect to the total solid content of the color forming composition. Is preferable, and it is more preferable that it is 30-80 mass%.

<On-press development binder>
As the binder for on-press development, a binder having an alkylene oxide group is preferred.
The binder having an alkylene oxide group used in the color forming composition of the present invention may have a poly (alkylene oxide) moiety in the main chain or a side chain, and may contain poly (alkylene oxide). The graft polymer in the side chain may be a block copolymer of a block composed of a poly (alkylene oxide) -containing repeating unit and a block composed of a (alkylene oxide) -free repeating unit.
When it has in a principal chain, a polyurethane resin is preferable. The main chain polymer in the case of the side chain includes acrylic resin, polyvinyl acetal resin, polyurethane resin, polyurea resin, polyimide resin, polyamide resin, epoxy resin, methacrylic resin, polystyrene resin, novolac type phenol resin, polyester resin Synthetic rubber and natural rubber can be mentioned, and acrylic resin is particularly preferable.

As said alkylene oxide, a C2-C6 alkylene oxide is preferable and especially an ethylene oxide or a propylene oxide is preferable.
The repeating number of alkylene oxide in the poly (alkylene oxide) moiety is 2 to 120, preferably in the range of 2 to 70, and more preferably in the range of 2 to 50.
If the number of alkylene oxide repeats is 120 or less, both the printing durability due to abrasion and the printing durability due to ink acceptance are not lowered, which is preferable.

  The poly (alkylene oxide) moiety is preferably contained as a side chain of the binder in a structure represented by the following general formula (5). More preferably, it is contained as a side chain of the acrylic resin in a structure represented by the following general formula (5).

In formula (5), y represents 2-120, the range of 2-70 is preferable and the range of 2-50 is more preferable. R ₁ represents a hydrogen atom or an alkyl group, and R ₂ represents a hydrogen atom or an organic group. As the organic group, an alkyl group having 1 to 6 carbon atoms is preferable, and methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, isobutyl group, t-butyl group, n -Pentyl group, isopentyl group, neopentyl group, n-hexyl group, isohexyl group, 1,1-dimethylbutyl group, 2,2-dimethylbutyl group, cyclopentyl group, and cyclohexyl group.
Among the above, R ₁ is preferably a hydrogen atom or a methyl group, and most preferably a hydrogen atom. R ₂ is most preferably a hydrogen atom or a methyl group.

The above binder may have crosslinkability in order to improve the film strength of the image area. In order to impart crosslinkability to the polymer, a crosslinkable functional group such as an ethylenically unsaturated bond may be introduced into the main chain or side chain of the polymer. The crosslinkable functional group may be introduced by copolymerization.
Examples of the polymer having an ethylenically unsaturated bond in the main chain of the molecule include poly-1,4-butadiene and poly-1,4-isoprene.
Examples of polymers having an ethylenically unsaturated bond in the side chain of the molecule are polymers of esters or amides of acrylic acid or methacrylic acid, wherein the ester or amide residue (R of -COOR or -CONHR) is Mention may be made of polymers having an ethylenically unsaturated bond.

Examples of the residue (the R) having an ethylenically unsaturated _{^{bond, - (CH 2) n CR}} 1 = CR 2 R 3, - (CH 2 O) n CH 2 CR 1 = CR 2 R 3, - _{(CH 2 CH 2 O) n} CH 2 CR 1 = CR 2 R 3, - (CH 2) n NH-CO-O-CH 2 CR 1 = CR 2 R 3, - (CH 2) n -O-CO —CR ¹ ═CR ² R ³ and — (CH ₂ CH ₂ O) ₂ —X (wherein R ^{1 to} R ³ are each independently a hydrogen atom, a halogen atom, or an alkyl group having 1 to 20 carbon atoms, Represents an aryl group, an alkoxy group or an aryloxy group, and R ¹ and R ² or R ³ may combine with each other to form a ring, n represents an integer of 1 to 10. X represents dicyclo. Represents a pentadienyl residue).

Specific examples of the ester residue include —CH ₂ CH═CH ₂ (described in JP-B-7-21633), —CH ₂ CH ₂ O—CH ₂ CH═CH ₂ , —CH ₂ C. _{(CH 3) = CH 2,} -CH 2 CH = CH-C 6 H 5, -CH 2 CH 2 OCOCH = CH-C 6 H 5, -CH 2 CH 2 -NHCOO-CH 2 CH = CH 2 and - CH ₂ CH ₂ O—X (wherein X represents a dicyclopentadienyl residue).
Specific examples of the amide residue include —CH ₂ CH═CH ₂ , —CH ₂ CH ₂ —Y (wherein Y represents a cyclohexene residue), —CH ₂ CH ₂ —OCO—CH═CH _2. Is mentioned.

  In the binder having crosslinkability, for example, free radicals (polymerization initiating radicals or growth radicals in the polymerization process of the polymerizable compound) are added to the crosslinkable functional group, and directly between the polymers or via a polymerization chain of the polymerizable compound. Then, addition polymerization is performed, and a crosslink is formed between the polymer molecules to be cured. Alternatively, atoms in the polymer (eg, hydrogen atoms on carbon atoms adjacent to the functional bridging group) are abstracted by free radicals to form polymer radicals that are bonded together, thereby causing cross-linking between polymer molecules. Forms and cures.

  The content of the crosslinkable group in the binder (content of unsaturated double bond capable of radical polymerization by iodine titration) is preferably 0.1 to 10.0 mmol, more preferably 1.0, per 1 g of the polymer compound. -7.0 mmol, most preferably 2.0-5.5 mmol. Within this range, good sensitivity and good storage stability can be obtained.

Specific examples (1) to (11) of the on-press development binder used in the present invention are shown below, but the present invention is not limited thereto.
In addition, in the following exemplary compounds, a numerical value written together with each repeating unit (a numerical value written together with the main chain repeating unit) represents a mole percentage of the repeating unit. The numerical value written together with the repeating unit of the side chain indicates the number of repetitions of the repeating site.

  In addition, it is preferable that the said binder in this invention is 2000 or more as a polystyrene conversion value by GPC method, It is more preferable that it is 5000 or more, It is 10,000 to 300,000. Further preferred.

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

  When the color forming composition of the present invention is applied to the image recording layer of a lithographic printing plate precursor, the form of the binder may be present in the color forming composition as a binder that functions as a linking material. It may exist in the form of fine particles. When present in the form of fine particles, the average particle size is in the range of 10 to 1000 nm, preferably in the range of 20 to 300 nm, and particularly preferably in the range of 30 to 120 nm.

  The content of the on-press developing binder of the present invention is preferably 5 to 90% by mass, more preferably 5 to 80% by mass, and further 10 to 70% by mass, based on the total solid content of the color forming composition. preferable.

(D) Onium-based radical generator Examples of the onium-based radical generator that can be used in the present invention 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. Ivonium salt described in Crivello et al, Macromolecules, 10 (6), 1307 (1977), European Patents 370,693, 233,567, 297,443, 297,442, US Patent 4,933,377, 4,760,013, 4,734,444, 2,833,827, German Patent 2,904,626, 3,604,580 Sulphonium salts described in the respective specifications of U.S. Pat. V. Crivello et al, J.A. Polymer Sci. , Polymer Chem. Ed. , 17, 1047 (1979), a selenonium salt described in C.I. S. Wen et al, Teh, Proc. Conf. Rad. Curing ASIA, p478 Tokyo, Oct (1988), and onium radical generators such as azonium salts described in JP2008-195018A.

  Among these, iodonium salts, sulfonium salts, and azinium salts are more preferable from the viewpoint of color developability. In particular, iodonium salts and sulfonium salts are more preferable when used for lithographic printing plate precursors. 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-chlorophenyl-4-phenyliodonium = hexafluorophosphate, 4- (2-Methylpropyl) phenyl-p-tolyliodonium = hexafluorophosphate, 4-hexyloxyphenyl-2,4,6-trimethoxyphenyliodonium = hexafluorophosphate, 4-hexyloxyphenyl-2,4- Diethoxyphenyliodonium = tetrafluoroborate, 4-octyloxyphenyl-2,4,6-trimethoxyphenyliodonium = 1-perfluorobutanesulfonate, 4-octyloxyphenyl-2,4 6- trimethoxyphenyl hexafluorophosphate, bis (4-t- butylphenyl) iodonium hexafluorophosphate.

  As an example of the sulfonium salt, a triarylsulfonium salt is preferable, and a triarylsulfonium salt substituted with an electron withdrawing group such as a halogen atom is particularly preferable, and a total number of halogen atoms is preferably 4 or more. . Specific examples include triphenylsulfonium = hexafluorophosphate, triphenylsulfonium = benzoylformate, bis (4-chlorophenyl) phenylsulfonium = benzoylformate, bis (4-chlorophenyl) -4-methylphenylsulfonium = tetrafluoro. Borate, tris (4-chlorophenyl) sulfonium = 3,5-bis (methoxycarbonyl) benzenesulfonate, tris (4-chlorophenyl) sulfonium = hexafluorophosphate, tris (2,4-dichlorophenyl) sulfonium = hexafluorophos Fert, bis (2,4-dichlorophenyl) phenylsulfonium = hexafluorophosphate, bis (2,4-dichlorophenyl) 4-methoxyphenylsulfonium = f Fluoro-phosphate

  Examples of azinium salts include 1-cyclohexylmethyloxypyridinium = hexafluorophosphate, 1-cyclohexyloxy-4-phenylpyridinium = hexafluorophosphate, 1-methoxypyridinium = hexafluorophosphate, 1-methoxy-4- t-butylpyridinium = hexafluorophosphate, 1-methoxy-4-methoxypyridinium = hexafluorophosphate, 1-ethoxy-4-phenylpyridinium = hexafluorophosphate, 1- (2-ethylhexyloxy) -4-phenyl Pyridinium = 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-phenethyloxy-4-phenylpyridinium = hexafluoro Phosphate, 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, 1-methoxy-4-tert-butylpyridinium hexafluorophosphate, 1-methoxy 4-methoxy pyridinium hexafluorophosphate and the like.

  The onium radical generator in the present invention is preferably 0.1 to 50% by mass, more preferably 0.5 to 30%, based on the total solid content constituting the color forming composition, color forming curable composition or image recording layer. It can be added at a ratio of mass%, particularly preferably 0.8 to 25 mass%. In this range, good color developability is obtained, and in the case of a lithographic printing plate precursor, good stain resistance of non-image areas during printing is obtained.

  Preferred combination of (D) onium-based polymerization initiator and (B) sensitizing dye of the present invention, and preferred combination of (D) onium-based polymerization initiator and (A) compound represented by formula (1) Is most preferably a combination of the preferred embodiments. In addition, (D) a preferred combination with an onium-based polymerization initiator, (B) a sensitizing dye, and (A) a preferred combination with the compound represented by the general formula (1) are also combinations of respective preferred embodiments. preferable.

(E) Polymerizable compound The (E) polymerizable compound that can be used in the composition of the present invention is an addition polymerizable compound having at least one ethylenically unsaturated double bond, and has a terminal ethylenically unsaturated bond. It is selected from compounds having at least 1, preferably 2 or more. These have chemical forms such as monomers, prepolymers, ie dimers, trimers and oligomers, or mixtures thereof. (E) The composition of the present invention containing a polymerizable compound is a color-forming curable composition having a function of polymerizing and curing in addition to the color-forming property.
In the present specification, the color-forming curable composition containing an infrared sensitizing dye as the sensitizing dye (B) is also referred to as an infrared color-forming curable composition.

  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. An ester of an acid and a polyhydric alcohol compound and an amide of an unsaturated carboxylic acid and a polyvalent amine compound are used. In addition, an addition reaction product of an unsaturated carboxylic acid ester or amide having a nucleophilic substituent such as a hydroxy group, amino group or mercapto group with a monofunctional or polyfunctional isocyanate or epoxy, and a monofunctional or polyfunctional compound. A dehydration condensation reaction product with a functional carboxylic acid is also preferably used. In addition, an addition reaction product of an isocyanate group, an unsaturated carboxylic acid ester or amide having an electrophilic substituent such as an epoxy group, and a monofunctional or polyfunctional alcohol, amine, or thiol, a halogeno group, Also suitable are substitution reaction products of unsaturated carboxylic acid esters or amides having a leaving substituent such as a tosyloxy group with monofunctional or polyfunctional alcohols, amines or thiols. As another example, it is also possible to use a group of compounds substituted with unsaturated phosphonic acid, styrene, vinyl ether or the like instead of the unsaturated carboxylic acid. These are disclosed in JP-T-2006-508380, JP-A-2002-287344, JP-A-2008-256850, JP-A-2001-342222, JP-A-9-179296, JP-A-9-179297. JP-A-9-179298, JP-A-2004-294935, JP-A-2006-243493, JP-A-2002-275129, JP-A-2003-64130, JP-A-2003-280187, It is described in references including Kaihei 10-333321.

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

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 (6) 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 (6)
(However, R ⁴ and R ⁵ each independently represent H or CH _3. )

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

  Details of the usage method such as the structure of these polymerizable compounds, whether they are used alone or in combination, and the amount added can be arbitrarily set in accordance with the intended use of the final color forming composition. 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 color-forming curable composition. The

[Application of coloring composition and coloring curing composition]
The color-forming composition and color-forming curable composition may contain additives other than those described above depending on the purpose. A liquid in which such a composition is dissolved or dispersed in a suitable solvent is applied to a support or the like and dried to form a color forming composition film, whereby an image forming material is produced. Examples of image forming materials include lithographic printing plate precursors, printed wiring boards, color filters, photomasks, and other image forming materials that use color development by image exposure, and image forming materials that use color development and polymerization curing. Especially, it is suitable for manufacture of a lithographic printing plate precursor.
The image forming material is exposed with a light source suitable for the photosensitive wavelength region of the composition to be used. Examples of the light source include an ultrahigh pressure mercury lamp, an InGaN-based semiconductor laser, a solid-state laser that emits infrared light, and a semiconductor laser.

[Lithographic printing plate precursor]
The lithographic printing plate precursor according to the invention has an image recording layer containing the color-forming curable composition on a support. In the lithographic printing plate precursor according to the invention, an undercoat layer can be provided between the support and the image recording layer, and a protective layer can be provided on the image recording layer, if necessary.
Hereinafter, components of the planographic printing plate precursor will be described.

(Image recording layer)
The image recording layer of the lithographic printing plate precursor is required to have developability and printability. Therefore, the color-forming curable composition for the image recording layer can further contain the following hydrophobizing precursor and other components in addition to the above-described components.

(F) Hydrophobized precursor In the present invention, a hydrophobized precursor can be used to improve on-press developability. The hydrophobized precursor in the present invention means fine particles capable of converting the image recording layer to hydrophobic when heat is applied. The fine particles are at least one selected from hydrophobic thermoplastic polymer fine particles, thermally reactive polymer fine particles, polymer fine particles having a polymerizable group, microcapsules enclosing a hydrophobic compound, and microgel (crosslinked polymer fine particles). It is preferable. Among these, polymer fine particles and microgels having a polymerizable group are preferable.

Hydrophobic thermoplastic polymer fine particles include Research Disclosure No. 1 of January 1992. 33303, hydrophobic thermoplastic polymer fine particles described in JP-A-9-123387, JP-A-9-131850, JP-A-9-171249, JP-A-9-171250 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 diameter of the hydrophobic thermoplastic polymer fine particles used in the present invention is preferably 0.01 to 2.0 μm.

  Examples of the heat-reactive polymer fine particles used in the present invention include polymer fine particles having a heat-reactive group, and these form a hydrophobized region by crosslinking due to 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 isocyanato 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.), and a condensation reaction Carboxy group and reaction partner hydroxy group or amino group, acid anhydride and reaction phase for ring-opening addition reaction , And the like as a preferable amino group or a hydroxy group is.

  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, the image recording layer containing microcapsules is preferably a mode in which hydrophobic constituent components are encapsulated in microcapsules and hydrophilic constituent components are contained outside the microcapsules.

  In this invention, the aspect containing a crosslinked resin particle, ie, a microgel, may be sufficient. This microgel can contain a part of the 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 further more preferable, and 0.10-1.0 micrometer is especially preferable. Within this range, good resolution and stability over time can be obtained.

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

(G) Other components The image recording layer in the invention may further contain other components as required.

(1) 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, betaines, and the like.

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

  Specific examples of organic sulfonates include alkyl sulfonates such as sodium n-butyl sulfonate, sodium n-hexyl sulfonate, sodium 2-ethylhexyl sulfonate, sodium cyclohexyl sulfonate, and sodium n-octyl sulfonate. Sodium 5,8,11-trioxapentadecane-1-sulfonate, sodium 5,8,11-trioxaheptadecane-1-sulfonate, 13-ethyl-5,8,11-trioxaheptadecane-1; Alkyl sulfonates containing ethylene oxide chains such as sodium sulfonate, sodium 5,8,11,14-tetraoxatetracosane-1-sulfonate; sodium benzenesulfonate, sodium p-toluenesulfonate, p-hydroxybenzene Sulfone 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 paragraph numbers [0026] to [0031] of JP 2007-276454 A and paragraph numbers [0020] to [0047] of JP 2009-154525 A Etc. 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 the compounds described in paragraph numbers [0034] to [0038] of JP-A-2007-276454.

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

  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 amount of these low molecular weight hydrophilic compounds added to the image recording layer is preferably 0.5% by mass or more and 20% by mass or less of the total solid content of the image recording layer. 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.

(2) 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. Fert, benzyldimethyldodecyl ammonium = hexafluorophosphate, compounds described in paragraph numbers [0021] to [0037] of JP-A-2008-284858, paragraph numbers [0030] to [0057] of JP-A-2009-90645, etc. Is mentioned.

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

  The ammonium salt-containing polymer has a reduced specific viscosity (unit: ml / g) determined by the measurement method described in JP-A-2009-208458, preferably in the range of 5 to 120, and in the range of 10 to 110. Are more preferable, and those in the range of 15 to 100 are particularly preferable. 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.

Specific examples of the ammonium group-containing polymer are shown below.
(1) 2- (Trimethylammonio) ethyl methacrylate = p-toluenesulfonate / 3,6-dioxaheptyl methacrylate copolymer (molar ratio 10/90 Mw 45,000)
(2) 2- (Trimethylammonio) ethyl methacrylate = hexafluorophosphate / 3,6-dioxaheptyl methacrylate copolymer (molar ratio 20/80 Mw 60,000)
(3) 2- (Ethyldimethylammonio) ethyl methacrylate = p-toluenesulfonate / hexyl methacrylate copolymer (molar ratio 30/70 Mw 45,000)
(4) 2- (Trimethylammonio) ethyl methacrylate = hexafluorophosphate / 2-ethylhexyl methacrylate copolymer (molar ratio 20/80 Mw 60,000)
(5) 2- (Trimethylammonio) ethyl methacrylate = methyl sulfate / hexyl methacrylate copolymer (molar ratio 40/60 Mw 7 million)
(6) 2- (Butyldimethylammonio) ethyl methacrylate = hexafluorophosphate / 3,6-dioxaheptyl methacrylate copolymer (molar ratio 25/75 Mw 650,000)
(7) 2- (Butyldimethylammonio) ethyl acrylate = hexafluorophosphate / 3,6-dioxaheptyl methacrylate copolymer (molar ratio 20/80 Mw 65,000)
(8) 2- (butyldimethylammonio) ethyl methacrylate = 13-ethyl-5,8,11-trioxa-1-heptadecanesulfonate / 3,6-dioxaheptyl methacrylate copolymer (molar ratio 20/80 Mw 75,000)
(9) 2- (butyldimethylammonio) ethyl methacrylate = hexafluorophosphate / 3,6-dioxaheptyl methacrylate / 2-hydroxy-3-methacryloyloxypropyl methacrylate copolymer (molar ratio 15/80/5 (Mw 650,000)

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

(3) 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 are included. 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. The compound and the addition amount described in paragraph [0060] of FIG.

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

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

  Examples of the compound used for the undercoat layer include polymers having an adsorptive group and a hydrophilic group that can be adsorbed on the support surface. In order to improve the adhesion to the image recording layer, a polymer having an adsorptive group and a hydrophilic group and further having a crosslinkable group is preferable. These compounds may be low molecular compounds or high molecular polymers. Moreover, these compounds may mix 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.
Examples of the adsorptive group that can be adsorbed on the support surface include a phenolic hydroxy group, a carboxy group, —PO ₃ H ₂ , —OPO ₃ H ₂ , —CONHSO ₂ —, —SO ₂ NHSO ₂ —, —COCH ₂ COCH _3. Is preferred. As the hydrophilic group, a sulfo group or a salt thereof, or a salt of a carboxy 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.

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

The protective layer 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.

The protective layer of the present invention preferably contains an inorganic layered compound in order to enhance oxygen barrier properties. Such an inorganic layered compound is a particle having a thin plate-like shape, for example, mica group such as natural mica and synthetic mica, talc represented by the formula 3MgO · 4SiO · H ₂ O, teniolite, montmorillonite, saponite, Examples include hectorite and zirconium phosphate.
The inorganic layered compound preferably used in the present invention is a mica compound. Examples of the mica compound include, for example, the general formula: A (B, C) _2-5 D ₄ O ₁₀ (OH, F, O) ₂ [where A is any of K, Na, Ca, and B and C are , Fe (II), Fe (III), Mn, Al, Mg, or V, and D is Si or Al. ] Mica groups such as natural mica and synthetic mica represented by

In the mica group, examples of natural mica include muscovite, soda mica, phlogopite, biotite and sericite. Further, as the synthetic mica, non-swelling mica such as fluorine phlogopite mica ₃ (AlSi ₃ O ₁₀ ) F ₂ , potassium tetrasilicon mica KMg _2.5 Si ₄ O ₁₀ ) F ₂ , and Na tetrasilicic mica NaMg _2.5 (Si ₄ O ₁₀ ) F ₂ , Na or Li Tenniolite (Na, Li) Mg ₂ Li (Si ₄ O ₁₀ ) F ₂ , Montmorillonite Na or Li Hectorite (Na, Li) _1/8 Mg Swellable mica such as _2/5 Li _1/8 (Si ₄ O ₁₀ ) F ₂ can be used. Synthetic smectite is also useful.

In the present invention, among the mica compounds, fluorine-based swellable mica is particularly useful. That is, this swellable synthetic mica has a laminated structure composed of unit crystal lattice layers with a thickness of about 10 to 15 mm, and the intra-lattice metal atom substitution is significantly larger than other clay minerals. As a result, the lattice layer is deficient in positive charge, and in order to compensate for this, cations such as Li ⁺ , Na ⁺ , Ca ²⁺ , and Mg ²⁺ are adsorbed between the layers. The cations present between these layers are called exchangeable cations and exchange with various cations. In particular, when the cation between the layers is Li + or Na +, since the ionic radius is small, the bond between the layered crystal lattices is weak, and the layer swells greatly with water. If shear is applied in this state, it will easily cleave and form a stable sol in water. Swellable synthetic mica has a strong tendency and is particularly preferably used in the present invention.

  The shape of the mica compound is preferably as small as possible from the viewpoint of diffusion control, and the plane size is preferably as long as the smoothness of the coated surface and the transmittance of actinic rays are not impaired. Accordingly, the aspect ratio is 20 or more, preferably 100 or more, particularly preferably 200 or more. The aspect ratio is the ratio of the major axis to the thickness of the particle, and can be measured from, for example, a projection drawing of a micrograph of the particle. The larger the aspect ratio, the greater the effect that can be obtained.

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

  0-60 mass% is preferable with respect to the total solid content of a protective layer, and, as for content of an inorganic layered compound, 3-50 mass% is more preferable. Even when a plurality of types of mica compounds are used in combination, the total amount of the mica compounds is preferably the above-described mass.

  Within these ranges, the oxygen barrier property is improved and good sensitivity can be obtained. Further, it is possible to prevent a decrease in inking property.

  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.}

[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.

[Plate making method]
The plate making method of the lithographic printing plate of the present invention includes at least a step of image-exposing a lithographic printing plate precursor (hereinafter also referred to as “exposure step”) and a step of developing with a processing solution (hereinafter referred to as “developing step”). It is preferable that the method includes:

<Exposure process>
The lithographic printing plate precursor used in the present invention is obtained by scanning and exposing digital data with a laser such as a visible light laser or an infrared laser, or by exposing a digital original with a light source such as a halogen lamp or a high-pressure mercury lamp through a transparent original image. An image can be recorded, but a scanning exposure method using a laser such as a visible laser or an infrared laser is preferred.
A desirable light source wavelength is preferably 300 nm to 450 nm or 750 nm to 1400 nm. In the case of 300 nm to 450 nm, a lithographic printing plate precursor having a sensitizing dye having an absorption maximum in this region in the image recording layer is used, and in the case of 750 nm to 1400 nm, infrared rays which are sensitizing dyes having absorption in this region. It is preferable to use a lithographic printing plate precursor containing an absorbent. As the light source of 300 nm to 450 nm, a semiconductor laser is suitable. As the light source of 750 nm to 1400 nm, a solid-state laser and a semiconductor laser that emit infrared rays are suitable. The exposure mechanism may be any of an internal drum system, an external drum system, a flat bed system, and the like.

<Development process>
The lithographic printing plate precursor used in the present invention is exposed to light and then developed with water or a developer having a pH of 2 to 14 (developer treatment), or developed with dampening water and ink on a printing press (machine). Top development).

  The developer treatment is usually performed in the following steps. (1) Remove non-image area with developer, (2) Implement gum solution treatment, (3) Dry in drying step. The lithographic printing plate precursor used in the present invention can be developed by a normal process (normal development), but it is preferable to perform the steps (1) and (2) simultaneously (simple development). In any development method, a water washing step for removing the protective layer may be performed before the step (1). The development in step (1) is carried out according to a conventional method at a temperature of 0 to 60 ° C., preferably about 15 to 40 ° C., for example, by immersing an exposed lithographic printing plate precursor in a developer and rubbing with a brush, spraying By a method of spraying a developer and rubbing with a brush.

  In the case of normal development, a water washing step for removing excess developer may be inserted between step (1) and step (2). Moreover, it is preferable to use a well-known alkali developing solution as a developing solution used for a process (1).

In the case of simple development, it is preferable to dry after removing the excess developer using a squeeze roller after development and gumming.
The developer used in the simple development is an aqueous solution having a pH of 2 to 11. 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 5 to 10.7, further preferably 6 to 10.5, and most preferably 7.5 to 10.3.

  The anionic surfactant used in the developer for simple development 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 propyl alkyl sulfonates, polyoxyethylene alkyl sulfophenyl ether salts, N-methylalkyl-N- Sodium oleyl taurine, disodium N-alkylsulfosuccinate monoamide, petroleum sulfonates, sulfated castor oil, sulfated beef tallow oil, sulfate ester of fatty acid alkyl ester Salts, alkyl sulfates, polyoxyethylene alkyl ether sulfates, fatty acid monoglyceride sulfates, polyoxyethylene alkylphenyl ether sulfates, polyoxyethylene styryl phenyl ether sulfates, alkyl phosphate esters, polyoxyethylene Alkyl ether phosphoric acid ester salts, polyoxyethylene alkylphenyl ether phosphoric acid ester salts, partial saponification products of styrene-maleic anhydride copolymer, partial saponification products of olefin-maleic anhydride copolymer, naphthalene sulfonate formalin condensation Things etc. are mentioned. Among these, alkylbenzene sulfonates, alkyl naphthalene 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 simple development, 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 for simple development 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) Side) 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. Is mentioned. 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 for simple development is not particularly limited, and examples thereof include amine oxides such as alkyldimethylamine oxide, betaines such as alkylbetaine, and amino acids such as alkylamino fatty acid sodium. . 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. Specific examples thereof include compounds represented by formula (2) in paragraph numbers [0255] to [0278] of JP-A-2008-203359, and formulas of paragraph numbers [0028] to [0052] in JP-A-2008-276166. Compounds described in (I), compounds represented by formula (II) and formula (VI), compounds represented by paragraph numbers [0022] to [0029] of JP2009-47927A, and the like can be used. .

  Two or more surfactants may be used, and the ratio of the surfactant contained in the developer is preferably 0.01 to 20% by mass, more preferably 0.1 to 10% by mass.

  In addition, as the plate-making process of the lithographic printing plate from the lithographic printing plate precursor according to the present invention, the entire surface may be heated before exposure, during exposure, and between exposure and development, if necessary. 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. Further, for the purpose of improving the image strength and printing durability, it is also effective to subject the developed image to full post heating or full exposure. Usually, the 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 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 strengthening action cannot be obtained. If the temperature is too high, problems such as deterioration of the support and thermal decomposition of the image area occur.

The lithographic printing plate precursor according to the invention can also be made by an on-press development method. The on-press development method includes a step of image-exposing a lithographic printing plate precursor, a printing step of supplying an oil-based ink and an aqueous component and printing without performing any development treatment on the exposed lithographic printing plate precursor, And the unexposed portion of the lithographic printing plate precursor is removed during the printing process. Imagewise exposure may be performed on the printing machine after the lithographic printing plate precursor is mounted on the printing machine, or may be separately performed with a plate setter or the like. In the latter case, the exposed lithographic printing plate precursor is mounted on a printing machine without undergoing a development process. Thereafter, by using the printing machine and supplying the oil-based ink and the aqueous component and printing as it is, an on-press development process, that is, an image recording layer in an unexposed area is removed at an early stage of printing, Accordingly, the surface of the hydrophilic support is exposed to form a non-image part. As the oil-based ink and the aqueous component, ordinary lithographic printing ink and fountain solution are used.
Here, dampening water or printing ink may be supplied to the printing plate first, but printing is first performed in order to prevent the dampening water from being contaminated by the removed image recording layer components. It is preferable to supply ink.
In this way, the lithographic printing plate precursor according to the invention is developed on the machine on an offset printing machine and used as it is for printing a large number of sheets.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to these. In the polymer compound, the molecular weight is a mass average molar mass (Mw), and the ratio of repeating units is a mole percentage, except for those specifically defined.

I. Color-forming composition film I-1. Preparation of chromogenic composition films A-1 to A-24 The following chromogenic composition solution (1) was prepared, and the dry coating amount was 1.0 g / m ² on a polyester film having a thickness of 0.18 mm. After bar coating as described above, oven-dried at 100 ° C. for 60 seconds to prepare color-forming composition films A-1 to A-24 (for Examples 1 to 24).

<Coloring composition solution (1)>
-Binder polymer (1) [the following structure] 0.636 g
・ Onium radical generator (compound described in Table 2) 0.150 g
-Specific compound shown in Formula (1) (compound described in Table 2) 0.030 g
Sensitizing dye (1) (following structure) 0.08 g
・ Fluorosurfactant (1) [The following structure] 0.008g
・ 2-butanone 1.091g
・ 1-methoxy-2-propanol 8.609g

  The structures of the binder polymer (1), the onium radical generator, the sensitizing dye (1), and the fluorosurfactant (1) are as shown below.

I-2. Production of Coloring Composition Film A′-1 A coloring composition film A′-1 was produced in the same manner except that the specific compound was not added in the coloring composition film A-1 [Comparative Example] 1].

I-3. Preparation of chromogenic composition film A′-2 The following chromogenic composition solution (2) was prepared, and a dry coating amount was 1.0 g / m ² on a 0.18 mm thick polyester film. After coating, oven-dried at 100 ° C. for 60 seconds to prepare a color forming composition film A′-2 [for Comparative Example 2].

<Coloring composition solution (2)>
-Binder polymer (1) [above] 0.636 g
・ Onium radical generator (compound described in Table 2) 0.150 g
・ Sodium tetraphenylborate (the following structure) 0.010 g
・ Crystal violet (the following structure) 0.020g
Sensitizing dye (1) [above] 0.080 g
・ Fluorosurfactant (1) [above] 0.008 g
・ 2-butanone 1.091g
・ 1-methoxy-2-propanol 8.609g

  The structure of sodium tetraphenylborate and crystal violet is as shown below.

I-4. Preparation of chromogenic composition film A′-3 The following chromogenic composition solution (3) was prepared, and a dry coating amount was 1.0 g / m ² on a polyester film having a thickness of 0.18 mm. After coating, oven-dried at 100 ° C. for 60 seconds to prepare a color forming composition film A′-3 [for Comparative Example 3].

<Coloring composition solution (3)>
-Binder polymer (1) [above] 0.636 g
・ Onium radical generator (compound described in Table 2) 0.150 g
Comparative compound (1) (the following structure) 0.030 g
Sensitizing dye (1) [above] 0.08 g
・ Fluorosurfactant (1) [above] 0.008 g
・ 2-butanone 1.091g
・ 1-methoxy-2-propanol 8.609g

  The structure of the comparative compound (1) is as shown below.

I-5. Evaluation of the color developability of the color developable composition film The produced color developable composition film was measured using a FUJIFILM Electronic Imaging Ltd. Violet semiconductor laser Vx9600 (InGaN semiconductor laser 405 nm ± 10 nm) with a resolution of 2483 dpi and an exposure pattern of 50%. Square dots were used for exposure with varying output. The exposure was performed under conditions of 25 ° C. and 50% RH.
The color development was measured immediately after exposure and after 2 hours in the dark and at room temperature after exposure. Further, the color development immediately after exposure of the color forming composition film subjected to forced aging for 3 days under the conditions of 60 ° C. and 70% humidity was also measured. For color development, the L value (brightness) of the L ^* a ^* b ^* color system was used, and expressed as the difference ΔL between the L value of the exposed area and the L value of the unexposed area. A larger value of ΔL means better color developability. The measurement was performed by the SCE (regular reflection light removal) method using a spectrocolorimeter CM2600d manufactured by KONICA-MINOLTA and operation software CM-S100W. The results are shown in Table 2.

  From the results shown in Table 2, the color forming composition film of the present invention exhibits good color developability, and also has good storage stability, and the composition film after coating can obtain high color even when exposed after forced aging. In particular, when a specific compound having a reduced electron density of the phenyl group on boron is used (Examples 19 to 24), the storage stability and color developability are excellent. Moreover, it is thought that the reason why the color developability was improved when the radical generator was added (Examples 1 to 17 and 19 to 24) was that the electron transfer efficiency was increased by the addition of the initiator.

II. Infrared coloring composition film II-1. Preparation of Infrared Coloring Composition Films B-1 to B-24 The following infrared coloring composition solution (4) was prepared, and the dry coating amount was 1.0 g / g on a 0.18 mm thick polyester film. After bar coating so as to be m ² , oven drying was performed at 100 ° C. for 60 seconds to prepare infrared color forming composition films B-1 to B-24 (for Examples 25 to 48).

<Infrared coloring composition solution (4)>
-Binder polymer (1) 0.636g
-Onium-based radical generator (compound described in Table 3) 0.150 g
-Specific compound shown in Formula (1) (compound described in Table 3) 0.030 g
Infrared absorber (1) [the following structure] 0.02 g
・ Fluorosurfactant (1) [above] 0.008 g
・ 2-butanone 1.091g
・ 1-methoxy-2-propanol 8.609g

  The structure of the infrared absorber (1) is as shown below.

II-2. Preparation of Infrared Coloring Composition Films B′-1 and B′-2 Infrared Coloring Composition Films B′-1 and B′-2 were prepared in the same manner except that the specific compound was not added. A membrane B′-2 was obtained [for Comparative Example 5].

II-3. Preparation of Infrared Coloring Composition Film B′-3 The following infrared coloring composition solution (5) was prepared, and the dry coating amount was 1.0 g / m ² on a polyester film having a thickness of 0.18 mm. After applying the bar as described above, it was oven-dried at 100 ° C. for 60 seconds to prepare an infrared coloring composition film B′-3 [for Comparative Example 6].

<Infrared coloring composition solution (5)>
-Binder polymer (1) [above] 0.636 g
-Onium-based radical generator (compound described in Table 3) 0.150 g
・ Sodium tetraphenylborate [above] 0.010 g
・ Crystal violet [above] 0.020g
・ Infrared absorber (1) [above] 0.020 g
・ Fluorosurfactant (1) [above] 0.008 g
・ 2-butanone 1.091g
・ 1-methoxy-2-propanol 8.609g

II-4. Preparation of Infrared Coloring Composition Film B′-4 The following infrared coloring composition solution (6) was prepared, and the dry coating amount was 1.0 g / m ² on a polyester film having a thickness of 0.18 mm. After applying the bar as described above, it was oven-dried at 100 ° C. for 60 seconds to prepare an infrared color forming composition film B′-4 [for Comparative Example 7].

<Infrared coloring composition solution (6)>
-Binder polymer (1) [above] 0.636 g
-Onium-based radical generator (compound described in Table 3) 0.150 g
Comparative compound (1) [above] 0.030 g
・ Infrared absorber (1) [above] 0.020 g
・ Fluorosurfactant (1) [above] 0.008 g
・ 2-butanone 1.091g
・ 1-methoxy-2-propanol 8.609g

II-5. Evaluation of color developability of infrared color developing composition film The produced infrared color forming composition film was output by a Creo Trendsetter 3244VX equipped with a water-cooled 40 W infrared semiconductor laser, output 11.7 W, outer drum rotation speed 250 rpm, resolution The exposure was performed at 2400 dpi. The color development of the infrared color developing composition film was evaluated by measuring the color development immediately after exposure and after 2 hours in the dark and at room temperature. Further, the color development immediately after exposure of the color forming composition film subjected to forced aging for 3 days under the conditions of 60 ° C. and 70% humidity was also measured.
The color development was measured in the same manner as in the case of the color developing composition film. A larger value of ΔL means better color developability. The results are shown in Table 3.

  From the results shown in Table 3, it is clear that the infrared color-forming composition film of the present invention exhibits good color development and maintains high color development over time after exposure color development. Further, the storage stability is also good, and the composition film after coating can obtain high color even when exposed after forced aging.

III. Infrared color-forming curable composition III-1. Preparation of Infrared Color-Curable Curing Composition Films C-1 to C-24 The following infrared color-forming curable composition solution (7) is prepared, and the dry coating amount is 1. on a polyester film having a thickness of 0.18 mm. After applying a bar so as to be 0 g / m ² , oven drying was performed at 100 ° C. for 60 seconds to prepare infrared color-forming curable composition films C-1 to C-24 (for Examples 49 to 72).

<Infrared color-forming curable composition solution (7)>
-Binder polymer (1) [above] 0.636 g
-Onium-based radical generator (compound described in Table 4) 0.150 g
-Specific compound shown in Formula (1) (compound described in Table 4) 0.030 g
・ Infrared absorber (1) [above] 0.02 g
Polymerizable compound tris (acryloyloxyethyl) isocyanurate (NK ester A-9300, manufactured by Shin-Nakamura Chemical Co., Ltd.) 0.192 g
・ Fluorosurfactant (1) [above] 0.008 g
・ 2-butanone 1.091g
・ 1-methoxy-2-propanol 8.609g

III-2. Production of Infrared Coloring Curing Composition Film C′-1 Infrared Coloring Curing Composition Film C-1 was prepared in the same manner except that no specific compound was added in Infrared Coloring Curing Composition Film C-1. '-1 was obtained [for Comparative Example 8].

III-3. Preparation of Infrared Color-Curable Curing Composition Film C′-2 The following infrared color-forming curable composition solution (8) was prepared, and the dry coating amount was 1.0 g / m on a polyester film having a thickness of 0.18 mm. After applying the bar so as to be ² , it was oven-dried at 100 ° C. for 60 seconds to prepare an infrared color-forming curable composition film C′-2 [for Comparative Example 9].

<Infrared color-forming curable composition solution (8)>
-Binder polymer (1) [above] 0.636 g
-Onium-based radical generator (compound described in Table 4) 0.150 g
・ Sodium tetraphenylborate [above] 0.010 g
・ Crystal violet [above] 0.020g
・ Infrared absorber (1) [above] 0.020 g
Polymerizable compound tris (acryloyloxyethyl) isocyanurate (NK ester A-9300, manufactured by Shin-Nakamura Chemical Co., Ltd.) 0.192 g
・ Fluorosurfactant (1) [above] 0.008 g
・ 2-butanone 1.091g
・ 1-methoxy-2-propanol 8.609g

III-4. Preparation of Infrared Color-Curable Curing Composition Film C′-3 The following infrared color-forming curable composition solution (9) was prepared, and the dry coating amount was 1.0 g / m on a 0.18 mm thick polyester film. After applying the bar so as to be ² , it was oven dried at 100 ° C. for 60 seconds to prepare an infrared color-forming curable composition film C′-3 [for Comparative Example 10].

<Infrared color-forming curable composition solution (9)>
-Binder polymer (1) [above] 0.636 g
-Onium-based radical generator (compound described in Table 4) 0.150 g
Comparative compound (1) [above] 0.030 g
Infrared absorber (1) [above] 0.020 g
Polymerizable compound tris (acryloyloxyethyl) isocyanurate (NK ester A-9300, manufactured by Shin-Nakamura Chemical Co., Ltd.) 0.192 g
・ Fluorosurfactant (1) [above] 0.008 g
・ 2-butanone 1.091g
・ 1-methoxy-2-propanol 8.609g

III-5. Evaluation of color developability of infrared color developing curable composition film The infrared color developable curable composition film thus prepared was output by a Creo Trendsetter 3244VX equipped with a water-cooled 40 W infrared semiconductor laser, an output of 11.7 W, and an outer drum rotation speed of 250 rpm. The exposure was performed under the condition of a resolution of 2400 dpi. The color development of the infrared color-curable curable composition film was measured immediately after exposure and after 2 hours in the dark and at room temperature after exposure. In addition, the color development immediately after exposure of the color-forming curable composition film that had been forced to age for 3 days under the conditions of 60 ° C. and 70% humidity was also measured. The color development was measured in the same manner as in the case of the color developing composition film. A larger value of ΔL means better color developability. The results are shown in Table 4.

III-6. Evaluation of Sensitivity of Infrared Color-Curable Curing Composition Film The prepared infrared color-forming curable composition film was subjected to a condition of 3250 dpi with an external drum rotation speed of 250 rpm using a Crendtrend 3244VX equipped with a water-cooled 40 W infrared semiconductor laser. Exposure was performed by shaking the output value. The minimum exposure that can produce a tack-free cured film was calculated in mJ / cm ² units, and the reciprocal thereof was used as an index of sensitivity. The evaluation result is that the sensitivity of the infrared color-curable curable composition film (C′-1) obtained in Comparative Example 8 is 100, and the sensitivity of other infrared color-curable curable composition films is relative to that. did. The larger the value, the better the sensitivity. The results are shown in Table 4.

  From the results shown in Table 4, it is clear that the infrared color-curable curable composition film of the present invention exhibits good sensitivity and color developability and maintains high color development even after lapse of time after exposure color development. Further, the storage stability is also good, and the composition film after coating can obtain high color even when exposed after forced aging.

IV. On-press development printing plate IV-1. Preparation of lithographic printing plate precursors D-1 to D-24

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

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

Subsequently, nitric acid electrolysis was performed with an aqueous solution of 0.5% by mass of hydrochloric acid (containing 0.5% by mass of aluminum ions) and an electrolytic solution having a liquid temperature of 50 ° C. under the condition of an electric quantity of 50 C / dm ² when the aluminum plate was the anode. Electrochemical surface roughening treatment was carried out in the same manner as above, followed by washing with water by spraying.
Next, the plate was provided with a direct current anodic oxide film having a current density of 15 A / dm ² and a current density of 15 g / m ² using 15% by mass sulfuric acid (containing 0.5% by mass of aluminum ions) as an electrolytic solution, followed by washing with water. It dried and the support body A was produced.
Thereafter, in order to ensure the hydrophilicity of the non-image area, the support A was subjected to a silicate treatment at 60 ° C. for 10 seconds using a 2.5 mass% No. 3 sodium silicate aqueous solution, and then washed with water to obtain the support B. Got. The adhesion amount of Si was 10 mg / m ² . The centerline average roughness (Ra) of this substrate was measured using a needle having a diameter of 2 μm and found to be 0.51 μm.

(Formation of undercoat layer)
Next, on the support B, the following undercoat layer coating solution was applied so that the dry coating amount was 20 mg / m ² to prepare a support having the following undercoat layer.

<Coating liquid for undercoat layer>
-Undercoat layer compound (1) having the following structure: 0.18 g
・ Hydroxyethyliminodiacetic acid 0.10g
・ Methanol 55.24g
・ Water 6.15g

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

<Photosensitive solution (1)>
-Binder polymer (1) [above] 0.240 g
・ Infrared absorber (1) [above] 0.030 g
-Specific compound shown in Formula (1) (compound described in Table 5) 0.030 g
-Onium-based radical generator (compound described in Table 5) 0.162 g
Polymerizable compound tris (acryloyloxyethyl) isocyanurate (NK ester A-9300, manufactured by Shin-Nakamura Chemical Co., Ltd.) 0.192 g
・ Low molecular weight hydrophilic compound Tris (2-hydroxyethyl) isocyanurate 0.062g
・ Low molecular weight hydrophilic compound (1) [the following structure] 0.050 g
-Sensitizing agent Phosphonium compound (1) [the following structure] 0.055 g
・ Sensitizer Benzyl-dimethyl-octylammonium ・ PF ₆ salt 0.018g
・ Grease sensitizer
Ammonium group-containing polymer [the following structure, reduced specific viscosity 44 ml / g] 0.035 g
・ Fluorosurfactant (1) [above] 0.008 g
・ 2-butanone 1.091g
・ 1-methoxy-2-propanol 8.609g

<Microgel solution>
・ Microgel [Synthesis method below] 2.640 g
・ Distilled water 2.425g

  The structure of the low molecular weight hydrophilic compound (1), the phosphonium compound (1), and the ammonium group-containing polymer and the method for synthesizing the microgel are as follows.

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

(Formation of protective layer)
A protective layer coating solution having the following composition was further bar coated on the image recording layer, followed by oven drying at 120 ° C. for 60 seconds to form a protective layer having a dry coating amount of 0.15 g / m ^2. Original plates D-1 to D-24 (for Examples 73 to 96) were obtained.

<Protective layer coating solution>
・ Inorganic layered compound dispersion (1) 1.5 g
-Polyvinyl alcohol (Nippon Synthetic Chemical Industry Co., Ltd. CKS50, sulfonic acid modification,
Saponification degree 99 mol% or more, polymerization degree 300) 6% by mass aqueous solution 0.55 g
・ Polyvinyl alcohol (PVA-405 manufactured by Kuraray Co., Ltd.)
Degree of saponification 81.5 mol%, degree of polymerization 500) 6% by weight aqueous solution 0.03 g
・ Nippon Emulsion Co., Ltd. surfactant (Emalex 710) 1% by weight aqueous solution 0.86g
・ Ion-exchanged water 6.0g

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

IV-2. Preparation of lithographic printing plate precursor D-25 (for Example 97) After applying the following image recording layer coating liquid (2) to a support having the same undercoat layer as in the case of lithographic printing plate precursor D-1, Oven drying was performed at 82 ° C. for 90 seconds to produce an image recording layer having a dry coating amount of 1.2 g / m ² , and a lithographic printing plate precursor D-25 (for Example 97) was obtained.

<Image recording layer coating solution (2)>
-Polymer fine particle aqueous dispersion (1) [Synthesis method below] 20.0 g
・ Infrared absorber (2) [the following structure] 0.020 g
-Specific compound shown in Formula (1) (compound described in Table 5) 0.030 g
Onium-based radical generator (compound described in Table 5) 0.30 g
-Monomer having an ethylenically unsaturated group 1.50 g
SR-399 (Sartomer)
・ Mercapto-3-triazole 0.2g
-Binder polymer Byk336 (byk Chimie) 0.4g
KlucelM (Hercules) 4.8g
ELVACITE 4026 (manufactured by Ineos Acrylica)
2.5g
・ N-propanol 55.0g
・ 2-butanone 17.0g

The onium radical generator (3) in Table 5 and the compounds described by trade names in the above composition are as follows.
Onium-based radical generator (3): Irgacure 250 (4-methoxyphenyl) [4- (2-methylpropyl) phenyl] iodonium = hexafluorophosphate (75% by mass propylene carbonate solution)
SR-399: Dipentaerythritol pentaacrylate Byk 336: Modified dimethylpolysiloxane copolymer (25% by mass xylene / methoxypropyl acetate solution)
・ Klucel M: Hydroxypropyl cellulose (2% by mass aqueous solution)
ELVACITE 4026: hyperbranched polymethyl methacrylate (10% by mass 2-butanone solution)

(Synthesis of polymer fine particle aqueous dispersion (1))
A 1000 ml four-necked flask was equipped with a stirrer, thermometer, dropping funnel, nitrogen inlet tube, reflux condenser, and nitrogen gas was 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 progressed 98% or more at the stage of reaction for a total of 20 hours, and a polymer fine particle aqueous dispersion (1) having a mass ratio of PEGMA / St / AN = 10/10/80 was obtained. The particle size distribution of the 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.

IV-3. Preparation of lithographic printing plate precursor D′-1 A lithographic printing plate precursor D′-1 was obtained in the same manner except that the specific compound was not added in the lithographic printing plate precursor D-1 [for Comparative Example 11] ].

IV-4. Preparation of lithographic printing plate precursor D′-2 In lithographic printing plate precursor D-1, a lithographic printing plate precursor D-1 was prepared in the same manner except that the following photosensitive solution (2) was prepared and an image recording layer coating solution was prepared. '-2 was obtained [for Comparative Example 12]

<Photosensitive solution (2)>
-Binder polymer (1) [above] 0.240 g
・ Infrared absorber (1) [above] 0.030 g
・ Sodium tetraphenylborate [above] 0.010 g
・ Crystal violet [above] 0.020g
-Onium-based radical generator (compound described in Table 5) 0.162 g
Polymerizable compound tris (acryloyloxyethyl) isocyanurate (NK ester A-9300, manufactured by Shin-Nakamura Chemical Co., Ltd.) 0.192 g
・ Low molecular weight hydrophilic compound Tris (2-hydroxyethyl) isocyanurate 0.062g
・ Low molecular weight hydrophilic compound (1) [above] 0.050 g
-Sensitizer Phosphonium compound (1) [above] 0.055 g
・ Grease sensitizer
Benzyl-dimethyl-octylammonium PF ₆ salt 0.018 g
・ Grease sensitizer
Ammonium group-containing polymer [above structure, reduced specific viscosity 44 ml / g] 0.035 g
・ Fluorosurfactant (1) [above] 0.008 g
・ 2-butanone 1.091g
・ 1-methoxy-2-propanol 8.609g

IV-5. Preparation of lithographic printing plate precursor D′-3 In the lithographic printing plate precursor D-1, a lithographic printing plate precursor D-1 was prepared in the same manner except that the following photosensitive solution (3) was prepared and an image recording layer coating solution was prepared. '-3 was obtained [for Comparative Example 13]

<Photosensitive solution (3)>
-Binder polymer (1) [above] 0.240 g
・ Infrared absorber (1) [above] 0.030 g
Comparative compound (1) [above] 0.030 g
-Onium-based radical generator (compound described in Table 5) 0.162 g
Polymerizable compound tris (acryloyloxyethyl) isocyanurate (NK ester A-9300, manufactured by Shin-Nakamura Chemical Co., Ltd.) 0.192 g
・ Low molecular weight hydrophilic compound Tris (2-hydroxyethyl) isocyanurate 0.062g
・ Low molecular weight hydrophilic compound (1) [above] 0.050 g
-Sensitizer Phosphonium compound (1) [above] 0.055 g
・ Grease sensitizer
Benzyl-dimethyl-octylammonium PF ₆ salt 0.018 g
・ Grease sensitizer
Ammonium group-containing polymer [above structure, reduced specific viscosity 44 ml / g] 0.035 g
・ Fluorosurfactant (1) [above] 0.008 g
・ 2-butanone 1.091g
・ 1-methoxy-2-propanol 8.609g

IV-6. Evaluation of lithographic printing plate precursor (i) Color development The obtained lithographic printing plate precursor was subjected to a Trendsetter 3244VX manufactured by Creo equipped with a water-cooled 40 W infrared semiconductor laser under the conditions of an output of 11.7 W, an outer drum rotational speed of 250 rpm, and a resolution of 2400 dpi. Exposed.
Color development was measured immediately after exposure and after 2 hours in the dark and at room temperature after exposure. The color development immediately after exposure of the lithographic printing plate precursor subjected to forced aging for 3 days under the conditions of 60 ° C. and 70% humidity was also measured.
Color development was measured in the same manner as in the case of the color developing composition film. A larger value of ΔL means better color developability. The results are shown in Table 5.

(Ii) On-machine developability The obtained lithographic printing plate precursor was subjected to an external drum rotation speed of 1000 rpm, a laser output of 70%, and a resolution of 2400 dpi on Fujifilm Corporation's Luxel PLASETTER T-6000III equipped with an infrared semiconductor laser. Exposed. 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. Using Equality-2 (Fuji Film Co., Ltd.) / Tap water = 2/98 (volume ratio) dampening water and Space Color Fusion G (N) Black Ink (DIC Graphics Co., Ltd.), LITHRONE26 In the standard automatic printing start method, dampening water and ink were supplied and developed on the machine, and then 100 sheets were printed on Tokishi Art (76.5 kg) paper at a printing speed of 10,000 sheets per hour.
The number of print sheets required until the on-press development on the printing press of the unexposed portion of the image recording layer was completed and the ink was not transferred to the non-image portion was measured as on-press developability. The results are shown in Table 5.

(Iii) Printing durability After the above-described evaluation of on-press developability immediately after coating, 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. . In the evaluation results, the number of completed lithographic printing plates obtained in Comparative Example 11 was 100, and the number of completed lithographic printing plates was relative evaluation. A larger value means better printing durability. The results are shown in Table 5.

  From the results shown in Table 5, the lithographic printing plate precursor of the present invention has excellent printing performance and color developability represented by on-press developability and printing durability, and high color development is maintained over time after exposure color development. It is clear that Furthermore, the storage stability is also good, and the prepared lithographic printing plate precursor can produce high color even when exposed after forced aging.

Claims (12)

(A) A color forming composition containing a compound represented by the general formula (1), (B) a sensitizer, and (C) a binder.

(In General Formula (1), Ar ¹ , Ar ² , and Ar ³ each represents an aryl group, Ar ⁴ and Ar ⁵ each independently represent a phenyl group or a naphthyl group having an amino group at the 4-position, and R ¹ represents a hydrogen atom, an alkyl group, or an aryl group, and when R ¹ represents an aryl group, Ar ⁴ and Ar ⁵ , or Ar ⁵ and R ¹ , respectively, are bonded to each other through an oxygen atom, a nitrogen atom, or a sulfur atom. And may be linked to form a ring structure. X ⁺ represents a cation.) The color-forming composition according to claim 1, wherein the compound represented by the general formula (1) is a compound represented by the general formula (2).

(In General Formula (2), R ² , R ³ , R ⁴ , R ⁷ , R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ , R ¹² and R ¹³ are each independently a hydrogen atom, alkyl group, aryl Represents a group, a halogen atom, or OR ^20. R ² and R ³ , R ⁶ and R ⁷ , or R ¹⁰ and R ¹¹ may be linked to each other to form a ring structure.
R ⁵ and R ⁶ are each independently a hydrogen atom, an alkyl group, an aryl group, a halogen atom, or OR ²⁰ , or R ⁵ and R ⁶ are each an oxygen atom, a nitrogen atom, or a sulfur atom It is the ring structure connected through either.
R ¹⁴ , R ¹⁵ , R ¹⁶ , R ¹⁷ , R ¹⁸ , and R ¹⁹ each independently represents an alkyl group or an aryl group. R ¹⁴ and R ¹⁵ , R ¹⁶ and R ¹⁷ , or R ¹⁸ and R ¹⁹ may be linked to each other to form a ring structure.
R ²⁰ represents an alkyl group.
Ar ^{< 1 >} -Ar ^{< 3 >} and X ^<+> are synonymous with General formula (1). ) In the general formula (2), R ² , R ⁶ , and R ¹⁰ each independently represents an alkyl group or OR ²⁰ (R ²⁰ represents an alkyl group), and R ³ , R ⁴ , R ⁵ , The chromogenic composition according to claim 2, wherein R ⁷ , R ⁸ , R ⁹ , R ¹¹ , R ¹² and R ¹³ are hydrogen atoms. The color-forming composition according to claim 2 or 3, wherein, in the general formula (2), Ar ¹ , Ar ² , and Ar ³ are each independently a phenyl group or a 1-naphthyl group.   The color-forming composition according to any one of claims 1 to 4, wherein the color-forming composition further contains (D) an onium-based radical generator.   The infrared color-forming composition according to any one of claims 1 to 5, wherein the (B) sensitizer is an infrared absorbing dye.   The color-forming curable composition according to any one of claims 1 to 6, wherein the color-forming composition further contains (E) a polymerizable compound.   A lithographic printing plate precursor having an image recording layer formed from the color-forming curable composition according to claim 7 on a support.   The lithographic printing plate precursor as claimed in claim 8, wherein the image recording layer comprises a hydrophobized precursor.   The lithographic printing plate precursor according to claim 8 or 9, further comprising a protective layer on the image recording layer.   The lithographic printing plate precursor as claimed in claim 10, wherein the protective layer contains an inorganic stratiform compound.   The lithographic printing plate precursor according to any one of claims 8 to 11 is imagewise exposed and then subjected to on-press development by supplying printing ink and fountain solution on a printing press to remove non-image portions. The plate making method.