JP2003295468A - Plate making method of photosensitive lithographic printing plate material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lithographic printing plate product having high sensitivity, stable storage property with time and favorable printing performance. <P>SOLUTION: A photosensitive lithographic printing plate containing an organic borate and a polymer binder having a polymerizable double bond in the side chain and a carboxyl group and having ≥50 mgKOH/g acid value is treated with developer containing a sulfonated aromatic hydrocarbon. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for making a photosensitive lithographic printing plate material. More specifically, it relates to a method for making a photosensitive lithographic printing plate material capable of forming an image using a laser.

[0002]

2. Description of the Related Art A polymerizable compound having a photopolymerization initiator, a dye sensitizer and a polymerizable compound, and utilizing the light energy absorbed by the dye sensitizer for radical cleavage of the photopolymerization initiator to generate a radical. The development of a lithographic printing plate utilizing the polymerization of was significantly improved in sensitivity to light in the visible light region in addition to the conventional method of forming an image by exposure to ultraviolet light,
Argon ion laser (488 nm) and FD-YAG
A system capable of direct drawing and plate making with these lasers using a light source such as (532 nm) has been put into practical use.

In addition to a visible light laser as an exposure light source, 7
High-power semiconductor lasers, YAG lasers, etc. that emit light in the region of 50 nm or more are now used as light sources
BACKGROUND OF THE INVENTION Photosensitive materials adapted to the output of these light sources and printing plates using the same have been actively developed.

A technique of combining a photopolymerization initiator and a sensitizer which constitute the above photopolymerization system is disclosed. For example, combinations of organic boron anions and cationic dyes are described in JP-A-62-143044, JP-A-62-1502242, JP-A-5-5988, and JP-A-2000-89455. As another example of the photopolymerization initiator, a combination of a titanocene compound and a sensitizer is disclosed in Japanese Patent Laid-Open No.
It is found in, for example, Japanese Patent Publication No. 3-221110. Further, combinations of trihaloalkyl-substituted triazine compounds and cyanine dyes are found in JP-A-2-189548 and the like, and combinations of hexaarylbiimidazole compounds and dyes are described in JP-A-1-279903. . Regarding the infrared absorbing dye and the polymerization initiator, JP-A-2000-122273 and JP-A-2001-2
No. 90271, JP 2001-228611 A, etc., but the effect on the storage stability of the photosensitive layer of the lithographic printing plate becomes more remarkable as the sensitivity and infrared sensitivity are increased. , The problem that the sensitivity of the photosensitive layer is lowered during storage and the problem that thermal fogging occurs, and the non-image area adheres strongly to the support (aluminum etc.) over time, causing poor elution during development, or There is a problem that the strength of the image area, which is indispensable as a lithographic printing plate, is reduced due to the elution of the non-image area adhered to the sheet, and a system that achieves both sufficient sensitivity and printing performance has not yet been found.

For these problems, Japanese Examined Patent Publication No. 56-39
464, JP-A-7-306528, and 10-301.
280, 10-312056 and JP 2000-
No. 112147, etc., ink receptivity is impaired and sufficient image strength is obtained even when developed with an alkaline developer containing benzyl alcohol, triethanolamine, polyoxyethylene-polyoxypropylene copolymer, or the like. It is not good as a lithographic printing plate such that the printing durability as a printing plate is not obtained and the non-image area cannot be completely eluted when the lithographic printing plate is stored with time and stains are generated during printing. Printing performance is not obtained.

In addition, JP-A-9-15870 discloses a color filter developer in which an anionic surfactant having a sulfonic acid group and a specific diol are combined to enhance the developability. Was not able to be stably developed. In addition, Japanese Patent Laid-Open No. 2001-133991
JP-A No. 1994-242 discloses a developing solution containing a water-miscible organic solvent and a surface-active compound, which is also a laser light direct-writing type photopolymerization type photosensitive lithographic printing plate which does not use a diazonium salt,
When the lithographic printing plate is stored with time, the non-image area cannot be completely eluted and stains are generated during printing, and thus good printing performance as a lithographic printing plate is not obtained.

In order to solve the above various problems,
(1) A developer that completely elutes the non-image area without lowering the printing performance and particularly the strength of the image area. (2)
A lithographic printing plate having a photosensitive layer that is highly sensitive and has excellent storage stability over time. There is a need for a lithographic printing plate precursor having high sensitivity, stable storage stability over time, and good printing performance, which can be achieved.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to provide a lithographic printing plate precursor having high sensitivity, stable storage stability over time, and good printing performance.

[0009]

Means for Solving the Problems The above problems are solved by the organic boron salt, and the polymer binder having a polymerizable double bond in the side chain and a carboxyl group with an acid value of 50 mgKOH / g.
It is basically solved by treating the photosensitive lithographic printing plate containing the above-mentioned polymer binder with a developer containing a sulfonated aromatic hydrocarbon compound.

The inventors of the present invention have conducted extensive studies to achieve the above-mentioned object. As a result, an organic boron salt which can be sensitized by a dye is used as a polymerization initiator, and a side chain has a polymerizable double bond and has a carboxyl group. Higher sensitivity was realized by using the polymer binder, and an extremely strong image required for a lithographic printing plate was formed. Also, the acid value of the polymer binder is limited,
By treating with a developer containing a sulfonated aromatic hydrocarbon compound, stable storability of the photosensitive layer of the lithographic printing plate was realized while forming a strong image.

That is, an organic boron salt, a polymer binder having a polymerizable double bond in a side chain and a carboxyl group, an acid value of the polymer binder, and a sulfonated aromatic hydrocarbon compound The present invention has been completed by finding out the performance of a lithographic printing plate that can be achieved by treating with a developing solution contained and combining these four factors.

Further, in a negative lithographic printing plate for infrared laser, it is necessary to add an infrared light absorbing dye, but the infrared light absorbing dye generally has a structure in which a conjugated system is elongated. Therefore, since the hydrophobicity is increased and the composition is easily decomposed, the composition has a great influence on the photosensitive layer of the lithographic printing plate, and the present invention is a useful means.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below. The sulfonated aromatic hydrocarbon used in the present invention is an aromatic sulfonic acid, and specifically, benzenesulfonic acid, nitrobenzenesulfonic acid, toluenesulfonic acid, xylenesulfonic acid, naphthalenesulfonic acid, or an alkali metal thereof. Examples include, but are not limited to, salt. Further, these compounds can be used alone or in combination of two or more kinds. Specific examples of preferred compounds include sodium alkylnaphthalenesulfonate, sodium alkylbenzenesulfonate, sodium alkyldiphenyl ether disulfonate, sodium dialkylsulfosuccinate, sodium alkylsulfate, potassium alkylsulfate, ammonium alkylsulfate, triethanolamine alkylsulfate, and alkylsulfate. Examples thereof include diethanolamine sulfate and sodium polyoxyethylene alkyl ether sulfate. A particularly preferred compound is alkylnaphthalene sulfonic acid or an alkali metal salt thereof.

There is a preferable range for the ratio of the sulfonated aromatic hydrocarbon in the developer, and the sulfonated aromatic hydrocarbon is contained in an amount of 3 to 40 parts by weight in a total amount of 1000 parts by weight of the developer. It is preferably contained in the range, more preferably from 10 parts by weight to 30 parts by weight.
The range is parts by weight.

As the organic boron salt used in the lithographic printing plate of the present invention, it is particularly preferable to use a compound having an organic boron anion represented by Chemical formula 1.

[0016]

[Chemical 1]

In the formula 1, R ₂₁ , R ₂₂ , R ₂₃ and R
₂₄ may be the same or different and each represents an alkyl group, an aryl group, an aralkyl group, an alkenyl group, an alkynyl group, a cycloalkyl group or a heterocyclic group. Of these, it is particularly preferable that one of R ₂₁ , R ₂₂ , R ₂₃ and R ₂₄ is an alkyl group and the other substituent is an aryl group.

In the above-mentioned organic boron anion, a cation which forms a salt with the organic boron anion simultaneously exists. Examples of cations in this case include alkali metal ions and onium ions. Onium salts include ammonium, sulfonium, iodonium and phosphonium compounds. When a salt of an alkali metal ion or an onium compound and an organic boron anion is used, a sensitizing dye is added separately to impart photosensitivity in the wavelength range of light absorbed by the dye.

As one of preferred embodiments of the present invention, there is provided a photosensitive composition containing an organic boron salt together with a sensitizing dye which sensitizes in a wavelength range of 380 nm to 1300 nm.
In this case, the organic boron salt does not exhibit photosensitivity in the wavelength region of visible light to infrared light, and exhibits sensitivity to light in such wavelength region only by adding a sensitizing dye.

In this case, the organic boron salt is a salt containing the organic boron anion represented by the above chemical formula 1, and as the cation forming the salt, an alkali metal ion and an onium compound are preferably used. A particularly preferred example is an onium salt with an organic boron anion,
Examples thereof include ammonium salts such as tetraalkylammonium salts, sulfonium salts such as triarylsulfonium salts, and phosphonium salts such as triarylalkylphosphonium salts. Examples of particularly preferable organic boron salts are shown below.

[0021]

[Chemical 2]

[0022]

[Chemical 3]

There is a preferable range for the ratio of the organic boron salt in the photosensitive composition, and the organic boron salt is in the range of 0.1 to 50 parts by weight in 100 parts by weight of the photosensitive composition. It is preferably included.

In the present invention, a polymer having a polymerizable double bond in the side chain and a carboxyl group-containing monomer as a copolymerization component is used as the polymer binder. The polymeric binder must have an acid value of 50 mgKOH / g or more in order to provide a lithographic printing plate having stable storage properties over time and good printing performance. When the acid value of the polymer binder is less than 50 mgKOH / g, the elution property of the unexposed area is reduced and the non-image area of the printed matter is stained during development using an alkaline aqueous solution. Alternatively, it takes too long a developing time to cause a decrease in productivity. Moreover,
Even if development is possible, dissolution of the planographic printing plate deteriorates significantly with time, and under the same conditions as before the time, development cannot be performed and stable performance cannot always be obtained.

There is a preferable range for the acid value of the polymer binder, which is 250 mgKOH / g or more and 500 mgKO.
It is H / g or less.

Examples of the above-mentioned carboxyl group-containing monomer include acrylic acid, methacrylic acid, acrylic acid 2-carboxyethyl ester, methacrylic acid 2-carboxyethyl ester, crotonic acid, maleic acid, fumaric acid, maleic acid monoalkyl ester and fumaric acid. Examples include acid monoalkyl esters, 4-carboxystyrene and the like.

As a monomer for introducing a polymerizable double bond into the above-mentioned polymer side chain, allyl acrylate,
Allyl methacrylate, vinyl acrylate, vinyl methacrylate, 1-propenyl-acrylate, 1-propenyl-methacrylate, β-phenyl-vinyl-methacrylate, β-phenyl-vinyl-acrylate,
Vinyl methacrylamide, vinyl acrylamide, α-
Examples thereof include chloro-vinyl-methacrylate, α-chloro-vinyl-acrylate, β-methoxy-vinyl-methacrylate, β-methoxy-vinyl-acrylate, vinyl-thio-acrylate and vinyl-thio-methacrylate.

The polymer binder used in the present invention is particularly preferably a polymer having a phenyl group substituted with a vinyl group in its side chain and a carboxy group-containing monomer as a copolymerization component. The phenyl group substituted with a vinyl group is bonded to the main chain either directly or via a linking group, and the linking group is not particularly limited and includes any group, atom or a composite group thereof. Further, the phenyl group may be substituted with a substitutable group or atom, and the vinyl group is a halogen atom, a carboxy group, a sulfo group, a nitro group, a cyano group, an amide group, an amino group, an alkyl group, It may be substituted with an aryl group, an alkoxy group, an aryloxy group or the like. More specifically, the above-mentioned polymer having a phenyl group in which a vinyl group is substituted in the side chain is a polymer having a group represented by the following chemical formula 4 in the side chain.

[0029]

[Chemical 4]

In the formula, Z ₁ represents a linking group, and R ₁ , R ₂ and R ₃ represent hydrogen atom, halogen atom, carboxy group, sulfo group, nitro group, cyano group, amido group, amino group, alkyl group. Groups, aryl groups, alkoxy groups, aryloxy groups, etc., and these groups may be substituted with alkyl groups, amino groups, aryl groups, alkenyl groups, carboxy groups, sulfo groups, hydroxy groups and the like. R ₄ represents a substitutable group or atom. n ₁ represents 0 or 1, m ₁ represents an integer of 0 to 4, and k ₁ represents an integer of ₁ to 4.

The above general formula will be described in more detail.
As the linking group for Z ₁ , an oxygen atom, a sulfur atom, an alkylene group, an alkenylene group, an arylene group, —N (R ₅ )
-, - C (O) -O -, - C (R 6) = N -, - C
Examples thereof include (O)-, a sulfonyl group, a heterocyclic group, and a group represented by the following chemical formula 5 or a single group or a complex group of two or more. Here, R ₅ and R ₆ represent a hydrogen atom, an alkyl group, an aryl group or the like. Further, the above-mentioned linking group may have a substituent such as an alkyl group, an aryl group and a halogen atom.

[0032]

[Chemical 5]

Examples of the heterocyclic group include a pyrrole ring, a pyrazole ring, an imidazole ring, a triazole ring, a tetrazole ring, an isoxazole ring, an oxazole ring, an oxadiazole ring, an isothiazole ring, a thiazole ring, a thiadiazole ring and a thiatriazole ring. , Indole ring, indazole ring, benzimidazole ring, benzotriazole ring, benzoxazole ring, benzthiazole ring,
Examples include nitrogen-containing heterocycles such as benzselenazole ring, benzothiadiazole ring, pyridine ring, pyridazine ring, pyrimidine ring, pyrazine ring, triazine ring, quinoline ring, and quinoxaline ring, furan ring, thiophene ring, and the like. A substituent may be bonded to the ring. Examples of the group represented by Chemical formula 4 are shown below, but the group is not limited to these examples.

[0034]

[Chemical 6]

[0035]

[Chemical 7]

[0036]

[Chemical 8]

[0037]

[Chemical 9]

Among the groups represented by the above chemical formula 4, there are preferable ones. That is, it is preferable that R ₁ and R ₂ are hydrogen atoms and R ₃ is a hydrogen atom or a lower alkyl group having 4 or less carbon atoms (methyl group, ethyl group, etc.). Further, the linking group for Z ₁ is preferably one containing a heterocycle, and k ₁ is 1
Alternatively, those of 2 are preferable.

An example of a polymer having the group represented by Chemical formula 4 and having a carboxy group-containing monomer as a copolymerization component is shown below. In the formula, the number is the total composition of the copolymer 10
Represents the weight percent of each repeating unit in 0 weight percent.

[0040]

[Chemical 10]

[0041]

[Chemical 11]

[0042]

[Chemical 12]

[0043]

[Chemical 13]

[0044]

[Chemical 14]

The polymer of the present invention may further contain another monomer as a copolymer component. Other monomers include styrene, 4-methylstyrene, 4-hydroxystyrene, 4-acetoxystyrene, 4-carboxystyrene, 4-aminostyrene, chloromethylstyrene, 4-methoxystyrene and other styrene derivatives, and methyl methacrylate. , Methacrylic acid alkyl esters such as ethyl methacrylate, butyl methacrylate, hexyl methacrylate, 2-ethylhexyl methacrylate, cyclohexyl methacrylate and dodecyl methacrylate, phenyl methacrylate, methacrylic acid aryl esters such as benzyl methacrylate, or alkylaryl. Ester, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, methoxydiethylene glycol monoester methacrylate, methoxypolyethylene glycol methacrylate And methacrylic acid esters having an alkyleneoxy group such as polypropylene glycol monoester and methacrylic acid polypropylene glycol, amino group-containing methacrylic acid esters such as 2-dimethylaminoethyl methacrylate and 2-diethylaminoethyl methacrylate, or acrylic acid esters. Examples similar to the corresponding methacrylic acid ester, or vinylphosphonic acid or the like as a monomer having a phosphoric acid group, or amino group-containing monomers such as allylamine and diallylamine, or vinylsulfonic acid and salts thereof, allylsulfonic acid and Monomers having sulfonic acid groups such as salts thereof, methallyl sulfonic acid and salts thereof, styrene sulfonic acid and salts thereof, 2-acrylamido-2-methylpropane sulfonic acid and salts thereof, 4-bi Monomers having a nitrogen-containing heterocycle such as nylpyridine, 2-vinylpyridine, N-vinylimidazole, and N-vinylcarbazole, or 4-vinylbenzyltrimethylammonium chloride, acryloyloxyethyltrimethylammonium chloride as a monomer having a quaternary ammonium salt group. , Methacryloyloxyethyltrimethylammonium chloride, quaternary compound of dimethylaminopropylacrylamide with methyl chloride, quaternary compound of N-vinylimidazole with methyl chloride, 4-vinylbenzylpyridinium chloride, etc., or acrylonitrile, methacrylonitrile, acrylamide, Methacrylamide, dimethyl acrylamide, diethyl acrylamide, N-isopropyl acrylamide, dia Tolacrylamide, N-methylolacrylamide, N-methoxyethylacrylamide, 4-hydroxyphenylacrylamide, and other acrylamide or methacrylamide derivatives, as well as acrylonitrile, methacrylonitrile, phenylmaleimide, hydroxyphenylmaleimide, vinyl acetate, vinyl chloroacetate, and Provion. Vinyl esters such as vinyl acetate, vinyl butyrate, vinyl stearate, vinyl benzoate, methyl vinyl ether,
Vinyl ethers such as butyl vinyl ether, etc.,
Examples include various monomers such as N-vinylpyrrolidone, acryloylmorpholine, tetrahydrofurfuryl methacrylate, vinyl chloride, vinylidene chloride, allyl alcohol, vinyltrimethoxysilane, and glycidyl methacrylate.

There is a preferable range for the molecular weight of the polymer binder according to the present invention, and the weight average molecular weight is 1
It is preferably in the range of 000 to 1,000,000, and more preferably in the range of 5,000 to 500,000.

The photosensitive layer of the photosensitive lithographic printing plate of the present invention preferably further contains an ethylenically unsaturated compound. By combining these, higher sensitivity can be achieved,
Further, a lithographic printing plate having excellent printing performance can be obtained.

The ethylenically unsaturated compound according to the present invention includes a polymerizable compound having two or more polymerizable double bonds in the molecule. Examples of preferred ethylenically unsaturated compounds are 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, tetraethylene glycol diacrylate, trisacryloyloxyethyl isocyanurate, tripropylene. Examples thereof include polyfunctional acrylic monomers such as glycol diacrylate, ethylene glycol glycerol triacrylate, glycerol epoxy triacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, and pentaerythritol tetraacrylate.

Alternatively, an oligomer having radical polymerizability is preferably used instead of the above-mentioned polymerizable compound, and various oligomers having an acryloyl group or a methacryloyl group introduced therein may be used as polyester (meth) acrylate, urethane (meth) acrylate, epoxy (meth). ) Acrylate and the like are used in the same manner, but these can be similarly preferably used as the ethylenically unsaturated compound.

As a more preferable embodiment of the ethylenically unsaturated compound, a polymerizable compound having two or more phenyl groups substituted with vinyl groups in the molecule can be mentioned. When the compound is used, the styryl radicals generated by the generated radicals are recombined with each other to effectively crosslink, and therefore, it is extremely preferable in producing a highly sensitive photosensitive lithographic printing plate.

The polymerizable compound having two or more phenyl groups substituted with vinyl groups in the molecule is typically represented by the following general formula.

[0052]

[Chemical 15]

In the formula, Z ₂ represents a linking group, and R ₁₁ , R ₁₂ and R ₁₃ represent hydrogen atom, halogen atom, carboxy group, sulfo group, nitro group, cyano group, amide group, amino group and alkyl group. , Aryl groups, alkoxy groups, aryloxy groups and the like, and these groups may be substituted with alkyl groups, amino groups, aryl groups, alkenyl groups, carboxy groups, sulfo groups, hydroxy groups and the like. R ₁₄ represents a substitutable group or atom. m ₂ represents an integer of 0 to 4, and k ₂ represents an integer of 2 or more.

A more detailed description will be given. The linking group for Z ₂ includes an oxygen atom, a sulfur atom, an alkylene group, an alkenylene group, an arylene group, —N (R ₁₅ ) —, and —C (O) —O.
Examples include —, —C (R ₁₆ ) ═N—, —C (O) —, a sulfonyl group, a heterocyclic group, and the like, alone or in combination of two or more. Here, R ₁₅ and R ₁₆ represent a hydrogen atom, an alkyl group, an aryl group, or the like. Furthermore, the above-mentioned linking group includes
It may have a substituent such as an alkyl group, an aryl group and a halogen atom.

Examples of the heterocyclic group include a pyrrole ring, a pyrazole ring, an imidazole ring, a triazole ring, a tetrazole ring, an isoxazole ring, an oxazole ring, an oxadiazole ring, an isothiazole ring, a thiazole ring, a thiadiazole ring and a thiatriazole ring. , Indole ring, indazole ring, benzimidazole ring, benzotriazole ring, benzoxazole ring, benzthiazole ring,
Examples include nitrogen-containing heterocycles such as benzselenazole ring, benzothiadiazole ring, pyridine ring, pyridazine ring, pyrimidine ring, pyrazine ring, triazine ring, quinoline ring, quinoxaline ring, furan ring, and thiophene ring. The group may be bonded.

Among the compounds represented by the chemical formula 15 above, there are preferable compounds. That is, compounds in which R ₁₁ and R ₁₂ are hydrogen atoms, R ₁₃ is a hydrogen atom or a lower alkyl group having 4 or less carbon atoms (methyl group, ethyl group, etc.), and k ₂ is 2 to 10 are preferable. Specific examples of the compound represented by Chemical formula 15 are shown below, but the compound is not limited to these examples.

[0057]

[Chemical 16]

[0058]

[Chemical 17]

[0059]

[Chemical 18]

The ethylenically unsaturated compound as described above is
There is a preferable range for the proportion of the photosensitive lithographic printing plate in the photosensitive layer, and the ethylenically unsaturated compound is preferably contained in the range of 1 to 60 parts by weight in 100 parts by weight of the total of the photosensitive layer. Further, it is particularly preferable that the content is in the range of 5 to 50 parts by weight.

Preferred photopolymerization initiators for use with the organoboron salts of the present invention include trihaloalkyl substituted compounds. The trihaloalkyl-substituted compound referred to here is specifically a compound having at least one trihaloalkyl group such as trichloromethyl group and tribromomethyl group in the molecule, and as a preferable example,
Examples of the compound in which the trihaloalkyl group is bonded to a nitrogen-containing heterocyclic group include s-triazine derivatives and oxadiazole derivatives, or the trihaloalkyl group is bonded to an aromatic ring or a nitrogen-containing heterocycle via a sulfonyl group. The trihaloalkylsulfonyl compound mentioned above can be mentioned.

Particularly preferable examples of the trihaloalkyl-substituted nitrogen-containing heterocyclic compound and the trihaloalkylsulfonyl compound are shown in Chemical formulas 19 and 20.

[0063]

[Chemical 19]

[0064]

[Chemical 20]

When the trihaloalkyl-substituted compound is used, there is a preferable range in the photosensitive layer of the photosensitive lithographic printing plate, and the ratio is 0.1 part by weight in the total 100 parts by weight of the photosensitive layer. It is preferably contained in the range of 50 to 50 parts by weight. Further, these are preferable because the sensitivity is particularly improved when they are contained in the photosensitive layer together with the above-mentioned organic boron salt. In this case, the ratio of the organic boron salt to the organic boron salt is 1 part by weight of the trihaloalkyl substitution. Compound from 0.1 to 5 parts by weight
It is preferably contained in the range of 0 parts by weight.

For the sensitizing dyes according to the present invention, 38
It sensitizes the decomposition of the photopolymerization initiator in the wavelength range of 0 nm to 1300 nm, and as various cationic dyes, anionic dyes and neutral dyes having no charge, merocyanine, coumarin, xanthene, thioxanthene,
An azo dye or the like can be used. Among these, particularly preferable examples are cyanine as a cationic dye, carbocyanine,
It is a dye selected from hemicyanine, methine, polymethine, triarylmethane, indoline, azine, thiazine, xanthene, oxazine, acridine, rhodamine, and azamethine dyes. It is particularly preferably used in combination with these cationic dyes because of its high sensitivity and excellent storage stability. Furthermore, in recent years 380-4
An output device (platesetter) equipped with a violet semiconductor laser having an oscillation wavelength in the range of 10 nm has been developed. As a highly sensitive photosensitive system corresponding to this output machine, a system containing a pyrylium compound or a thiopyrylium compound as a sensitizing dye is preferable. Examples of preferred sensitizing dyes relating to the present invention are shown below.

[0067]

[Chemical 21]

[0068]

[Chemical formula 22]

[0069]

[Chemical formula 23]

[0070]

[Chemical formula 24]

[0071]

[Chemical 25]

[0072]

[Chemical formula 26]

Further, in a system which makes light in the wavelength region from near infrared to 750 nm or more to infrared light sensitive, it is necessary that the sensitizing dye has absorption in the infrared wavelength region. There is a particularly preferable example used for such a purpose.
7 and 28.

[0074]

[Chemical 27]

[0075]

[Chemical 28]

There is a preferable range in the quantitative ratio of the sensitizing dye and the photopolymerization initiator as described above. Sensitizing dye
1 to 1 part by weight of the photopolymerization initiator is 0.01 to 1 part by weight.
It is preferably used in the range of 00 parts by weight, more preferably 0.1 to 50 parts by weight of the photopolymerization initiator.

A polymerization inhibitor may be preferably added as another element constituting the photosensitive lithographic printing plate. For example, quinone-based and phenol-based compounds are preferably used, and hydroquinone, p-methoxyphenol, catechol, t-butylcatechol, 2-naphthol, 2,
A compound such as 6-di-t-butyl-p-cresol is preferably used. The preferred ratio of these polymerization inhibitors to the above-mentioned ethylenically unsaturated compound is preferably 0.001 to 0.1 part by weight relative to 1 part by weight of the ethylenically unsaturated compound.

A colorant may be preferably added as another element constituting the photosensitive lithographic printing plate. The colorant is used for the purpose of enhancing the visibility of the image area after exposure and development processing, and various types of carbon black, phthalocyanine dyes, triarylmethane dyes, anthraquinone dyes, azo dyes, etc. The above dyes and pigments can be used, and can be preferably added in the range of 0.005 to 0.5 parts by weight with respect to 1 part by weight of the binder.

With respect to the elements constituting the photosensitive lithographic printing plate, other elements may be additionally contained for various purposes other than the above-mentioned elements. For example, it is also preferable to add inorganic fine particles or organic fine particles for the purpose of preventing blocking or improving the sharpness of the image after development.

Regarding the thickness of the photosensitive layer itself of the lithographic printing plate, it is preferable to form the photosensitive layer on the support at a dry thickness in the range of 0.5 to 10 μm, and further in the range of 1 to 5 μm. It is extremely preferable because the printing durability is significantly improved. The photosensitive layer is prepared by preparing a solution in which the above-mentioned three elements are mixed, is coated on the support by various known coating methods, and is dried. As the support, for example, a film or polyethylene-coated paper may be used, but a more preferred support is an aluminum plate which is polished and has an anodized film.

A particularly preferable laser light source used for laser scanning exposure according to the present invention is a laser having an oscillation wavelength in the near infrared region, various semiconductor lasers, YAG.
Most preferred are solid state lasers such as lasers and glass lasers.

The alkaline aqueous solution used in the developing solution of the present invention may be a developing solution containing alkali silicate or a base, and preferably has a pH of 12.5 to 13.5. The alkali silicate used in the present invention preferably exhibits alkalinity when dissolved in water, and examples thereof include alkali metal silicates such as sodium silicate, potassium silicate, and lithium silicate, and ammonium silicate. They can be used alone or in combination of two or more.

In a preferred embodiment of the present invention, the alkali silicate is an alkali metal silicate or ammonium silicate, and its SiO ₂ / M ₂ 0 molar ratio (M represents an alkali metal atom or an ammonium group) is 0.5. Is preferably 0.3 to 0.3, more preferably 0.5 to 2.0.

The developer used in the present invention can be used in combination with various other surfactants, and examples thereof include anionic, cationic, nonionic and amphoteric surfactants.
These surfactants used in combination have a content of 0.001 in the developer.
10 to 10% by weight, more preferably 0.01 to 5% by weight.

Various development stabilizers can be used in the developing solution used in the present invention. Preferable examples thereof include polyethylene glycol adducts of sugar alcohols, phosphonium salts such as tetrabutylphosphonium bromide and iodonium salts such as diphenyliodonium chloride described in JP-A-6-282079. Furthermore, JP-A-50-5132
4, anionic surfactants or amphoteric surfactants, water-soluble cationic polymers described in JP-A-55-95946, and water-soluble amphoteric surfactants described in JP-A-56-142528. There is a molecular electrolyte. Furthermore, an alkylene glycol-added organic boron compound described in JP-A-59-84241, JP-A-61-21
Polyethylene glycol having a weight average molecular weight of 300 or more described in JP-A-5554, a fluorine-containing surfactant having a cationic group described in JP-A-63-175858, JP-A-2.
Examples of the water-soluble ethylene oxide adduct obtained by adding 4 mol or more of ethylene oxide to the acid or alcohol of JP-A-39157, and a water-soluble polyalkylene compound.

It is advantageous in terms of transportation that the developing solution used in the present invention is a concentrated solution containing less water than that in use, and is diluted with water in use. In this case, it is appropriate that the degree of concentration is such that each component does not cause separation or precipitation.
It can be concentrated to about 1: 0 to 1:10. Further, since the container is alkaline, it is preferable to use a material that does not permeate carbon dioxide and is not damaged during transportation for safety. Usually, a resin container such as a hard bottle or a cubic container is preferably used.

In the processing method of the present invention, processing is usually carried out by an automatic developing machine after exposure. An automatic developing machine is generally composed of a developing section and a post-processing section, and is composed of a device for transporting a printing plate, each processing liquid tank and a spray tank, and an exposed printing plate was transported horizontally while being assembled by a pump. Each processing solution is sprayed from a spray nozzle for development and post-processing. In addition, recently, a method of developing the printing plate by immersing and transporting the printing plate in a developing tank filled with a developing solution by a submerged guide roll or the like has been developed, and such a developing method can also be suitably applied to the present invention. . In such an automatic developer,
Processing can be performed while replenishing the replenisher according to the development processing amount, operating time, and the like.

The printing plate developed with the developing solution having such a composition is post-treated with washing water, a rinse solution containing a surfactant, a finisher or a protective gum solution containing gum arabic or a starch derivative as a main component. Is given. The post-treatment of the printing plate of the present invention may be carried out in various combinations of these treatments. For example, development → washing → treatment with a rinse solution containing a surfactant or development → washing → finisher solution is a rinse solution or a finisher. It is preferable because it causes less liquid fatigue. Further, a countercurrent multi-stage treatment using a rinse liquid or a finisher liquid is also a preferable embodiment. These post-treatments are generally performed using an automatic developing machine including a developing section and a post-processing section. The post-treatment liquid is sprayed from a spray nozzle,
A method of transporting in a processing tank filled with the processing liquid is used. Also known is a method in which after development, a small amount of a small amount of aqueous water is supplied to the plate surface to wash it, and the waste liquid is reused as dilution water for the developing solution stock solution. In such automatic processing,
It is possible to perform processing while supplementing each replenisher with each replenisher according to the treatment amount and operating time. Further, a so-called disposable treatment method of treating with a substantially unused post-treatment liquid can be applied. The planographic printing plate obtained by such treatment is set on an offset printing machine and used for printing.

[0089]

EXAMPLES The present invention will be described in more detail with reference to examples below, but the present invention is not limited to these examples in addition to the effects.

Example 1 A monomer obtained by reacting chloromethylstyrene and bismuthiol in an equimolar amount according to the method described in JP-A-2000-290271 as a synthesis example of an alkalizable soluble polymer used as a polymer binder Methacrylic acid was neutralized with triethylamine and polymerized in ethanol,
After the completion of the polymerization, the charged amounts (x, y) of the compound 29 synthesized by adding chloromethylstyrene were changed to synthesize Synthesis Examples 1 to 5. The charged amounts x and y are shown in Table 1.

[0091]

[Chemical 29]

[0092]

[Table 1]

Using the polymeric binder synthesis examples 1 to 5 shown in Table 1, a photosensitive composition liquid having the following formulation was subjected to a graining treatment and anodization treatment having a thickness of 0.24 mm using a wire bar. A sample having a dry film thickness of 3 μm was applied onto the aluminum plate, and the photosensitive composition was applied to the sample. Polymer binder (Synthesis Examples 1 to 5) 10% dioxane solution 100 parts by weight As a photopolymerization initiator in Chemical formula 3 (BC-5) 2 parts by weight Chemical formula 20 in (BS-1) 1 part by weight Ethylenically unsaturated Compound Compound 16 (C-1) 5 parts by weight As sensitizing dye Compound 27 (S-33) 0.3 parts by weight Polymerization inhibitor 2,6-di-t-butylcresol 0.1 parts by weight As solvent 1,3-Dioxolane 20 parts by weight Cyclohexanone 20 parts by weight

In order to examine the heat storage stability of the prepared lithographic printing plate sample, a sample stored by changing the heating time between 0 and 6 hours in a dryer adjusted to 80 ° C. was used, and exposure was carried out as a development evaluation. 3 using developer 1 below without
The developing property was evaluated by immersing the film in a developing solution at an interval of 1 second at a liquid temperature of 5 ° C. and determining the minimum time during which the photosensitive layer coating film can be eluted. It is preferable that this time is short and there is little change even when heated at 80 ° C. The results are summarized in Table 2.

<Developer 1> 35% sodium alkylnaphthalene sulfonate (Helex NBL (surfactant manufactured by Kao Corporation) 60 g KOH 15 g 20% potassium silicate aqueous solution (containing 20% SiO ₂ ) 10 g benzyl alcohol 10 g with water 1L

[0096]

[Table 2]

Samples 1 to 5 prepared were used as photosensitive printing plates, and in order to examine the storage stability, they were stored together with the sample immediately after preparation for 1 month in a humidifier adjusted to a temperature of 40 ° C. and a relative humidity of 80%. A sample was also created (Samples 6-1)
0). Using PT-R4000 manufactured by Dainippon Screen Mfg. Co., Ltd. as an external drum type platesetter equipped with an 830 nm semiconductor laser for each sample, the laser irradiation energy was 100 mJ / cm at a drum rotation speed of 1200 rpm for a sensitive material. Exposure was performed at ² . After the exposure, an automatic developing machine PD-912 for PS plate manufactured by Dainippon Screen Mfg. Co., Ltd. was used, and the developing solution 1 and the developing solution 2 described below were used to develop at a liquid temperature of 30 ° C. for 15 seconds. The following gum solution was applied onto the planographic printing plate to prepare a printing sample.

<Developer 2> KOH 15 g 20% potassium silicate aqueous solution (containing 20% SiO ₂ ) 10 g benzyl alcohol 10 g 1 L with water

<Gum solution> Phosphoric acid 1 potassium 5g Arabia gum                   30 g Dehydroacetic acid Na 0.5 g EDTA2Na 1g 1L with water

A printing test was performed on the prepared sample. As a printing test, an ink printing test was carried out using an offset printing machine Ryobi 3200 (trademark of offset printing machine manufactured by Ryobi Co., Ltd.) and an ink GEOS-G indigo H.
(Manufactured by Dainippon Ink and Chemicals Co., Ltd.), the dampening solution was evaluated by the number of inks using a 1% aqueous solution of Astromark III (manufacturing solution by Nikken Chemical Laboratory Co., Ltd.). Regarding the stain resistance, the printing machine is Heidelberg TOK (Heidelberg
(Trademark of offset printing machine manufactured by the company), ink is FINE I
NK New Champion Purple S (manufactured by Dainippon Ink and Chemicals, Inc.), and the fountain solution used is a 0.5% aqueous solution of Eu-3 (fountain solution for PS plate manufactured by Fuji Photo Film Co., Ltd.). Then, the background stain of the sample printed on 10,000 sheets was evaluated. As for printing durability, the printing machine uses Heidelberg TOK (trademark of Heidelberg offset printing machine), and the ink is BES.
Tone ink H (manufactured by T & K TOKA Co., Ltd.), the dampening water is a 1% aqueous solution of Astromark III (manufactured by Niken Kagaku Kenkyusho Co., Ltd.). Evaluated by the number of missing items. For stain resistance and printing durability,
The evaluation was made according to the following evaluation criteria and summarized in Table 3.

Ink riding Evaluated by the number of sheets of ink evenly applied. Dirtiness ○: extremely good ○ △: Good △: Slightly soiled △ ×: Dirt ×: All surfaces are dirty Printing durability ○: 200,000 or more ○ △: 100,000 to less than 200,000 △: 50,000 to less than 100,000 ×: less than 50,000 sheets

[0102]

[Table 3]

[0103]

As is clear from the above examples, the lithographic printing plate precursor of the present invention has high sensitivity, stable storage stability over time, and good printing performance.

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 2H025 AA01 AA11 AA12 AB03 AC08                       AD01 BC32 BC42 BC51 BC81                       BC85 CA28 CA50 CC20 FA10                       FA17                 2H096 AA07 BA06 BA20 EA04 GA08                       GA10

Claims (5)

[Claims] 1. A photosensitive material containing an organic boron salt and a polymer binder having a polymerizable double bond in a side chain and a carboxyl group and having an acid value of 50 mgKOH / g or more. A method for making a photosensitive lithographic printing plate, comprising treating the lithographic printing plate having a layer with a developer containing a sulfonated aromatic hydrocarbon compound. 2. The polymer binder has an acid value of 250 mgK.
OH / g or more and 500 mgKOH / g or less.
A method for making a photosensitive lithographic printing plate as described above. 3. The plate-making method for a photosensitive lithographic printing plate as claimed in claim 1, wherein the polymer binder is a polymer having a phenyl group substituted with a vinyl group in a side chain. 4. The method for making a photosensitive lithographic printing plate according to claim 1, 2 or 3, wherein the photosensitive layer further contains an ethylenically unsaturated compound. 5. The method of making a photosensitive lithographic printing plate according to claim 1, 2, 3 or 4, wherein the lithographic printing plate is a negative lithographic printing plate for infrared laser.