JP2003084428A - Original plate of planographic printing plate and planographic printing plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a positive-working original plate of a planographic printing plate for an infrared laser having a good image forming property and excellent particularly in printing resistance and to provide a planographic printing plate. SOLUTION: The positive-working original plate of a planographic printing plate is obtained by disposing a recording layer comprising (A) a water-insoluble and alkali-soluble resin, (B) an IR absorbent and (C) 0.1-20 wt.% polymerizable compound with an ethylenic double bond and having solubility in an alkaline aqueous solution increased by exposure with infrared laser light on a support. A planographic printing plate using the original plate is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lithographic printing plate precursor that can be used as an offset printing master, and more particularly to a positive type lithographic printing plate precursor for infrared laser for so-called direct plate making which can be made directly from a digital signal of a computer or the like. It relates to a lithographic printing plate using it.

[0002]

2. Description of the Related Art The development of lasers in recent years has been remarkable, especially solid-state lasers having a light emitting region from the near infrared to the infrared.
High-power and small-sized semiconductor lasers are easily available. These lasers are very useful as an exposure light source when making a plate directly from digital data of a computer or the like.

The positive type lithographic printing plate precursor for infrared laser is
An alkaline aqueous solution-soluble binder resin and an IR dye that absorbs light to generate heat are essential components, and the IR dye dissolves in the unexposed area (image area) due to the interaction with the binder resin. It acts as a dissolution inhibitor that substantially lowers the property, and in the exposed area (non-image area) the heat generated weakens the interaction between the IR dye and the binder resin and dissolves in an alkaline developer to form a lithographic printing plate. To do.

However, in such a method of forming an image in which the non-image can be removed by releasing the interaction due to heat, good developing property is exhibited in the non-image area of the recording layer, but in the image area, The original strength (film property) of the recording layer and the adhesiveness with the support directly affect the strength of the image area and thus the printing durability. Therefore, for the purpose of improving printing durability, measures such as adding a component to the recording layer for improving the adhesion between the recording layer and the surface of the support have been studied, but it is widely used as a substrate for lithographic printing plate precursors. When the heat-sensitive layer is provided directly on the aluminum substrate, the heat generated by exposure is absorbed by the aluminum substrate having high thermal conductivity, so that sufficient thermal energy is formed near the interface between the substrate and the heat-sensitive layer. That is, in addition to the characteristics of the positive type recording layer that is not used for releasing the interaction of the recording layer and the removability of the non-image area becomes low,
There is a concern that the developability of the non-image area may be further deteriorated by the additive for improving the adhesiveness, and the non-image area may be easily soiled.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above problems and achieve the following objects. That is, an object of the present invention is to provide a positive lithographic printing plate precursor for infrared laser, which has good image forming property and particularly excellent printing durability, and a lithographic printing plate using the same.

[0006]

As a result of intensive studies, the present inventors have used a positive type photosensitive composition for infrared laser containing a predetermined amount of a polymerizable compound having an ethylenic double bond as a recording layer. As a result, they have found that the above problems can be solved, and have completed the present invention.

That is, the positive type lithographic printing plate precursor of the present invention is
(A) water-insoluble and alkali-soluble resin on the support,
(B) contains an infrared absorber and (C) a polymerizable compound having an ethylenic double bond in an amount of 0.1 to 20% by weight,
It is characterized by comprising a recording layer whose solubility in an alkaline aqueous solution is increased by exposure to infrared laser.

According to the present invention, by containing a predetermined amount of the polymerizable compound having an ethylenic double bond in the recording layer, it becomes possible to form an image without impairing the releasing property of the interaction by exposure and after development. It is presumed that the curing of the image area proceeds during the heat treatment and the like, and the printing durability is significantly improved. Further, the lithographic printing plate according to claim 2 of the present invention is characterized in that it is obtained by exposing the positive type lithographic printing plate precursor imagewise by an infrared laser, developing it, and then heating it.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION [Positive lithographic printing plate precursor] The positive lithographic printing plate precursor of the present invention (hereinafter, appropriately referred to as "lithographic printing plate precursor") has a recording layer containing a predetermined amount of ethylenic niobium. It is necessary to contain a polymerizable compound having a heavy bond, an alkali-soluble resin and an infrared absorber. Hereinafter, each component and the like constituting the planographic printing plate precursor of the invention will be sequentially described.

[(C) Polymerizable compound having ethylenic double bond] The polymerizable compound having an ethylenic double bond, which is a characteristic component of the present invention, has at least one terminal ethylenically unsaturated bond, It is preferably a compound having two or more, and in the present invention, one kind or two or more kinds can be arbitrarily selected from these compounds.

Specific examples of the polymerizable compound having an ethylenic double bond include, for example, a monomer and a prepolymer (oligomers including a dimer and a trimer), a mixture thereof, and a low amount thereof. Examples thereof include those having a chemical form such as a molecular weight copolymer.

Examples of monomers and their low molecular weight copolymers include unsaturated carboxylic acids (eg acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid,
Maleic acid) and an aliphatic polyhydric alcohol compound, and an amide of an unsaturated carboxylic acid and an aliphatic polyhydric amine compound.

Specific examples of the monomer which is an ester of an aliphatic polyhydric alcohol compound and an unsaturated carboxylic acid include:
The following are listed. Examples of the acrylate ester include ethylene glycol diacrylate, triethylene glycol diacrylate, 1,3-butanediol diacrylate, tetramethylene glycol diacrylate, propylene glycol diacrylate, neopentyl glycol diacrylate, trimethylolpropane triacrylate, and trimethylolpropane triacrylate. Methylolpropane 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, sorbitol pentaacrylate, sorbitol hexaacrylate, tri (Acryloyloxyethyl) isocyanurate, polyester acrylate oligomer and the like can be mentioned.

Methacrylic acid esters include tetramethylene glycol dimethacrylate, triethylene glycol dimethacrylate, neopentyl glycol dimethacrylate, trimethylolpropane trimethacrylate, trimethylolethane trimethacrylate, ethylene glycol dimethacrylate, 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- (acryloxy ethoxy)
Phenyl] dimethyl methane and the like.

The itaconic acid esters include ethylene glycol diitaconate, propylene glycol diitaconate, 1,3-butanediol diitaconate,
1,4-butanediol diitaconate, tetramethylene glycol diitaconate, pentaerythritol diitaconate, sorbitol tetritaconate and the like can be mentioned.

As the crotonic acid ester, ethylene glycol dicrotonate, tetramethylene glycol dicrotonate, pentaerythritol dicrotonate,
Examples thereof include sorbitol tetradicrotonate.

Examples of isocrotonic acid esters 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. Furthermore, mixtures of these monomers can also be mentioned.

Specific examples of the monomer which is an amide of an aliphatic polyamine compound and an unsaturated carboxylic acid include:
Examples thereof include methylenebis-acrylamide, methylenebis-methacrylamide, 1,6-hexamethylenebis-acrylamide, 1,6-hexamethylenebis-methacrylamide, diethylenetriaminetrisacrylamide, xylylenebisacrylamide, xylylenebismethacrylamide. .

Other examples include Japanese Patent Publication No. 48-417.
No. 08, the polyisocyanate compound having two or more isocyanate groups in one molecule is added with a vinyl monomer having a hydroxyl group represented by the following general formula (A) in one molecule. Examples thereof include vinyl urethane compounds containing a polymerizable vinyl group.

General formula (A) CH ₂ = C (R) COOCH ₂ CH (R ') OH (wherein R and R'represent H or CH ₃ )

Further, urethane accelerators as described in JP-A-51-37193, JP-A-4,
Polyester acrylates such as those described in JP-B No. 8-64183, JP-B-49-43191 and JP-B-52-30490, epoxy acrylates obtained by reacting an epoxy resin with (meth) acrylic acid, and the like. Mention may be made of functional acrylates and methacrylates.

Furthermore, the magazine of Japan Adhesion Society, vol. 20, N
o. The materials introduced as photocurable monomers and oligomers on pages 7,300 to 308 (1984) can also be used.

In the present invention, these monomers are used in a chemical form such as a prepolymer (oligomers including a dimer and a trimer), a mixture thereof, and a low molecular weight copolymer thereof. sell.

Further, compounds having a structure represented by the general formula (I) described in JP 2001-92127 A can also be suitably used. In the following, Japanese Patent Laid-Open No. 2001-92127
Specific examples of the compound having the structure represented by the general formula (I) described in JP-A No. 1993-242242 are shown below.

[0025]

[Chemical 1]

[0026]

[Chemical 2]

[0027]

[Chemical 3]

[0028]

[Chemical 4]

[0029]

[Chemical 5]

[0030]

[Chemical 6]

[0031]

[Chemical 7]

[0032]

[Chemical 8]

[0033]

[Chemical 9]

[0034]

[Chemical 10]

[0035]

[Chemical 11]

[0036]

[Chemical 12]

The amount of all the polymerizable compounds having an ethylenic double bond used is required to be 0.1 to 20% by weight based on the weight of all solid components in the recording layer, and 0.5 to 1
5% by weight is preferable, and 1 to 10% by weight is more preferable.
When the amount used exceeds 20% by weight, the image forming property as a positive image forming material is deteriorated, and even when an image is obtained, the film forming property of the image part is deteriorated, so that sufficient strength of the image part is obtained. You won't get it. On the other hand, the amount used is 0.1% by weight
If it is less than the above range, the improvement of printing durability by heating after image formation, which is the effect of the present invention, becomes insufficient.

[(A) Water-Insoluble and Alkali-Soluble Resin] As the water-insoluble and alkali-soluble resin (hereinafter appropriately referred to as “alkali-soluble resin”) that can be used in the positive recording layer of the present invention, It includes a homopolymer containing an acidic group in the main chain and / or side chain, a copolymer thereof, or a mixture thereof. Above all, (1) ~
Those having an acidic group listed in (6) in the main chain and / or side chain of the polymer are preferable in terms of solubility in an alkaline developing solution and expression of dissolution inhibiting ability.

[0039] (1) phenol group (-Ar-OH) (2) sulfonamide group _{(-SO 2 NH-R) (} 3) substituted sulfonamide-based acid group [(hereinafter, referred to as "active imide group".) - SO ₂ NHCOR, -SO ₂ NHSO
₂ R, -CONHSO ₂ R] (4) carboxylic acid group (-CO ₂ H) (5) sulfonic acid group (-SO ₃ H) (6) phosphoric acid group (-OPO ₃ H ₂₎

In the above (1) to (6), Ar represents a divalent aryl linking group which may have a substituent, and R represents a hydrocarbon group which may have a substituent. .

Among the alkali-soluble resins having an acidic group selected from the above (1) to (6), the alkali-soluble resin having (1) a phenol group, (2) a sulfonamide group and (3) an active imide group is preferable. In particular, an alkali-soluble resin having (1) a phenol group or (2) a sulfonamide group is most preferable from the viewpoint of ensuring sufficient solubility in an alkaline developing solution, development latitude and film strength.

Examples of the alkali-soluble resin having an acidic group selected from the above (1) to (6) include the following. (1) Examples of the alkali-soluble resin having a phenol group include a condensation polymer of phenol and formaldehyde, a condensation polymer of m-cresol and formaldehyde,
Condensation polymer of p-cresol and formaldehyde, m-
/ P-condensation polymer of mixed cresol and formaldehyde, phenol and cresol (m-, p-, or m- /
and a novolak resin such as a condensation polymer of formaldehyde, and a condensation polymer of pyrogallol and acetone. Further, a copolymer obtained by copolymerizing a compound having a phenol group in its side chain can be mentioned. Alternatively, a copolymer obtained by copolymerizing a compound having a phenol group on its side chain can be used.

Examples of the compound having a phenol group include acrylamide, methacrylamide, acrylic acid ester, methacrylic acid ester, and hydroxystyrene having a phenol group.

As the alkali-soluble resin having a sulfonamide group (2), for example, a polymer having a minimum constitutional unit derived from a compound having a sulfonamide group as a main constituent can be mentioned. Examples of the compound as described above include a compound having at least one sulfonamide group in which at least one hydrogen atom is bonded to a nitrogen atom and a polymerizable unsaturated group in the molecule. Among them, a low molecular weight compound having an acryloyl group, an allyl group, or a vinyloxy group and a substituted or mono-substituted aminosulfonyl group or a substituted sulfonylimino group in the molecule is preferable, and for example, the following general formula (i) to general formula ( The compound represented by v) is mentioned.

[0045]

[Chemical 13]

In the general formulas (i) to (v), X
¹, X²Are each independently -O- or -NR⁷Represents
R¹, R^FourAre each independently a hydrogen atom or -CH₃The table
You R², R^Five, R⁹, R¹², And R¹⁶Are each independent
In addition, an alkyl group having 1 to 12 carbon atoms which may have a substituent.
Ren group, cycloalkylene group, arylene group or aral
Represents a xylene group. R³, R⁷, And R¹³Are each independent
In addition, a hydrogen atom and a carbon number of 1 to 1 which may have a substituent
2 alkyl group, cycloalkyl group, aryl group or
Represents a aralkyl group. Also, R⁶, R¹⁷Are each independently
C1-C12 alkyl which may have a substituent
Group, cycloalkyl group, aryl group, aralkyl group
You R⁸, R^Ten, R¹⁴Are each independently a hydrogen atom or-
CH₃Represents R¹¹, R ¹⁵Are each independently a single bond or
Alkylene having 1 to 12 carbon atoms which may have a substituent
Group, cycloalkylene group, arylene group or aralkyl group
Represents a group. Y¹, Y²Are each independently a single bond or C
Represents O.

Among the compounds represented by the general formulas (i) to (v), in the positive type lithographic printing material of the present invention, particularly m-aminosulfonylphenyl methacrylate, N
-(P-Aminosulfonylphenyl) methacrylamide, N- (p-aminosulfonylphenyl) acrylamide and the like can be preferably used.

As the alkali-soluble resin having an active imide group (3), for example, a polymer having a minimum constitutional unit derived from a compound having an active imide group as a main constitutional component can be mentioned. Examples of the compound as described above include compounds having one or more active imide groups represented by the following structural formulas and at least one polymerizable unsaturated group in the molecule.

[0049]

[Chemical 14]

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

(4) As the alkali-soluble resin having a carboxylic acid group, for example, a main constituent is a minimum constitutional unit derived from a compound having at least one carboxylic acid group and at least one polymerizable unsaturated group in the molecule. The polymer used as a component can be mentioned. (5) As the alkali-soluble polymer having a sulfonic acid group, for example, a minimum structural unit derived from a compound having at least one sulfonic acid group and at least one polymerizable unsaturated group in the molecule is a main structural unit. Polymers can be mentioned. (6) As the alkali-soluble resin having a phosphate group,
For example, there may be mentioned a polymer having a minimum constitutional unit derived from a compound having one or more phosphoric acid groups and one or more polymerizable unsaturated groups in the molecule as a main constitutional component.

The minimum constitutional unit having an acidic group selected from the above (1) to (6), which constitutes the alkali-soluble resin used in the positive recording layer in the lithographic printing plate precursor according to the invention, is particularly only one kind. It is not necessary to use two or more kinds of minimum structural units having the same acidic group, or a copolymer of two or more kinds of minimum structural units having different acidic groups.

The above-mentioned copolymer is copolymerized (1) to
A compound having an acidic group selected from (6) is preferably contained in the copolymer in an amount of 10 mol% or more, more preferably 20 mol% or more. 10 mol%
If it is less than 1, the developing latitude tends to be insufficiently improved.

In the present invention, when the compound is copolymerized and the alkali-soluble resin is used as the copolymer, as the compound to be copolymerized, the other compound containing no acidic group of the above (1) to (6) is used. You can also Examples of the other compounds (1) to (6) not containing an acidic group include the following (m1)
The compounds listed in (m12) to (m12) can be exemplified, but the invention is not limited thereto. (M1) Acrylic acid esters and methacrylic acid esters having an aliphatic hydroxyl group such as 2-hydroxyethyl acrylate or 2-hydroxyethyl methacrylate. (M2) methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, amyl acrylate,
Alkyl acrylates such as hexyl acrylate, octyl acrylate, benzyl acrylate, 2-chloroethyl acrylate and glycidyl acrylate. (M3) Methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, amyl methacrylate, hexyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, methacrylic acid-2-
Alkyl methacrylates such as chloroethyl, glycidyl methacrylate, etc. (M4) acrylamide, methacrylamide, N-methylol acrylamide, N-ethyl acrylamide, N
-Hexyl methacrylamide, N-cyclohexyl acrylamide, N-hydroxyethyl acrylamide, N
-Acrylamide or methacrylamide such as phenylacrylamide, N-nitrophenylacrylamide, N-ethyl-N-phenylacrylamide.

(M5) Vinyl ethers such as ethyl vinyl ether, 2-chloroethyl vinyl ether, hydroxyethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, octyl vinyl ether and phenyl vinyl ether. (M6) vinyl acetate, vinyl chloroacetate,
Vinyl esters such as vinyl butyrate and vinyl benzoate. (M7) Styrenes such as styrene, α-methylstyrene, methylstyrene and chloromethylstyrene. (M8) Vinyl ketones such as methyl vinyl ketone, ethyl vinyl ketone, propyl vinyl ketone, and phenyl vinyl ketone. (M9) Olefins such as ethylene, propylene, isobutylene, butadiene and isoprene. (M10) N-vinylpyrrolidone, acrylonitrile,
Methacrylonitrile etc. (M11) Unsaturated imides such as maleimide, N-acryloylacrylamide, N-acetylmethacrylamide, N-propionylmethacrylamide, and N- (p-chlorobenzoyl) methacrylamide. (M12) An unsaturated carboxylic acid such as acrylic acid, methacrylic acid, maleic anhydride or itaconic acid.

The alkali-soluble resin preferably has a phenolic hydroxyl group from the viewpoint of excellent image formability when exposed to an infrared laser or the like, and examples thereof include phenol formaldehyde resin, m-cresol formaldehyde resin and p-cresol formaldehyde resin. , M
Preference is given to novolak resins such as − / p-mixed cresol formaldehyde resin and phenol / cresol (m-, p-, or m- / p-mixed) mixed formaldehyde resin, and pyrogallolacetone resin.

Further, as the alkali-soluble resin having a phenolic hydroxyl group, there are further known US Pat.
As described in Japanese Patent No. 279, there may be mentioned condensation polymers of phenol and formaldehyde having a C3-8 alkyl group as a substituent, such as t-butylphenol formaldehyde resin and octylphenol formaldehyde resin.

The weight average molecular weight of the alkali-soluble resin is preferably 500 or more from the viewpoint of image forming property, and more preferably 1,000 to 700,000. The number average molecular weight is preferably 500 or more, more preferably 750 to 650,000. The dispersity (weight average molecular weight / number average molecular weight) is preferably 1.1 to 10.

Further, these alkali-soluble resins may be used alone or in combination of two or more kinds. When combined, US Pat. No. 4,12
An alkyl group having 3 to 8 carbon atoms as a substituent, such as a polycondensation polymer of t-butylphenol and formaldehyde or a polycondensation polymer of octylphenol and formaldehyde as described in Japanese Patent No. 3,279. And a polycondensate of phenol and formaldehyde, and an alkali-soluble resin having a phenol structure having an electron-withdrawing group on the aromatic ring described in JP-A-2000-241972 previously filed by the present inventors. May be.

The total content of the alkali-soluble resin in the present invention is preferably 30 to 98% by weight, more preferably 40 to 95% by weight based on the total solid content of the recording layer. When the content is less than 30% by weight, the durability tends to deteriorate, and when it exceeds 98% by weight, the sensitivity and the image forming property tend to decrease, which is not preferable.

[(B) Infrared Absorbing Agent] The infrared absorbing agent used in the image recording material of the present invention is a substance which absorbs a light energy irradiation ray used for recording and generates heat, particularly in an absorption wavelength range. Can be used without limitation, but from the viewpoint of compatibility with easily available high-power lasers,
An infrared absorbing dye or pigment having an absorption maximum at a wavelength of 760 nm to 1200 nm is preferable.

As the dye, commercially available dyes and known dyes described in documents such as "Dye Handbook" (edited by the Society of Synthetic Organic Chemistry, published in 1970) can be used. Specifically, 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, metal thiolate complexes, oxonol dyes. , Dyes such as diimonium dyes, aminium dyes, and croconium dyes.

Preferred dyes include, for example, JP-A-5
8-125246, JP-A-59-84356, JP-A-59-202829, and JP-A-60-7.
Cyanine dyes described in JP-A-8787, JP-A-58-173696, JP-A-58-18169
No. 0, JP-A-58-194595, etc., methine dyes, JP-A-58-112793, JP-A-58-224793, and JP-A-59-4.
Naphthoquinone dyes described in JP-A-8187, JP-A-59-73996, JP-A-60-52940 and JP-A-60-63744, and JP-A-58.
Examples thereof include squarylium dyes described in JP-A-112792 and cyanine dyes described in British Patent 434,875.

The near-infrared absorption sensitizer described in US Pat. No. 5,156,938 is also preferably used, and
Substituted arylbenzo (thio) pyrylium salts described in U.S. Pat. No. 3,881,924, JP-A-57-
Trimethine thiapyrylium salt described in Japanese Patent No. 142645 (U.S. Pat. No. 4,327,169), JP-A-SHO-5
No. 8-181051, No. 58-220143, No. 59-41363, No. 59-84248, No. 59-84249, No. 59-14606.
3 and 59-146061, pyrylium compounds, cyanine dyes described in JP-A-59-216146, and U.S. Pat. No. 4,283,475.
The pentamethine thiopyrylium salt described in the specification and the pyrylium compounds disclosed in Japanese Examined Patent Publication Nos. 5-13514 and 5-19702 are also preferably used.

Another preferred example of the dye is the compound of formula (I) in US Pat. No. 4,756,993.
The near infrared absorbing dye described as (II) can be mentioned.

Among these dyes, particularly preferred are cyanine dyes, phthalocyanine dyes, oxonol dyes, squarylium dyes, pyrylium salts, thiopyrylium dyes, and nickel thiolate complexes. Furthermore, the dyes represented by the following general formulas (a) to (e) are preferable because they are excellent in photothermal conversion efficiency, and the cyanine dye represented by the following general formula (a) is particularly used in the polymerizable composition of the present invention. In this case, it is most preferable because it gives a high polymerization activity and is excellent in stability and economy.

[0067]

[Chemical 15]

In the general formula (a), X ¹ represents a hydrogen atom, a halogen atom, -NPh ₂ , X ² -L ¹ or a group shown below. Here, X ² represents an oxygen atom or a sulfur atom, and L ¹
Represents a hydrocarbon group having 1 to 12 carbon atoms, an aromatic ring having a hetero atom, and a hydrocarbon group having 1 to 12 carbon atoms containing a hetero atom. Here, the hetero atom means N,
S, O, a halogen atom and Se are shown.

[0069]

[Chemical 16]

R ¹ and R ² each independently have 1 carbon atom.
~ 12 hydrocarbon groups are shown. From the storage stability of the photosensitive layer coating solution, R ¹ and R ² are preferably a hydrocarbon group having 2 or more carbon atoms, and R ¹ and R ² are bonded to each other to form a 5-membered ring or It is particularly preferable to form a 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. Moreover, as a preferable substituent, a hydrocarbon group having 12 or less carbon atoms,
Examples thereof include a halogen atom and an alkoxy group having 12 or less carbon atoms. Y ¹ and Y ^{2, which} may be the same or different, each represents a sulfur atom or a dialkylmethylene group having 12 or less carbon atoms. R ³ and R ^{4, which} may be the same or different, each represents a hydrocarbon group having 20 or less carbon atoms, which may have a substituent. Preferred substituents include an alkoxy group having 12 or less carbon atoms, a carboxyl group and a sulfo group. R ⁵ , R ⁶ , R ⁷ and R ^{8, which} may be the same or different, each represents a hydrogen atom or a hydrocarbon group having 12 or less carbon atoms. From the availability of raw materials, hydrogen atom is preferable. In addition, Za ^-
Represents a counter anion. However, when any of R ^{1 to} R ⁸ is substituted with a sulfo group, Za ⁻ is not necessary. Preferred Za ⁻ is a halogen ion, a perchlorate ion, a tetrafluoroborate ion, a hexafluorophosphate ion, and a sulfonate ion from the storage stability of the photosensitive layer coating solution, and a perchlorate ion is particularly preferred,
Hexafluorophosphate ion and aryl sulfonate ion.

Specific examples of the cyanine dye represented by the general formula (a) which can be preferably used in the present invention include those shown below and Japanese Patent Application No. 11-31062.
Paragraph numbers [0017] to [0019] of the specification No. 3 and paragraph number [001] of the specification of Japanese Patent Application No. 2000-224031.
2] to [0038], and those described in paragraph Nos. [0012] to [0023] of Japanese Patent Application No. 2000-211147.

[0073]

[Chemical 17]

[0074]

[Chemical 18]

[0075]

[Chemical 19]

[0076]

[Chemical 20]

[0077]

[Chemical 21]

In the general formula (b), L represents a methine chain having 7 or more conjugated carbon atoms, and the methine chain may have a substituent, and the substituents are bonded to each other to form a ring structure. May be. Zb ⁺ represents a counter cation. Preferred counter cations include ammonium, iodonium, sulfonium, phosphonium, pyridinium, alkali metal cations (Ni ⁺ , K ⁺ , Li ⁺ ) and the like. R ^{9 to} R ¹⁴ and R ^{15 to} R ²⁰ are each independently a hydrogen atom, a halogen atom, a cyano group, an alkyl group, an aryl group, an alkenyl group, an alkynyl group, a carbonyl group, a thio group, a sulfonyl group, a sulfinyl group or an oxy group. , Or a substituent selected from an amino group, or a substituent in which two or three of these are combined, and may be bonded to each other to form a ring structure. Here, in the general formula (b), L represents a methine chain having 7 conjugated carbon atoms, and R ^{9 to} R ¹⁴ and R ¹⁵
It is preferable that R ²⁰ all represent hydrogen atoms from the viewpoint of easy availability and effects.

In the present invention, specific examples of the dye represented by formula (b) which can be preferably used include the followings.

[0080]

[Chemical formula 22]

[0081]

[Chemical formula 23]

In the general formula (c), Y ³ and Y ⁴ each independently represent an oxygen atom, a sulfur atom, a selenium atom or a tellurium atom. M represents a methine chain having a conjugated carbon number of 5 or more. R
^{21 to} R ²⁴ and R ^{25 to} R ²⁸ may be the same or different and each is a hydrogen atom, a halogen atom, a cyano group, an alkyl group, an aryl group, an alkenyl group, an alkynyl group, a carbonyl group, a thio group. Represents a sulfonyl group, a sulfinyl group, an oxy group, or an amino group. Also, in the formula Z
a ^- represents a counter anion, Za in the general formula (a) ^-
Is synonymous with.

In the present invention, specific examples of the dye represented by formula (c) which can be preferably used include the followings.

[0084]

[Chemical formula 24]

[0085]

[Chemical 25]

In the general formula (d), R²⁹To R³¹Each is independent
Shows a hydrogen atom, an alkyl group, or an aryl group. R
³³And R³⁴Are each independently an alkyl group, a substituted oxy group,
Alternatively, it represents a halogen atom. n and m are each independently 0
Indicates an integer from 4 to 4. R²⁹And R ³⁰, Or R³¹And R³²Is it
Each may be bonded to form a ring, or R²⁹And / or
R³⁰Is R³³And again R³¹And / or R³²Is R³⁴Combined with
To form a ring, and further R³³Or R³⁴Multiple
R, if present³³Each other or R³⁴Mutual bond
To form a ring. X²And X³Each independently, water
An atom, an alkyl group, or an aryl group, X²as well as
X³At least one of them represents a hydrogen atom or an alkyl group.
You Q is a trimethine group which may have a substituent or a group
It is a tammethine group and forms a ring structure with a divalent organic group.
May be done. Zc^-Represents a counter anion and is represented by the general formula
Za in (a)^-Is synonymous with.

In the present invention, specific examples of the dye represented by formula (d) which can be preferably used include the followings.

[0088]

[Chemical formula 26]

[0089]

[Chemical 27]

In formula (e), R ^{35 to} R ⁵⁰ are each independently a hydrogen atom which may have a substituent, a halogen atom, a cyano group, an alkyl group, an aryl group, an alkenyl group, an alkynyl group or a hydroxyl group. , A carbonyl group, a thio group, a sulfonyl group, a sulfinyl group, an oxy group, an amino group, and an onium salt structure. M represents two hydrogen atoms or a metal atom, a halometal group or an oxymetal group, and the metal atom contained therein is IA, IIA, IIIB or IV in the periodic table.
Group B atoms, first-, second-, and third-period transition metals and lanthanoid elements are mentioned, among which copper, magnesium, iron,
Zinc, cobalt, aluminum, titanium and vanadium are preferred.

In the present invention, specific examples of the dye represented by formula (e) which can be preferably used include the followings.

[0092]

[Chemical 28]

Examples of the pigment used as the infrared absorber in the present invention include commercially available pigments and color index (CI) handbooks, "Latest Pigment Handbook" (edited by Japan Pigment Technology Association, 1977), "Latest Pigment". Applied Technology "(CMC
Published in 1986), "Printing Ink Technology" published by CMC, published in 1984).

The types of pigments include black pigments, yellow pigments, orange pigments, brown pigments, red pigments, purple pigments,
Blue pigment, green pigment, fluorescent pigment, metal powder pigment, etc.
Polymer bound dyes may be mentioned. Specifically, insoluble azo pigments, azo lake pigments, condensed azo pigments, chelate azo pigments, phthalocyanine pigments, anthraquinone pigments,
Perylene and perinone pigments, thioindigo pigments, quinacridone pigments, dioxazine pigments, isoindolinone pigments, quinophthalone pigments, dyed lake pigments,
Azine pigment, nitroso pigment, nitro pigment, natural pigment, fluorescent pigment, inorganic pigment, 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. The surface treatment method includes a method of surface-coating a resin or wax, a method of attaching a surfactant, a method of binding a reactive substance (for example, a silane coupling agent, an epoxy compound, polyisocyanate, etc.) to the pigment surface, etc. Can be considered. The above surface treatment method is "property and application of metal soap" (Koushobo),
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 0.1 μm to 1 μm.
It is preferably in the range of. Particle size of pigment is 0.01μ
When it is less than m, it is not preferable from the viewpoint of stability of the dispersion in the coating liquid for the image-sensitive layer, and when it exceeds 10 μm, it is not preferable from the viewpoint of uniformity of the image-sensitive layer.

As a method for dispersing the pigment, a known dispersion technique used in ink production, toner production or the like 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, see "Latest Pigment Application Technology" (CMC Publishing, 1
986).

These pigments or dyes are used in an amount of 0.01 to 50% by weight, preferably 0.1 to 10% by weight, and particularly preferably 0.5 to 10% by weight, based on the total solids constituting the image recording material. % By weight, particularly preferably in the case of pigments of 0.
It can be added in a ratio of 1 to 10% by weight. If the amount of the pigment or dye added is less than 0.01% by weight, the sensitivity will be low, and if it exceeds 50% by weight, the uniformity of the photosensitive layer will be lost and the durability of the image recording material will be deteriorated.

[Other Components] In forming the positive recording layer in the present invention, various additives can be further added, if necessary. For example onium salt,
The combined use of a substance that is thermally decomposable, such as an o-quinonediazide compound, an aromatic sulfone compound, and an aromatic sulfonic acid ester compound, that substantially reduces the solubility of the alkali-soluble resin in the state of not decomposing, is It is preferable from the viewpoint of improving the dissolution inhibiting property in the developing solution. Examples of onium salts include diazonium salts, ammonium salts, phosphonium salts, iodonium salts, sulfonium salts, selenonium salts, arsonium salts and the like.

Suitable onium salts used in the present invention include, for example, SI Schlesinger,
Photogr. Sci. Eng., 18, 387 (1974), TS Bal et a
l, Polymer, 21, 423 (1980), JP-A-5-158230
Diazonium salt described in U.S. Pat. No. 4,069,055
No. 4,069,056, ammonium salts described in JP-A-3-140140, DC Necker et al, Macromolecul
es, 17, 2468 (1984), CS Wen et al, Teh, Proc. Co
nf. Rad. Curing ASIA, p478 Tokyo, Oct (1988), U.S. Pat. No. 4,069,055, 4,069,0.
Phosphonium salt described in Japanese Patent No. 56, JVCrivello
et al, Macromorecules, 10 (6), 1307 (1977), Chem. &
Eng. News, Nov. 28, p31 (1988), European Patent No. 10
No. 4,143, U.S. Pat. No. 339,049, No. 410,201, and JP-A No. 2-1508.
48, JP-A-2-296514, iodonium salts, JVCrivello et al, Polymer J. 17,
73 (1985), JV Crivello et al. J. Org. Chem., 43,
3055 (1978), WR Watt et al, J. Polymer Sci., Pol
ymer Chem. Ed., 22, 1789 (1984), JV Crivello et
al, Polymer Bull., 14, 279 (1985), JV Crivell
o et al, Macromorecules, 14 (5), 1141 (1981), JV
Crivello et al, J. Polymer Sci., Polymer Chem. E
d., 17, 2877 (1979), European Patent Nos. 370,693, 233,567, 297,443, 297,442, and U.S. Pat. No. 4,9.
No. 33,377, No. 3,902,114, No. 410,201, No. 339,049, No. 4,760,013, No. 4,734.
No. 444, No. 2,833,827, German Patent No. 2,904,626, No. 3,604,5.
No. 80, 3,604,581, sulfonium salts, JV Crivello et al, Macromorecul
es, 10 (6), 1307 (1977), JV Crivello et al, J.P.
Olymer Sci., Polymer Chem. Ed., 17, 1047 (1979), selenonium salt, CS Wen et al, Teh, Proc. C
Examples include the arsonium salt described in onf. Rad. Curing ASIA, p478 Tokyo, Oct (1988). Among the onium salts, the diazonium salt is particularly preferable. Further, particularly preferable diazonium salts include those described in JP-A-5-158230.

As the counter ion of the onium salt, tetrafluoroboric acid, hexafluorophosphoric acid, triisopropylnaphthalenesulfonic acid, 5-nitro-o-toluenesulfonic acid, 5
-Sulfosalicylic acid, 2,5-dimethylbenzenesulfonic acid, 2,4,6-trimethylbenzenesulfonic acid, 2
-Nitrobenzenesulfonic acid, 3-chlorobenzenesulfonic acid, 3-bromobenzenesulfonic acid, 2-fluorocaprylnaphthalenesulfonic acid, dodecylbenzenesulfonic acid, 1-naphthol-5-sulfonic acid, 2-methoxy-4-hydroxy-5- Examples thereof include benzoyl-benzenesulfonic acid and paratoluenesulfonic acid. Among these, alkylaromatic sulfonic acids such as hexafluorophosphoric acid, triisopropylnaphthalenesulfonic acid and 2,5-dimethylbenzenesulfonic acid are particularly preferable.

Suitable quinonediazides include o-quinonediazide compounds. The o-quinonediazide compound used in the present invention is a compound having at least one o-quinonediazide group, which increases alkali solubility by thermal decomposition, and compounds having various structures can be used. That is, o-quinonediazide loses the ability to suppress the dissolution of the binder due to thermal decomposition, and
The quinonediazide itself helps the solubility of the light-sensitive material system by both effects of changing into an alkali-soluble substance. Examples of the o-quinonediazide compound used in the present invention include those described in J. The compounds described on pages 339 to 352 of "Light-Sensitive Systems" (John Wiley & Sons. Inc.) by Coser can be used, but in particular, they have been reacted with various aromatic polyhydroxy compounds or aromatic amino compounds. -Sulfonic acid esters or sulfonic acid amides of quinonediazide are preferred. In addition, Japanese Examined Japanese Patent Publication No. 43-2840
Benzoquinone (1,
2) -Diazide sulfonic acid chloride or naphthoquinone- (1,2) -diazide-5-sulfonic acid chloride with pyrogallol-acetone resin, US Pat. Nos. 3,046,120 and 3,188. , 21
Benzoquinone- (1,2) described in No. 0
-Diazide sulfonic acid chloride or naphthoquinone-
An ester of (1,2) -diazide-5-sulfonic acid chloride and a phenol-formaldehyde resin is also preferably used.

Further, an ester of naphthoquinone- (1,2) -diazide-4-sulfonic acid chloride and a phenol formaldehyde resin or a cresol-formaldehyde resin, naphthoquinone- (1,2) -diazide-
Esters of 4-sulfonic acid chloride and pyrogallol-acetone resin are likewise preferably used. Other useful o-quinonediazide compounds are reported and known in numerous patents. For example, JP-A-47-530
3, JP-A-48-63802, JP-A-48-638.
03, JP-A-48-96575, JP-A-49-38.
701, JP-A-48-13354, JP-B-41-1
No. 1222, Japanese Patent Publication No. 45-9610, Japanese Patent Publication No. 49-1
7481, U.S. Pat. No. 2,797,213
No. 3,454,400, No. 3,544,32
No. 3, No. 3,573,917, No. 3,674,4
95, 3,785,825, British Patents 1,2
No. 27,602, No. 1,251,345, No. 1,
267,005, 1,329,888, 1,330,932, and German Patent No. 854,890 can be cited as examples.

The amount of the o-quinonediazide compound added is preferably 1 to 50% by weight, based on the total solid content of the printing plate material.
More preferably 5 to 30% by weight, particularly preferably 10 to
It is in the range of 30% by weight. These compounds can be used alone, but may be used as a mixture of several kinds.

The additive amount other than the o-quinonediazide compound is preferably 1 to 50% by weight, more preferably 5 to 30% by weight, and particularly preferably 10 to 30% by weight. The additive of the present invention and the binder are preferably contained in the same layer.

Further, for the purpose of further improving the sensitivity, cyclic acid anhydrides, phenols and organic acids can be used in combination. As the cyclic acid anhydride, US Pat. No. 4,115,
128, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, 3,
6-endooxy-Δ4-tetrahydrophthalic anhydride,
Tetrachlorophthalic anhydride, maleic anhydride, chloromaleic anhydride, α-phenylmaleic anhydride, succinic anhydride, pyromellitic anhydride and the like can be used. Examples of the phenols include bisphenol A, p-nitrophenol, p-ethoxyphenol, 2,4,4'-trihydroxybenzophenone, 2,3,4-trihydroxybenzophenone, 4-hydroxybenzophenone, 4,
4 ', 4 "-trihydroxytriphenylmethane, 4,
4 ', 3 ", 4"-tetrahydroxy-3,5,3',
5'-tetramethyltriphenylmethane and the like can be mentioned. Further, as organic acids, JP-A-60-88942 is used.
And Japanese Patent Application Laid-Open No. 2-96755.
There are sulfonic acids, sulfinic acids, alkylsulfuric acids, phosphonic acids, phosphoric acid esters, carboxylic acids, and the like, and specifically, p-toluenesulfonic acid, dodecylbenzenesulfonic acid, p-toluenesulfinic acid, ethylsulfate, phenyl. Phosphonic acid, phenylphosphinic acid, phenyl phosphate, diphenyl phosphate, benzoic acid, isophthalic acid, adipic acid, p-toluic acid, 3,4-dimethoxybenzoic acid, phthalic acid, terephthalic acid, 4-cyclohexene-1,2. -Dicarboxylic acid, erucic acid, lauric acid,
Examples thereof include n-undecanoic acid and ascorbic acid. The proportion of the cyclic acid anhydride, phenols and organic acids in the printing plate material is preferably 0.05 to 20% by weight, more preferably 0.1 to 15% by weight, particularly preferably 0.1 to 15% by weight. It is 10% by weight.

Further, in the coating liquid for the recording layer of the present invention, in order to extend the stability of the treatment against the developing conditions, JP-A-62-251740 and JP-A-3-208514 are used.
Nonionic surfactants as described in JP-A-59-121044 and JP-A-4-13149.
Amphoteric surfactants as described in Japanese Patent Publication No. EP9
Siloxane compounds as described in 50517 and fluorine-containing monomer copolymers as described in JP-A No. 11-288093 can be added.

Specific examples of the nonionic surfactant include sorbitan tristearate, sorbitan monopalmitate, sorbitan trioleate, stearic acid monoglyceride and polyoxyethylene nonylphenyl ether. Specific examples of the amphoteric surfactant include alkyldi (aminoethyl) glycine, alkylpolyaminoethylglycine hydrochloride, 2-alkyl-N-carboxyethyl-N-hydroxyethylimidazolinium betaine and N-tetradecyl-N, N-. Betaine type (for example, trade name "Amogen K": manufactured by Daiichi Kogyo Co., Ltd.) and the like can be mentioned. As the siloxane compound, a block copolymer of dimethyl siloxane and polyalkylene oxide is preferable, and specific examples thereof include DBE-22 manufactured by Chisso Corporation.
4, DBE-621, DBE-712, DBP-73
2, DBP-534, Tego Gl made by Tego, Germany
Examples thereof include polyalkylene oxide-modified silicone such as ide100. The ratio of the nonionic surfactant and the amphoteric surfactant in the printing plate material is 0.0
5 to 15% by weight is preferable, and 0.1 to 5 is more preferable.
% By weight.

In the recording layer of the present invention, a printing-out agent for obtaining a visible image immediately after heating by exposure and a dye or pigment as an image colorant can be added. A typical example of the print-out agent is a combination of a compound that releases an acid when heated by exposure (photo-acid releasing agent) and an organic dye capable of forming a salt. Specifically, combinations of o-naphthoquinonediazide-4-sulfonic acid halogenide and a salt-forming organic dye described in JP-A Nos. 50-36209 and 53-8128, and JP-A No.
No. 3-36223, No. 54-74728, No. 60-3
No. 626, No. 61-143748, No. 61-1516.
Combinations of a trihalomethyl compound and a salt-forming organic dye described in JP-A-44 and JP-A-63-58440 can be mentioned. Such trihalomethyl compounds include oxazole-based compounds and triazine-based compounds, both of which have excellent stability over time and give a clear printout image.

As the image colorant, other dyes can be used in addition to the above-mentioned salt-forming organic dyes. Suitable dyes, including salt-forming organic dyes, include oil-soluble dyes and basic dyes. Specifically, Oil Yellow # 101, Oil Yellow # 103, Oil Pink #
312, Oil Green BG, Oil Blue BOS, Oil Blue # 603, Oil Black BY, Oil Black BS, Oil Black T-505 (all manufactured by Orient Chemical Industry Co., Ltd.), Victoria Pure Blue, Crystal Violet (CI42555), Methyl. Violet (CI42535), ethyl violet, Rhodamine B (CI145170B), malachite green (CI42000), methylene blue (CI5201).
5) etc. can be mentioned. Also, JP-A-62-29
The dyes described in Japanese Patent No. 3247 are particularly preferable.
The amount of these dyes is 0.01
It can be added to the printing plate material in a proportion of from 10 to 10% by weight, preferably from 0.1 to 3% by weight. Further, a plasticizer is added to the printing plate material of the present invention, if necessary, in order to impart flexibility to the coating film. For example, butylphthalyl, polyethylene glycol, tributyl citrate, diethyl phthalate, dibutyl phthalate, dihexyl phthalate, dioctyl phthalate, tricresyl phosphate, tributyl phosphate, trioctyl phosphate, tetrahydrofurfuryl oleate, acrylic acid or methacrylic acid. Oligomers and polymers are used.

In addition to these, epoxy compounds,
Vinyl ethers, and further, JP-A-8-276558
JP-A-11-16, which has been previously proposed by the present inventors.
The crosslinkable compound having an alkali dissolution suppressing action described in JP-A No. 0860 can be appropriately added depending on the purpose.

[Preparation of lithographic printing plate precursor] The lithographic printing plate precursor of the present invention is prepared by dissolving a component for a coating liquid of a desired layer such as a coating liquid for a photosensitive layer (recording layer) or a protective layer in a solvent to obtain a suitable support. It can be manufactured by applying it on the body. Further, depending on the purpose, a protective layer, a resin intermediate layer, a back coat layer and the like can be similarly formed. As the solvent used here, ethylene dichloride, cyclohexanone,
Methyl ethyl ketone, methanol, ethanol, propanol, ethylene glycol monomethyl ether, 1-
Methoxy-2-propanol, 2-methoxyethyl acetate, 1-methoxy-2-propyl acetate, dimethoxyethane, methyl lactate, ethyl lactate, N, N-dimethylacetamide, N, N-dimethylformamide, tetramethylurea, N- Examples thereof include methylpyrrolidone, dimethyl sulfoxide, sulfolane, γ-butyrolactone, and toluene, but are not limited thereto. These solvents may be used alone or as a mixture.
The concentration of the above components (total solids including additives) in the solvent is
It is preferably 1 to 50% by weight. The coating amount (solid content) on the support obtained after coating and drying varies depending on the use, but is generally 0.5 for a photosensitive printing plate.
˜5.0 g / m ² is preferred.

Various methods can be used for coating, and examples thereof include bar coater coating, spin coating, spray coating, curtain coating, dip coating, air knife coating, blade coating, and roll coating. You can As the coating amount decreases, the apparent sensitivity increases, but the film characteristics of the photosensitive film deteriorate. In the recording layer of the present invention, a surfactant for improving the coatability, for example, a fluorinated surfactant as described in JP-A-62-170950 can be added. The preferable addition amount is from 0.01 to
It is 1% by weight, more preferably 0.05 to 0.5% by weight.

[Resin Intermediate Layer] In the lithographic printing plate precursor according to the invention, a resin intermediate layer may be provided between the recording layer and the support, if desired. By providing this resin intermediate layer,
The recording layer, which is an infrared-sensitive layer whose solubility in an alkaline developer is improved by exposure, has good sensitivity to an infrared laser by being provided on or near the exposed surface, and the support and the infrared-sensitive layer There is a polymer intermediate layer consisting of a polymer between them, and it functions as a heat insulating layer, and the heat generated by the exposure of the infrared laser does not diffuse to the support, so it can be used for image formation with high sensitivity It also has the advantage that In the unexposed area, the recording layer itself, which is impermeable to the alkaline developer, functions as a protective layer for the resin intermediate layer, resulting in good development stability and excellent discrimination. Is formed, and it is considered that stability over time is also secured, and in the exposed portion, the components of the recording layer from which the dissolution suppressing ability has been released are rapidly dissolved and dispersed in the developing solution, and further, Since the resin intermediate layer itself which is present adjacent to the support is composed of an alkali-soluble polymer, it has good solubility in a developing solution and, for example, even when a developing solution having reduced activity is used, the residual It is considered that the resin intermediate layer is useful because it dissolves quickly without forming a film and contributes to the improvement of developability.

[Support] The support used in the present invention is a dimensionally stable plate-like material, for example, paper laminated with paper or plastic (eg, polyethylene, polypropylene, polystyrene, etc.). , Metal plate (eg, aluminum, zinc, copper, etc.), plastic film (eg, cellulose diacetate, cellulose triacetate, cellulose propionate, cellulose butyrate, cellulose acetate butyrate, cellulose nitrate, polyethylene terephthalate, polyethylene, polystyrene, polypropylene, Polycarbonate, polyvinyl acetal, etc.), paper laminated with the above-mentioned metals, or vapor-deposited, or a plastic film. As the support of the present invention, 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. The preferred aluminum plate is a pure aluminum plate or an alloy plate containing aluminum as a main component and a slight amount of a foreign element, and may be a plastic film on which aluminum is laminated or vapor-deposited. The foreign elements contained in the aluminum alloy are
There are 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. Aluminum which is particularly preferred in the present invention is pure aluminum, but completely pure aluminum is difficult to produce in terms of refining technology, and thus 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 which is a publicly known and conventionally used material can be appropriately used. The thickness of the aluminum plate used in the present invention is about 0.1 mm to 0.6 mm, preferably 0.15 mm to 0.4 mm, particularly preferably 0.2 mm.
~ 0.3 mm.

Prior to the surface roughening of the aluminum plate, if desired, a degreasing treatment for removing rolling oil on the surface is carried out, for example, with a surfactant, an organic solvent or an alkaline aqueous solution. 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 melting the surface and a method of selectively melting the surface chemically. It is performed by the method. As the mechanical method, known methods such as a ball polishing method, a brush polishing method, a blast polishing method and a buff polishing method can be used. Further, as an electrochemical graining method, there is a method of performing alternating current or direct current in a hydrochloric acid or nitric acid electrolytic solution. Further, as disclosed in Japanese Patent Laid-Open No. 54-63902, a method in which both are combined can be used.
The thus roughened aluminum plate is subjected to an alkali etching treatment and a neutralization treatment, if necessary, and then subjected to anodizing treatment if desired to enhance the water retention and abrasion resistance of the surface. As the electrolyte used for the anodizing treatment of the aluminum plate, various electrolytes that form a porous oxide film can be used, and generally sulfuric acid, phosphoric acid, oxalic acid, chromic acid or a mixed acid thereof is used. The concentration of these electrolytes is appropriately determined depending on the type of electrolyte.

[0118] The treatment conditions for anodic oxidation cannot be unconditionally specified because they vary depending on the electrolyte used, but generally the concentration of the electrolyte is 1 to 80% by weight solution, the liquid temperature is 5 to 70 ° C, and the current density is 5 to 60A. / Dm ² , voltage 1 to 100 V, electrolysis time 10 seconds to 5 minutes are suitable. If the amount of the anodic oxide film is less than 1.0 g / m ² , printing durability may be insufficient, or the non-image area of the planographic printing plate may be easily scratched.
So-called "scratch stains" tend to occur in which ink adheres to the scratched portion during printing. After being subjected to anodizing treatment, the aluminum surface is optionally subjected to hydrophilic treatment. Examples of the hydrophilic treatment used in the present invention include US Pat.
14,066, 3,181,461, 3,280,734 and 3,902.
There is an alkali metal silicate (for example, sodium silicate aqueous solution) method as disclosed in Japanese Patent No.
In this method, the support is immersed in an aqueous solution of sodium silicate or electrolyzed. Other special public Sho3
6-22063 and potassium fluorozirconate disclosed in US Pat. Nos. 3,276,868, 4,153,461 and 4,68.
The method of treating with polyvinylphosphonic acid as disclosed in the specification of No. 9,272 and the like are used.

The lithographic printing plate precursor according to the invention has a positive type recording layer provided on a support, but an undercoat layer may be provided between them if necessary. As the undercoat layer component, various organic compounds are used, and examples thereof include phosphonic acids having an amino group such as carboxymethyl cellulose, dextrin, gum arabic, and 2-aminoethylphosphonic acid, and phenylphosphonic acid which may have a substituent. , Naphthylphosphonic acid, alkylphosphonic acid, glycerophosphonic acid, organic phosphonic acid such as methylenediphosphonic acid and ethylenediphosphonic acid, optionally substituted phenylphosphoric acid, naphthylphosphoric acid, alkylphosphoric acid and glycerophosphoric acid, etc. Organic phosphoric acid, optionally substituted phenylphosphinic acid, naphthylphosphinic acid, organic phosphinic acids such as alkylphosphinic acid and glycerophosphinic acid, amino acids such as glycine and β-alanine, and hydrochloric acid of triethanolamine Of amines having hydroxy groups such as salts Although selected from acid salts, it may be used by mixing two or more.

This organic undercoat layer can be provided by the following method. That is, water or a solution of the above organic compound dissolved in an organic solvent such as methanol, ethanol, methyl ethyl ketone or a mixed solvent thereof is applied on an aluminum plate and dried, and a method of providing water or methanol, ethanol, methyl ethyl ketone, etc. Is a method in which an aluminum plate is immersed in a solution prepared by dissolving the above organic compound in an organic solvent or a mixed solvent thereof to adsorb the above compound, followed by washing with water or the like and drying to form an organic undercoat layer. . In the former method, a solution having a concentration of 0.005 to 10% by weight of the above organic compound can be applied by various methods. In the latter method, the solution has a concentration of 0.
01 to 20% by weight, preferably 0.05 to 5% by weight, and the immersion temperature is 20 to 90 ° C, preferably 25 to 50 ° C.
And the immersion time is 0.1 second to 20 minutes, preferably 2 seconds to 1 minute. The solution used for this can also be adjusted to a pH range of 1 to 12 with a basic substance such as ammonia, triethylamine, potassium hydroxide, or an acidic substance such as hydrochloric acid or phosphoric acid. Further, a yellow dye may be added to improve the tone reproducibility of the image recording material. The suitable amount of the organic undercoat layer is ² to 200 mg / m ² ,
It is preferably 5 to 100 mg / m ² . If the coating amount is less than 2 mg / m ² , sufficient printing durability cannot be obtained. The same applies when the amount is larger than 200 mg / m ² .

[Plate making] The positive type lithographic printing plate precursor prepared as described above is usually subjected to image exposure, development treatment, and
It is preferably subjected to heat treatment.

[Exposure] As a light source of a light beam used for image exposure, a light source having an emission wavelength in the near infrared to infrared region is preferable, and a solid laser and a semiconductor laser are particularly preferable.

[Development] As a developing solution and a replenishing solution for the planographic printing plate of the invention, conventionally known alkaline aqueous solutions can be used. For example, sodium silicate, potassium, sodium triphosphate, potassium, ammonium, dibasic sodium, potassium, ammonium, sodium carbonate, potassium, ammonium, sodium bicarbonate, potassium, Examples thereof include inorganic alkali salts such as ammonium, sodium borate, potassium, ammonium, sodium hydroxide, ammonium, potassium and lithium. Further, monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monoisopropylamine, diisopropylamine, triisopropylamine, n-butylamine, monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, diisopropanolamine,
Organic alkaline agents such as ethyleneimine, ethylenediamine and pyridine are also used. These alkaline agents may be used alone or in combination of two or more. Among these alkaline agents, a particularly preferable developer is an aqueous silicate solution such as sodium silicate or potassium silicate. The reason is that the developability can be adjusted by the ratio and concentration of silicon oxide SiO ₂ which is a component of silicate and alkali metal oxide M ₂ O. For example, JP-A-54-62.
Alkali metal silicates such as those described in Japanese Patent Publication No. 004 and Japanese Patent Publication No. 57-7427 are effectively used.

Further, when developing using an automatic developing machine, the developer in the developing tank should be exchanged for a long time by adding an aqueous solution (replenisher) having a higher alkaline strength than the developer to the developer. However, it is known that a large amount of PS plate can be processed. Also in the present invention, this replenishment system is preferably applied. If necessary, various surfactants and organic solvents may be added to the developing solution and the replenishing solution for the purpose of accelerating or suppressing the developing property, dispersing the development residue and enhancing the ink affinity of the printing plate image area. Preferred surfactants include anionic, cationic, nonionic and amphoteric surfactants. Further, in the developing solution and the replenishing solution, if necessary, a reducing agent such as a sodium salt or potassium salt of an inorganic acid such as hydroquinone, resorcin, sulfurous acid, and bisulfite, an organic carboxylic acid, a defoaming agent, and a water softener. Can also be added.

The printing plate developed using the above-mentioned developing solution and replenishing solution is post-treated with washing water, a rinse solution containing a surfactant and the like, and a desensitizing solution containing gum arabic and a starch derivative. As the post-treatment when the image recording material of the present invention is used as a printing plate, various combinations of these treatments can be used.

In recent years, automatic developing machines for printing plates have been widely used in the plate making / printing industry in order to rationalize and standardize the plate making work. This automatic developing machine is generally composed of a developing section and a post-processing section, and is composed of a device for conveying a printing plate, each processing liquid tank and a spraying device, which conveys an exposed printing plate horizontally while pumping it up with each pump. The processing liquid is sprayed from a spray nozzle for development processing. Further, recently, a method has also been known in which a printing plate is dipped and conveyed by a submerged guide roll or the like in a processing liquid tank filled with the processing liquid for processing. In such automatic processing, it is possible to perform processing while supplementing each processing solution with a replenishing solution according to the processing amount, operating time, and the like. Further, a so-called disposable processing method of processing with a substantially unused processing liquid can be applied.

In the lithographic printing plate precursor of the present invention, an unnecessary image portion (for example, a film of an original image film) obtained on the lithographic printing plate obtained by imagewise exposing, developing, washing and / or rinsing and / or gumming If there are edge marks etc.),
The unnecessary image portion is erased. Such erasing is preferably performed, for example, by applying an erasing liquid as described in Japanese Patent Publication No. 2-13293 to an unnecessary image portion, leaving it as it is for a predetermined time, and then rinsing with water. A method of irradiating an active ray guided by an optical fiber to an unnecessary image portion and then developing it as described in JP-A-59-174842 can also be used.

[Heat Treatment] The planographic printing plate obtained as described above is coated with a desensitizing gum, if desired, and then
Although it can be subjected to a printing step, when the recording layer according to the present invention is used, it is characterized in that the printing durability is further enhanced by performing a heat treatment (for example, a burning treatment).

In the case of burning a lithographic printing plate, before the burning, JP-B-61-2518 and 55-280.
62, JP-A-62-31859 and JP-A-61-1596.
It is preferable to treat with a leveling solution as described in JP-A-55. As the method, with a sponge or absorbent cotton soaked with the surface-adjusting solution, it is applied on the lithographic printing plate, or by immersing the printing plate in a vat filled with the surface-adjusting solution, Application by an automatic coater is applied. Further, making the coating amount uniform with a squeegee or a squeegee roller after coating gives more preferable results. The amount of the surface conditioning solution is generally 0.03 to
0.8 g / m ² (dry weight) is suitable.

The temperature and time when the lithographic printing plate is subjected to a heating treatment such as a burning treatment depend on the kind of the components forming the image, but in the range of 180 to 300 ° C., 1 to 2
The range of 0 minutes is preferred. Further, the heating method, it is possible to apply any known method, for example, a contact type heating device such as a heat roller may be used, hot air, infrared rays,
A non-contact heating device such as a non-contact heater may be used. Further, a burning processor generally used for post-treatment after drying of the planographic printing plate (for example, burning processor: “BP-1300” sold by Fuji Photo Film Co., Ltd.) is used. You can also

The heat-treated lithographic printing plate can be appropriately subjected to conventional treatments such as washing with water and gumming, if necessary. When a liquid is used, so-called desensitizing treatment such as gumming can be omitted. The lithographic printing plate obtained by such a treatment is particularly excellent in printing durability and is used in an offset printing machine or the like to print a large number of sheets.

[0132]

EXAMPLES The present invention will be described below with reference to examples.
The scope of the invention is not limited to these examples.

[Production of Substrate] Aluminum 0.3 mm thick
Wash the aluminum plate (material 1050) with trichlorethylene.
After degreasing with a nylon brush and 400 mesh
Grain this surface with a water-suspension and wash it thoroughly with water.
Clean 25% sodium hydroxide aqueous solution at 45 ℃
Immerse in the liquid for 9 seconds to perform etching, wash with water, and then
It was immersed in 20% nitric acid for 20 seconds and washed with water. The grain at this time
The amount of etching on the vertical surface is about 3g / m ²Met. next
This plate has a current density of 15 A / dm with 7% sulfuric acid as an electrolyte.
²At 3 g / m²After providing the DC anodized film of, washed with water,
Dried and then with a 2.5% by weight aqueous solution of sodium silicate
Treat at 30 ° C for 10 seconds, apply the following undercoat liquid, and apply the coating film
A substrate was obtained by drying at 80 ° C. for 15 seconds. Covering the coating after drying
Coverage is 15 mg / m²Met.

[0134] [Undercoat liquid]   ・ The following compound 0.3g   ・ Methanol 100g   ・ Water 1g

[0135]

[Chemical 29]

Example 1 The following photosensitive solution 1 was applied to the obtained substrate so that the coating amount was 0.9 g / m ² , and
PERFECT OPEN PH20 manufactured by Tabai
Set WindControl to 7 at 0 and 140 ℃
After drying for 50 seconds, a lithographic printing plate precursor 1 was obtained.

[Synthesis of Copolymer 1 Used for Photosensitive Solution 1] 31.0 g (0.36 mol) of methacrylic acid was added to a 500 ml three-necked flask equipped with a stirrer, a condenser and a dropping funnel.
39.1 g (0.36 mol) of ethyl chloroformate and 200 ml of acetonitrile were added, and the mixture was stirred while cooling with an ice water bath. Triethylamine 36.
4 g (0.36 mol) was added dropwise with a dropping funnel over about 1 hour. After the dropping was completed, the ice-water bath was removed, and the mixture was stirred at room temperature for 30 minutes.

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

Next, in a 20 ml three-necked flask equipped with a stirrer, a condenser and a dropping funnel, 4.61 g (0.01 mg of N- (p-aminosulfonylphenyl) methacrylamide) was added.
92 mol), methyl methacrylate 2.58 g (0.02
58 mol), acrylonitrile 0.80 g (0.015)
Mol) and 20 g of N, N-dimethylacetamide were added, and the mixture was stirred while heating to 65 ° C. in a hot water bath. Add "V-65" to this mixture (manufactured by Wako Pure Chemical Industries, Ltd.)
0.15 g was added and the mixture was stirred under a nitrogen stream for 2 hours while maintaining the temperature at 65 ° C. Further N- (p-
Aminosulfonylphenyl) methacrylamide 4.61
g, methy methacrylate 2.58 g, acrylonitrile 0.80 g, N, N-dimethylacetamide and "V
-65 "0.15 g of the mixture was added dropwise by the dropping funnel over 2 hours. After the dropping was completed, the obtained mixture was further stirred at 65 ° C. for 2 hours.

After the completion of the reaction, 40 g of methanol was added to the mixture, the mixture was cooled, and the resulting mixture was added to 2 liters of water while stirring this water. The mixture was stirred for 30 minutes, and the precipitate was taken out by filtration and dried. By doing so, 15 g of a white solid was obtained. 15 g of the obtained white solid was made into a slurry with 100 ml of methanol, stirred for 1 hour, and then the solid was collected by filtration. Furthermore, this methanol slurry and filtration are
The white solid thus obtained was dried repeatedly to obtain 13 g of Copolymer 1. The weight average molecular weight of the copolymer 1 (polystyrene standard) was measured by gel permeation chromatography to be 54,000, and no component attributed to the monomer used as the raw material was detected.

[0141] [Photosensitive liquid 1]   -M, p-cresol novolac (m / p ratio = 6/4, weight average molecular weight       3500, containing 0.5% by weight of unreacted cresol) 0.474 g   -The above copolymer 1 2.20 g   -Polymerizable compound shown in Table 1 0.18 g   ・ Cyanine dye A (the following structure) 0.155 g   ・ 2-Methoxy-4- (N-phenylamino) benzene     Diazonium hexafluorophosphate 0.03g   ・ Tetrahydrophthalic anhydride 0.19g   ・ The counter ion of ethyl violet is 6-hydroxy-β-       Naphthalenesulfonic acid 0.05g   ・ Fluorosurfactant (MegaFac F176PF,       Dainippon Ink and Chemicals Co., Ltd.) 0.035g   -Fluorine-based surfactant (MegaFac MCF-312,       Dainippon Ink and Chemicals Co., Ltd.) 0.05g   -P-toluenesulfonic acid 0.008 g   -Bis-p-hydroxyphenyl sulfone 0.063 g   -Stearic acid n-dodecyl 0.02g   ・ N-dodecyl palmitate 0.01 g   ・ Dimyristyl thiodipropionate 0.03g     (Sumitomo Chemical Co., Ltd. Sumilizer TPM)   ・ Γ-Butyrolactone 13 g   ・ Methyl ethyl ketone 24g   ・ 1-Methoxy-2-propanol 11 g

[0142]

[Chemical 30]

(Examples 2 to 6) In the photosensitive liquid 1 of Example 1, the planographic printing plate was prepared in the same manner as in Example 1 except that the polymerizable compound was changed to the kind and addition amount shown in Table 1 below. Original plates 2 to 6 were obtained.

[0144]

[Table 1]

Comparative Example 1 Example 1 was repeated except that the polymerizable compound was not added and the amount of the copolymer 1 added was changed from 2.20 g to 2.38 g in the photosensitive solution 1 of Example 1.
A lithographic printing plate precursor 7 was obtained in the same manner as.

Comparative Example 2 A lithographic printing plate precursor 8 was obtained in the same manner as in Example 1 except that the polymerizable compound in the photosensitive liquid 1 of Example 1 was changed as shown in Table 1.

[Evaluation of lithographic printing plate precursors 1 to 8] The lithographic printing plate precursors 1 to 8 produced as described above were evaluated for performance according to the following criteria.

The obtained lithographic printing plate precursor was imaged (exposed) in an image of a test pattern with a Trendsetter manufactured by Creo under the conditions of a beam intensity of 8.5 W and a drum rotation speed of 150 rpm. First, the lithographic printing plate precursor exposed under the above conditions was developed with Fuji Photo Film Co., Ltd. developer DT-1 (diluted with 1: 9) and Fuji Photo Film Co., Ltd. Finisher FP2W (1: 1). PS made by Fuji Photo Film Co., Ltd.
Using processor 900H, the liquid temperature was kept at 30 ° C., and the development time was 12 seconds. With the lithographic printing plate obtained, a good image was formed without stains on the non-image areas, except for the lithographic printing plate of Comparative Example 2. The lithographic printing plate of Comparative Example 2 was found to be difficult to use as a lithographic printing plate because the non-image area was stained and a remarkable decrease in the density of the image area was observed.

Next, gum G manufactured by Fuji Photo Film Co., Ltd.
The plate surface was treated with a liquid obtained by diluting U-7 by 2 times with water, left for 1 day, and then printed with a Heidel KOR-D machine. The printing durability was evaluated by counting the number of sheets from which a normal printed matter was obtained by printing. The results are shown in Table 2.

Further, in order to confirm the improvement of printing durability by heating after exposure, the plate surface is wiped with a burning surface-adjusting solution BC-3 manufactured by Fuji Photo Film Co., Ltd., and a burning device BP-1 is used.
300 was used and it processed at 200 degreeC for 3 minute (s). Then
The plate surface was treated with a liquid obtained by diluting Gum GU-7 manufactured by Fuji Photo Film Co., Ltd. with water by a factor of 2 and printed with a Heidel KOR-D machine in the same manner as the plate which was not heat-treated. The number of sheets from which a normal printed matter was obtained by printing was counted. The results are shown in Table 2.
Shown in.

[0151]

[Table 2]

As is clear from Table 2, the positive type lithographic printing plate precursors 1 to 6 of the invention have good image formability, and the printing durability is remarkably improved by heat treatment after exposure. It was confirmed. On the other hand, when the compound having an ethylenic double bond is not added, or when the addition amount of the compound having an ethylenic double bond is too large, it is confirmed that the effect of the present invention is not exhibited. It was

Example 7 The following photosensitive solution 2 was applied to the obtained substrate so that the coating amount was 1.5 g / m ² , and
Drying was performed under the same conditions as in Example 1 to obtain a lithographic printing plate precursor 9.

[0154] [Photosensitive liquid 2]   -Polymerizable compound shown in Table 1 0.18 g   -M, p-cresol novolac (m / p ratio = 6/4, weight average molecular weight       5000, containing 0.5% by weight of unreacted cresol) 2.10 g   -Octylphenol novolac (weight average molecular weight: 2500) 0.015 g   ・ Cyanine dye A 0.105g   ・ 2-Methoxy-4- (N-phenylamino) benzene     Diazonium hexafluorophosphate 0.03g   ・ Tetrahydrophthalic anhydride 0.10 g   ・ The counter ion of ethyl violet is 6-hydroxy-β-       Naphthalenesulfonic acid 0.063g   ・ Fluorosurfactant (MegaFac F176PF,     Dainippon Ink and Chemicals Co., Ltd.) 0.035g   -Fluorine-based surfactant (MegaFac MCF-312,       Dainippon Ink and Chemicals Co., Ltd. 0.13g   -Bis-p-hydroxyphenyl sulfone 0.08 g   -N-dodecyl stearyl acid (Synthesis example 2) 0.02 g   -N-dodecyl palmitate (Synthesis example 1) 0.01 g   ・ Dimyristyl thiodipropionate 0.03g     (Sumitomo Chemical Co., Ltd. Sumilizer TPM)   ・ Methyl ethyl ketone 16g   ・ 1-Methoxy-2-propanol 10 g

(Comparative Example 3) A lithographic printing plate precursor 10 was prepared in the same manner as in Example 7 except that the polymerizable compound was not added to the photosensitive solution 2 of Example 7.

Example 8 The following photosensitive solution A-1 was applied to the substrate used in Example 1 and dried at 100 ° C. for 2 minutes,
The (A) layer was formed. The applied amount after drying is 0.4 g / m ^2.
Met. Then, the following photosensitive solution B-1 was applied, and 10
It was dried at 0 ° C. for 2 minutes to form a layer (B) (upper layer) to obtain a lithographic printing plate precursor 11. The total coating amount of the photosensitive liquid after drying was 1.0 g / m ² .

[0157] [Photosensitive solution A-1]   -Polymerizable compound described in Table 1 0.02 g   -0.73 g of the above copolymer 1   ・ Phthalocyanine dye B 0.04 g   -P-toluenesulfonic acid 0.002 g   ・ Tetrahydrophthalic anhydride 0.05g   ・ The counter anion of Victoria Pure Blue BOH is 1-naphthalene     Dye 0.015g made into sulfonate anion   -Fluorine-based surfactant (MegaFac F-177,     Dainippon Ink and Chemicals Co., Ltd.) 0.02g   ・ Γ-Butyrolactone 8g   ・ Methyl ethyl ketone 7g   ・ 1-Methoxy-2-propanol 7 g

[0158]

[Chemical 31]

[0159] [Photosensitive solution B-1]   -0.01 g of the polymerizable compound shown in Table 1   ・ Dimyristyl thiodipropionate 0.01g     (Sumitomo Chemical Co., Ltd. Sumilizer TPM)   -M, p-cresol novolac (m / p ratio = 6/4, weight average molecular weight     5000, containing 0.5% by weight of unreacted cresol) 0.26 g   ・ Cyanine dye A 0.03g   -Fluorine-based surfactant (MegaFac F-177,     Dainippon Ink and Chemicals Co., Ltd.) 0.05g   ・ Methyl ethyl ketone 7g   ・ 1-Methoxy-2-propanol 7 g

Comparative Example 4 The following photosensitive solution A-2 was applied to the substrate used in Example 1 and dried at 100 ° C. for 2 minutes,
The (A) layer was formed. The applied amount after drying is 0.4 g / m ^2.
Met. Then, the following photosensitive solution B-2 was applied, and 10
It was dried at 0 ° C. for 2 minutes to form a layer (B) (upper layer), and a lithographic printing plate precursor 12 was obtained. The total coating amount of the photosensitive liquid after drying was 1.0 g / m ² .

[0161] [Photosensitive solution A-2]   -0.75 g of the copolymer 1   ・ Phthalocyanine dye B 0.04 g   -P-toluenesulfonic acid 0.002 g   ・ Tetrahydrophthalic anhydride 0.05g   ・ The counter anion of Victoria Pure Blue BOH is 1-naphthalene     Dye 0.015g made into sulfonate anion   -Fluorine-based surfactant (MegaFac F-177,     Dainippon Ink and Chemicals Co., Ltd.) 0.02g   ・ Γ-Butyrolactone 8g   ・ Methyl ethyl ketone 7g   ・ 1-Methoxy-2-propanol 7 g

[0162] [Photosensitive solution B-2]   ・ Dimyristyl thiodipropionate 0.01g     (Sumitomo Chemical Co., Ltd. Sumilizer TPM)   -M, p-cresol novolac (m / p ratio = 6/4, weight average molecular weight     5000, containing 0.5% by weight of unreacted cresol) 0.27 g   ・ Cyanine dye A 0.03g   -Fluorine-based surfactant (MegaFac F-177,     Dainippon Ink and Chemicals Co., Ltd.) 0.05g   ・ Methyl ethyl ketone 7g   ・ 1-Methoxy-2-propanol 7 g

[Evaluation of lithographic printing plate precursors 9 to 12] The lithographic printing plate precursors 9 to 12 prepared as described above were evaluated in the same manner as the lithographic printing plate precursors 1 to 8. The results are also shown in Table 2.

As is clear from Table 2, the positive type lithographic printing plate precursor of the present invention has good image formability even when the composition of the photosensitive layer is different or when a photosensitive layer having a multilayer structure is provided. It was also confirmed that the printing durability was significantly improved by performing the heat treatment after the exposure. On the other hand, when the compound having an ethylenic double bond was not added, the effect of the present invention was not exhibited, and the same tendency as in Comparative Example 1 was exhibited even when the constitution of the photosensitive layer was different.

[0165]

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a positive working lithographic printing plate precursor for infrared laser and a lithographic printing plate using the same which are excellent in image formability and particularly excellent in printing durability. it can.

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 2H025 AA12 AB03 AC08 AD03 BC32                       BC42 CB41 CB42 CB43 CB45                       CC20 FA03 FA17 FA29                 2H096 AA07 AA08 BA11 BA16 BA20                       EA04 GA08 HA01 JA04

Claims (2)

[Claims] 1. A support comprising (A) a water-insoluble and alkali-soluble resin, (B) an infrared absorber, and (C) a polymerizable compound having an ethylenic double bond in an amount of 0.1 to 20% by weight. A positive lithographic printing plate precursor containing a recording layer containing the recording layer, the solubility of which is increased by exposure to an infrared laser. 2. A lithographic printing plate obtained by exposing the positive type lithographic printing plate precursor according to claim 1 imagewise by an infrared laser, developing and then heat-treating it.