JPH11291652A - Image forming material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a positive type image forming material for suitably obtaining a lithographic printing plate having excellent image formability (sensitivity, developing latitude) by directly engraving by using an infrared laser or the like to directly engrave the plate. SOLUTION: The image forming material comprises (A) an infrared absorbent having an onium salt structure, (B) water insoluble and alkali aqueous solution soluble polymer binder, (C) an oxidizer having a reducing potential of -1.2 V (standard calomel electrode reference) or more, or (B) water insoluble and alkali developable polymer binder, and (D) an infrared absorbent having an onium salt structure having a reducing potential of -1.2 V (standard calomel electrode reference) or more.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming material, and more particularly, to a writable material such as laser light, heat generated by laser light irradiation, etc., which is suitable for use in a lithographic printing plate. The present invention relates to an infrared laser image forming material suitable for use in a so-called direct plate making lithographic printing plate which can directly make a plate using an infrared laser or the like from a digital signal of a computer or the like.

[0002]

2. Description of the Related Art Lasers have been remarkably developed in recent years. In particular, solid-state lasers and semiconductor lasers which emit infrared rays having a wavelength of 760 nm to 1200 nm have become easily available in high power and small size. These lasers are very useful as a recording light source when making a plate directly from digital data of a computer or the like. As an image forming material recordable by such an infrared laser, there is a positive recording material using a tetrahydropyranyl ester as an alkali-soluble polymer compound described in EP 703499 A1. Further, Japanese Patent Application Laid-Open No. 8-31
No. 0148 describes a positive type recording material formed by abrasion with an ultraviolet laser. However, plate materials using these image forming materials have a problem that image forming properties are significantly reduced after storage under high temperature and high humidity conditions.

In addition, a substance which has an infrared absorbing agent and an alkali dissolution inhibiting action of an alkali-soluble polymer compound and is decomposed by light or heat (hereinafter, also referred to as a "photothermal decomposition substance") may be added to the alkali-soluble polymer compound. ) Has been proposed in which an image forming material is written with an infrared laser by using a positive photosensitive composition containing the same. However, in the case of this type, the irradiation of the irradiation part is not sufficiently performed by the laser having the energy used for writing because the decomposition of the photothermal decomposition substance, in other words, the action of suppressing the alkali solubility is not sufficiently released or eliminated. A large difference in alkali solubility between the non-irradiated part and the non-irradiated part cannot be caused, and as a result, image formation is not good.

In particular, since an onium salt generally has an action (positive action) of suppressing the alkali solubility of an alkali-soluble polymer compound, an infrared absorber having an onium salt structure in a molecule can be used for an image forming material. . However, although the infrared absorber having such a structure absorbs laser light and generates heat in the portion irradiated with the laser beam, the infrared absorber itself is less decomposed and completely eliminates the action of suppressing alkali solubility. Can not. In other words, there is no significant difference in alkali solubility between the irradiated part and the non-irradiated part, and there has been a problem that a good image cannot be formed.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has as its object to directly write data based on digital data from a computer or the like using a solid-state laser or semiconductor laser that emits infrared rays. It is an object of the present invention to provide an image forming material suitable for obtaining a lithographic printing plate excellent in image forming properties (sensitivity, development latitude).

[0006]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that a compound which promotes the decomposition of an infrared absorber having an onium salt structure has an oxidizing agent of -1.2 V or more (based on a standard calomel electrode). It has been found that the use of a compound accelerates the decomposition of an infrared absorber having an onium salt structure during laser exposure. That is, the following (A), (B) and (C)
An image forming material comprising the following three components: (A) an infrared absorber having an onium salt structure, (B) a polymer binder which is insoluble in water and soluble in an aqueous alkaline solution,
(C) an oxidizing agent having a reduction potential of -1.2 V (based on a standard calomel electrode),

Further, a component having a structure having a reduction potential of -1.2 V or more (based on a standard calomel electrode) is connected to an infrared absorbing agent having an onium salt structure, ie, the component (A) and the component (A). When a compound having the component (C) in one molecule is used, the decomposition rate of the infrared absorber having an onium salt structure is further improved. That is, the following two components (B) and (D): (B) a polymer binder that is insoluble in water and soluble in an aqueous alkaline solution;
An image forming material comprising an infrared absorber having an onium salt structure of 1.2 V (based on a standard calomel electrode) or more.

In the image forming material of the present invention, the rate of decomposition of the infrared absorber having an onium salt structure contained in the photosensitive layer upon exposure can be improved, and the alkali solubility accompanying the decomposition can be improved. That is, there is a large difference in alkali solubility between the irradiated part and the non-irradiated part, and a good positive image can be formed.

At this stage, it is not clear how the oxidizing agent accelerates the decomposition of the infrared absorbing agent having an onium salt structure. However, the infrared absorbing agent having an onium salt structure has an oxidation potential of +0.3 V to +0 in a polar solvent. 0.7 V (standard calomel electrode reference (hereinafter referred to as “SCE”)), and when it is in an excited state by absorbing infrared light, if it absorbs the shortest infrared light, at least the excited state The oxidation potential becomes -1.2 V (SCE) or more. Therefore, when an oxidizing agent having a reduction potential of -1.2 V (SCE) or more coexists, electrons move from the excited infrared absorbing agent having an onium salt structure to the oxidizing agent, and the infrared absorbing agent having an onium salt structure Is presumed to be destabilized and decomposed by forced oxidation because it is cationic.

From these facts, the higher the potential difference between the electron transfer and the closer the intermolecular distance, the higher the decomposition rate. In other words, the decomposition rate is increased by using an oxidizing agent having a strong oxidizing power (an oxidizing agent having a positive reduction potential in a positive direction), or by increasing the concentration of the oxidizing agent or connecting the oxidizing agent structure to an infrared absorbing agent having an onium salt structure. Further improve. In addition, in principle, the bonding form of the oxidizing agent structure and the infrared absorbing agent, which is a method of shortening the intermolecular distance, can be either a covalent bond or an ionic bond. It is preferable to connect to an ionic bond.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The image forming material of the present invention comprises at least (A) an infrared absorbing agent having an onium salt structure,
It comprises (B) a polymer binder insoluble in water and soluble in an aqueous alkaline solution, and (C) an oxidizing agent of -1.2 V (SCE) or more, and may contain other components as necessary. Further, instead of the components (A) and (C), the reduction potential −
It is also effective to use a structure in which a structure having 1.2 V (SCE) or more is linked to an infrared absorber having an onium salt structure.

In the present invention, the term "reduction potential" refers to the use of a hydrogen electrode, a glass electrode, a quinhydrone electrode or the like as an indicator electrode in a polar solvent such as acetonitrile or methanol, and a saturated sweetpotato electrode or a silver-silver chloride electrode as a reference electrode. Is a value obtained by converting the measured value to a value for a standard calomel electrode by potentiometry using

Hereinafter, the configuration of the present invention will be described in detail.

[(A) Infrared absorber having an onium salt structure] In the present invention, the infrared absorber having an onium salt structure refers to an infrared absorber having an onium salt structure in the molecule and absorbing infrared laser light to generate heat. Dyes or pigments. Among these, a dye having an onium salt structure is preferable from the viewpoint of the scattering of the composition in the image forming material at the time of exposure by ablation being small.

Examples of the dye having an onium salt structure include known dyes such as commercially available dyes and dyes described in literatures (eg, “Dye Handbook” edited by The Society of Synthetic Organic Chemistry, 1970). Examples thereof include azo dyes, metal complex salt azo dyes, pyrazolone azo dyes, anthraquinone dyes, phthalocyanine dyes, carbonium dyes, quinone imine dyes, methine dyes, cyanine dyes, aminium dyes, diimonium dyes, and squarylium dyes.

Among these dyes, dyes whose light absorption maximum shifts to the longer wavelength side and which absorbs infrared light and near-infrared light are particularly preferable from the viewpoint of image forming properties. For example, JP-A-58-125246 and JP-A-59-125246.
No. 84356, No. 59-202829, or No. 60-
No. 78787, cyanine dyes described in JP-A-58-173696 and JP-A-58-181690,
Or methine dyes described in JP-A-58-194595, JP-A-58-112793, and JP-A-58-22.
No. 4793, No. 59-48187, No. 59-7399
No. 6, No. 60-52490 or No. 60-63744
Naphthoquinone dyes described in JP-A-5
Squarylium dyes described in JP-A-8-112792, cyanine dyes described in British Patent 434,875, U.S. Pat. No. 3,557,012, or
A diimmonium dye described in 349462, an aminium dye described in U.S. Pat. No. 3,631,147 and the like are preferably used. No. 5,156,938.
The near-infrared absorbing agent described in No. 1 is also preferably used.

Further, substituted arylbenzo (thio) pyrylium salts described in US Pat. No. 3,881,924,
JP-A-57-142645 (U.S. Pat.
7,169)), trimethinethiapyrylium salts described in JP-A-58-181051, JP-A-58-220143,
Nos. 59-41363, 59-84248, 59
No. -84249, No. 59-146063, or No. 59
Pyrylium compounds described in JP-A-146061; cyanine dyes described in JP-A-59-216146; pentamethinethiopyrylium salts described in U.S. Pat. No. 4,283,475; -13514
And the pyrylium compounds described in JP-A-5-19702 are particularly preferably used. Another particularly preferred example is a near-infrared absorbing dye described as formulas (I) and (II) in US Pat. No. 4,756,993.

Hereinafter, specific examples of the infrared absorbing agent having an onium salt structure used in the present invention (A-1 to A-56)
However, the present invention is not limited to these.

[0019]

Embedded image

[0020]

Embedded image

[0021]

Embedded image

[0022]

Embedded image

[0023]

Embedded image

[0024]

Embedded image

[0025]

Embedded image

[0026]

Embedded image

[0027]

Embedded image

[0028]

Embedded image

[0029]

Embedded image

[0030]

Embedded image

[0031]

Embedded image

[0032]

Embedded image

[0033]

Embedded image

[0034] In the structural formulas of A-1~A-56, T ^- A,
Represents a monovalent counter anion, preferably a halogen anion (F ⁻ , Cl ⁻ , Br ⁻ , I ⁻ ), a Lewis acid anion (BF ₄ ⁻ , PF ₆ ⁻ , SbCl ₆ ⁻ , ClO ₄ ⁻ ),
An alkylsulfonic acid anion and an arylsulfonic acid anion. As used herein, alkyl refers to a group having 1 carbon atom.
To 20 means a linear, branched, or cyclic alkyl group, specifically, a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group,
Octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, hexadecyl, octadecyl, eicosyl, isopropyl, isobutyl, 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, and 21-norbornyl group. Among them, those having 1 to 12 carbon atoms
More preferred are straight-chain alkyl groups, branched alkyl groups having 3 to 12 carbon atoms, and cyclic alkyl groups having 5 to 10 carbon atoms. In addition, the aryl referred to herein refers to those composed of one benzene ring, those formed by condensing two or three benzene rings, and those formed by condensing a benzene ring and a 5-membered unsaturated ring. Specific examples include a phenyl group, a naphthyl group, an anthryl group, a phenanthryl group, an indenyl group, an acenabutenyl group, and a fluorenyl group. Of these, a phenyl group and a naphthyl group are more preferred .

In the present invention, the infrared absorber having an onium salt structure is preferably added in an amount of 0.01 to 50% by weight, more preferably 0.1 to 50% by weight, based on the total solid content of the image forming material of the present invention. It is 20% by weight, more preferably 0.5 to 15% by weight. When the addition amount is less than 0.01% by weight, the sensitizing effect is not seen and the problem of image forming property is liable to occur. On the other hand, when it exceeds 50% by weight, during printing,
Non-image areas tend to be stained.

[(C) The reduction potential is -1.2 V (SCE)
The above oxidizing agent] The oxidizing agent used in the present invention is not particularly limited as long as the oxidizing agent has a reduction potential of -1.2 V (SCE) or more. Reduction potential is -1.2V (SCE)
As described above, when the infrared absorbing agent having an onium salt structure is in an excited state by absorbing infrared light, the oxidation potential of the excited state when absorbing the shortest infrared light is at least -1. .2 V (SCE) or more, at a minimum potential required for forced oxidation by transferring electrons from an infrared absorber having an onium salt structure in an excited state to an oxidizing agent, destabilizing and causing decomposition. is there. As the reduction potential increases (the reduction potential increases in the positive direction), the decomposition rate of the infrared absorbing agent having an onium salt structure increases, but when the reduction potential exceeds +0.5 V (SCE), even if no excitation occurs, Electron transfer occurs even in the ground state, which may degrade storage stability. Therefore, the reduction potential is set to (+0.5 V
(SCE) to -1.2 V (SCE)). Since the dielectric constant and rigidity of the medium in which the molecule is placed are effective due to the nature of electron transfer, it is clearly defined only by the potential. From a general point of view, (+0.3
V (SCE) to -1.0 V (SCE)).

The reduction potential preferably used in the present invention is-
As an oxidizing agent of 1.2 V (SCE) or more, 2,3-di
Chloro-5,6-dicyano-1,4-benzoquinone
(0.51 V), 2,3-dicyano-1,4-benzoxy
Non, tetrabromo-1,4-benzoquinone (0.0
V), tetrachloro-1,4-benzoquinone (0.01
V), trichloro-1,4-benzoquinone (-0.08
V), 2,5-dichloro-1,4-benzoquinone (-
0.18 V), 2,6-dichloro-1,4-benzoquino
(-0.18V), chloro-1,4-benzoquinone
(-0.34 V), iodo-1,4-benzoquinone,
2,5-dimethyl-1,4-benzoquinone (-0.67
V), 2,6-dimethyl-1,4-benzoquinone, 2-
Methyl-5-isopropyl-1,4-benzoquinone,
Limethyl-1,4-benzoquinone, 2,6-di-t-butyl
Tyl-1,4-benzoquinone, tetramethyl-1,4-
Benzoquinone, methyl-1,4-benzoquinone (-0.
58V), 2,5-dihydroxy-1,4-benzoquino
, Such as 1,4-benzoquinone (-0.51 V)
4-benzoquinone and its derivatives, 4-nitro-1,2
-Benzoquinone, 4-benzoyl-1,2-benzoquino
, 4-formyl-1,2-benzoquinone, 4-acetyl
1,2-benzoquinone, tetrachloro-1,2-be
Nzoquinone, tetrabromo-1,2-benzoquinone, 4
-T-butyl-1,2-benzoquinone, 3,5-di-t
-Butyl-1,2-benzoquinone, 3,4,5-trime
Tyl-1,2-benzoquinone, tetramethyl-1,2-
1,2-benzoquinones such as benzoquinone and derivatives thereof
Body, 1,4-naphthoquinone (-0.71V), 2-hydr
Roxy-1,4-naphthoquinone (-0.64V), 5-
Hydroxy-1,4-naphthoquinone (-0.52V),
1,2-naphthoquinone (-0.56), 9,10-anne
Traquinone (-0.94V), 1-hydroxy-9,1
0-anthraquinone (-0.77V), 1,8-dihydro
Roxy-9,10-anthraquinone (-0.64V),
1,2-anthraquinone, 9,10-phenanthrene
Non (-0.66V), 2,4,7-trinitro-9,
10-phenanthrenequinone (-0.098 V), 3,
6-dinitro-9,10-phenanthrenequinone (-
0.15 V), 2,7-dinitro-9,10-phenane
Trenquinone (-0.20V), 2,5-dinitro-
9,10-phenanthrenequinone (-0.27 V),
1,2-phenanthrenequinone, 3,3 ', 5,5'-
Tetrachloro-4,4'-diphenoquinone, 4,4'-
Diphenoquinone, 3,3 ', 5,5'-tetramethyl-
4,4'-diphenoquinone, 3,3 ', 5,5'-tet
Laisopropyl-4,4'-diphenoquinone, 3,
3 ', 5,5'-tetra-s-butyl-4,4'-diff
Enoquinone, 3,3 ', 5,5'-tetra-t-butyl
-4,4'-diphenoquinone, 5,12-naphthacene
Quinone derivatives such as nonone, semi-quino of methyl viologen
, Ethylquinolone semiquinone, benzylviologen
Pyridinium salts, such as semiquinone, nitrobenzene,
Examples thereof include nitro compounds such as dinitrobenzene.
(The contents in parentheses are described in TK Mukherjee, J. Mol.
Phys. Chem. , 71, 2277 (1967),
M. E. FIG. Peover, J .; Chem. Soc. , 45
40 (1962). )
Other, Fe ³⁺Complex, Ce⁴⁺Metal complex type oxidation such as complex
Agent, trihalomethyltriazine, diazonium salt, iodine
Oxidizing power of sodium, sulfonium and phosphonium salts
Are preferred.

In the present invention, the reduction potential is -1.2 V
The oxidizing agent (SCE) or more is preferably added in an amount of 0.01 to 50% by weight, more preferably 0.1 to 20% by weight, and still more preferably 0 to 50% by weight based on the total solid content of the image forming material of the present invention. 0.5 to 15% by weight. The amount added is 0.01
When the content is less than 5% by weight, it is difficult to obtain an image.
If the content exceeds 0% by weight, stains tend to occur in the non-image area during printing.

[(D) Infrared absorbent having an onium salt structure having a reduction potential of -1.2 V (SCE) or more] Infrared absorption having an onium salt structure having a reduction potential of -1.2 V (SCE) or more used in the present invention The agent has a reduction potential of -1.2.
A portion having a structure of V (SCE) or more (hereinafter, referred to as “oxidant portion”) is used as an infrared absorber having an onium salt structure (hereinafter, referred to as “infrared absorber core”). Although they are linked by an ionic bond or a covalent bond, ionic bonds, that is, those in which an oxidizing agent site is linked as a counter anion, are preferable because they can be easily synthesized.

Examples of the oxidizing agent site include those having the same structure as that of the oxidizing agent having a reduction potential of -1.2 V (SCE) or higher (C). Examples of the mother nucleus include a site having the same structure as that of the infrared absorber having the onium salt structure.

The reduction potential at the oxidizing agent site is-
1.2V (SCE) means that when the infrared absorbent core is in an excited state by absorbing infrared light, the oxidation potential in the excited state when absorbing the shortest infrared light is at least −1. 2V
(SCE) or higher, the minimum potential required for forced oxidation by transferring electrons from the infrared absorber core having an excited onium salt structure to the oxidizing agent site, destabilizing and causing decomposition. It is. The larger this reduction potential is (the larger the reduction potential is in the positive direction),
Although the decomposition rate of the infrared absorbent mother nucleus having an onium salt structure is increased, if it exceeds +0.5 V (SCE), electron transfer may occur even in the ground state without excitation, and storage stability may be degraded. Therefore, the reduction potential is set to (+0.5 V
(SCE) to -1.2 V (SCE)). Since the dielectric constant and rigidity of the medium in which the molecule is placed are effective due to the nature of electron transfer, it is clearly defined only by the potential. From a general point of view, (+0.3
V (SCE) to -1.0 V (SCE)).

In the present invention, the reduction potential is -1.2 V (S
CE) The infrared absorber having the above onium salt structure,
The oxidizing agent moiety is preferably linked to the infrared absorbent core as a counter anion. Examples of the oxidizing agent site counter anion include 9,10-anthraquinone-1-sulfonate,
9,10-anthraquinone-2-sulfonate, 9.1
0-anthraquinone-1,5-disulfonate, 9.1
0-anthraquinone-1,8-disulfonate, 9.1
0-anthraquinone-2,6-disulfonate, 1,2
-Sulfonates such as naphthoquinone-4-sulfonate and 2,4-dinitrobenzenesulfonate (all-
1.2 V (SCE) or more) and a sulfonate anion (sulfonate group: —SO ₃ θ) were linked to the specific examples of the oxidizing agent having the (C) reduction potential of −1.2 V (SCE) or more. And the like.

Preferred specific examples of the infrared absorber having an onium salt structure having a reduction potential of -1.2 V (SCE) or more preferably used in the present invention are as follows: -1) to (A'-3)
9)) and the following oxidizing agent site counter anions ((D-1) to (D
-14)), and a compound ionically bonded thereto, and more preferably the following ((Y-1) to (Y-1)).
(Y-17)). However, the present invention is not limited to these.

[0044]

Embedded image

[0045]

Embedded image

[0046]

Embedded image

[0047]

Embedded image

[0048]

Embedded image

[0049]

Embedded image

[0050]

Embedded image

[0051]

Embedded image

[0052]

Embedded image

[0053]

Embedded image

[0054]

Embedded image

[0055]

Embedded image

[0056]

Embedded image

[0057]

Embedded image

[0058]

Embedded image

[0059]

Embedded image

[0060]

Embedded image

[0061]

Embedded image

[0062]

Embedded image

Next, the reduction potential used in the present invention-1.
A synthesis example of an infrared absorber having an onium salt structure of 2 V (SCE) or more will be described, but the present invention is not limited thereto.

Reduction potential -1.2 V used in the present invention
(SCE) As shown in the following reaction formula, an infrared absorber having an onium salt structure above has an infrared absorbing mother nucleus paired with a cation (Dye) as shown in the following reaction formula.
⁺⁾ And terminal connection portion counter anion (Zy ^-) becomes from a,
When the oxidizing agent having a reduction potential of -1.2 V (SCE) or more is composed of an oxidizing agent site counter anion (Ox ⁻ ) and a monovalent metal counter cation (Zy ′ ⁺ ), it can be easily obtained by a salt exchange reaction. it can. Examples of the monovalent metal counter cation here include a sodium ion, a potassium ion, and a lithium ion. Further, a general method for producing an infrared absorber having an onium salt structure to be used is a method described in (A) the publication cited in the publication cited above for the infrared absorber having an onium salt structure, and has a reduction potential of-. 1.2V
Regarding the counter anion having an oxidizing agent site (SCE) or higher, commercially available counter anions (for example, “1,2” manufactured by Aldrich)
-Naphthoquinone-4-sulfonic acid sodium salt "," Anthraquinone-2-sulfonic acid sodium salt-hydrate "
Etc.) may be used.

[0065] ^{Dye + Zy - + Zy '+} Ox - → D
^{ye + Ox - + Zy '+} Zy -

Synthesis Example of Compound Y-1 YA (0.1 mol) and methanol (600 ml)
Into a beaker, R-2 (0.5mol / 600m
The aqueous solution of 1) was added and stirred for 30 minutes. The reaction solution was filtered, and the precipitated crystals were collected by filtration. Thereafter, the crystals were put into a beaker together with methanol (600 ml),
An aqueous solution of R-1 (0.5 mol / 600 ml) was added,
Stir for 30 minutes. The reaction solution was filtered, and the precipitated crystals were collected by filtration. Thereafter, the crystals were washed with a 3/7 mixed solution of methanol / water to obtain Y-1 in a yield of 95%. The structure of Y-1 was confirmed by mass spectrometry, ¹ H-NMR, and infrared absorption spectrum. The synthetic route is schematically shown below.

[0067]

Embedded image

Synthesis Example of Compound Y-2 YA (0.1 mol) and methanol (600 ml)
Into a beaker, R-2 (0.5mol / 600m
The aqueous solution of 1) was added and stirred for 30 minutes. The reaction solution was filtered, and the precipitated crystals were collected by filtration. Thereafter, the crystals were put into a beaker together with methanol (600 ml),
An aqueous solution of R-2 (0.5 mol / 600 ml) was added,
Stir for 30 minutes. The reaction solution was filtered, and the precipitated crystals were collected by filtration. Thereafter, the crystals were washed with a 3/7 mixed solution of methanol / water to obtain Y-2 in a yield of 95%. The structure of Y-2 was confirmed by mass spectrometry, ¹ H-NMR, and infrared absorption spectrum. The synthetic route is schematically shown below.

[0069]

Embedded image

Further, for Y-3 to Y-17, Y-
A method similar to the above, except that A, R-1, and R-2 are changed,
Can be easily manufactured.

In the present invention, the reduction potential is -1.2 V (S
CE) The infrared absorber having the above onium salt structure,
0.01 to 5 based on the total solid content of the image forming material of the present invention.
0% by weight, more preferably 0.1% by weight.
1 to 20% by weight, more preferably 0.5 to 15% by weight
It is. If the addition amount is less than 0.01% by weight, it is difficult to obtain an image, while if it exceeds 50% by weight, the non-image area tends to be stained during printing.

[(B) Polymer Binder Insoluble in Water and Soluble in Alkaline Aqueous Solution] The polymer binder insoluble in water and soluble in an aqueous alkali solution used in the present invention has a structure in its main chain and / or side chain. A polymer containing an acidic group,
And mixtures thereof. Among them, the following (a-1)
Those having an acidic group of (a-6) in the structure of the main chain and / or the side chain are preferred from the viewpoint of solubility in an alkaline developer.

(A-1) Phenol group (-Ar-O
H) (a-2) sulfonamide group _{(-SO 2 NH-R) (} a-3) substituted sulfonamide-based acid group (hereinafter, referred to as "active imide _{group".) (-SO 2 NHCOR, -SO} 2 NHSO ₂ R, -CO
_{NHSO 2 R) (a-4} ) a carboxylic acid group _{(-CO 2 H) (a-} 5) a sulfonic acid group _{(-SO 3 H) (a-} 6) phosphoric acid group (-OPO ₃ H ₂₎

In (a-1) to (a-6), Ar represents a divalent aryl linking group which may have a substituent;
Represents a hydrocarbon group which may have a substituent.

Among the polymer binders (a-1) to (a-6) having an acidic group, which are water-insoluble and soluble in an aqueous alkaline solution, (a-1) a phenol group and (a-2) a sulfonamide group And (a-3) a water-insoluble and aqueous alkali-soluble polymer binder having an active imide group is preferable, and (a-1) a water-insoluble and aqueous alkali-soluble polymer binder having a phenol group is preferably It is further preferable in terms of solubility in an alkaline developer, inking property during printing, and printing durability. Furthermore, (a-1)
It has a phenol group and has (a) a part of the main chain and / or
Copolymers having acidic groups of -1) to (a-3) are also preferred from the viewpoint of development latitude.

(A-1) Examples of the polymer binder having a phenolic hydroxyl group, which is insoluble in water and soluble in an aqueous alkali solution, include phenol formaldehyde resin and m-
Cresol formaldehyde resin, p-cresol formaldehyde resin, m- / p-mixed cresol formaldehyde resin, phenol / cresol (m-, p-,
Or a mixture of m- / p-), a novolak resin such as a mixed formaldehyde resin, and a pyrogallol acetone resin. As the polymer binder having a phenolic hydroxyl group and being water-insoluble and soluble in an aqueous alkali solution, a polymer binder having a phenolic hydroxyl group in a side chain and soluble in an aqueous alkali solution can be used. As the high molecular compound having a phenolic hydroxyl group in the side chain, a polymerizable monomer composed of a low molecular compound having at least one unsaturated bond capable of polymerizing with the phenolic hydroxyl group may be homopolymerized, or another polymerizable monomer may be used. Examples include a polymer compound obtained by copolymerizing a monomer. Examples of the polymerizable monomer having a phenolic hydroxyl group include acrylamide, methacrylamide, acrylate, methacrylate or hydroxystyrene having a phenolic hydroxyl group, and specifically, N- (2-hydroxyphenyl) acrylamide, N- (3-hydroxyphenyl) acrylamide, N- (4-hydroxyphenyl) acrylamide, N- (2-hydroxyphenyl)
Methacrylamide, N- (3-hydroxyphenyl) methacrylamide, N- (4-hydroxyphenyl) methacrylamide, o-hydroxyphenyl acrylate,
m-hydroxyphenyl acrylate, p-hydroxyphenyl acrylate, o-hydroxyphenyl methacrylate, m-hydroxyphenyl methacrylate, p
-Hydroxyphenyl methacrylate, o-hydroxystyrene, m-hydroxystyrene, p-hydroxystyrene, 2- (2-hydroxyphenyl) ethyl acrylate, 2- (3-hydroxyphenyl) ethyl acrylate, 2- (4-hydroxyphenyl) Ethyl acrylate, 2- (2-hydroxyphenyl) ethyl methacrylate, 2- (3-hydroxyphenyl) ethyl methacrylate, 2- (4-hydroxyphenyl) ethyl methacrylate, and the like can be preferably used. These resins having a phenolic hydroxyl group may be used alone or in combination of two or more. Further, as described in U.S. Pat. No. 4,123,279, a condensate of phenol having a C3-8 alkyl group as a substituent and formaldehyde, such as t-butylphenol formaldehyde resin and octylphenol formaldehyde resin. May be used in combination.

(A-2) As a water-insoluble and alkaline aqueous solution-soluble polymer binder having a sulfonamide group, a polymerizable monomer having a sulfonamide group is homopolymerized, or another polymerizable monomer is used as the monomer. Examples thereof include polymer compounds obtained by copolymerization. Examples of the polymerizable monomer having a sulfonamide group include, in one molecule, at least one sulfonamide group —NH—SO ₂ — in which at least one hydrogen atom is bonded to a nitrogen atom, and at least one polymerizable unsaturated bond. And a polymerizable monomer composed of a low-molecular compound. Among them, a low-molecular compound having an acryloyl group, an allyl group, or a vinyloxy group and a substituted or monosubstituted aminosulfonyl group or a substituted sulfonylimino group is preferable. Examples of such compounds include compounds represented by the following general formulas (1) to (5).

[0078]

Embedded image

In the formula, X ¹ and X ² each represent -O- or-
NR ²⁷ -is shown. R ²¹ and R ²⁴ each represent a hydrogen atom or-
Represents CH ₃ . ^{R 22, R 25, R 29} , R 32, R 36 are each a substituent having optionally an alkylene group having 1 to 12 carbon atoms, cycloalkylene group, arylene group, or aralkylene group. R ²³ , R ²⁷ and R ³³ each represent a hydrogen atom, an alkyl group having 1 to 12 carbon atoms which may have a substituent, a cycloalkyl group, an aryl group or an aralkyl group. R ²⁶ and R ³⁷ each represent an optionally substituted alkyl group having 1 to 12 carbon atoms, a cycloalkyl group, an aryl group, or an aralkyl group. R ²⁸ , R ³⁰ , R
³⁴ represents a hydrogen atom or -CH _3. R ³¹ and R ³⁵ each have a single bond or a carbon number of 1 to 12 which may have a substituent.
Represents an alkylene group, a cycloalkylene group, an arylene group or an aralkylene group. Y ¹ and Y ² each represent a single bond or —CO—.

Specifically, m-aminosulfonylphenyl methacrylate, N- (p-aminosulfonylphenyl) methacrylamide, N- (p-aminosulfonylphenyl) acrylamide and the like can be preferably used.

(A-3) A water-insoluble and aqueous alkali-soluble polymer binder having an active imide group has an active imide group represented by the following formula in the molecule. Is a homopolymerization of a polymerizable monomer composed of a low-molecular compound having at least one active imino group represented by the following formula and one or more polymerizable unsaturated bonds in one molecule, or another polymerization of the monomer. And a polymer compound obtained by copolymerizing a hydrophilic monomer.

[0082]

Embedded image

As such a compound, specifically,
N- (p-toluenesulfonyl) methacrylamide, N
-(P-Toluenesulfonyl) acrylamide and the like can be suitably used.

Similarly, the (a-4) water-insoluble and aqueous alkali-soluble polymer binder having a carboxylic acid group includes, for example, one or more carboxylic acid groups and polymerizable unsaturated bonds in each molecule. Examples of the polymer having a (a-5) sulfonic acid group as a water-insoluble and alkali-soluble polymer binder in which a polymer having a compound as a main monomer is a sulfonic acid group and a polymerizable unsaturated bond. A polymer having a compound having at least one in each molecule as a main monomer; and (a-6) a water-insoluble and alkaline polymer-soluble polymer binder having a phosphate group, for example, a phosphate group And a polymer having a compound having at least one polymerizable unsaturated bond in the molecule as a main monomer.

The polymer binder in the present invention, which is insoluble in water and soluble in an aqueous alkali solution, comprises the aforementioned (a-1)
The monomer having an acidic group of (a-6) does not need to be one kind, and two or more kinds of monomers having the same acidic group or two or more kinds of monomers having different acidic groups are copolymerized. Those can also be used.

When the monomers having acidic groups (a-1) to (a-6) are copolymerized, the blending ratio of these components is preferably in the range of 50:50 to 5:95, More preferably, it is in the range of 40:60 to 10:90.

In the present invention, (a-1) to (a-6)
In the case of a copolymer of a monomer having an acidic group of (i) and another polymerizable monomer, the monomer imparting alkali water solubility is preferably contained in an amount of 10 mol% or more, more preferably 20 mol% or more. . When the amount of the copolymer component is less than 10 mol%, alkali solubility tends to be insufficient, and the effect of improving development latitude may not be sufficiently achieved.

As the other copolymerizable monomer component to be copolymerized with the monomer having an acidic group (a-1) to (a-6), for example, the following monomers (1) to (12) may be used. However, the present invention is not limited to these. (1) Acrylic esters having an aliphatic hydroxyl group, such as 2-hydroxyethyl acrylate or 2-hydroxyethyl methacrylate, and methacrylic esters. (2) Methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, amyl acrylate, hexyl acrylate, octyl acrylate, benzyl acrylate, 2-chloroethyl acrylate, glycidyl acrylate, N-dimethylaminoethyl Alkyl acrylates such as acrylates; (3) Methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, amyl methacrylate, hexyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, 2-chloroethyl methacrylate, glycidyl methacrylate, N-dimethylaminoethyl Alkyl methacrylates such as methacrylate. (4) acrylamide, methacrylamide, N-methylolacrylamide, N-ethylacrylamide, N-
Hexyl methacrylamide, N-cyclohexyl acrylamide, N-hydroxyethyl acrylamide, N-
Acrylamide or methacrylamide such as phenylacrylamide, N-nitrophenylacrylamide, and N-ethyl-N-phenylacrylamide. (5) Vinyl ethers such as ethyl vinyl ether, 2-chloroethyl vinyl ether, hydroxyethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, octyl vinyl ether, and phenyl vinyl ether.

(6) Vinyl esters such as vinyl acetate, vinyl chloroacetate, vinyl butyrate and vinyl benzoate. (7) Styrenes such as styrene, α-methylstyrene, methylstyrene, and chloromethylstyrene. (8) Vinyl ketones such as methyl vinyl ketone, ethyl vinyl ketone, propyl vinyl ketone, and phenyl vinyl ketone. (9) Olefins such as ethylene, propylene, isobutylene, butadiene and isoprene. (10) N-vinylpyrrolidone, N-vinylcarbazole, 4-vinylpyridine, acrylonitrile, methacrylonitrile and the like. (11) Unsaturated imides such as maleimide, N-acryloylacrylamide, N-acetylmethacrylamide, N-propionylmethacrylamide, N- (p-chlorobenzoyl) methacrylamide. (12) acrylic acid, methacrylic acid, maleic anhydride,
Unsaturated carboxylic acids such as itaconic acid;

As the copolymerization method, a conventionally known random copolymerization method, graft copolymerization method, block polymerization method, or the like can be used.

In the present invention, the polymer binder insoluble in water and soluble in an aqueous alkali solution is selected from the above-mentioned (a-1) to (a
In the case of the homopolymer or copolymer of the monomer containing an acidic group of -6), those having a weight average molecular weight of 2,000 or more and a number average molecular weight of 500 or more are preferable. More preferably, the weight average molecular weight is 5,000 to 300,000, the number average molecular weight is 800 to 250,000, and the degree of dispersion (weight average molecular weight / number average molecular weight) is 1.1 to 10. In the present invention, when the polymer binder insoluble in water and soluble in an aqueous alkaline solution is a resin such as a phenol formaldehyde resin or a cresol aldehyde resin, the number average molecular weight is 500 to 20,000 and the number average molecular weight is 200 to 10,000. Are preferred.

These polymer binders which are insoluble in water and soluble in an aqueous alkali solution may be used alone or in combination of two or more. 30 to 99% by weight, preferably 30 to 99% by weight, based on the total solid content of the image forming material. It is used in an amount of 40 to 95% by weight, particularly preferably 50 to 90% by weight. If the amount of the polymer binder insoluble in water and soluble in an aqueous alkaline solution is less than 30% by weight, the durability of the recording layer is deteriorated, and if it exceeds 99% by weight, both sensitivity and durability are not preferred.

[Other Components] To the image-forming material of the present invention, other dyes, pigments and the like may be added for the purpose of further improving the image-forming properties (the infrared absorbing agent having the onium salt structure, The reduction potential -1.2 V (SCE)
The above oxidizing agent and the above-mentioned infrared absorbing agent having an onium salt structure having a reduction potential of -1.2 V (SCE) or more may be added to the same layer, or another layer may be provided and added as a material for the layer. Is also good. ). As for the dyes, the conventionally known dyes such as azo dyes, metal complex salt azo dyes, pyrazolone azo dyes, anthraquinone dyes, phthalocyanine dyes, carbonium dyes, quinone imine dyes, methine dyes, cyanine dyes, aminium dyes, diimonium dyes, squarylium Dyes and the like that are commercially available and described in a literature (“Dye Handbook”, edited by The Society of Synthetic Organic Chemistry, 1970) can be used. As the pigments, conventionally known commercially available pigment and color index (CI) handbook, “Latest Pigment Handbook” (edited by Japan Pigment Technical Association, 1977), “Latest Pigment Application Technology” (C
MC Publishing, 1986), "Printing ink technology" CMC
Published in 1984) can be used. For example, black pigments, yellow pigments, orange pigments, brown pigments, red pigments, purple pigments, blue pigments, green pigments, fluorescent pigments, metal powder pigments, and other polymer-bound dyes can be used. Specifically, insoluble azo pigments, azo lake pigments, condensed azo pigments, chelated azo pigments, phthalocyanine pigments, anthraquinone pigments, perylene and perinone pigments, thioindigo pigments, quinacridone pigments, dioxazine pigments, isoindolinone pigments And quinophthalone pigments, dyed lake pigments, azine pigments, nitroso pigments, nitro pigments, natural pigments, fluorescent pigments, inorganic pigments, carbon black and the like. Among these dyes and pigments, those that absorb infrared light or near infrared light are particularly preferable. Further, two or more dyes and pigments may be used in combination.

Various additives can be added to the image forming material of the present invention. For example, onium salts, aromatic sulfone compounds, aromatic sulfonate compounds, and the like act as a thermally decomposable substance, and thus the addition of such a substance can improve the dissolution inhibiting property of the image area in a developing solution. It is preferred.

Examples of the onium salts include diazonium salts, ammonium salts, phosphonium salts, iodonium salts, sulfonium salts, selenonium salts, arsonium salts and the like. Suitable onium salts for use in the present invention include, for example, S.I. I. Schles
inger, Photogr. Sci. Eng. , 1
8, 387 (1974); S. Bal et a
1, Polymer, 21, 423 (1980), or diazonium salts described in JP-A-5-158230, U.S. Pat. Nos. 4,069,055 and 4,06.
Ammonium salts described in JP-A-9,056 or JP-A-3-140140; C. Necker et a
1, Macromolecules, 17, 2468
(1984), C.I. S. Wen et al, Teh,
Proc. Conf. Rad. CuringASIA,
p478 Tokyo, Oct (1988), U.S. Pat. No. 4,069,055 or 4,069,056; V. Crivello
et al, Macromorecules, 10
(6), 1307 (1977), Chem. & En
g. News, Nov .; 28, p31 (1988), EP 104,143, US Patent 339,049.
Iodonium salts described in JP-A No. 410,201, JP-A-2-150848, or JP-A-2-296514; V. Crivello et al,
Polymer J. J. 17, 73 (1985);
V. Crivello et al. J. Org. Che
m. 43, 3055 (1978); R. Watt
et al, J.A. Polymer Sci. , Pol
ymer Chem. Ed. , 22, 1789 (198
4). V. Crivello etal, Poly
mer Bull. , 14, 279 (1985);
V. Crivello et al, Macromor
ecules, 14 (5), 1141 (1981),
J. V. Crivello et al, J. Mol. Poly
mer Sci. , Polymer Chem. E
d. , 17, 2877 (1979), EP 37
No. 0,693, No. 233,567, No. 297,443
No. 297,442, U.S. Pat. No. 4,933,37.
7, 3,902,114, 410,201,
339,049, 4,760,013, 4,
Nos. 7,34,444 and 2,833,827, German Patent Nos. 2,904,626, 3,604,580, and 3,604,581.
J. V. Crivello et al, Macrom
orecules, 10 (6), 1307 (197
7) or J. V. Crivello et al.
Polymer Sci. , Polymer Che
m. Ed. , 17, 1047 (1979); S. Wen etal, Teh, Pr
oc. Conf. Rad. Curing ASIA, p
478 Tokyo, Oct (1988).

The counter ions of the onium salt include tetrafluoroboric acid, hexafluorophosphoric acid, triisopropylnaphthalenesulfonic acid, 5-nitro-o-toluenesulfonic acid,
-Sulfosalicylic acid, 2,5-dimethylbenzenesulfonic acid, 2,4,6-trimethylbenzenesulfonic acid, 2
-Nitrobenzenesulfonic acid, 3-chlorobenzenesulfonic acid, 3-bromobenzenesulfonic acid, 2-fluorocaprylnaphthalenesulfonic acid, dodecylbenzenesulfonic acid, 1-naphthol-5-sulfonic acid, 2-methoxy-4-hydroxy-5- Benzoyl-benzenesulfonic acid, paratoluenesulfonic acid and the like can be mentioned. Among them, alkyl aromatic sulfonic acids such as hexafluorophosphoric acid, triisopropylnaphthalenesulfonic acid and 2,5-dimethylbenzenesulfonic acid are particularly preferable.

The amount of the onium salt additive is preferably 1 to 50% by weight, more preferably 5 to 30% by weight, particularly preferably 10 to 30% by weight. In the present invention, the additive and the binder are preferably contained in the same layer.

For the purpose of further improving the sensitivity, cyclic acid anhydrides, phenols and organic acids can be added. As the cyclic acid anhydride, US Pat. No. 4,115,
No. 128, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, 3,
6-endooxy-Δ ⁴ -tetrahydrophthalic anhydride,
Tetrachlorophthalic anhydride, maleic anhydride, chloromaleic anhydride, α-phenylmaleic anhydride, succinic anhydride, pyromellitic anhydride and the like can be used. Examples of phenols include bisphenol A, p-nitrophenol, p-ethoxyphenol, 2,4,4'-trihydroxybenzophenone, 2,3,4-trihydroxybenzophenone, 4-hydroxybenzophenone,
4 ', 4 "-trihydroxytriphenylmethane, 4,
4 ', 3 ", 4"-tetrahydroxy-3,5,3',
5'-tetramethyltriphenylmethane and the like. Further, as the organic acids, JP-A-60-88942
Sulfonic acids, sulfinic acids, alkyl sulfates, and the like described in JP-A-2-96755 and JP-A-2-96755.
Examples thereof include phosphonic acids, phosphoric esters, and carboxylic acids. Specific examples include p-toluenesulfonic acid, dodecylbenzenesulfonic acid, p-toluenesulfinic acid, ethyl sulfate, phenylphosphonic acid, phenylphosphinic acid, and phenyl phosphate. Diphenyl phosphate, benzoic acid, isophthalic acid, adipic acid, p-toluic acid, 3,4-dimethoxybenzoic acid, phthalic acid, terephthalic acid, 4-cyclohexene-1,2-dicarboxylic acid, erucic acid, lauric acid, n-Undecanoic acid, ascorbic acid and the like.

The proportion of the cyclic acid anhydride, phenols and organic acids in the printing plate material is 0.05 to 20.
% By weight, more preferably 0.1 to 15% by weight, particularly preferably 0.1 to 10% by weight.

The image forming material of the present invention includes:
In order to improve the stability of processing under development conditions, Japanese Patent Application Laid-Open Nos. 62-251740 and 3-208514
Non-ionic surfactants described in JP-A-59-121044, JP-A-4-13149.
An amphoteric surfactant such as that described in JP-A No. 2-211 can be added. Specific examples of the nonionic surfactant include sorbitan tristearate, sorbitan monopalmitate, sorbitan triolate, monoglyceride stearic acid, and polyoxyethylene nonyl phenyl ether. Specific examples of the surfactant include alkyl di (aminoethyl) glycine, alkyl polyaminoethyl glycine hydrochloride, 2-alkyl-N-carboxyethyl-N-hydroxyethylimidazolinium betaine and N-tetradecyl-N, N-betaine. Type (for example,
Trade name “Amogen K”: manufactured by Dai-ichi Kogyo Co., Ltd.) and the like.

The proportion of the nonionic surfactant and amphoteric surfactant in the printing plate material is preferably 0.05 to 15% by weight, more preferably 0.1 to 5% by weight.

In the image forming material of the present invention, a printing-out agent for obtaining a visible image immediately after heating by exposure,
Dyes and pigments as image colorants can be added.
Representative examples of the printing-out agent include a combination of a compound that releases an acid by heating upon exposure (photoacid releasing agent) and an organic dye that can form a salt. In particular,
Combinations of o-naphthoquinonediazide-4-sulfonic acid halogenide and salt-forming organic dyes described in JP-A-50-36209 and JP-A-53-8128, and JP-A-53-36223, 54-74728, 6
No. 0-3626, No. 61-143748, No. 61-1
Combinations of trihalomethyl compounds and salt-forming organic dyes described in JP-A-51644 and JP-A-63-58440 can be exemplified. Such trihalomethyl compounds include oxazole-based compounds and triazine-based compounds, both of which have excellent temporal stability and give clear print-out images.

As the colorant for the image, other dyes can be used in addition to the above-mentioned salt-forming organic dyes. Suitable dyes, including salt-forming organic dyes, include oil-soluble dyes and basic dyes. Specifically, Oil Yellow # 101, Oil Yellow # 103, Oil Pink #
312, oil green BG, oil blue BOS, oil blue # 603, oil black BY, oil black BS, oil black T-505 (all manufactured by Orient Chemical Industry Co., Ltd.), Victoria Pure Blue, crystal violet (CI42555), methyl Violet (CI42535), ethyl violet, rhodamine B (CI145170B), malachite green (CI42000), methylene blue (CI5201)
5) and the like. Further, Japanese Patent Application Laid-Open No.
The dyes described in JP 93247 A are particularly preferred. These dyes are used in an amount of 0.1 to the total solid content of the printing plate material.
It can be added to the printing plate material in a proportion of from 01 to 10% by weight, preferably from 0.1 to 3% by weight.

Also, an epoxy compound, a vinyl ether compound, a phenol compound having a hydroxymethyl group or an alkoxymethyl group described in Japanese Patent Application No. 7-18120, and an alkali dissolution inhibiting effect described in Japanese Patent Application No. 9-328937. Adding a cross-linking compound that enhances
Burning after exposure and development is preferred in that printing durability is improved.

Further, a plasticizer may be added to the image forming material of the present invention, if necessary, for imparting flexibility to the coating film. For example, butylphthalyl, polyethylene glycol, tributyl citrate, diethyl phthalate, dibutyl phthalate, dihexyl phthalate, dioctyl phthalate, tricresyl phosphate, tributyl phosphate,
An oligomer or polymer of trioctyl phosphate, tetrahydrofurfuryl oleate, acrylic acid or methacrylic acid, or the like is used.

Further, in the image forming material of the present invention, a surfactant for improving coating properties, for example, JP-A-62-1
A fluorine-based surfactant as described in JP-A-70950 can be added. The preferred addition amount is 0.01 to 1% by weight of the total printing plate material, more preferably 0.1 to 1% by weight.
0.5 to 0.5% by weight.

[Lithographic printing plate] The image forming material of the present invention comprises:
It is suitable for use in the form of a lithographic printing plate, but is not limited thereto. Hereinafter, a general method for producing a lithographic printing plate will be described. A lithographic printing plate is usually produced by dissolving each of the above-mentioned components in a solvent and coating the solution on a suitable support. As the solvent used herein, ethylene dichloride, cyclohexanone, methyl ethyl ketone, methanol, ethanol, propanol, ethylene glycol monomethyl ether, 1-methoxy-2-propanol, 2-methoxyethyl acetate, 1-methoxy-2-propyl acetate, dimethoxy Ethane, methyl lactate, ethyl lactate, N, N-dimethylacetamide, N, N-dimethylformamide, tetramethylurea, N-methylpyrrolidone, dimethylsulfoxide, sulfolane, γ-butyrolactone, toluene and the like can be mentioned. It is not limited. These solvents are used alone or as a mixture. The concentration of the above components (total solids including additives) in the solvent is preferably 1
５０50% by weight. The amount of coating (solid content) on the support obtained after coating and drying varies depending on the application, but when it is used as a photosensitive printing plate, it is generally 0.5 to 0.5%.
5.0 g / m ² is preferred. Various methods can be used as the method of coating, and examples thereof include bar coater coating, spin coating, spray coating, curtain coating, dip coating, air knife coating, blade coating, and roll coating. As the coating amount decreases, the apparent sensitivity increases, but the film characteristics of the photosensitive film deteriorate. This coating layer becomes a photosensitive layer in a lithographic printing plate.

The support is a dimensionally stable plate, for example, paper, paper laminated with plastic (eg, polyethylene, polypropylene, polystyrene, etc.), metal plate (eg, aluminum, zinc, Copper film), plastic film (eg, cellulose diacetate, cellulose triacetate, cellulose propionate, cellulose butyrate, cellulose acetate butyrate, cellulose nitrate, polyethylene terephthalate, polyethylene, polystyrene, polypropylene, polycarbonate, polyvinyl acetal, etc.) Examples include paper or plastic film on which metal is laminated or deposited. As the support of the present invention, a polyester film or an aluminum plate is preferable, and among them, an aluminum plate having good dimensional stability and relatively low cost is particularly preferable. Suitable aluminum plates are a pure aluminum plate and an alloy plate containing aluminum as a main component and containing a trace amount of a different element, and may be a plastic film on which aluminum is laminated or vapor-deposited. The foreign elements contained in the aluminum alloy include silicon, iron, manganese, copper, magnesium, chromium, zinc, bismuth, nickel, titanium and the like. The content of the foreign element in the alloy is at most 10% by weight or less. Aluminum which is particularly preferred in the present invention is pure aluminum. However, completely pure aluminum is difficult to produce due to refining technology, and therefore may contain a slightly different element. As described above, the composition of the aluminum plate applied to the present invention is not specified, and an aluminum plate of a conventionally known and used material can be appropriately used. The thickness of the aluminum plate used in the present invention is about 0.1 mm to 0.6 mm, preferably 0.15 mm to 0.4 mm, particularly preferably 0.1 mm to 0.4 mm.
It is 2 mm to 0.3 mm.

The aluminum plate is used after being roughened. Before the surface is roughened, if necessary, a degreasing treatment with, for example, a surfactant, an organic solvent or an alkaline aqueous solution for removing the rolling oil on the surface may be performed. it can. The surface roughening treatment of the aluminum plate is performed by various methods. For example, a method of mechanically roughening the surface, a method of electrochemically dissolving the surface, and a method of selectively dissolving the surface chemically. It is performed by the method of causing. As a mechanical method, a known method such as a ball polishing method, a brush polishing method, a blast polishing method, and a buff polishing method can be used. In addition, as an electrochemical surface roughening method, there is a method of performing an alternating or direct current in a hydrochloric acid or nitric acid electrolyte. Also, Japanese Patent Application Laid-Open No. 54-63
As disclosed in Japanese Patent Application Laid-Open No. 902, a method combining the two can also be used.

The aluminum plate thus roughened is subjected to an alkali etching treatment and a neutralization treatment, if necessary, and then subjected to an anodic oxidation treatment, if necessary, to enhance the water retention and abrasion resistance of the surface. You. As the electrolyte used for the anodizing treatment of the aluminum plate, various electrolytes that form a porous oxide film can be used, and generally, sulfuric acid, phosphoric acid, oxalic acid, chromic acid, or a mixed acid thereof is used. . The concentration of these electrolytes is appropriately determined depending on the type of the electrolyte.

Since the anodizing treatment conditions vary depending on the electrolyte used, they cannot be specified unconditionally. Generally, however, the concentration of the electrolyte is 1 to 80% by weight, the solution temperature is 5 to 70 ° C., and the current density is 5 to 60 A. / Dm ² , a voltage of 1 to 100 V, and an electrolysis time of 10 seconds to 5 minutes are appropriate. When the amount of the anodic oxide film is less than 1.0 g / m ² , the printing durability is insufficient or the non-image portion of the lithographic printing plate is easily scratched,
So-called "scratch stains" in which ink adheres to scratches during printing are likely to occur.

After the anodic oxidation treatment, the aluminum surface is subjected to a hydrophilic treatment as required. The hydrophilic treatment used in the present invention is described in U.S. Pat.
No. 66, No. 3,181,461, No. 3,280,7
No. 34 and 3,902,734, there is an alkali metal silicate (for example, sodium silicate aqueous solution) method. In this method, the support is immersed in an aqueous solution of sodium silicate or electrolytically treated. In addition, potassium fluoride zirconate disclosed in JP-B-36-22063 and U.S. Pat.
No. 76,868, No. 4,153,461, No. 4,
For example, a method of treating with polyvinyl phosphonic acid as disclosed in JP-A-689,272 is used.

An undercoat layer may be provided between the support and the photosensitive layer, if necessary. As the undercoat layer component, various organic compounds are used, for example, carboxymethyl cellulose, dextrin, gum arabic, phosphonic acids having an amino group such as 2-aminoethylphosphonic acid, and phenylphosphonic acid optionally having a substituent , Naphthylphosphonic acid, alkylphosphonic acid, organic phosphonic acids such as glycerophosphonic acid, methylenediphosphonic acid and ethylenediphosphonic acid, phenylphosphoric acid which may have a substituent, naphthylphosphoric acid, alkylphosphoric acid and glycerophosphoric acid Organic phosphoric acid, optionally substituted phenylphosphinic acid, naphthylphosphinic acid, organic phosphinic acid such as alkylphosphinic acid and glycerophosphinic acid, amino acids such as glycine and β-alanine, and hydrochloric acid of triethanolamine Has hydroxy group such as salt -Alanine, and hydrochlorides of amines that may be used in combination of two or more.

This organic undercoat layer can be provided by the following method. Water or methanol, ethanol, a method of applying a solution obtained by dissolving the above organic compound in an organic solvent such as methyl ethyl ketone or a mixed solvent thereof on an aluminum plate, drying and providing,
Ethanol, an organic solvent such as methyl ethyl ketone or a mixed solvent thereof is dissolved in the above organic compound, a solution of the above organic compound is immersed in the aluminum plate, and the above compound is adsorbed. It is a method of providing. In the former method, a solution of the above organic compound having a concentration of 0.005 to 10% by weight can be applied by various methods. In the latter method, the concentration of the solution is 0.0
1 to 20% by weight, preferably 0.05 to 5% by weight, and the immersion temperature is 20 to 90 ° C, preferably 25 to 50 ° C.
And the immersion time is 0.1 second to 20 minutes, preferably 2 seconds to 1 minute. The solution used for this can be adjusted to pH 1 to 12 with a basic substance such as ammonia, triethylamine, potassium hydroxide or the like, or an acidic substance such as hydrochloric acid or phosphoric acid. Further, a yellow dye may be added for improving the tone reproducibility of the image forming material.

The coating amount of the organic undercoat layer is 2 to 200 mg /
m ² is appropriate, and preferably 5 to 100 mg / m ² . If the coating amount is less than 2 mg / m ² , sufficient printing durability cannot be obtained. The same is true even if it is larger than 200 mg / m ² .

The lithographic printing plate manufactured is usually subjected to image exposure,
A development process is performed to form an image. Examples of the light source of the actinic ray used for the image exposure include a mercury lamp, a metal halide lamp, a xenon lamp, a chemical lamp, a carbon arc lamp, and the like. As radiation, electron beam, X
There are lines, ion beams, far infrared rays, and the like. G line, i
Lines, Deep-UV light, high density energy beams (laser beams) are also used. Examples of the laser beam include a helium / neon laser, an argon laser, a krypton laser, a helium / cadmium laser, a KrF excimer laser, a solid laser, and a semiconductor laser. In the present invention, a light source having an emission wavelength in the near infrared to infrared region is preferable, and a solid-state laser and a semiconductor laser are particularly preferable.

As a developer and a replenisher to be used, conventionally known aqueous alkali solutions can be used. For example, sodium silicate, potassium potassium, tribasic sodium phosphate,
Same potassium, same ammonium, dibasic sodium phosphate,
Same potassium, same ammonium, sodium carbonate, same potassium, same ammonium, sodium hydrogen carbonate, same potassium, same ammonium, sodium borate, same potassium,
Same ammonium, sodium hydroxide, same ammonium,
Inorganic alkali salts such as the same potassium and the same lithium. Also, monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine,
Organic alkaline agents such as triethylamine, monoisopropylamine, diisopropylamine, triisopropylamine, n-butylamine, monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, diisopropanolamine, ethyleneimine, ethylenediamine and pyridine are also used.

These alkaline agents are used alone or in combination of two or more. Among these alkali agents, particularly preferred developers are aqueous silicate solutions such as sodium silicate and potassium silicate. The reason is silicon oxide SiO ₂ and alkali metal oxides are components of the silicate
This is because developability can be adjusted by the ratio and concentration of M ₂ O. For example, JP-A-54-62004 discloses
The alkali metal silicate described in JP-B-57-7427 is effectively used.

In the case of developing using an automatic developing machine, an aqueous solution having a higher alkali strength than the developing solution (replenisher) is used.
It has been known that a large amount of PS plates can be processed without replacing the developing solution in the developing tank for a long time by adding to the developing solution. This replenishment system is also preferably applied in the present invention. Various surfactants and organic solvents can be added to the developing solution and the replenishing solution as needed for the purpose of promoting or suppressing the developing property, dispersing the developing residue and increasing the ink affinity of the printing plate image area. Preferred surfactants include anionic, cationic, nonionic and amphoteric surfactants. Further, the developing solution and the replenisher may contain, if necessary, a reducing agent such as a sodium salt or a potassium salt of an inorganic acid such as hydroquinone, resorcinol, sulfurous acid, and bisulfite, and further include an organic carboxylic acid, an antifoaming agent, and a water softener. Can be added.

The lithographic printing plate developed using the above developer and replenisher is post-treated with washing water, a rinsing solution containing a surfactant and the like, and a desensitizing solution containing gum arabic and a starch derivative. As the post-processing when the image forming material of the present invention is used as a printing plate, these processings can be used in various combinations.

In recent years, in the plate making and printing industry, automatic developing machines for printing plates have been widely used in order to rationalize and standardize plate making operations. The lithographic printing plate of the present invention can also be processed by this automatic developing machine. This automatic developing machine generally comprises a developing section and a post-processing section, and comprises a device for transporting a printing plate, each processing solution tank and a spray device,
While the exposed printing plate is transported horizontally, each processing liquid pumped up by a pump is sprayed from a spray nozzle to perform development processing. Recently, a method has been known in which a printing plate is immersed and conveyed by a submerged guide roll or the like in a processing liquid tank filled with a processing liquid to perform processing. In such an automatic processing, the processing can be performed while replenishing each processing liquid with a replenisher according to the processing amount, the operating time, and the like. Further, a so-called disposable processing method in which processing is performed with a substantially unused processing liquid can also be applied.

After image exposure, development, washing with water and / or rinsing and / or gumming, if there is an unnecessary image portion (for example, a film edge mark of the original film) on the lithographic printing plate, A measure for erasing the unnecessary image portion can be taken. As the erasing method, for example, a method described in Japanese Patent Publication No. 213293/1990, in which an erasing liquid is applied to an unnecessary image portion, left as it is for a predetermined time, and then washed with water, is preferable. 1748
No. 42, a method of irradiating an unnecessary image area with an actinic ray guided by an optical fiber and developing the same is also applicable.

The lithographic printing plate that has been subjected to the above-mentioned treatment can be subjected to a printing step after applying a desensitized gum as required. Burning treatment may be performed for the purpose of improving high printing durability. When the lithographic printing plate is to be subjected to a burning process, the lithographic printing plate must be burned before the burning process.
No. 18, 55-28062 and JP-A-62-2185.
No. 9 and No. 61-159655 are preferably treated with surface-regulating liquids as described in JP-A Nos. As a method, a sponge or absorbent cotton impregnated with the surface conditioning liquid is applied on a lithographic printing plate, or a method in which the printing plate is immersed in a vat filled with the surface conditioning solution and applied, Application by an automatic coater or the like is applied. Further, it is more preferable that the application amount is made uniform using a squeegee or a squeegee roller after the application. The application amount of the surface conditioning liquid is generally 0.1.
An appropriate amount is from 03 to 0.8 g / m ² (dry weight).

After drying the lithographic printing plate coated with the surface conditioning solution, a burning processor (for example, a burning processor sold by Fuji Photo Film Co., Ltd.):
"BP-1300") or the like. The heating temperature and time in this case depend on the type of the component forming the image, but are in the range of 180 to 300 ° C. and 1 to 20.
A range of minutes is preferred.

The burning-processed lithographic printing plate can be subjected to conventional treatment such as washing with water and gumming as needed. When a liquid is used, a so-called desensitizing treatment such as gumming can be omitted.

The lithographic printing plate obtained by such a process is incorporated in an offset printing machine or the like and used for printing on paper or the like.

[0127]

Hereinafter, the present invention will be described with reference to Examples.
The scope of the present invention is not limited to these examples.

Example 1 <Preparation of Substrate> A 0.3 mm thick aluminum plate (material
1050) was degreased by washing with trichloroethylene.
After, nylon brush and 400 mesh pumice-water suspension
The surface was grained using a liquid and washed well with water. This
Plate for 9 seconds in a 25% aqueous solution of sodium hydroxide at 45 ° C
Etching by immersion, washing with water, and then 20% nitric acid
For 20 seconds and washed with water. At this time,
Etching amount is about 3g / m ^TwoMet. Next, this plate
% Sulfuric acid as electrolyte and current density 15A / dm^Two3g /
m^TwoAfter providing a direct current anodic oxide coating of
Furthermore, the following undercoat liquid is applied, and the coating film is dried at 90 ° C. for 1 minute.
Dried. The coating amount of the dried coating film is 10 mg / m^TwoSo
Was.

<Composition of Undercoat Liquid> 0.5 g of β-alanine 95 g of methanol 5 g of water

On the obtained substrate, the following photosensitive solution 1 was applied so as to have a coating amount of 1.8 g / m ² to obtain a lithographic printing plate of Example 1.

<Composition of Photosensitive Solution 1> m, p-cresol novolak (m / p ratio = 6/4, weight average molecular weight 3500, unreacted cresol 0.5% by weight) 1.0 g * water-insoluble And a polymer binder soluble in an aqueous alkali solution ・ Infrared absorber (N-1) having an onium salt structure 0.2 g ・ Oxidizing agent (Ox-1) 0.6 g ・ Counter anion of Victoria Pure Blue BOH is 1 -Dye converted to naphthalenesulfonic acid anion 0.02 g-Fluorosurfactant (Megafac F-177, manufactured by Dainippon Ink and Chemicals, Inc.) 0.05 g-γ-butyrolactone 3 g-Methyl ethyl ketone 8 g-1 -Methoxy-2-propanol 7 g

[0132]

Embedded image

Example 2 A lithographic printing plate of Example 2 was obtained in the same manner as in Example 1, except that Ox-2 shown below was used as an oxidizing agent.

[0134]

Embedded image

Example 3 A lithographic printing plate of Example 3 was obtained in the same manner as in Example 1, except that Ox-3 shown below was used as an oxidizing agent.

[0136]

Embedded image

Example 4 A lithographic printing plate of Example 4 was obtained in the same manner as in Example 1 except that Ox-4 shown below was used as an oxidizing agent.

[0138]

Embedded image

Example 5 A lithographic printing plate of Example 5 was obtained in the same manner as in Example 1, except that Ox-5 shown below was used as an oxidizing agent.

[0140]

Embedded image

Example 6 The following N-2 was used as an infrared absorbing agent having an onium salt structure, and the above-mentioned Ox- was used as an oxidizing agent.
Except for using Sample No. 3, a lithographic printing plate of Example 6 was obtained in the same manner as in Example 1.

[0142]

Embedded image

Example 7 The following N-3 was used as an infrared absorbing agent having an onium salt structure, and the above-mentioned Ox- was used as an oxidizing agent.
Except for using Sample No. 3, a lithographic printing plate of Example 7 was obtained in the same manner as in Example 1.

[0144]

Embedded image

Example 8 The following N-4 was used as an infrared absorber having an onium salt structure, and the above-mentioned Ox- was used as an oxidant.
Except for using Sample No. 4, a lithographic printing plate of Example 8 was obtained in the same manner as in Example 1.

[0146]

Embedded image

Example 9 The following N-5 was used as an infrared absorber having an onium salt structure, and the above-mentioned Ox- was used as an oxidant.
Except for using Sample No. 4, a lithographic printing plate of Example 9 was obtained in the same manner as in Example 1.

[0148]

Embedded image

Example 10 The following N-6 was used as an infrared absorbing agent having an onium salt structure, and the above-mentioned Ox was used as an oxidizing agent.
Except that -4 was used, a lithographic printing plate of Example 10 was obtained in the same manner as in Example 1.

[0150]

Embedded image

Example 11 <Synthesis of Specific Copolymer as Polymer Binder Insoluble in Water and Soluble in Alkaline Aqueous Solution> Synthesis Example (Copolymer 1) 500 ml provided with a stirrer, a cooling pipe and a dropping funnel A three-necked flask was charged with 31.0 g (0.36 mol) of methacrylic acid, 39.1 g (0.36 mol) of ethyl chloroformate and 200 ml of acetonitrile, and the mixture was stirred while being cooled in an ice water bath. To this mixture, 36.4 g (0.36 mol) of triethylamine was dropped by a dropping funnel over about 1 hour. After the addition, the ice-water bath was removed, and the mixture was stirred at room temperature for 30 minutes.

To the reaction mixture was added 51.7 g (0.30 mol) of p-aminobenzenesulfonamide, and the mixture was stirred for 1 hour while warming to 70 ° C. in an oil bath. After completion of the reaction, the mixture was added to 1 liter of water while stirring the water, and the resulting mixture was stirred for 30 minutes. The mixture was filtered to remove the precipitate, which was then washed with 500 m of water.
Then, the slurry was filtered and the obtained solid was dried to obtain a white solid of N- (p-aminosulfonylphenyl) methacrylamide (yield 46.9 g).

Next, 5.04 g of N- (p-aminosulfonylphenyl) methacrylamide was placed in a 100 ml three-necked flask equipped with a stirrer, a condenser and a dropping funnel.
210 mol), and 2.05 g (0.05 g) of ethyl methacrylate.
180 mol), acrylonitrile 1.11 g (0.02
1 mol) and 20 g of N, N-dimethylacetamide, and the mixture was stirred while being heated to 65 ° C. in a hot water bath. This mixture was mixed with “V-65” (manufactured by Wako Pure Chemical Industries, Ltd.).
0.15 g was added, and the mixture was stirred for 2 hours under a nitrogen stream while maintaining at 65 ° C. N- (p-
Aminosulfonylphenyl) methacrylamide 5.04
g, 2.05 g of ethyl methacrylate, 1.11 g of acrylonitrile, 20 g of N, N-dimethylacetamide, and 0.15 g of "V-65" were dropped by a dropping funnel over 2 hours. After the addition was completed, the resulting mixture was further stirred at 65 ° C. for 2 hours. After completion of the reaction, methanol 40
g was added to the mixture, the mixture was cooled, and the obtained mixture was poured into 2 liters of water while stirring the water. After stirring the mixture for 30 minutes, the precipitate was taken out by filtration and dried to obtain 15 g of a white solid. I got The weight average molecular weight of this copolymer 1 (polystyrene standard) was measured by gel permeation chromatography and found to be 53,000.
It was 0.

The same substrate as that obtained in Example 1
Photosensitive solution 2 shown below was applied so that the coating amount was 1.8 g / m ² , to obtain a lithographic printing plate of Example 11. <Composition of Photosensitive Liquid 2> ・ 11.0 g of the above copolymer ・ 0.1 g of infrared absorber (Y-2) having an onium salt structure having a reduction potential of −1.2 V (SCE) or more ・ p-toluene Sulfonic acid 0.002 g ・ Dye with the counter anion of Victoria Pure Blue BOH converted to 1-naphthalenesulfonic acid anion 0.02 g ・ Fluorinated surfactant (MegaFac F-177, manufactured by Dainippon Inki Chemical Industry Co., Ltd.) ) 0.05 g ・ γ-butyrolactone 8 g ・ Methyl ethyl ketone 8 g ・ 1-methoxy-2-propanol 4 g

Example 12 Reduction potential -1.2 V (SC
E) A lithographic printing plate of Example 12 was obtained in the same manner as in Example 1, except that the above-mentioned Y-4 was used as the infrared absorber having the above onium salt structure.

Example 13 Reduction potential -1.2 V (SC
E) A lithographic printing plate of Example 13 was obtained in the same manner as in Example 1, except that the above-mentioned Y-8 was used as the infrared absorber having the above onium salt structure.

Example 14 Reduction potential -1.2 V (SC
E) A lithographic printing plate of Example 14 was obtained in the same manner as in Example 1, except that the above-mentioned Y-11 was used as the infrared absorber having the above onium salt structure.

Example 15 Reduction potential -1.2 V (SC
E) A lithographic printing plate of Example 15 was obtained in the same manner as in Example 1, except that the above-mentioned Y-13 was used as the infrared absorber having the above onium salt structure.

[Comparative Example 1] Except that no oxidizing agent was added,
Comparative Example 1 A lithographic printing plate was obtained in the same manner as in Example 1.

[Comparative Example 2] Except that no oxidizing agent was added,
Comparative Example 1 A lithographic printing plate was obtained in the same manner as in Example 2.

[Comparative Example 3] Except that no oxidizing agent was added,
Comparative Example 1 A lithographic printing plate was obtained in the same manner as in Example 3.

Comparative Example 4 Except that no oxidizing agent was added,
Comparative Example 1 A lithographic printing plate was obtained in the same manner as in Example 4.

[Comparative Example 5] Except that no oxidizing agent was added,
Comparative Example 1 A lithographic printing plate was obtained in the same manner as in Example 5.

[Comparative Example 6] Except that no oxidizing agent was added,
Comparative Example 1 A lithographic printing plate was obtained in the same manner as in Example 6.

Comparative Example 7 A lithographic printing plate was obtained in the same manner as in Example 1 except that no oxidizing agent was added and N-7 shown below was used as an infrared absorbing agent.

[0166]

Embedded image

Comparative Example 8 Reduction potential -1.2 V (SC
E) A lithographic printing plate of Comparative Example 8 was obtained in the same manner as in Example 11, except that the oxidizing agent was replaced with the infrared absorbing agent N-1 in the infrared absorbing agent having the above onium salt structure.

[Comparative Example 9] Reduction potential -1.2 V (SC
E) A lithographic printing plate of Comparative Example 9 was obtained in the same manner as in Example 11, except that the oxidizing agent was replaced with the infrared absorbing agent N-2 in the infrared absorbing agent having the above onium salt structure.

Comparative Example 10 Reduction potential -1.2 V (SC
E) A lithographic printing plate of Comparative Example 10 was obtained in the same manner as in Example 11, except that the oxidizing agent was replaced with the infrared absorbing agent N-3 in the infrared absorbing agent having the above onium salt structure.

[Comparative Example 11] Reduction potential -1.2 V (SC
E) A lithographic printing plate of Comparative Example 11 was obtained in the same manner as in Example 11, except that the oxidizing agent was replaced with the infrared absorbing agent N-4 in the infrared absorbing agent having the above onium salt structure.

[Comparative Example 12] Reduction potential -1.2 V (SC
E) A lithographic printing plate of Comparative Example 12 was obtained in the same manner as in Example 11, except that the oxidizing agent was replaced with the infrared absorbing agent N-5 in the infrared absorbing agent having the above onium salt structure.

Comparative Example 13 Reduction potential -1.2 V (SC
E) A lithographic printing plate of Comparative Example 13 was obtained in the same manner as in Example 11, except that the oxidizing agent was replaced with the infrared absorbing agent N-6 in the infrared absorbing agent having the above onium salt structure.

[Comparative Example 14] Reduction potential -1.2 V (SC
E) A lithographic printing plate of Comparative Example 14 was obtained in the same manner as in Example 11, except that the oxidizing agent was replaced with the infrared absorbing agent N-7 in the infrared absorbing agent having the above onium salt structure.

[Evaluation of Performance of Lithographic Printing Plate] The lithographic printing plates of Examples 1 to 15 and Comparative Examples 1 to 14 produced as described above were evaluated for performance according to the following criteria. The evaluation results are shown in Tables 1 and 2.

<Sensitivity and development latitude (image formation)
Evaluation)> The obtained lithographic printing plate was treated with a wavelength of 840 nm.
Semiconductor laser or YAG laser with a wavelength of 1064 nm
Exposure was performed using Which laser to use
Is appropriately selected according to the absorption wavelength of the infrared absorbing dye contained.
I chose. After exposure, developer DP manufactured by Fuji Photo Film Co., Ltd.
-4, automatic development with rinsing liquid FR-3 (1: 7)
Machine (Fuji Photo Film Co., Ltd .: "PS Processor 9
00VR "). The developer DP-4 is 1:
Two levels, one diluted at 6 and one diluted at 1:12
And the line of the non-image area obtained with each developer
Measure the width and irradiate the laser energy corresponding to the line width.
Energy (mJ / cm) ^Two). Ma
And a 1: 6 standard developer solution and a 1:12
Measure the difference in sensitivity between the diluted developer and the difference
Development latitude is better, and 20 mJ / cm^Two
Below is a practical level.

[0176]

[Table 1]

[0177]

[Table 2]

<Evaluation of Storage Stability> The obtained lithographic printing plate was stored at 60 ° C. for 3 days, and then subjected to laser exposure and development in the same manner as in the evaluation of the sensitivity and the development latitude (image forming property). The sensitivity was measured and the difference between before and after storage was compared. For all lithographic printing plates, the sensitivity variation is 2
0 mJ / cm ² or less, and the lithographic printing plates of Examples 1 to 15 preserved by adding an oxidizing agent having a reduction potential of −1.2 V or more (based on a standard calomel electrode) and an infrared absorber having an onium salt structure No decrease in stability was seen.

As can be seen from Tables 1 and 2, the lithographic printing plates of Examples 1 to 15 have higher sensitivity to infrared laser, a better development latitude, and better image formation than the lithographic printing plates of Comparative Examples 1 to 15. It turns out that it is excellent. Also,
It can be seen that there is little change in sensitivity before and after storage, and the storage stability is excellent.

[0180]

According to the present invention, therefore, it is possible to directly write data on the basis of digital data from a computer or the like by using a solid-state laser or semiconductor laser that emits infrared rays.
An image forming material suitable for obtaining a lithographic printing plate excellent in image formability (sensitivity, development latitude) and storage stability can be provided.

Claims (2)

[Claims] 1. An image-forming material comprising the following (A), (B) and (C). (A) an infrared absorber having an onium salt structure, (B) a polymer binder which is insoluble in water and soluble in an aqueous alkaline solution,
(C) An oxidizing agent having a reduction potential of -1.2 V (based on a standard calomel electrode) or more. 2. An image forming material comprising the following (B) and (D). (B) a polymer binder insoluble in water and soluble in an aqueous alkali solution; and (D) an infrared absorber having an onium salt structure of a reduction potential of −1.2 V or more (based on a standard calomel electrode).