JP2001343742A - Thermosensitive composition, and original plate of planographic printing plate using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermosensitive composition which can undergo irreversible changes of physical properties by heating which has high sensitivity and a negative type original plate of a planographic printing plate using the composition, having high sensitivity and good alkali development resistance in the image area, satisfactory in printing resistance and capable of recording by a heat mode. SOLUTION: The thermosensitive composition contains I) a compound of the formula R-COO-M+ (where R is alkyl or aryl and M+ is a counter cation selected from among sulfonium, iodonium, diazonium, ammonium and azonium) which generates a radical under heat and II) a compound, whose physical or chemical characteristics are changed irreversibly by the radical. The original plate is obtained by disposing a photosensitive layer, containing I) the compound of the formula R-COO-M+, II-1), a compound having a polymerizable unsaturated group, III) a photothermal converting agent and IV) a polymer binder on the base.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-sensitive composition which can be widely applied as a heat-sensitive recording material, and a high-sensitivity, alkali-developable image-recording layer of the recording layer using the same. And a lithographic printing plate precursor having a negative recording layer with excellent printing durability.

[0002]

2. Description of the Related Art In recent years, the development of lasers has been remarkable, and in particular, solid lasers and semiconductor lasers having a light emitting region in the near infrared to infrared region have been increasing in output and miniaturization. Therefore, these lasers are very useful as an exposure light source when making a plate directly from digital data of a computer or the like. Using an infrared laser having an emission region in the infrared region as an exposure light source, a negative type lithographic printing plate material for an infrared laser, a photothermal conversion agent,
The lithographic printing plate material has a photosensitive layer containing a polymerization initiator that generates a radical by light or heat and a polymerizable compound.

Usually, such a negative type image recording material employs a recording system in which a polymerization reaction is caused by using a radical generated by light or heat as an initiator, and a recording layer in an exposed portion is cured to form an image portion. We are using. Such a negative type image forming material has a lower image forming property than a positive type in which the recording layer is solubilized by the energy of infrared laser irradiation, and promotes a curing reaction by polymerization to form a strong image portion. In general, a heat treatment is performed before the development step in order to form. As a negative type image recording material to be subjected to such a post-heating treatment, for example, US Pat. No. 5,340,699
And a recording material comprising a resol resin and a novolak resin described in the above item. In particular, when an aluminum support is used, the energy from the infrared laser irradiation diffuses into the support having high thermal conductivity, and is not used for initiating or accelerating a polymerization reaction for image formation, and sufficient sensitivity is obtained. There was no problem.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above problems, and an object of the present invention is to provide a heat-sensitive composition capable of irreversibly changing physical properties by heating. And high sensitivity using the composition, heat treatment before development is unnecessary or heat treatment can be simplified, and alkali development resistance in the image area is good, An object of the present invention is to provide a negative type lithographic printing plate precursor excellent in printability and recordable in a heat mode.

[0005]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that a radical generator represented by the following general formula (A) and a compound whose physical properties are irreversibly changed by a radical are provided on a support. By containing, it is found that the composition is excellent in heat curability and color development by heat.Furthermore, by providing a recording layer containing such a composition, the recording sensitivity of a lithographic printing plate can be increased. And improved printing durability, and completed the present invention. That is, the heat-sensitive composition of the present invention comprises a compound represented by the following general formula (A), which generates a radical by heat (hereinafter, appropriately referred to as a radical generator); It is characterized by containing a compound whose irreversible or chemical properties change. Formula (A) R-COO ^- M ^{+ In the} formula, R represents an alkyl group or an aryl group, and M ⁺ represents a counter cation selected from sulfonium, iodonium, diazonium, ammonium, and azinium. By further containing III) a photothermal conversion agent in this composition, III) by exposure to an absorption wavelength of the photothermal conversion agent, I) a radical of a compound which generates a radical by heat represented by the general formula (A) Generated, II) by radicals, the physical or chemical properties of a compound whose physical or chemical properties change irreversibly change, and recording by exposure becomes possible.
Further, the lithographic printing plate precursor of the present invention according to claim 3 is capable of recording by heat mode exposure,
I) a radical polymerization initiator represented by the following general formula (A),
It is characterized by being provided with a photosensitive layer containing III) a photothermal conversion agent, II-1) a compound having a polymerizable unsaturated group, and IV) a binder polymer. Formula (A) R-COO ^- M ^{+ In the} formula, R represents an alkyl group or an aryl group, and M ⁺ represents a counter cation selected from sulfonium, iodonium, diazonium, ammonium, and azinium.

In the present invention, "corresponding to the heat mode" means that recording by heat mode exposure is possible. The definition of the heat mode exposure in the present invention will be described in detail. Hans-Joachim Tim
pe, IS & Ts NIP 15: 1999 Inte
rational Conference on D
digital printing technology
ies. P. As described in 209, a photoabsorbing substance (for example, a dye) is photoexcited in a photoreceptor material, and undergoes a chemical or physical change to form a chemical or physical change from the photoexcitation of the photoabsorbing substance forming an image. It is known that there are roughly two modes in the above processes. One is that the photo-excited light-absorbing substance deactivates due to some photochemical interaction (eg, energy transfer, electron transfer) with other reactants in the photosensitive material,
As a result, a so-called photon mode in which the activated reactant causes a chemical or physical change required for the above-described image formation, and the other is that the photoexcited light absorbing substance generates heat and deactivates, and the heat is lost. This is a so-called heat mode in which a reactant causes a chemical or physical change required for image formation by utilizing the above-mentioned method. In addition, there are special modes such as ablation in which substances are explosively scattered by the energy of light locally collected and multiphoton absorption in which one molecule absorbs many photons at a time, but these modes are omitted here.

[0007] The exposure processes utilizing the above-described modes are called font mode exposure and heat mode exposure. The technical difference between the font mode exposure and the heat mode exposure is whether or not the energy amount of several photons to be exposed can be added to the energy amount of the target reaction.
For example, consider a case where a certain reaction occurs using n photons. In the font mode exposure, photochemical interaction is used, so that the energy of one photon cannot be added and used due to the requirement of the law of conservation of quantum energy and momentum. That is, in order to cause a certain reaction, the relationship of “energy amount of one photon ≧ energy amount of reaction” is necessary. On the other hand, in heat mode exposure, heat is generated after light excitation, and light energy is converted into heat and used, so that the amount of energy can be added. Therefore, the relationship “energy amount of n photons ≧ energy amount of reaction” is sufficient. However, this energy addition is restricted by thermal diffusion. In other words, if the next photoexcitation-deactivation process occurs and heat is generated before heat escapes from the exposed portion (reaction point) of interest by thermal diffusion, the heat is reliably accumulated and added, and the temperature rises in that portion. Leads to. However, when the next heat is generated slowly, the heat escapes and is not accumulated. In other words, in the heat mode exposure, even if the total exposure energy is the same, the result is different between the case where the high energy light is irradiated for a short time and the case where the low energy light is irradiated for a long time. It becomes advantageous for accumulation of.

Of course, in the font mode exposure, a similar phenomenon may occur due to the influence of the diffusion of the subsequent reactive species, but basically, this does not occur. That is, in terms of the characteristics of the photosensitive material, in the font mode, the intrinsic sensitivity of the photosensitive material (energy for reaction required for image formation) versus exposure power density (w / cm ² ) (= energy density per unit time). Amount) is constant, but in the heat mode, the intrinsic sensitivity of the photosensitive material increases with respect to the exposure power density. Therefore, when the exposure time is fixed so that the productivity necessary for practical use as an image recording material can be maintained, a high sensitivity of about 0.1 mJ / cm ² is usually obtained in the font mode exposure when comparing the modes. Reaction can be achieved at any low exposure, although
The problem of low-exposure fog is likely to occur in the unexposed area. On the other hand, in the heat mode exposure, a reaction does not occur unless the exposure amount exceeds a certain value, and usually about 50 mJ / cm ² is required in relation to the thermal stability of the photosensitive material. Is avoided. In fact, in heat mode exposure, the exposure power density on the plate surface of the photosensitive material is 500
0 w / cm ² or more, preferably 10,000
w / cm ² or more is required. However, although not described in detail here, when a high power density laser of 5.0 × 10 ⁵ / cm ² or more is used, ablation occurs, which is not preferable because of problems such as soiling the light source.

Although the action of the present invention is not clear, I) a radical generator represented by the general formula (A) contained in the heat-sensitive composition of the present invention is a compound having an onium salt structure and having a carboxylate as a counter anion as a counter anion. And a sulfonate (-S) generally used as a radical polymerization initiator.
The thermal decomposition temperature is lower than that of the compound having O ₃ ⁻ ) as the counter anion, and the compound is contained together in the composition II)
It is considered that the radical can change the physical properties of a compound whose physical or chemical properties change irreversibly with high sensitivity. Further, the acid generated when the radical generator is decomposed is a carboxylic acid, that is, a relatively weak acid, which is effective in initiating and promoting polymerization, but compared with a compound which generates a strong acid such as sulfonic acid. Because the permeability to alkaline water is low, when this composition is used as a recording layer of a lithographic printing plate precursor, damage by an alkaline developer during development is small, and the film strength of an image portion is increased,
As a result, it is considered that the printing durability is improved, and a lithographic printing plate precursor having excellent characteristics is obtained in addition to the fact that a curing reaction occurs with high sensitivity to heat or exposure by the above-mentioned action.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
The heat-sensitive composition of the present invention contains (I) a radical generator represented by the general formula (A) and (II) a compound containing a compound whose physical and chemical properties change irreversibly by a radical. I) the radical generator represented by the general formula (A) is decomposed by heat to generate radicals, and the radicals II) the physical properties of the compound whose physical and chemical properties are irreversibly changed by the radicals The physical properties or chemical properties change, and a curing reaction, a color development, a color erasure reaction, and the like by radical polymerization occur. Further, the heat-sensitive composition further comprises II
I) By containing a photothermal conversion agent, by irradiating light having an absorption wavelength of the photothermal conversion agent, for example, an infrared laser or the like, III) The photothermal conversion agent generates heat and heat of the infrared laser light itself, or III) Due to the heat generated by the photothermal conversion agent, I) the radical generator represented by the general formula (A) is decomposed to generate radicals, and II) the radicals
A change in the properties of the compound occurs where the chemical properties change irreversibly.

I) Compound of the formula (A) that generates a radical by heat The radical generator used in the present invention is represented by the following formula (A).

Formula (A) R-COO ^- M ^{+ In the} above formula, R preferably represents an alkyl group having 1 to 20 carbon atoms or an aryl group having 1 to 20 carbon atoms. R may have a ring structure. In addition, these alkyl groups or aryl groups may have a substituent, and specific examples of the substituent that can be introduced include, for example, an alkyl group, an alkoxy group, an alkenyl group, an alkynyl group, an amino group,
Examples include a cyano group, a hydroxyl group, a halogen atom, an amide group, an ester group, a carbonyl group, a carboxyl group, and the like, and these may further have a substituent as described above. Further, two or more substituents may be bonded to each other to form a ring, and the ring structure may be a heterocyclic structure containing a nitrogen atom, a sulfur atom, or the like. The polymerization initiator according to the present invention preferably has a pKa in water of 2 or more, and more preferably a pKa of 3 or more. If the pKa in water is 2 or more, the thermal decomposition temperature of the initiator tends to decrease, which is considered to contribute to the improvement of sensitivity.

M ⁺ represents a counter cation selected from sulfonium, iodonium, diazonium, ammonium and azinium. Here, azinium has a azine ring which is a six-membered ring containing a nitrogen atom in its structure, and includes pyridinium, diazinium, and triazinium. Azinium contains one or more aromatic rings fused to an azine ring and includes, for example, quinolinium, isoquinolinium, benzoazinium, naphthoazinium and the like. Specifically, for example, USP 4,743,5
No. 28, JP-A-63-138345, JP-A-63-142
No. 345, No. 63-142346, JP-B-46-42
No. 363, and 1-methoxy-
4-phenylpyridinium tetrafluoroborate, N
-Counter cations forming alkoxypyridinium salts and the like.

Among these counter cations, stability,
From the viewpoint of sensitivity, a compound having iodonium or sulfonium as a counter cation is preferable, and a compound having a diaryliodonium or triarylsulfonium skeleton is more preferable. Hereinafter, specific examples of the polymerization initiator represented by the general formula (A) are shown in combination with a cation moiety corresponding to a preferable counter cation, but the present invention is not limited thereto. As a preferable structure of the iodonium skeleton, a diarylsulfonium skeleton is preferable from the viewpoint of stability, and the aryl group may be substituted in the same manner as the above-mentioned aryl group. First, preferred iodonium salts (iodonium as a counter cation) compounds [exemplified compounds (IA-1) to (IJ-8)] are exemplified below.

[0015]

Embedded image

[0016]

Embedded image

[0017]

Embedded image

[0018]

Embedded image

[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

The preferred structure of the sulfonium skeleton is a triarylsulfonium skeleton from the viewpoint of sensitivity and stability, and the aryl group may be substituted in the same manner as the above-mentioned aryl group. Next, a preferred sulfonium salt (having sulfonium as a counter cation) compound [exemplary compound (S
A-1) to Exemplified Compound (SJ-12)].

[0032]

Embedded image

[0033]

Embedded image

[0034]

Embedded image

[0035]

Embedded image

[0036]

Embedded image

[0037]

Embedded image

[0038]

Embedded image

[0039]

Embedded image

[0040]

Embedded image

[0041]

Embedded image

[0042]

Embedded image

[0043]

Embedded image

[0044]

Embedded image

[0045]

Embedded image

[0046]

Embedded image

[0047] In the radical polymerization initiator according to the present invention, the cation portion ^- shows an example of a suitable carboxylic acids for forming the (R-COOH) the following (R-COO).

[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

As a typical example, the exemplified compound (IB-1)
4: shows a synthesis example of di (4-t-amylphenyl) iodonium acetate. a) Synthesis of triphenylsulfonium benzoate 50.9 g of diphenylsulfoxide was added to 800 m of benzene.
and 200 g of aluminum chloride was added thereto and refluxed for 24 hours. The reaction solution was slowly poured into 2 L of water under ice cooling, and 400 ml of concentrated hydrochloric acid was added thereto, followed by heating at 70 ° C. for 10 minutes. The aqueous solution was washed with 500 ml of ethyl acetate, filtered, and a solution prepared by dissolving 200 g of ammonium iodide in 400 ml of water was added. The precipitated powder was collected by filtration, washed with water, washed with ethyl acetate and dried to obtain 70 g of triphenylsulfonium iodide. 30.5 g of triphenylsulfonium iodide was added to methanol 1
000 ml, and 19.1 g of silver oxide was added to this solution, followed by stirring at room temperature for 4 hours. The solution was filtered and excess benzoic acid was added to it. The reaction mixture was concentrated, the concentrate was washed with ethyl acetate and hexane, and dried under vacuum to obtain triphenylsulfonium benzoate. Other sulfonium salts can be similarly synthesized.

B) Synthesis of di (4-t-amylphenyl) iodonium acetate (IB-14) 60 g of t-amylbenzene, 39.5 potassium iodate
g, 81 g of acetic anhydride, and 170 ml of dichloromethane were mixed, and 66.8 g of concentrated sulfuric acid was slowly added dropwise thereto under ice cooling. After stirring for 2 hours under ice cooling, the mixture was stirred at room temperature for 10 hours. To the reaction solution stirred at room temperature for 10 hours, 500 ml of water was added under ice-cooling, and components dissolved in the reaction were extracted with dichloromethane. An organic bath made of dichloromethane was washed with an aqueous solution of sodium hydrogen carbonate and then with water. After washing, the organic phase was concentrated to obtain di (4-t-amylphenyl) iodonium sulfate. The sulfate was added to an excess of an aqueous solution of potassium iodide. This solution was extracted with dichloromethane, washed with water, and the organic phase was concentrated to obtain di (4-t-amylphenyl) iodonium iodide. 75 g were obtained. 42.2 g of di (4-t-amylphenyl) iodonium iodide obtained above was added to methanol 20
The solution was dissolved in 00 ml, and 19.1 g of silver oxide was added to the solution, followed by stirring at room temperature for 4 hours. The solution was filtered and excess acetic acid was added to it. The reaction solution was concentrated, the concentrate was washed with ethyl acetate and hexane, and dried under vacuum to obtain di (4-t-amylphenyl) iodonium acetate [exemplified compound (IB-14)]. Other sulfonium salts and iodonium salts can be similarly synthesized by appropriately selecting starting materials and carboxylic acids to be added.

As another method for obtaining iodonium iodide, Bull. Chem. Soc. Jpn. 7
0, 219-224 (1997), Bull. Che
m. Soc. Jpn. 70, 1665-1669 (19
97), Bull. Chem. Soc. Jpn. 70,
115-120 (1999); Amer. Che
m. Soc; 82; 1960,725-731, J. A
mer. Chem. Soc; 81; 1959, 342.
346 can be used.

Another method for obtaining sulfonium iodide is described in J. Am. Amer. Chem. Soc; 91; 196
9; 145-150, etc. can be used. Other methods for obtaining sulfonium carboxylate are described in J. Am. Org. Chem 35; 197
0 2539-2543.

In the heat-sensitive composition of the present invention, the radical generator represented by the general formula (A) may be contained in an amount of 0.5 to 15% by weight based on the total solid content of the composition. preferable.

In the present invention, in addition to the above-mentioned specific radical generator, as long as the effects of the present invention are not impaired,
Other known photopolymerization initiators, thermal polymerization initiators and the like can be selected and used in combination. Examples of these polymerization initiators that can be used in combination include, for example, known onium salts having no carboxylic acid structure in the counter cation portion, triazine compounds having a trihalomethyl group, peroxides, azo-based polymerization initiators, azide compounds, quinonediazides And the like.

Specific examples of onium salts that can be suitably used as a radical generator that can be used in combination include paragraphs [0030] to [0030] of Japanese Patent Application No. 11-310623.
Examples described in [0033] can be given.

The general formula (I) described in paragraphs [0012] to [0050] of JP-A-9-34110
-Onium salts represented by formulas (IV) to (IV):
Known polymerization initiators such as the thermal polymerization initiator described in Paragraph No. [0016] of JP-A-1 (1998) are also preferably used. When other polymerization initiators are used in combination, their content is preferably not more than 50% by weight of the specific radical generator. The radical generator used in the present invention preferably has a maximum absorption wavelength of 400 nm or less, and more preferably 360 nm or less. By setting the absorption wavelength in the ultraviolet region, the image forming material can be handled under a white light.

II) Compound whose Physical and Chemical Properties Change Irreversibly Due to Radicals I, a second essential component in the heat-sensitive composition of the present invention.
I) Compounds whose physical and chemical properties change irreversibly by radicals are described. This compound is a compound whose physical property or chemical property is changed by the action of a radical generated by the heat of the radical generator and the changed state is maintained, and a compound having such properties. There is no particular limitation as long as any compound can be used. For example, in many cases, the compounds listed in the above-mentioned I) radical generator have such properties. The characteristics of the compound of II) that are changed by radicals generated from the radical generator include, for example, molecular properties such as absorption spectrum (color), chemical structure, polarizability, solubility, strength, refractive index, fluidity, and adhesion. Physical properties such as properties.

When a compound whose absorption spectrum is changed by oxidation / reduction or nucleophilic addition reaction is used as the compound of II), oxidation or reduction by radicals generated from a radical generator is caused, and an image can be formed. . Such examples are described, for example, in J. Am. Chem. Soc., 108, 12
8 (1986), J. Imaging. Soc., 30, 215 (1
986), Israel. J. Chem., 25, 264 (1986).
Year).

Further, a compound capable of addition polymerization or polycondensation can be used as the compound (II) and a thermosetting resin or a negative type photopolymer can be formed by combining the compound (I) with a radical generator. It is.

The content of the compound (II) is appropriately selected in accordance with the desired property change or the compound to be used, but the absorption spectrum generally changes due to oxidation / reduction or nucleophilic addition reaction. When a compound is used, it is about 1 to 50% by weight based on the total solid content of the composition, and when a compound capable of addition polymerization or polycondensation is used, about 1 to 60% by weight based on the total solid content of the composition , Preferably 5 to 50% by weight
It is about.

As one of the objects of the present invention, as a compound of II) suitable for producing a highly sensitive lithographic printing plate precursor, II-1)
Compounds having a polymerizable unsaturated group are exemplified. Hereinafter, this compound will be described in detail. II-1) Compound having a polymerizable unsaturated group The compound having a polymerizable unsaturated group used in the present invention is an addition polymerizable compound having at least one ethylenically unsaturated double bond, and is preferably Is selected from compounds having at least one, and preferably at least two, terminal ethylenically unsaturated bonds. Such compounds are widely known in the industrial field, and they can be used in the present invention without any particular limitation. These are, for example, monomers, prepolymers, ie dimers,
Includes those having chemical forms such as trimers and oligomers, or mixtures thereof, and copolymers thereof. Examples of monomers and copolymers thereof include unsaturated carboxylic acids (eg, acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid, maleic acid, etc.) and esters and amides thereof, and are preferred. As the ester, an ester of an unsaturated carboxylic acid and an aliphatic polyhydric alcohol compound and an amide of an unsaturated carboxylic acid and an aliphatic polyamine compound are used. Further, an unsaturated carboxylic acid ester having a nucleophilic substituent such as a hydroxyl group, an amino group or a mercapto group, an addition reaction product of an amide with a monofunctional or polyfunctional isocyanate, an epoxy,
A dehydration condensation product with a monofunctional or polyfunctional carboxylic acid is also preferably used.

Further, an isocyanate group, an epoxy group,
Having an electrophilic substituent such as an unsaturated carboxylic acid ester, an amide and a monofunctional or polyfunctional alcohol,
Amines, addition products with thiols, halogen groups,
Substitution products of unsaturated carboxylic esters and amides having a leaving substituent such as a tosyloxy group with monofunctional or polyfunctional alcohols, amines and thiols are also suitable. As another example, it is also possible to use a group of compounds in which the above unsaturated carboxylic acid is replaced with unsaturated phosphonic acid, styrene, vinyl ether or the like.

Specific examples of the ester monomer of the aliphatic polyhydric alcohol compound and the unsaturated carboxylic acid include acrylic acid esters such as ethylene glycol diacrylate, triethylene glycol diacrylate, and 1,3.
-Butanediol diacrylate, tetramethylene glycol diacrylate, propylene glycol diacrylate, neopentyl glycol diacrylate, trimethylolpropane triacrylate, trimethylolpropane tri (acryloyloxypropyl) ether, trimethylolethane triacrylate, hexanediol diacrylate 1,4-cyclohexanediol diacrylate, tetraethylene glycol diacrylate, pentaerythritol diacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol diacrylate, dipentaerythritol hexaacrylate, sorbitol triacrylate, sorbitol Tetraacrylate, SO Bito one Le pentaacrylate, sorbitol hexaacrylate, tri (acryloyloxyethyl) isocyanurate, polyester acrylate oligomer.

Examples of the methacrylate include tetramethylene glycol dimethacrylate, triethylene glycol dimethacrylate, neopentyl glycol dimethacrylate, trimethylolpropane trimethacrylate, trimethylolethane trimethacrylate, ethylene glycol dimethacrylate, and 1,3-butanediol. Dimethacrylate, hexanediol dimethacrylate, pentaerythritol dimethacrylate, pentaerythritol trimethacrylate, pentaerythritol tetramethacrylate, dipentaerythritol dimethacrylate, dipentaerythritol hexamethacrylate, sorbitol trimethacrylate, sorbitol tetramethacrylate, bis [p- (3- Methacryloxy-2-hi Rokishipuropokishi) phenyl] dimethyl methane, bis - [p- (methacryloxyethoxy) phenyl] dimethyl methane.

Examples of itaconic acid esters include ethylene glycol diitaconate, propylene glycol diitaconate, 1,3-butanediol diitaconate,
There are 1,4-butanediol diitaconate, tetramethylene glycol diitaconate, pentaerythritol diitaconate, sorbitol tetritaconate and the like.

The crotonates include ethylene glycol dicrotonate, tetramethylene glycol dicrotonate, pentaerythritol dicrotonate,
Sorbitol tetradicrotonate and the like. Examples of the isocrotonic acid ester include ethylene glycol diisocrotonate, pentaerythritol diisocrotonate, and sorbitol tetraisocrotonate.

Examples of the maleic acid ester include ethylene glycol dimaleate, triethylene glycol dimaleate, pentaerythritol dimaleate, and sorbitol tetramaleate.

Examples of other esters include aliphatic alcohol esters described in JP-B-46-27926, JP-B-51-47334 and JP-A-57-196231, and JP-A-59-5240 and JP-A-59-5240. 59-524
1, those having an aromatic skeleton described in JP-A-2-226149 and those containing an amino group described in JP-A-1-165613 are also preferably used. Further, the above-mentioned ester monomers can be used as a mixture.

Specific examples of the amide monomer of the aliphatic polyamine compound and the unsaturated carboxylic acid include methylenebis-acrylamide, methylenebis-methacrylamide, 1,6-hexamethylenebis-acrylamide, 1,6- Hexamethylene bis-methacrylamide,
Examples include diethylenetriaminetrisacrylamide, xylylenebisacrylamide, xylylenebismethacrylamide, and the like. Examples of other preferred amide-based monomers include those having a cyclohexylene structure described in JP-B-54-21726.

Further, urethane-based addition-polymerizable compounds produced by an addition reaction between an isocyanate and a hydroxyl group are also suitable.
JP-A-8-41708 discloses a polyisocyanate compound having two or more isocyanate groups per molecule and a hydroxyl-containing vinyl monomer represented by the following general formula (2) added to one molecule. Examples include vinyl urethane compounds containing two or more polymerizable vinyl groups.

[0080]

Embedded image

In the general formula (2), R and R ′ represent H or CH3. Also, urethane acrylates described in JP-A-51-37193, JP-B-2-32293 and JP-B-2-16765, and
Urethane compounds having an ethylene oxide skeleton described in JP-A-8-49860, JP-B-56-17654, JP-B-62-39417, and JP-B-62-39418 are also suitable.

Further, by using addition polymerizable compounds having an amino structure or a sulfide structure in the molecule described in JP-A-63-277563, JP-A-63-260909 and JP-A-1-105238. Can obtain a photosensitive composition having an extremely high photosensitive speed.

Another example is disclosed in JP-A-48-641.
No. 83, JP-B-49-43191, JP-B-52-30
No. 490, polyfunctional acrylates and methacrylates such as polyester acrylates and epoxy acrylates obtained by reacting an epoxy resin with (meth) acrylic acid as described in each publication. Also,
JP-B-46-43946, JP-B-1-40337,
Specific unsaturated compounds described in JP-B-1-40336,
Vinyl phosphonic acid compounds described in JP-A-2-25493 can also be mentioned. In some cases, a structure containing a perfluoroalkyl group described in JP-A-61-22048 is preferably used. Further, the Journal of the Adhesion Society of Japan vol. 20, no. 7, pages 300 to 308 (1
984) as photocurable monomers and oligomers.

Regarding these addition polymerizable compounds, what kind of structure is used, whether they are used alone or in combination,
Details of the method of use, such as the amount of addition, can be arbitrarily set in accordance with the final performance design of the light-sensitive material. For example, it is selected from the following viewpoints. From the viewpoint of the photosensitive speed, a structure having a large unsaturated group content per molecule is preferable, and in many cases, a bifunctional or more functional structure is preferable. In order to increase the strength of the image area, that is, the cured film, those having three or more functional groups are preferable, and further, different functional numbers and different polymerizable groups (for example, acrylates, methacrylates, styrene compounds, vinyl ethers) It is also effective to adjust both the photosensitivity and the intensity by using the compound (1) in combination. A compound having a large molecular weight or a compound having a high hydrophobicity is excellent in photosensitive speed and film strength, but may not be preferable in terms of developing speed and precipitation in a developing solution.

Further, compatibility with other components (eg, binder polymer, initiator, colorant, etc.) in the heat-sensitive composition,
The selection and use of the addition polymerization compound is also an important factor for the dispersibility. For example, the use of a low-purity compound or the combination of two or more compounds may improve the compatibility.

The heat-sensitive composition of the present invention is characterized by exhibiting an irreversible property change due to heat. By adding a light-to-heat conversion agent in addition to the above components, heat mode exposure, typically, The above-mentioned property change can be caused by a laser emitting infrared rays, that is, a composition having photosensitivity can be obtained. This II below
I) The photothermal conversion agent will be described. III) Photothermal conversion agent The photothermal conversion agent used in the present invention has a function of absorbing a predetermined wavelength of light and converting it into heat. By the heat generated at this time, that is, by the heat mode exposure of a wavelength which can be absorbed by the photothermal conversion agent III), the radical generator as the component I) is decomposed to generate radicals. The photothermal conversion agent used in the present invention is not particularly limited as long as it has a function of converting absorbed light into heat.In general, the wavelength of an infrared laser used for writing, that is,
Having an absorption maximum at a wavelength of 760 nm to 1200 nm,
Dyes or pigments known as so-called infrared absorbers are mentioned.

As the dye, commercially available dyes and known dyes described in literatures such as “Dye Handbook” (edited by The Society of Synthetic Organic Chemistry, Japan, 1970) can be used. Specifically, dyes such as azo dyes, metal complex salt azo dyes, pyrazolone azo dyes, naphthoquinone dyes, anthraquinone dyes, phthalocyanine dyes, carbonium dyes, quinone imine dyes, methine dyes, cyanine dyes, squarylium dyes, pyrylium salts, and metal thiolate complexes Is mentioned.

Preferred dyes include, for example, those described in
Cyanine dyes described in JP-A-8-125246, JP-A-59-84356, JP-A-59-202829, JP-A-60-78787, etc .;
No. 96, JP-A-58-181690, JP-A-58-1
No. 94595, etc., methine dyes described in
8-112793, JP-A-58-224793, JP-A-59-48187, JP-A-59-73996,
Naphthoquinone dyes described in JP-A-60-52940 and JP-A-60-63744;
Squarylium dyes described in No. 12792, etc.,
Cyanine dyes described in British Patent 434,875 and the like can be mentioned.

Further, a near infrared absorption sensitizer described in US Pat. No. 5,156,938 is preferably used, and a substituted arylbenzo (thio) described in US Pat. No. 3,881,924 is also preferable. Pyrylium salt, JP-A-57-142645
No. (U.S. Pat. No. 4,327,169) described in JP-A-58-181051, JP-A-58-220143, JP-A-59-41363, and JP-A-59-41363.
Nos. -84248, 59-84249, 59-14
Pyrylium compounds described in JP-A Nos. 6063 and 59-146061, cyanine dyes described in JP-A-59-216146, pentamethine thiopyrylium salts described in U.S. Pat. No. 4,283,475, and the like. Fairness 5-13
Pyrylium compounds disclosed in JP-A-514 and JP-A-5-19702 are also preferably used.

Further, as another preferred example of the dye, US Pat. No. 4,756,993 discloses a compound represented by the formula (I):
Near-infrared absorbing dyes described as (II) can be mentioned.

Among these dyes, particularly preferred are a cyanine dye, a squarylium dye, a pyrylium salt, and a nickel thiolate complex. Further, a cyanine dye is preferable, and a cyanine dye represented by the following general formula (I) is most preferable.

[0092]

Embedded image

In the general formula (I), X ¹ is a halogen atom,
Or an X ² -L ^1. Here, X ² represents an oxygen atom or a sulfur atom, and L ¹ represents a hydrocarbon group having 1 to 12 carbon atoms. R ¹ and R ² each independently represent a hydrocarbon group having 1 to 12 carbon atoms. From the viewpoint of storage stability of a photosensitive layer coating liquid, R ¹ and R ² are preferably a hydrocarbon group having two or more carbon atoms, further, R ¹ and R ²
And particularly preferably combine with each other to form a 5- or 6-membered ring.

Ar ¹ and Ar ² may be the same or different and each represents an aromatic hydrocarbon group which may have a substituent. Preferred aromatic hydrocarbon groups include a benzene ring and a naphthalene ring. Preferred examples of the substituent include a hydrocarbon group having 12 or less carbon atoms, a halogen atom, and an alkoxy group having 12 or less carbon atoms. Y ¹ and Y ² may be the same or different and each represents a sulfur atom or a dialkylmethylene group having 12 or less carbon atoms. R ³ and R ⁴ may be the same or different, and represent a hydrocarbon group having 20 or less carbon atoms which may have a substituent. Preferred substituents include alkoxy groups having 12 or less carbon atoms,
Examples include a carboxyl group and a sulfo group. R ⁵ , R ⁶ , R
⁷ and R ⁸ may be the same or different,
It represents a hydrogen atom or a hydrocarbon group having 12 or less carbon atoms. From the viewpoint of availability of raw materials, a hydrogen atom is preferable. Z ^1- represents a counter cation. However, when any of R ^{1 to} R ⁸ is substituted with a sulfo group, Z ^1- is not required. Preferred Z ¹⁻ is, from the storage stability of the photosensitive layer coating solution, a halogen ion, a perchlorate ion, a tetrafluoroborate ion, a hexafluorophosphate ion,
And sulfonate ions, particularly preferably perchlorate ion, hexafluorophosphate ion and arylsulfonate ion.

In the present invention, specific examples of the cyanine dye represented by the general formula (I) which can be suitably used include paragraph [0] of Japanese Patent Application No. 11-310623.
017] to [0019].

The pigment used in the present invention includes:
Commercial Pigment and Color Index (CI) Handbook,
"Latest Pigment Handbook" (edited by Japan Pigment Technical Association, 1977), "Latest Pigment Application Technology" (CMC Publishing, 1986), "Printing Ink Technology" CMC Publishing, 1984)
Can be used.

The types of pigments include black pigment, yellow pigment, orange pigment, brown pigment, red pigment, purple pigment,
Blue pigment, green pigment, fluorescent pigment, metal powder pigment, etc.
Polymer-bound dyes. Specifically, insoluble azo pigments, azo lake pigments, condensation azo pigments, chelate azo pigments, phthalocyanine pigments, anthraquinone pigments,
Perylene and perinone pigments, thioindigo pigments, quinacridone pigments, dioxazine pigments, isoindolinone pigments, quinophthalone pigments, dyeing lake pigments,
Azine pigments, nitroso pigments, nitro pigments, natural pigments, fluorescent pigments, inorganic pigments, carbon black and the like can be used.
Preferred among these pigments is carbon black.

These pigments may be used without surface treatment, or may be used after surface treatment. Examples of the surface treatment include a method of surface coating a resin or wax, a method of attaching a surfactant, and a method of bonding a reactive substance (eg, a silane coupling agent, an epoxy compound, a polyisocyanate, etc.) to the pigment surface. Can be considered. The above surface treatment methods are described in "Properties and Applications of Metallic Soap" (Koshobo),
It is described in "Printing Ink Technology" (CMC Publishing, 1984) and "Latest Pigment Application Technology" (CMC Publishing, 1986).

The particle size of the pigment is preferably in the range of 0.01 μm to 10 μm, more preferably in the range of 0.05 μm to 1 μm, and particularly preferably in the range of 0.1 μm to 1 μm.
Is preferably within the range. Pigment particle size 0.01μ
If it is less than m, the dispersion is not preferred in terms of stability in the coating solution of the image-sensitive layer.

As a method for dispersing the pigment, a known dispersion technique used in the production of ink or toner can be used. Examples of the disperser include an ultrasonic disperser, a sand mill, an attritor, a pearl mill, a super mill, a ball mill, an impeller, a disperser, a KD mill, a colloid mill, a dynatron, a three-roll mill, and a pressure kneader. For details, refer to “Latest Pigment Application Technology” (CMC Publishing, 1
986).

These photothermal conversion agents are preferably added to the heat-sensitive composition in an amount of 0.1 to 20% by weight of the total solids. If the amount is less than this range, the sensitivity of the property change due to exposure is low, and the photosensitivity tends to be insufficient.If the amount is too large, the uniformity and strength of the film tend to decrease. Is also not preferred.

Next, the lithographic printing plate precursor of the present invention using the above heat-sensitive composition will be described. In the lithographic printing plate precursor according to the invention, the heat-sensitive composition is used for a recording layer. (Recording Layer) First, the recording layer (photosensitive layer) having an image forming function in the lithographic printing plate precursor according to the invention will be described.
The photosensitive layer of the lithographic printing plate precursor according to the invention comprises: I) a radical polymerization initiator represented by the following general formula (A); III) a photothermal conversion agent; II-1) a compound having a polymerizable unsaturated group; ,
IV) Although it contains a binder polymer, by irradiation of infrared laser, III) the photothermal conversion agent generates heat and the light of the infrared laser or III) heat generated by the photothermal conversion agent,
I) The radical generator represented by the general formula (A) is decomposed to generate radicals. II-1) The curing reaction of the compound having a polymerizable unsaturated group is accelerated, and the exposed portion is cured to form an image. A negative image serving as a copy is formed.

In forming the photosensitive layer of the lithographic printing plate precursor according to the present invention, the above-mentioned I) the radical generator represented by the general formula (A) is used in an amount of 0.5 to 1 based on the total solid content of the photosensitive layer.
It is preferably contained at 5% by weight. This radical generator is used in combination with a III) photothermal conversion agent described later, and generates a radical by the light or heat or both energy when irradiating an infrared laser, and II-1) polymerizable unsaturated groups. It has the function of initiating and promoting the polymerization of compounds having

II- used for the recording layer of the lithographic printing plate precursor II-
1) As the compound having a polymerizable unsaturated group, a compound described in detail in the description of the compound of the above II) is used. A specific structure may be selected for the purpose of improving the adhesion of the body, the overcoat layer, and the like.
Regarding the compounding ratio of the II-1) addition-polymerizable compound in the heat-sensitive composition, the larger the ratio, the more advantageous in sensitivity. However, if the ratio is too large, undesired phase separation occurs or the heat-sensitive composition of Problems in the production process due to stickiness (for example, poor production due to transfer of photosensitive material components and adhesion) and problems such as precipitation from a developing solution may occur when a lithographic printing plate precursor is used. From these viewpoints, the preferable compounding ratio is, in many cases, 5 to 80 with respect to the total solid content of the composition constituting the recording layer.
% By weight, preferably 25 to 75% by weight. These may be used alone or in combination of two or more. In addition, the method of using the addition polymerizable compound can be arbitrarily selected from the viewpoints of the degree of polymerization inhibition with respect to oxygen, resolution, fogging property, refractive index change, surface tackiness, etc. Depending on the case, a layer structure and a coating method such as undercoating and overcoating may be performed.

In the lithographic printing plate precursor according to the present invention,
III) The photothermal conversion agent may be added to the same layer as other components, or may be added to another layer provided separately. However, when a negative-type image forming material is prepared, Wavelength 760nm
It is preferable that the optical density at the absorption maximum in the range of -1200 nm is between 0.1 and 3.0. Outside of this range, sensitivity tends to decrease. Since the optical density is determined by the above III) the amount of the photothermal conversion agent added and the thickness of the recording layer, the predetermined optical density can be obtained by controlling both conditions. The optical density of the recording layer can be measured by a conventional method. As a measuring method, for example, on a transparent or white support, a coating layer after drying is formed to a recording layer having a thickness appropriately determined in a range necessary for a lithographic printing plate, and a transmission type optical densitometer is used. Examples include a method of measuring, a method of forming a recording layer on a reflective support such as aluminum, and measuring a reflection density.

IV) Binder Insoluble in Water and Soluble in Alkaline Aqueous Solution In the lithographic printing plate precursor according to the invention, it is preferable to further use a binder polymer in the recording layer. It is preferable to include a linear organic high molecular polymer as the binder. Any of such “linear organic high molecular polymers” may be used. Preferably, a water-soluble or weakly alkaline water-soluble or swellable linear organic high molecular polymer that enables water development or weakly alkaline water development is selected. The linear organic high molecular polymer is selected and used not only as a film forming agent of the composition but also as a water, weakly alkaline water or organic solvent developing agent. For example, when a water-soluble organic high molecular polymer is used, water development becomes possible. Examples of such a linear organic high molecular polymer include an addition polymer having a carboxylic acid group in a side chain, for example, Japanese Unexamined Patent Publication No.
Nos. 9-44615, JP-B-54-34327, JP-B-58-12577, JP-B-54-25957, JP-A-54-92723, JP-A-59-53836, and JP-A-59-71048. Those described, that is, methacrylic acid copolymer, acrylic acid copolymer, itaconic acid copolymer, crotonic acid copolymer, maleic acid copolymer, partially esterified maleic acid copolymer, and the like. Similarly, there is an acidic cellulose derivative having a carboxylic acid group in the side chain. In addition, those obtained by adding a cyclic acid anhydride to an addition polymer having a hydroxyl group are useful.

In particular, among these, [benzyl (meth) acrylate / (meth) acrylic acid / optionally other addition-polymerizable vinyl monomers] copolymer and [allyl (meth) acrylate / (meth) acrylic acid / Other addition-polymerizable vinyl monomers as needed) copolymer,
It is suitable because it has an excellent balance of film strength, sensitivity and developability.

In addition, Japanese Patent Publication No. Hei 7-2004,
JP-A-120041, JP-B-7-120042, JP-B-8-12424, JP-A-63-287944, JP-A-63-287947, JP-A-1-271174,
The urethane-based binder polymer containing an acid group described in Japanese Patent Application No. 10-116232 is very excellent in strength, and is advantageous in terms of printing durability and low exposure suitability.
Further, a binder having an amide group described in JP-A-11-171907 is suitable because it has excellent developability and film strength.

In addition, polyvinyl pyrrolidone, polyethylene oxide and the like are useful as the water-soluble linear organic polymer. In order to increase the strength of the cured film, alcohol-soluble nylon, polyether of 2,2-bis- (4-hydroxyphenyl) -propane and epichlorohydrin, and the like are also useful. These linear organic high molecular polymers can be incorporated in any amount into the entire composition. However, if it exceeds 90% by weight, no favorable result is obtained in view of the strength of the formed image and the like. Preferably 30 to 85
% By weight. In addition, the compound having an ethylenically unsaturated double bond and the linear organic high molecular weight are 1/9 to 7 by weight ratio.
/ 3 is preferable.

The binder polymer of the present invention is substantially insoluble in water and soluble in an aqueous alkali solution. For this reason, an organic solvent which is not environmentally unfavorable is not used or the amount used is extremely small as a developer.
The acid value (the acid content per gram of the polymer expressed by a chemical equivalent number) and the molecular weight of such a binder polymer are appropriately selected from the viewpoint of image strength and developability. The preferred acid value is 0.4 to 3.0 meq / g, and the preferred molecular weight is in the range of 3,000 to 500,000, more preferably the acid value is in the range of 0.6 to 2.0, and the molecular weight is in the range of 10,000 to 300,000. It is.

(V) Other components In the composition constituting the recording layer of the lithographic printing plate of the present invention,
Further, other components suitable for the use, the production method and the like can be appropriately added. Hereinafter, preferred additives will be exemplified. (V-1) Co-sensitizer The sensitivity can be further improved by using a certain additive (hereinafter referred to as a co-sensitizer). Although their mechanism of action is not clear, most are thought to be based on the following chemical processes. That is, a co-sensitizer reacts with a photoreaction initiated by a thermal polymerization initiator and various intermediate active species (radicals, cations) generated during the subsequent addition polymerization reaction to generate a new active radical. It is estimated that These are roughly (a) those that can be reduced to produce active radicals, (b) those that can be oxidized to produce active radicals, and (C) those that react with less active radicals and are more active radicals. Or acting as a chain transfer agent, but it is often unconventional as to which of these compounds an individual compound belongs to.

(A) Compound that generates an active radical by being reduced Compound having a carbon-halogen bond: It is considered that the carbon-halogen bond is reductively cleaved to generate an active radical. Specifically, for example, trihalomethyl-s-
Triazines, trihalomethyloxadiazoles and the like can be suitably used. Compound having a nitrogen-nitrogen bond: It is considered that the nitrogen-nitrogen bond is reductively cleaved to generate an active radical. Specifically, hexaarylbiimidazoles and the like are preferably used. Compound having an oxygen-oxygen bond: It is considered that an oxygen-oxygen bond is reductively cleaved to generate an active radical. Specifically, for example, organic peroxides and the like are preferably used. Onium compound: a carbon-hetero bond or an oxygen-
It is thought that the nitrogen bond is cleaved to generate an active radical. Specifically, for example, diaryliodonium salts,
Triarylsulfonium salts, N-alkoxypyridinium (azinium) salts and the like are preferably used. Ferrocene, iron arene complexes: can generate active radicals reductively.

(B) Compound which is oxidized to generate an active radical Alkyl ate complex: It is considered that a carbon-hetero bond is oxidatively cleaved to generate an active radical. Specifically, for example, triarylalkyl borates are preferably used. Alkylamine compound: It is considered that the CX bond on carbon adjacent to nitrogen is cleaved by oxidation to generate an active radical. X is preferably a hydrogen atom, a carboxyl group, a trimethylsilyl group, a benzyl group, or the like.
Specific examples include ethanolamines, N-phenylglycines, N-trimethylsilylmethylanilines and the like. Sulfur- and tin-containing compounds: Compounds in which the nitrogen atom of the above-mentioned amines is replaced with a sulfur atom or a tin atom can generate an active radical by the same action. Compounds having an SS bond are also known to be sensitized by SS cleavage.

Α-Substituted methylcarbonyl compound: An active radical can be generated by the cleavage of the carbonyl-α carbon bond by oxidation. In addition, those obtained by converting carbonyl to oxime ether also show the same action. In particular,
2-alkyl-1- [4- (alkylthio) phenyl]
-2-morpholinopronones-1 and oxime ethers obtained by reacting these with hydroxyamines and then etherifying N-OH. Sulfinates: Active radicals can be generated reductively. Specific examples include sodium arylsulfin and the like.

(C) Compounds that react with radicals to convert them into highly active radicals or act as chain transfer agents: For example, compounds having SH, PH, SiH, and GeH in the molecule are used. These can generate a radical by donating hydrogen to a low-activity radical species, or can generate a radical by being oxidized and then deprotonated. Specific examples include 2-mercaptobenzimidazoles.

More specific examples of these co-sensitizers are described in, for example, Japanese Patent Application Laid-Open No. 9-236913 as additives for the purpose of improving the sensitivity. Can also be applied. These co-sensitizers can be used alone or in combination of two or more. The amount is suitably in the range of 0.05 to 100 parts by weight, preferably 1 to 80 parts by weight, more preferably 3 to 50 parts by weight, per 100 parts by weight of the compound having an ethylenically unsaturated double bond.

(V-2) Polymerization Inhibitor In the present invention, in addition to the above basic components, there is no need for a compound having an ethylenically unsaturated double bond which can be polymerized during the production or storage of the photosensitive composition. It is desirable to add a small amount of a thermal polymerization inhibitor in order to prevent a thermal polymerization. Suitable thermal polymerization inhibitors include hydroquinone, p
-Methoxyphenol, di-t-butyl-p-cresol, pyrogallol, t-butylcatechol, benzoquinone, 4,4'-thiobis (3-methyl-6-t-butylphenol), 2,2'-methylenebis (4- Methyl-
6-t-butylphenol), cerium N-nitrosophenylhydroxyamine, and the like. The amount of the thermal polymerization inhibitor added is about 0.01 to the weight of the whole composition.
% By weight to about 5% by weight is preferred. Also, if necessary, a higher fatty acid derivative such as behenic acid or behenic acid amide is added to prevent polymerization inhibition by oxygen, and when used as a lithographic printing plate precursor, after application to a support or the like, During the drying process, it may be unevenly distributed on the surface of the photosensitive layer. The amount of the higher fatty acid derivative to be added ranges from about 0.5% by weight to about 10% by weight of the total composition.
% By weight is preferred.

(V-3) Colorant, etc. When the photosensitive composition of the present invention is used in a lithographic printing plate precursor, a dye or pigment may be added for the purpose of coloring the photosensitive layer. As a result, as a printing plate,
It is possible to improve so-called plate inspection properties such as visibility after plate making and suitability for an image density measuring device. As a coloring agent, since many dyes cause a decrease in the sensitivity of the photopolymerizable photosensitive layer,
As the colorant, use of a pigment is particularly preferable. Specific examples include pigments such as phthalocyanine pigments, azo pigments, carbon black, and titanium oxide, and dyes such as ethyl violet, crystal violet, azo dyes, anthraquinone dyes, and cyanine dyes. Dyes and pigments may be added in an amount of about 0.5% to about 5% by weight of the total composition.
% By weight is preferred.

(V-4) Other Additives When the photosensitive composition of the present invention is used for a lithographic printing plate precursor, an inorganic filler, other plasticizers, and a photosensitive agent are used to improve the physical properties of the cured film. A known additive such as a sensitizer capable of improving the ink inking property of the layer surface may be added.

Examples of the plasticizer include dioctyl phthalate, didodecyl phthalate, triethylene glycol dicaprylate, dimethyl glycol phthalate, tricresyl phosphate, dioctyl adipate, dibutyl sebacate, triacetyl glycerin and the like. A binder was used. In this case, it can be added in an amount of 10% by weight or less based on the total weight of the compound having an ethylenically unsaturated double bond and the binder.

Further, a UV initiator, a mature cross-linking agent or the like can be added to enhance the effect of heating and exposure after development for the purpose of improving the film strength (printing durability) described later. In addition, it is possible to provide an additive and an intermediate layer for improving the adhesion between the photosensitive layer and the support and for improving the development and removability of the unexposed photosensitive layer. For example, a compound having a diazonium structure or a phosphone compound, such as a compound having a relatively strong interaction with the substrate or an undercoat, the adhesion is improved,
The printing durability can be increased, while the addition or undercoating of a hydrophilic polymer such as polyacrylic acid or polysulfonic acid improves the developability of the non-image area and improves the stain resistance.

When the photosensitive composition of the present invention is coated on a support to provide a lithographic printing plate, it is used after being dissolved in various organic solvents. As the solvent used here, acetone, methyl ethyl ketone, cyclohexane, ethyl acetate, ethylene dichloride, tetrahydrofuran, toluene, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol dimethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, Acetylacetone, cyclohexanone, diacetone alcohol, ethylene glycol monomethyl ether acetate, ethylene glycol ethyl ether acetate, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether acetate, 3-methoxypropanol, methoxymethoxyethanol, diethylene glycol monomethyl ether, Ethylene glycol monoethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, 3-methoxypropyl acetate, N,
N-dimethylformamide, dimethyl sulfoxide, γ
-Butyrolactone, methyl lactate, ethyl lactate, etc. These solvents can be used alone or as a mixture. And the concentration of solids in the coating solution is 2
~ 50% by weight is suitable.

The amount of the photosensitive layer to be applied to the support is desirably appropriately selected depending on the application in consideration of the sensitivity, developability of the photosensitive layer, and the strength and printing durability of the exposed film. When the coating amount is too small, the printing durability becomes insufficient. On the other hand, if the amount is too large, the sensitivity is lowered, the exposure takes time, and the developing process requires a longer time, which is not preferable. The coating amount of the lithographic printing plate precursor according to the invention is generally about 0. lg / m ² to about 10 g / m ²
Is appropriate. More preferably 0.5 to 5 g / m
²

"Protective layer" In the lithographic printing plate precursor according to the invention,
A protective layer can be provided on the recording layer containing the photopolymerizable compound, if necessary. Such lithographic printing plate precursors are usually exposed in the air, but the protective layer is a low-molecular-weight substance such as oxygen or a basic substance present in the atmosphere that inhibits an image forming reaction caused by exposure in the photosensitive layer. The compound is prevented from being mixed into the photosensitive layer, and the image formation reaction due to exposure in the air is prevented. Therefore, the desired property of such a protective layer is that the permeability of low molecular compounds such as oxygen is low,
Furthermore, it is desirable that the light used for exposure has good transparency, excellent adhesion to the photosensitive layer, and that it can be easily removed in the development step after exposure.

Such a device for the protective layer has been conventionally devised, which is described in detail in US Pat. No. 3,458,311 and JP-A-55-49729. As a material that can be used for the protective layer, for example, a water-soluble polymer compound having relatively excellent crystallinity is preferably used, and specifically, polyvinyl alcohol, polyvinylpyrrolidone, acidic celluloses, gelatin, gum arabic, and polystyrene. Although water-soluble polymers such as acrylic acid are known, use of polyvinyl alcohol as a main component gives the best results in terms of basic properties such as oxygen barrier properties and development removability. The polyvinyl alcohol used for the protective layer may be partially substituted with an ester, an ether, or an acetal as long as it contains an unsubstituted vinyl alcohol unit for obtaining necessary oxygen barrier properties and water solubility. Similarly, a part thereof may have another copolymer component.

Specific examples of polyvinyl alcohol include 7
1-100% hydrolyzed, molecular weight 300-240
A range of 0 can be given. Specifically, Kuraray's PVA-105, PVA-110, PVA
A-117, PVA-117H, PVA-120, PV
A-124, PVA-124H, PVA-CS, PVA
-CST, PVA-HC, PVA-203, PVA-2
04, PVA-205, PVA-210, PVA-21
7, PVA-220, PVA-224, PVA-217
EE, PVA-217E, PVA-220E, PVA-
224E, PVA-405, PVA-420, PVA-
613, L-8 and the like.

The components of the protective layer (selection of PVA, use of additives), the amount of coating, etc. are selected in consideration of fogging properties, adhesion, and scratch resistance in addition to oxygen barrier properties and development removability. Generally, the higher the hydrolysis rate of the PVA used (the higher the content of unsubstituted vinyl alcohol units in the protective layer) and the thicker the film thickness, the higher the oxygen barrier property, which is advantageous in terms of sensitivity. However, when the oxygen-barrier property is extremely increased, there arises a problem that an unnecessary polymerization reaction occurs during production or raw storage, and unnecessary fogging and thickening of an image occur during image exposure. Further, the adhesion to the image area and the scratch resistance are also extremely important in handling the plate. That is, when a hydrophilic layer made of a water-soluble polymer is laminated on a lipophilic polymer layer, film peeling due to insufficient adhesive force tends to occur, and the peeled portion causes defects such as poor film curing due to inhibition of oxygen polymerization.

On the other hand, various proposals have been made to improve the adhesiveness between these two layers. For example, US Patent No. 2
No. 92,501 and U.S. Pat. No. 44,563, an acrylic emulsion or a water-insoluble vinylpyrrolidone-vinyl acetate copolymer or the like is mixed in a hydrophilic polymer mainly composed of polyvinyl alcohol in an amount of 20 to 60% by weight. It is described that sufficient adhesiveness can be obtained by laminating on a polymer layer. Any of these known techniques can be applied to the protective layer in the present invention. Regarding the method of applying such a protective layer,
For example, U.S. Pat. No. 3,458,311;
No. 49729.

Further, other functions can be imparted to the protective layer. For example, by adding a colorant (such as a water-soluble dye), which has excellent transmittance for light used for exposure (for example, a wavelength of 760 to 1200 nm for an infrared laser) and can efficiently absorb light having a wavelength not related to exposure. Further, the suitability for safelight can be further increased without lowering the sensitivity.

(Support) The support used in the lithographic printing plate precursor according to the invention is not particularly limited as long as it is a dimensionally stable plate-like material.
Paper, metal plate (eg, aluminum, zinc, copper, etc.), plastic film (eg, cellulose diacetate, cellulose triacetate, cellulose propionate, cellulose butyrate, cellulose acetate butyrate) laminated with polyethylene, polypropylene, polystyrene, etc. Cellulose nitrate, polyethylene terephthalate, polyethylene, polystyrene, polypropylene, polycarbonate, polyvinyl acetal, etc.). These are single component sheets such as resin films and metal plates,
The laminate may be a laminate of two or more materials, for example, such as the above-described metal-laminated or vapor-deposited paper or plastic film, or a laminated sheet of different types of plastic films.

As the support, a polyester film or an aluminum plate is preferable, and among them, an aluminum plate which has good dimensional stability and is relatively inexpensive is particularly preferable. Suitable aluminum plates are a pure aluminum plate and an alloy plate containing aluminum as a main component and 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 foreign elements in the alloy is at most 10% by weight
It is as follows. Particularly preferred aluminum 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,
About 0.1 to 0.6 mm, preferably 0.15 to
It is 0.4 mm, particularly preferably 0.2 to 0.3 mm.

Prior to roughening the aluminum plate, if necessary, a degreasing treatment with, for example, a surfactant, an organic solvent or an alkaline aqueous solution for removing rolling oil on the surface is performed. 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. Known mechanical methods such as a ball polishing method, a brush polishing method, a blast polishing method, and a buff polishing method can be used as the mechanical method. 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,
As disclosed in JP-A-54-63902, a method in which both are combined can also be used. The aluminum plate thus roughened can be subjected to an anodic oxidation treatment through alkali etching treatment and neutralization treatment, if desired, in order to increase the water retention and abrasion resistance of the surface. As the electrolyte used for the anodic oxidation 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.

The anodizing treatment conditions vary depending on the electrolyte to be used and cannot be specified unconditionally. However, in general, the concentration of the electrolyte is 1 to 80% by weight, and the solution temperature is 5 to 70 ° C.
Current density 5 to 60 A / dm ^2, voltage 1 to 100 V, which is an electrolyzing time of 10 seconds to 5 minutes. The amount of the anodized film is suitably 1.0 g / m ² or more, but more preferably in the range of 2.0 to 6.0 g / m ^2. When the anodic oxide coating is less than 1.0 g / m ² , the printing durability is insufficient, and the non-image area of the lithographic printing plate is easily damaged, and the ink adheres to the damaged area during printing. "Scratch dirt" is likely to occur. Although such anodizing treatment is performed on a surface used for printing of the support of lithographic printing plates, the back around the electric lines of force, 0.01 to 3 g / m ² on the back surface
Is generally formed.

The hydrophilizing treatment of the surface of the support is performed after the anodic oxidation treatment, and a conventionally known treatment method is used. As such a hydrophilic treatment,
U.S. Pat. Nos. 2,714,066 and 3,181,4
No. 61, No. 3,280,734 and No. 3,902,7
There is an alkali metal silicate (for example, an aqueous solution of sodium silicate) disclosed in Japanese Patent No. 34-34. In this method, the support is immersed in an aqueous solution of sodium silicate or electrolytically treated. In addition, Japanese Patent Publication No. 36-22
No. 063, and potassium fluoride zirconate disclosed in U.S. Pat. Nos. 3,276,868 and 4,15.
For example, a method of treating with polyvinyl phosphonic acid as disclosed in JP-A-3,461 and JP-A-4,689,272 is used. Among these, a particularly preferred hydrophilic treatment in the present invention is a silicate treatment. The silicate treatment will be described below.

The anodic oxide film of the aluminum plate treated as described above was coated with an alkali metal silicate in an amount of 0.1 to 30% by weight, preferably 0.5 to 10% by weight, and a pH of 10 at 25 ° C. Aqueous solution, for example, 15 to 80
Soak at 0.5C for 0.5-120 seconds. If the pH of the alkali metal silicate aqueous solution is lower than 10, the solution will gel, and if it is higher than 13.0, the oxide film will be dissolved. As the alkali metal silicate used in the present invention, sodium silicate, potassium silicate, lithium silicate and the like are used. Hydroxides used to increase the pH of the aqueous alkali metal silicate solution include sodium hydroxide, potassium hydroxide and lithium hydroxide. In addition, an alkaline earth metal salt or a Group IVB metal salt may be added to the above-mentioned processing solution.
Examples of the alkaline earth metal salts include nitrates such as calcium nitrate, strontium nitrate, magnesium nitrate, and barium nitrate, and water-soluble salts such as sulfate, hydrochloride, phosphate, acetate, oxalate, and borate. No. Group IVB metal salts include titanium tetrachloride, titanium trichloride, potassium titanium fluoride, potassium titanium oxalate, titanium sulfate, titanium tetraiodide, zirconium chloride, zirconium dioxide, zirconium oxychloride, zirconium tetrachloride, and the like. Can be. Alkaline earth metal salt or
The Group IVB metal salts can be used alone or in combination of two or more. The preferred range of these metal salts is 0.0
1 to 10% by weight, more preferably 0.05 to 10% by weight.
5.0% by weight. Since the silicate treatment further improves the hydrophilicity on the aluminum plate surface, the ink hardly adheres to the non-image area during printing, and the stain performance is improved.

On the back surface of the support, a back coat is provided if necessary. Examples of the back coat include a coating comprising a metal oxide obtained by hydrolyzing and polycondensing an organic polymer compound described in JP-A-5-45885 and an organic or inorganic metal compound described in JP-A-6-35174. Layers are preferably used. Among these coating layers, Si (OCH ₃ ) ₄ , Si (OC
_{2 H 5) 4, Si (} OC 3 H 7) 4, Si (OC
Alkoxy compounds of silicon such as ₄ H ₉ ) ₄ are inexpensive and readily available, and a coating layer of a metal oxide provided therefrom is particularly preferred because of its excellent development resistance.

(Exposure) As described above, the planographic printing plate precursor of the invention can be prepared. This lithographic printing plate precursor is image-exposed by a solid-state laser and a semiconductor laser that emit infrared light having a wavelength of 760 nm to 1200 nm. In the present invention, the developing treatment may be performed immediately after the laser irradiation, or the heat treatment may be performed between the laser irradiation step and the developing step. The conditions of the heat treatment are 80 ° C to 15 ° C.
It is preferable to carry out for 10 seconds to 5 minutes within the range of 0 ° C. By this heat treatment, the laser energy required for recording at the time of laser irradiation can be reduced.

(Developer) When a photosensitive material using the photosensitive composition of the present invention is used as an image forming material, usually
After image exposure, an unexposed portion of the photosensitive layer is removed with a developer to obtain an image. Preferred developers when these photopolymerizable compositions are used for preparing a lithographic printing plate include those described in JP-B-57-7427, such as sodium silicate and potassium silicate. Like sodium hydroxide, potassium hydroxide, lithium hydroxide, tribasic sodium phosphate, dibasic sodium phosphate, tribasic ammonium phosphate, dibasic ammonium phosphate, sodium metasilicate, sodium bicarbonate, aqueous ammonia, etc. An aqueous solution of a suitable inorganic alkali agent or an organic alkali agent such as monoethanolamine or diethanolamine is suitable. The alkaline solution is added so that the concentration of the alkaline solution is 0.1 to 10% by weight, preferably 0.5 to 5% by weight.

Also, such an alkaline aqueous solution includes:
If necessary, a small amount of a surfactant or an organic solvent such as benzyl alcohol, 2-phenoxyethanol or 2-butoxyethanol can be contained. For example, those described in U.S. Pat. Nos. 3,375,171 and 3,615,480 can be mentioned. Further, Japanese Unexamined Patent Publication No.
No. 0-26601, No. 58-54341, Tokubo Sho56
The developing solutions described in JP-A-39464 and JP-A-56-42860 are also excellent.

The lithographic printing plate obtained as described above can be subjected to a printing step after applying a desensitized gum if desired. Is subjected to a burning process. When burning a lithographic printing plate, before burning,
No. 2518, No. 55-28062, JP-A-62-3
It is preferable to treat with a surface-regulating liquid as described in JP-A Nos. 1859 and 61-159655. 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 to make the amount of the coating uniform with a squeegee or a squeegee roller after the coating.

The lithographic printing plate that has been subjected to the burning treatment can be subjected to a conventional treatment such as washing with water or gumming if necessary. 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 set on an offset printing machine or the like and used for printing a large number of sheets.

[0142]

EXAMPLES Examples of the present invention will be described below, but the present invention is not limited to these examples.

(Examples 1 to 22, Comparative Examples 1 to 4) [Preparation of Substrate] An aluminum plate (material 1050) having a thickness of 0.3 mm was washed with trichloroethylene and degreased, and then a nylon brush and a 400 mesh pumice were used. The surface was grained with a water suspension and washed well with water. This plate was immersed in a 25% aqueous solution of sodium hydroxide at 45 ° C. for 9 seconds to perform etching, washed with water, further immersed in 20% nitric acid for 20 seconds, and washed with water. At this time, the etching amount of the grained surface was about 3 g / m ² . Then this board is 7%
3 g / m ² at a current density of 15 A / dm ^{2 using} sulfuric acid as an electrolyte
Was provided, and then washed with water and dried to produce a substrate [A]. The substrate [A] was treated with a 2% by weight aqueous solution of sodium silicate at 25 ° C. for 15 seconds, and washed with water to prepare a substrate [B].

[Formation of a lithographic printing plate precursor] The following photosensitive layer coating solution was coated on the substrate [A] or [B] prepared as described above so that the coating amount was 1.5 g / m ^2. Then, the lithographic printing plate precursors of Examples 1 to 17 were obtained. Substrate used, I)
The radical polymerization initiator, II) photothermal conversion agent, III) a compound having a polymerizable unsaturated group (denoted as an addition polymerizable compound), and IV) a binder are as shown in Table 1 below.

(Coating solution for photosensitive layer)-Addition polymerizable compound (compound described in Table 1) 1.5 g-Binder (compound described in Table 1) 2.0 g-Photothermal conversion agent (compound described in Table 1) 0.1 g・ Polymerization initiator (compounds shown in Table 1) 0.2 g ・ Fluorine nonionic surfactant (Megafac F-177, manufactured by Dainippon Ink and Chemicals, Inc.) 0.02 g ・ Victoria Pure Blue 0.04 g ・ Methyl ethyl ketone 10 g ・ Methanol 7 g ・ 2-Methoxy-1-propanol 10 g

[0146]

[Table 1]

[0147]

Embedded image

(Addition polymerizable compounds in Table 1) (M-1) pentaerythritol tetraacrylate (M-2) glycerin dimethacrylate hexamethylene diisocyanate urethane prepolymer

(Binder in Table 1) (B-1) Allyl methacrylate / methacrylic acid / N-isopropylamide copolymer (copolymerization molar ratio: 67/13/20) Acid value (actually measured by NaOH titration) 15meq / g Polymerization average molecular weight 130,000 (B-2) Allyl methacrylate / methacrylic acid copolymer (copolymerization molar ratio: 83/17) Acid value (actually measured by NaOH titration) 1.55meq / g Polymerization average molecular weight 12.5 (B-3) Polyurethane resin which is a condensate of the following diisocyanate and diol (a) 4,4'-diphenylmethane diisocyanate (b) hexamethylene diisocyanate (c) polypropylene glycol (weight average molecular weight: 10
00) (d) 2,2-bis (hydroxymethyl) propionic acid ((a) / (b) / (c) / (d) copolymer molar ratio: 40/10/1)
5/35) Acid value (actually measured by NaOH titration) 1.05 meq / g Polymerization average molecular weight 45,000

(Comparative Examples 1-4) For comparison, the substrate [A]
Alternatively, other than those represented by the general formula (A) on the substrate [B], a counter anion having no carboxylate in an onium salt structure, for example, sulfonate (—SO ₃ ⁻ )
Using known radical polymerization initiators H-1, H-2, H-3, and H-4 (the structures are as shown below), each having the following formula: A photosensitive layer was formed using the layer coating solution to obtain a lithographic printing plate precursor (Comparative Examples 1 to 4).

[0151]

Embedded image

[Exposure and Development] The obtained lithographic printing plate precursor was output at a power of 500 mW, a wavelength of 830 nm, and a beam diameter of 17 μm.
After exposure at a main scanning speed of 5 m / sec using a (l / e ² ) semiconductor laser, a DN3C developer or a DP-4 developer and a rinsing solution FR-3 (1:
7) Automatic developing machine (Fuji Photo Film Co., Ltd.)
(Manufactured by PS Processor 900VR) and the following evaluation was performed. Table 1 also shows which developing solution was used in the developing process.

[Printing durability test] R201 manufactured by Roland was used as a printing machine, and G
EOS-G (N) was used. The printed matter in the solid image area was observed, and the printing durability was examined by the number of sheets at which the image began to fade. It was represented by a relative ratio where the numerical value (number of sheets) in Comparative Example 1 was 100. The greater the number, the better the printing durability.

[Evaluation of Sensitivity] The lithographic printing plate precursor was set to a wavelength of 83
Exposure was performed with a semiconductor laser emitting infrared light of about 0 to 850 nm. After exposure, developer D from Fuji Photo Film Co., Ltd.
The film was developed with N-3C (diluted with water at a ratio of 1: 2) or Developer DP-4 (diluted with water at a ratio of 1: 8) manufactured by Fuji Photo Film Co., Ltd., and washed with water. The amount of energy required for recording was calculated based on the line width and laser output of the images obtained at these times, the loss in the optical system, and the scanning speed. The smaller the value, the higher the sensitivity. These evaluation results are also shown in Table 1.

From the results in Table 1, it can be seen that the lithographic printing plate precursor according to the present invention has a high resistance of the image area to an alkali developing solution.
It can be seen that the printing durability is excellent and the sensitivity is high. On the other hand, the lithographic printing plate precursors of Comparative Examples 1 to 4 using known radical polymerization initiators were compared with each of Examples 3, 8, 1, and 10 obtained under the same conditions except for the polymerization initiator. It was found that both printing durability and sensitivity were poor.

(Examples 22 to 42, Comparative Examples 5 to 8) Polyvinyl alcohol (degree of saponification: 98) was formed on the photosensitive layer of the lithographic printing plate precursor obtained in Examples 1 to 21 and Comparative Examples 1 to 4.
Mol%, degree of polymerization: 550) in an amount of 2 g / m ² after drying.
After drying for 5 minutes, a lithographic printing plate precursor having a protective layer provided on the photosensitive layer was obtained, and Examples 22 to 42 and Comparative Examples 5 to 8, respectively. The resulting lithographic printing plate precursor was exposed and developed under the same conditions as in Examples 1 to 21 and Comparative Examples 1 to 4 to make a lithographic printing plate. The adhesion and printing durability were evaluated. The results are shown in Table 1 above.

From the results in Table 1, it can be seen that even when a protective layer was provided on the photosensitive layer, Examples 1 to 22 having no protective layer were used.
The same tendency is seen, and the lithographic printing plate precursor of the present invention is
It can be seen that the image portion has high resistance to an alkali developing solution, is excellent in printing durability, and has high sensitivity, and furthermore, the provision of a protective layer further improves the performance in both sensitivity and printing durability.

(Example 43) The following recording layer coating solution was applied on a polyethylene terephthalate film (0.1 mm thick) as a support so that the coating amount after drying was 2.0 g / m ² , Was obtained. (Recording layer coating solution) Addition polymerizable compound (M-1) 2.0 g Binder (B-1) 1.6 g Radical generator (SB-1) 0.4 g Methyl ethyl ketone 10 g Methanol 5 g 2- Methoxy-1-propanol 10 g

This recording material was placed in an oven at 200 ° C. for 1 hour.
The recording layer on the heating support was cured by heating for 5 seconds. Thereafter, the recording layer was immersed in dimethyl sulfoxide for 5 minutes, and the insolubilization rate of the recording layer was determined from the amount of the remaining recording layer.
The insolubilization rate was 97%. From this, it was confirmed that the recording layer made of the heat-sensitive composition of the present invention containing the radical generator of the general formula (A) was successfully cured by heating.

[0160] (Comparative Example 9) the radical generator of the recording layer coating liquid (SB-1: a counter cation CH ₃ COO ^-) instead of, SbF ₆ as a counter cation ^- those containing a radical generating agent having a The recording layer was heated and cured in the same manner as in Example 43, and the insolubilization rate was measured. As a result, the insolubilization rate was 14%. It was confirmed that the heat-sensitive composition of the present invention was excellent in sensitivity in comparison with a radical generator having a similar anion moiety.

Example 44 A recording layer coating solution described below was coated on a polyethylene terephthalate film (0.1 mm thick) as a support so that the coating amount after drying was 2.0 g / m ² , A yellow transparent recording material was obtained. (Recording layer coating solution)-Oxidizing color dye (leuco crystal violet) 0.2 g-Binder (polymethyl methacrylate) 2.7 g-Radical generator (SA-1) 0.3 g-Methyl ethyl ketone 10 g-Methanol 8 g-2-methoxy 8 g of -1-propanol

The recording material was placed in an oven at 200 ° C. for 15 minutes.
The recording layer on the heated support was heated for 2 seconds to develop a color. The recording layer developed a bright blue color. From this, it is presumed that in the recording layer composed of the heat-sensitive composition of the present invention containing the radical generator of the general formula (A), the leuco dye is oxidized and colored by the generation of radicals.

[0163]

According to the heat-sensitive composition of the present invention, irreversible changes in physical properties with high sensitivity can be obtained by heating. In addition, a negative type lithographic printing plate precursor using this heat-sensitive composition can be written by an infrared laser, has a good alkali developing solution resistance in an image area, has excellent printing durability, and has high sensitivity. It works.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Kunihiko Kodama Inventor 4000F, Kawajiri, Yoshida-cho, Haibara-gun, Shizuoka Pref. CB52 CC20 FA10 FA17 2H096 AA07 AA08 BA05 BA16 BA20 EA04 GA08 2H114 AA04 AA23 AA24 DA52 DA53 EA02 EA03

Claims (3)

[Claims] (1) a compound represented by the following general formula (A) which generates a radical by heat; and II) a compound whose physical and chemical properties are irreversibly changed by the radical. A heat-sensitive composition characterized. Formula (A) R-COO ^- M ^{+ In the} formula, R represents an alkyl group or an aryl group, and M ⁺ represents a counter cation selected from sulfonium, iodonium, diazonium, ammonium, and azinium. 2. The composition of claim 2, further comprising a photothermal conversion agent.
I) Exposure to the absorption wavelength of the photothermal conversion agent generates I) a radical of a compound which generates a radical by heat represented by the general formula (A), and II) Physical or chemical characteristics are irreversible due to the radical. 2. The heat-sensitive composition according to claim 1, wherein the physical or chemical properties of the compound that changes to the above change. 3. On a support, I) a radical polymerization initiator represented by the following general formula (A), III) a photothermal conversion agent, II-
A lithographic printing plate precursor compatible with a heat mode, comprising: 1) a compound having a polymerizable unsaturated group; and IV) a photosensitive layer containing a binder polymer. Formula (A) R-COO ^- M ^{+ In the} formula, R represents an alkyl group or an aryl group, and M ⁺ represents a counter cation selected from sulfonium, iodonium, diazonium, ammonium, and azinium.